Diseases and Injuries to the Head, Face and Neck: A Guide to Diagnosis and Management [1 ed.] 3030530981, 9783030530990, 9783030530983

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Diseases and Injuries to the Head, Face and Neck A Guide to Diagnosis and Management Michael Perry  Editor

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Diseases and Injuries to the Head, Face and Neck

Michael Perry Editor

Diseases and Injuries to the Head, Face and Neck A Guide to Diagnosis and Management

Editor Michael Perry Oral and Maxillofacial Surgery Northwick Park Hospital Harrow UK

ISBN 978-3-030-53098-3    ISBN 978-3-030-53099-0 (eBook) https://doi.org/10.1007/978-3-030-53099-0 © Springer Nature Switzerland AG 2021 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

Contents

Volume I 1 Embryology of the Head and Neck: An Aid to Understanding Our Complex Anatomy and Some Interesting Anomalies������������������������������������������������������������������������������    1 Priya Rogers and Michael Perry 2 Initial Assessment of the “Head and Neck” Patient������������������������������   57 Ishita Basu and Michael Perry 3 The Injured Patient����������������������������������������������������������������������������������  135 Soudeh Chegini and Michael Perry 4 Anaesthetic Considerations��������������������������������������������������������������������  245 Ranil Soysa, Chima Oti, and Amardeep Riyat 5 Nutritional Consideration in Some Head and Neck Diseases��������������  283 Michael Perry 6 The Skull, Brain and Associated Structures: Part I Applied Anatomy and Physiology������������������������������������������������  297 Neil Simms and Jonathan Poots 7 The Skull, Brain and Associated Structures: Part II The Patient with a Headache������������������������������������������������������  345 Neil Simms and Jonathan Poots 8 The Skull, Brain and Associated Structures: Part III��������������������������  427 Neil Simms and Jonathan Poots 9 The Vertebral Column, Spine and Associated Structures: Part I����������  495 Kevin Maguire, Gina Hooper, and Michael Perry 10 The Vertebral Column, Spine and Associated Structures: Part II��������  521 Kevin Maguire, Gina Hooper, and Michael Perry 11 The Vertebral Column, Spine and Associated Structures: Part III ������  579 Kevin Maguire, Gina Hooper, and Michael Perry

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12 The Viscera and Glands of the Neck: Part I������������������������������������������  589 Ramesh Kumar Gurunathan, Annakan Navaratnam, and Michael Perry 13 The Viscera and Glands of the Neck: Part II����������������������������������������  637 Ramesh Kumar Gurunathan, Annakan Navaratnam, and Michael Perry 14 The Viscera and Glands of Neck: Part III (Trauma and Injuries to the Neck)��������������������������������������������������������  729 Ramesh Kumar Gurunathan, Annakan Navaratnam, and Michael Perry 15 The Cheek and Orbit: Part I������������������������������������������������������������������  757 John Hanratty and Michael Perry 16 The Cheek and Orbit: Part II ����������������������������������������������������������������  791 John Hanratty and Michael Perry 17 The Cheek and Orbit: Part III ��������������������������������������������������������������  825 John Hanratty and Michael Perry 18 The Upper Jaw (“Midface”) and Sinuses: Part I����������������������������������  857 John Hanratty and Michael Perry 19 The Upper Jaw (“Midface”) and Sinuses: Part II��������������������������������  879 John Hanratty and Michael Perry 20 The Upper Jaw (“Midface”) and Sinuses: Part III������������������������������  915 John Hanratty and Michael Perry Volume II 21 The Lower Jaw (Mandible) and Associated Structures: Part I ����������  933 Peter Gordon and Michael Perry 22 The Lower Jaw (Mandible) and Associated Structures: Part II���������  957 Peter Gordon and Michael Perry 23 The Lower Jaw (Mandible) and Associated Structures: Part III Injuries to the Lower Jaw �������������������������������������������������������� 1013 Peter Gordon and Michael Perry 24 The Lips, Mouth, Tongue and Teeth: Part I������������������������������������������ 1041 Omar Sheikh and Michael Perry 25 The Lips, Mouth, Tongue and Teeth: Part II���������������������������������������� 1085 Omar Sheikh and Michael Perry

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26 The Lips, Mouth, Tongue and Teeth: Part III �������������������������������������� 1169 Omar Sheikh and Michael Perry 27 The Eye (Globe), Eyelids and Associated Structures: Part I �������������� 1189 Wing Chan, Vasuki Jothi, and Michael Perry 28 The Eye (Globe), Eyelids and Associated Structures: Part II�������������� 1249 Wing Chan, Vasuki Jothi, and Michael Perry 29 The Eye (Globe), Eyelids and Associated Structures: Part III������������ 1305 Wing Chan, Vasuki Jothi, and Michael Perry 30 The Throat: Part I������������������������������������������������������������������������������������ 1337 Michael Perry 31 The Throat: Part II - Inflammation, Infections and the Acutely Painful Throat�������������������������������������������������������������� 1359 Michael Perry 32 The Throat: Part III�������������������������������������������������������������������������������� 1409 Michael Perry 33 The Nose and Associated Structures: Part I������������������������������������������ 1413 Nida Tehseen Ilahi and Michael Perry 34 The Nose and Associated Structures: Part II���������������������������������������� 1433 Nida Ilahi and Michael Perry 35 The Nose and Associated Structures: Part III�������������������������������������� 1471 Nida Ilahi and Michael Perry 36 The Ear and Associated Structures: Part I�������������������������������������������� 1485 Ramesh Kumar Gurunathan and Michael Perry 37 The Ear and Associated Structures: Part II������������������������������������������ 1511 Ramesh Kumar Gurunathan and Michael Perry 38 The Ear and Associated Structures: Part III���������������������������������������� 1589 Ramesh Kumar Gurunathan and Michael Perry 39 The Skin (Integument): PART I ������������������������������������������������������������ 1609 Kristofer Holte and Gemma McIntyre 40 The Skin (Integument): PART II—Dermatological Diseases Commonly Seen in the Head and Neck���������������������������������� 1625 Kristofer Holte and Gemma McIntyre 41 Burns to the Head, Face and Neck: PART I������������������������������������������ 1685 AL Dancey 42 Burns to the Head, Face and Neck: PART II���������������������������������������� 1701 AL Dancey

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Embryology of the Head and Neck: An Aid to Understanding Our Complex Anatomy and Some Interesting Anomalies Priya Rogers and Michael Perry

1.1

Introduction

The head and neck is without doubt one of the more complex anatomical regions of the body. A number of highly specialised organs and structures are crammed into a relatively small space, each with their own functional, neural, muscular and vascular elements. Many highly specialised and varied tissues exist, notably neural, much of which is contained within a number of complex bony structures (the calvarium and vertebrae). These differ significantly in their structure from conventional “long bones”. Consequently, the study of head and neck anatomy, not surprisingly can be quite daunting, and trying to understand some of the disorders that affect this region even more so. Yet the anatomy of this region is (in the most part) predictable and reproducible from generation to generation, and this is because of our ‘preprogrammed’ embryological development. When this process is broken down into ‘bite-size’ pieces of knowledge, head and neck anatomy and many disorders of the head and neck become much easier to understand and remember. Therefore a brief overview of this fascinating area of development, which the vast majority of us have all gone through, will be presented. This is just an synopsis and will not include all aspects in comprehensive detail. Embryological development of some of the specific organs and structures is also noted in their relevant chapters hereafter. The term “embryogenesis” is often used to describe the ongoing process of cellular multiplication and differentiation which occurs in the embryo during the early stages of development. In our species, this all starts from a single cell zygote and ends with a fully developed human being. The normal period of gestation (pregnancy) is around 9 months, or 38 weeks. P. Rogers (*) Addenbrooke’s Hospital, Cambridge University Hospitals Trust, Cambridge, UK e-mail: [email protected] M. Perry Oral and Maxillofacial Surgery, Northwick Park Hospital, Harrow, UK © Springer Nature Switzerland AG 2021 M. Perry (ed.), Diseases and Injuries to the Head, Face and Neck, https://doi.org/10.1007/978-3-030-53099-0_1

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1.1.1 Germinal Stage This refers to the initial development of the embryo, from its initial stage of fertilisation, until it becomes implanted in the uterus. This takes around 10  days. Approximately 1 day after fertilisation, the fertilised oocyte (egg) or ‘zygote’ divides into two cells called blastomeres. Subsequent divisions of these structures then occur around every 12–24  h. During these early days the zygote does not increase in size. At first, the cells are undifferentiated and remain clumped together as a small sphere. This is enclosed within a “zona pellucida”—a thick transparent glycoprotein membrane which prevents premature implantation of the cell mass as it passes along the fallopian tubes. This layer thus prevents the development of ectopic pregnancy. After several more divisions, when there are around 16 cells, the cell mass is referred to as a ‘morula’ (named after its apparent resemblance to the mulberry fruit). At this stage it is still very small and contain very little cytoplasm.

1.1.2 Blastulation During this stage, the ever increasing number of cells arrange themselves to form a cavity, the ‘blastocoele’. At this point, the morula becomes known as the ‘blastocyst’. This is comprised of two different cell types, still enclosed within the zona pellucida: 1. An outer cell mass (the trophoblast). This will eventually make contact with the endometrium of the uterus and facilitate implantation and the development of the placenta. 2. An inner cell mass (the embryoblast). These cells will develop into the embryo itself, the amnion, yolk sac and allantois. These latter structures develop in parallel to the embryo, but will not be discussed further in this synopsis (Fig. 1.1). The trophoblast cells soon secrete fluid into the blastocoele. As its cavity enlarges the outer cells become flattened. At the same time, the inner cell mass (embryoblast) becomes “compacted” and attached to the trophoblast at one pole—the ‘embryonic

2-Cell stage

4-Cell stage

Morula

30 hours

45 hours

3rd Day

Zona pellucida Blastocyst disappers

4th Day

Fig. 1.1  Division of the zygote to produce a blastocyst stage embryo

Inner cell mass Outer cell mass

Trophoblast

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pole’. As a result of the increase in size of the blastocyst, the zona pellucida becomes stretched and thinned and is eventually breached. It subsequently disintegrates, thereby enabling implantation of the blastocoele within the uterine endometrium. Occasionally the blastocyst will implant in other sites, such as the surface of the ovaries, within the fallopian tubes and even the peritoneal cavity. This implantation stimulates the development of new blood vessels at that site, which are prone to rupture as the embryo grows. This is known as an ectopic pregnancy and is treated as a gynaecological emergency if rupture occurs. During the second week, both the trophoblast and embryoblast divide and develop into increasingly specialised cell types. 1. The trophoblast divides into the syncytiotrophoblast and the cytotrophoblast. The syncytiotrophoblast fuses with the uterine endometrium and becomes invaded by maternal blood vessels, forming an initial uteroplacental circulation. The cytotrophoblast (or layer of Langhans) contains stem cells that also play a role in implantation, by secreting proteolytic enzymes. 2. The embryoblast divides into an epiblast and hypoblast, thereby forming a two-­ layered structure—the ‘bilaminar disk’. The hypoblast and epiblast layers will subsequently go on to form the “embryonic disc”—this will develop into the embryo proper. The amniotic cavity also forms within the epiblast (Figs.  1.2 and 1.3).

1.1.3 Gastrulation Around the third week of embryonic development, the cells of the bilaminar disk (epiblast and hypoblast) undergo a highly specialised process called gastrulation. During this process, the two cell layers reorganise into three “germ cell” layers (the trilaminar disc). This involves complex cellular rearrangements including migration, invagination and differentiation of the epiblast. The future body axes (i.e. the Embryonic pole

Endometrium

Annic blast Blastocoel Syncytiotrophoblast Cytotrophoblast

Amniotic cavity

Fig. 1.2  Early stages of implantation

Ectoderm Endoderm

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P. Rogers and M. Perry Maternal sinusoids

Trophoblastic lacunae

Endoderm

Aminotic cavity

Ectoderm Heuser’s membrane

Syncytiotrophoblast

Cytotrophoblast Yolk Sac

Endometrial cells

Fibrin clot

Fig. 1.3  Establishment of the embryonic layers and extra-embryonic membranes and cavities

head-to-tail, right/left and front-to-back orientation) also become established at this time. As a result of these processes, the initial spherical embryo becomes converted into the shape of a double-walled cup, or ‘gastrula’. During this stage, any defects in the chemicals that control this process (“signalling proteins” and “transcription factors”) can lead to a condition known as ‘situs inversus visceral totalis’. In this anomaly the viscera in the fully developed embryo (heart, GI tract) are reversed from their normal positions. This is not a life-threatening or symptomatic condition, but those with it are encouraged to wear some form of medical identification, should injures or emergency surgery be required. Although the head and neck is a generally symmetric structure, interestingly, it has been suggested that this condition can also affect the development of the brain, resulting in cerebral asymmetry. One of the many genes involved in this process of lateralisation is PITX2. Defects in this gene can give rise to Axenfeld-Rieger syndrome type I, a condition which affects the development of the eyes, teeth and anterior face. Most patients with this disorder have abnormalities involving the anterior segment of the eye and develop glaucoma. They will also commonly have microdontia, widely spaced eyes, and a flattened mid-face. As the embryonic disc develops, at one of its ends a rounded area becomes thicker and more prominent than the remainder of the disc. This is termed the prochordal plate. With ongoing development of this plate, the head and tail ends of the embryo become determined. The end at which the prochordal plate appears is called the ‘cranial’ (head) end, the other end is termed the ‘caudal’ (tail) end. The prochordal plate thus determines the central axis of the embryo.

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Gastrulation occurs around the time of development of the primitive streak. This streak is a linear band of ectodermal cells which proliferate and migrate towards the midline of the epiblast. These cells are pluripotent (i.e. they have the ability to transform into any type of cell). The primitive streak is an important structure, which undertakes several key functions during embryonic development: 1. It gives rise to the embryonic mesoderm, the notochord and the septum transversum (that subsequently develops into part of the diaphragm, pericardium and ventral mesentery of the foregut). 2. It determines the three dimensional orientation of the embryo (cranio-caudal, right-left, ventral-dorsal) (Fig. 1.4). At the cranial end of the primitive streak a ‘primitive node’ (Henson’s node) develops, and within the primitive node lies the primitive pit. From here, a cord of

Cephalic end

Formation of the primitive steak

Primitive steak

Caudal end

T.S

Ectoderm

Endroderm

Fig. 1.4  Formation of the primitive streak signalling the start of gastrulation

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cells grows cranially from the bottom of the pit to the prechordal plate. These will form the ‘notochord’. The cells of the primitive streak then invaginate, forming a groove on its surface—the ‘primitive groove’. From the bottom of this groove, the cells detach and migrate under the ectoderm to form the intraembryonic mesoderm—the ‘third germ layer’. Thus three new germ cell layers become established 1 . Ectoderm. This is formed by the epiblast cells that remain in position. 2. Mesoderm. This is formed by epiblast cells that have migrated through the primitive groove and lie between the epiblast and endoderm. 3. Endoderm. This is formed by the epiblast cells that have migrated through the primitive groove, displacing the hypoblast cells (Figs. 1.5 and 1.6). Primitive mode and pit Primitive Streak

Proch. plate

Cloacal membrane

L.S

A.C (out) T.S

Notochordal process

Ectoderm Notochordal canal

Endoderm

A.C

Endoderm Yolk sac

Neurenteric canal and notochordal plate

Definitive notochord

Fig. 1.5  Formation of the notochord

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Ectoderm Mesoderm Paraxial mesoderm

A.C

Intermediate mesoderm

Ectoderm Endoderm T.S

Lateral plate mesoderm

y.sac Notochord

Endoderm

Fig. 1.6  Formation of the mesoderm layer

These changes all occur during the third week. During this time the embryonic disc elongates and becomes pear shaped, with a wider cephalic end and a narrower-­ shaped caudal end. Later, the primitive streak will regress and completely disappear by the end of the fourth week. Caudal remnants of the streak can give rise to a sacrococcygeal teratoma. Most sacrococcygeal teratomas are benign and will present in children less than 5  months in age. When these tumours present in older children, they are more likely to become malignant. These three germ layers will ultimately become the source of all the different tissues that will make up the foetus. These varied tissues are derived through the processes of somitogenesis, histogenesis and organogenesis. All three germ layers are derived originally from the epiblast, but undergo differentiation. This process subsequently results in: 1. An upper layer of ectoderm, which gives rise to the outermost layer of skin and its appendages (the nails and hair), central and peripheral nervous systems, sensory epithelia of the eye, ear, and nose, the mammary glands, hypophysis and the enamel of the teeth. 2. A middle layer of mesoderm, which gives rise to the connective tissues, cartilage and bone, striated and smooth muscles, the heart walls, blood and lymphatic vessels, kidneys, gonads and genital ducts, serous membranes lining the body cavities, the spleen and the suprarenal (adrenal) cortices. 3. An inner layer of endoderm, which gives rise to the epithelial lining of the gastrointestinal and respiratory tracts, parenchyma of the tonsils, the liver, thymus, thyroid, parathyroids and the pancreas, the epithelial lining of the urinary bladder and urethra, tympanic cavity, tympanic antrum and auditory tube (Fig. 1.7). During this time the three germ layers appear as three overlapping flat discs. The mesoderm spreads out in all directions throughout the embryonic disc, except in the following three regions.

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P. Rogers and M. Perry Mesoderm

Endoderm

Endoderm I-Epithelial lining of (1) the alimentary canal except; -anterior part of mouth -lower part of anal canal (2) the respiratory tract (3) the urinary bladder (except the trigone) (4) most of urethra (5) Ear: (a)pharyngotympanic tube (b)middle ear cavity (c)inner layer of eardrum II- parenchyma of: (1) Tonsil (2) Thyroid & parathyroid glands (3) Thymus gland

Ectoderm

Mesoderm (1) All types of connective tissue, cartilage. bone & jcints

Ectoderm (1) Nervous system -brain & spinal cord

(2) All types of muscles: Skeletal, smooth and cardiac muscle

-Oia & arachnoid mater

(3) All cardiovascular system: the heart, blood vessels (4) Bone marrow & blood cells (5) Lymph vessels & all lymph tissue: Lymph nodes & spleen

organs

(6) Sercus membranes: pleura pericardium & pentoneum (7) Dura matter & microgtia of the nervous system (8) Dermis of the skin (9) Urogenital system except most of the urinary bladder & urethra (10) Cortec of the suprareral gland

-sensory epithelium of the sense (2) Skin: epidermis. hair & mails (3) Giands: pitutary gland & the medula of suprarenal gland (4) Digestive system: lining of -ant part of the oral cavity -lower part of anal canal (5) Respiratory system: Epithelium of the nose (6) Ear: External auditory meatus & outer layer of eardrum

Fig. 1.7  Derivatives of the three germ layers

1. The prochordal plate where the ectoderm and endoderm are in firm contact with each other. This will form the buccopharyngeal membrane. Cranial to the prochordal plate the mesoderm from both sides is continuous with each other. This will later become the septum transversum. 2. The cloacal membrane, where the ectoderm and endoderm are also in contact with each other. 3. The notochord. This is found in the midline of the disc, between the prochordal plate and the primitive node (Fig. 1.8). The septum transversum will later develop myoblast cells and derive its innervation from the adjacent ventral rami of spinal nerves C3, C4 and C5 (the precursor of the phrenic nerve). With subsequent development, the dorsal end of the embryo grows much faster than the ventral side. This results in an apparent descent of the septum transversum through the neck and chest. Thus the septum ‘moves’ to a more caudal position at the level of the thoracic vertebrae. As it does so, the fibres of the phrenic nerve follows. This process explains the motor and sensory innervation of the muscular diaphragm by the phrenic nerve and its long descending pathway through the neck and thorax.

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a

Amniotic cavity

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Amniotic cavity

Mesoderm Endoderm

Yolk sac

Yolk sac Yolk sac

Yolk sac

b

T.S

Neural plate

Neural fold

Neural groove

Neural tube

Fig. 1.8 (a) Establishment of the ectoderm layer from the embryonic disc. (b) Establishment of the neural plate from the ectoderm layer

Gastrulation abnormalities can lead to malformations either at the caudal or the cranial regions. Caudal dysplasia is usually secondary to insufficient mesoderm production in the caudal region of the embryo. This can lead to lumbar and sacral vertebral malformations, an imperforate anus, agenesis of the internal genitalia, and in some extreme cases fusion of the lower limb buds (sirenomyelia). During this stage of development, alcohol-related toxicity can cause damage to the cells in the anterior midline germinal disc. This may lead to a deficiency in craniofacial structures in the midline. The resulting syndromes are referred to as

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Fig. 1.9  Foetal alcohol syndrome

Foetal Alcohol Syndrome, of which holoprosencephaly (arhinencephaly) is the most severe form. In this condition there is a failure of midline cleavage of the embryonic forebrain (described later). As a result the telencephalon contains a single ventricle. This condition is also seen in trisomy 18 (Edward syndrome), Meckel syndrome and trisomy 13 (Patau syndrome), where the corpus callosum may be absent. It is characterised by the absence of olfactory bulbs and tracts (hence the name, arhinencephaly). Because the face develops at the same time as the brain, severe facial anomalies (cyclopia, cleft lip, cleft palate) are commonly associated (Fig. 1.9). Holoprosencephaly manifests with microcephaly and congenital heart disease. It is the most severe manifestation of foetal alcohol syndrome, from alcohol abuse during pregnancy (especially in the first 4 weeks). Three types are described 1. Alobar prosencephaly (most severe form) occurs when there is complete absence of cleavage of the prosencephalon. Infants are stillborn or die shortly after birth and have cyclopia, a single rudimentary proboscis, cleft lip, cleft palate, hypotelorism, and micrognathia. There is a single horseshoe-shaped ventricle (‘monoventricle’) and a layer of undifferentiated cerebral cortex.

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Fig. 1.10  Clinical picture of encephalocele anterior (face)

Fig. 1.11 Encephalocele

2. Semilobar prosencephaly (intermediate form). This occurs when there is failure to cleave the prosencephalon anteriorly, with only partial cleavage posteriorly. 3. Lobar prosencephaly (least severe form). This occurs when there is failure to cleave the prosencephalon anteriorly, but cleavage of the prosencephalon posteriorly (Figs. 1.10 and 1.11).

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1.1.4 The Notochord This is an important midline structure that develops between the primitive streak and the prochordal plate. It is derived from the primitive node. This structure forms the central axis of the embryonic disc and induces the formation of neural tube, which are described later. During development the cells of primitive node proliferate and produce a central depression called the ‘blastopore’. From this site cells migrate forward in the midline between the ectoderm and the endoderm of the bilaminar germ disc, to form a solid cord of cells called the ‘notochordal process’. The notochord increases in length caudally whilst the primitive streak regresses. Later the notochordal process becomes canalised to form the ‘notochordal tube’. The cavity of this tube is continuous with the blastopore. The important notochord functions are to 1 . form the central axis of the developing embryo 2. induce the formation of the ‘neural tube’, which is derived from the overlying ectoderm. 3. provide a central column, around which the vertebral bodies and intervertebral discs will later develop. The notochord itself eventually disappears, but remnants remain and are found in the intervertebral discs, and in the apical ligament of the dens (second cervical vertebra). Current opinion suggests that notochord remnants secrete signalling factors that regulate function of the nucleus pulposus (in the vertebral disc), protect the nucleus pulposus from cytokine-related damage, and preserve the nucleus pulposus by inhibiting apoptosis. Chordomas are tumours that arise from the remnants of notochord. There are therefore found in all places where the notocord once existed, including the clivus, sella turcica, foramen magnum, upper cervical spine and nasopharynx. In the head they are most commonly seen at the base of the skull. About 30% of chordomas are malignant or locally aggressive and have a tendency to spread into the nasopharynx. Chordomas account for approximately 20% of primary spinal tumours.

1.1.5 Neurulation As development of the epithelial and neural tissues progresses along with formation of the neural tube, the gastrula becomes known as the ‘neurula’. The neural tube is derived from the ectoderm overlying the notochord. The cells of the ectoderm in this region become differentiated into specialised neuroectodermal cells. These then proliferate to form a thick ‘neural plate’—which will form the basis of the developing nervous system. The neural plate forms initially in the cranial region, and then develops caudally. The cranial-most end of the neural plate is much wider, and will eventually develop into the brain. The process of neurulation converts the neural plate into the neural tube. The margins of the neural plate become elevated to form neural folds, as the “paraxial

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mesoderm” (described later) proliferates and develops on either side of the notochord. This change in shape of the plate results in the formation of a “neural groove”. With further growth the neural groove becomes deeper and the neural folds move towards the midline and begin to fuse together to form the cylindrical neural tube. The term neurulation specifically refers to this folding process, whereby the flat neural plate becomes the neural tube. This takes place during the fourth week. Closure of the neural tube is an essential part of neural development and commences in the middle of the tube, extending in both cephalic and caudal directions. During this time the openings at both ends of the tube are called the ‘neuropores’. Amniotic fluid enters these openings and circulates throughout the neural tube, providing nutrition. With the final closure of the neuropores some of the amniotic fluid gets trapped inside the tube. This marks the beginning of the CSF circulation. Cells at the tips of neural folds (‘neural crest’) do not take part in this process, but instead proliferate to form bilateral clusters, dorsolateral to the neural tube under the ectoderm. The neural tube later gives rise to three primary vesicles (described below), which divide further into secondary vesicles. The caudal part of the neural tube remains tubular and forms the spinal cord. Alpha-fetoprotein (AFP) is a protein found in amniotic fluid and maternal serum. Abnormal levels during pregnancy may indicate the presence of some neural tube defects (such as spina bifida or anencephaly). AFP levels are also reduced in foetuses with Down syndrome (Figs. 1.12 and 1.13). Fig. 1.12  Neural plate

Neural plate

Neural Crest

Mesoderm Endoderm

Notochordal plate

Neural Crest

Somite

Neural crest Neural canal Notochard

14 Fig. 1.13  The closed neural tube develops into the spinal cord and the brain

P. Rogers and M. Perry

Ant-neuropore

Neural tube

Post-neuropore

During this period, certain genetic anomalies or environmental factors can disrupt the normal process of development of the nervous system, and result in a wide range of defects which are collectively referred to as ‘neural tube defects’. These comprise the second most common set of congenital defects worldwide. In the UK and other countries, all pregnant mothers are encouraged to take folic acid supplementation to reduce the risk of their foetus developing neural tube defects. Several types exist 1. ‘Open’ neural tube defects represent a failure of primary neurulation. Often these open defects are incompatible with life. Here, there is a failure of closure of the neural tube. One example includes anencephaly, in which there is absence of a significant portion of the brain, skull, and scalp. This occurs when a major part of the brain and cranial vault fails to develop. During development of the brain, anencephaly is usually preceded by exencephaly, in which the neuroepithelial tissues continue to differentiate, but become damaged, as they are exposed in utero. Anencephaly remains the most serious birth defect seen in stillborn infants. If not stillborn, infants with anencephaly survive only a few hours or at most, weeks. It can be diagnosed pre-natally by ultrasonography and a raised alpha-fetoprotein level. 2. Myelomeningocoele is a form of spina bifida in which the vertebral arches are unable to develop following failure of neurulation. In this anomaly, the spinal

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cord may either be completely exposed to the amniotic fluid (termed ­myelocoele), or may be encased within a sheath of meninges to form a sac around the open lesion (meningomyelocoele). 3. Craniorachischisis is considered the most severe form of neural tube defect in which both anencephaly and myelocoele are present. In posterior rachischisis, the entire neural tube remains open. This is incompatible with life. 4. ‘Closed’ neural tube defects include ‘occult’ spina bifida, and represent a much less severe form of defect than ‘open’ defects. These comprise defects in axial skeleton development, and may also include abnormalities of the spinal cord. The aetiology of occult spina bifida is unclear, but it has been suggested that these lesions result from a failure of secondary neurulation. As a result, most of these closed defects affect the most caudal regions of the spine and spinal cord. Defects are often associated with tethering of the caudal end of the spinal cord, which can lead to neuropathic bladder problems and lower limb deficits. Examples include dimyelia, diplomyelia or diastematomyelia, in which there is duplication or splitting of the caudal spinal cord. Hydromyelia is a condition in which the central canal of the spinal cord is distended. Some closed defects may also be associated with anal atresia or anal stenosis. 5. ‘Herniation’ neural tube defects develop from deficiencies in the cranial mesoderm and lead to apertures in the skull. These are usually seen in the occipital region of the skull, but have also been described in the parietal and fronto-­ ethmoidal regions. These apertures permit the meninges to herniate out of the cranium, sometimes with brain tissue. These abnormalities are known as encephaloceles, of which three major types have been described (depending upon the tissues herniated): (1) meningocele, (2) meningoencephalocele and (3) meningohydroencephalocele. Cranium bifidum results from a defect in the occipital bone through which meninges, cerebellar tissue, and the fourth ventricle may herniate (Figs. 1.14 and 1.15).

1.2

Development of the Brain

The entire nervous system is derived from ectoderm, with the exception of its blood vessels and some neuroglial tissues. The brain itself develops from an enlarging cranial (rostral) swelling at the end of the neural tube. At about the end of fourth week, this swelling begins to develop three separate dilatations—the primary brain vesicles. Craniocaudally, these are (1) prosencephalon (forebrain), (2) mesencephalon (midbrain), and (3) rhombencephalon (hindbrain). All three are hollow and interconnected. These fluid filled cavities will eventually become the ventricular system of the adult brain. During the fifth week both the prosencephalon and rhombencephalon each divide further into two vesicles, thus producing five ‘secondary brain vesicles’. These are 1. Telencephalon 2. Diencephalon. The prosencephalon gives rise to a rostral telencephalon and caudal diencephalon. The telencephalon grows substantially outwards bilaterally

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Fig. 1.14 Anencephaly

Fig. 1.15 (a) Meningocele. (b) Myelomeningocele

and surrounds the diencephalon. This becomes the cerebral hemispheres. The diencephalon is therefore hidden. It becomes the thalamus, hypothalamus, etc. 3. Mesencephalon—This gives rise to midbrain. Here, its central cavity narrows to form the cerebral aqueduct. 4. Metencephalon

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Forebrain or prosencephalon Telencephalon

Midbrain or mesencephalon

Prosencephalon

Diencephalon

Mesencephalon

Mesencephalon

Melencephalon Hindbrain or rhombencephalon

Rhombencephalon Myelencephalon

Fig. 1.16  Development of the brain—a lateral diverticulum appears on each side of the forebrain

5. Myelencephalon. The rhombencephalon divides into a cranial metencephalon (which becomes the pons and cerebellum) and a caudal myelencephalon, which becomes the medulla oblongata (Fig. 1.16).

1.2.1 Flexures and Ventricles Whilst these changes are occurring, the developing brain also undergoes a number of folds, often called flexures. Three flexures arise (1) a ventrally concave cephalic (mesencephalic) flexure in the region of midbrain (2) a ventrally convex pontine flexure in the middle of the rhombencephalon and (3) another ventrally concave cervical flexure at the junction of the rhombencephalon with the spinal cord. This latter cervical flexure forms almost a 90° angle between the hindbrain and spinal cord, resulting in the fully developed brain being oriented almost at a right angle to the spinal cord. At the pontine flexure the shape of the tube also changes significantly, with its cavity becoming diamond-shaped—the fourth ventricle. This tapers superiorly in the midbrain (the aqueduct of Sylvius) and inferiorly in the lower medulla oblongata. The thin roof of this cavity also extends laterally and breaks down, to form several openings (the foramina of Magendie and Luschka). Through these, the cavity of the neural tube now communicates with the surrounding subarachnoid space. Failure of these tissues to break down can result in hydrocephalus and brain atrophy (Figs. 1.17 and 1.18).

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Fig. 1.17  Expansion of the cerebral cortex

Fig. 1.18  Obstructive hydrocephalus due to congenital aqueduct (of Sylvius) stenosis (inset) caused by X-linked recessive L1CAM gene mutation

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The cavities of these secondary vesicles eventually become the ventricular system of adult brain. 1 . The right and left telencephalic cavities become the lateral ventricles. 2. The diencephalic cavity becomes the third ventricle. 3. The narrow mesencephalic cavity becomes the cerebral aqueduct (of Sylvius) 4. The hindbrain cavity becomes the fourth ventricle. These changes thus form an interconnecting system of cavities (ventricles) and channels, through which cerebrospinal fluid (CSF) can circulate. The two lateral ventricles communicate with the third ventricle via the interventricular foramina (of Monro). The third ventricle communicates with the fourth ventricle through the cerebral aqueduct and the fourth ventricle continues into the central canal of the spinal cord. CSF plays an important role in brain development. Its flow exerts a pressure within the developing brain, stimulating growth and enlargement. If CSF is shunted away from the primitive ventricular system of the brain, or if too little CSF is produced, brain development will be stunted and result in a hypoplastic brain (reduced brain tissue). More than 2000 different congenital malformations of the brain have been described in the literature, and their incidence is reported to be about 1% of all live births. Developmental anomalies during this stage include 1. Porencephaly (encephaloclastic porencephaly). This is the presence of one or more fluid-filled cystic cavities within the brain. These may communicate with the ventricles, but do not extend to the cortical surface. They occur as a result of localised brain damage early in development, before the brain is capable of producing a glial (scar tissue) response. The clinical effects of these depend on their location and the amount of damage sustained. 2. Schizencephaly. This is the presence of a fluid-filled cleft in the cerebral tissue that extends from the ventricles to the cortical surface. This forms as a result of abnormal neuronal migration during development of the brain. 3. Foetal brain disruption sequence. This has been suggested to arise from partial brain disruption during the second or third trimester. Interruption of the blood supply to selected areas of the brain (following viral infection or hyperthermia) results in severe microcephaly and calvarial collapse.

1.2.2 Cerebrospinal Fluid Production and Function Cerebrospinal fluid (CSF) is formed by the choroid plexus in the lateral ventricles and passes into the subarachnoid space through the foramina of Magendie and Luschka. The choroid plexus develops in the roof of the rhombencephalon and diencephalon and within the choroid fissure of the telencephalon. It is derived from a layer of ependymal cells covered by a vascular pia mater—the tela choroidea. This proliferates to form tiny sac-like invaginations into the ventricles. The choroid

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plexus produces around 500 mL of CSF per day. This is returned to the venous system via the arachnoid (granulations) villi of the venous dural sinuses (superior sagittal sinus). In adults, the primary function of CSF is to cushion and protect the brain within the skull, acting as a shock absorber for the central nervous system. It also provides nutrients and chemicals which have been filtered from the blood and removes some waste products from the brain. Any condition affecting free passage of CSF can result in a condition known as hydrocephalus and raised intracranial pressure. Hydrocephalus that presents at birth or before birth is usually due to an anatomical anomaly which result in a mismatch between CSF production and absorption in the foetal brain (either increased production or reduced absorption). Hydrocephalus can be divided into either non-­ communicating or communicating types. In non-communicating hydrocephalus, obstruction occurs within the ventricular system or at the level of the fourth ventricular foramina. This prevents free flow of CSF between the ventricles. In communicating hydrocephalus, there is an obstruction or impairment of CSF flow distal to the fourth ventricular foramina, but CSF can still flow freely between the ventricles. 1. The commonest cause of foetal non-communicating hydrocephalus is the Arnold-Chiari (type II Chiari) malformation. This arises following development of a myelomeningocoele (described above). The Chiari malformations are a group of developmental anomalies that occur within the hindbrain, which result in impaired flow of CSF. The type II malformation occurs in 1:1000. In the presence of a meningomyelocoele, the medulla oblongata and the inferior vermis of the cerebellum sag downwards and herniates into the foramen magnum. This obstructs the flow of cerebrospinal fluid thereby causing the hydrocephalus. 2. Aqueductal stenosis is the second commonest cause of foetal non-­communicating hydrocephalus. This can be identified on foetal MRI by the presence of enlarged lateral and third ventricles, but with normal sized fourth ventricles (indicating a stenosed Aqueduct of Sylvius). Aqueductal stenosis is usually caused by intraventricular haemorrhage, or congenital infections such as toxoplasmosis or cytomegalovirus. It can have severe adverse effects. Ventricular distension often results in damage to the corpus callosum and the overlying cortex. Specifically, this condition can result in agenesis of the cerebellar vermis, occipital meningocoele and agenesis of the corpus callosum. A rare X-linked form of aqueductal stenosis has also been reported, related to the L1CAM gene. This is termed ‘CRASH syndrome’—Corpus callosum hypoplasia, Retardation, Adducted thumbs, Spastic paraplegia and Hydrocephalus. Due to the X-linked nature of inheritance, this syndrome is only seen in males, but some female carriers may experience mild symptoms. 3. Other common causes of foetal non-communicating hydrocephalus include the Dandy Walker malformation, which has a frequency of 1:25,000. This may result from alcoholic abuse, ingestion of riboflavin inhibitors, posterior fossa trauma or some viral infections. It occurs following blockage of median aperture (Foramen of Magendie) and the lateral apertures (Foramina of Luschka). As a result, the

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cavity of the fourth ventricle enlarges. This anomaly is limited to the posterior cranial fossa. 4. Rarer causes of foetal hydrocephalus include arachnoid cysts and posterior fossa tumours, as well as communicating hydrocephalus.

1.2.3 Further Growth and Myelination With further growth, the developing cerebral hemispheres enlarge upwards, backwards and anteroinferiorly, to become the frontal, parietal, occipital and temporal lobes, also called the ‘neocortex’. This curved expansion causes the structures related to it (lateral ventricle, corpus callosum and choroid fissure) to acquire their adult C-shaped forms. The cerebral hemispheres thus eventually surround the bulk of the midbrain. The three meninges (dura, arachnoid and pia mater) surrounding the brain and spinal cord are derived from the mesenchyme surrounding the neural tube (dura) and from neural crest cells (arachnoid and pia). The optic vesicle (which eventually becomes the optic nerve, retina and iris) develops at the base of the prosencephalon. This subsequently grows forwards to become the optic nerve. Myelination begins in the fourth month of gestation. This is a very long and complex process. Myelination of the corticospinal tracts is not completed until the end of the second postnatal year, when the tracts become functional. Myelination in the cerebral cortex is reported to continue into the third decade of life. Myelination of the CNS is undertaken by oligodendrocytes. Myelination of the PNS is accomplished by Schwann cells. The presence of myelin enables rapid transmission of action potentials (by saltatory conduction) and protects the axons of the neurones. Disorders of myelin development comprise a group called the hypomyelinating leukodystrophies (as opposed to the degenerative leukodystrophies in which myelin is completed but is subsequently destroyed). The leukodystrophies cover a broad spectrum of pathologies, but most are inherited diseases. Usually these conditions present in neonates with axial hypotonia and nystagmus. These eventually progress to spastic quadriparesis. Most patients will develop cerebellar signs, but in a few cases they may exhibit extrapyramidal signs, cognitive dysfunction or peripheral neuropathy.

1.3

Embryonic Folding

Folding of the entire embryo is a complex process that occurs in both the median and horizontal planes, as a result of rapid differential growth of the entire structure. Consequently, the original flat embryonic disc becomes somewhat cylindrical in shape and becomes completely enclosed by the amniotic cavity. Also as a result, the ectodermal tissues now become the outer covering of the embryo. A depression soon develops between the head bulge and pericardial bulge (developing heart). This is called the ‘stomodeum’, and is separated from the cranial end of the primitive foregut by the buccopharyngeal membrane (the caudal end of primitive gut is

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P. Rogers and M. Perry Body stalk

Embryamic disc 2. Lateral folds

Endoderm Yolk sac

Fig. 1.19 (a) Embryonic folding during week 4 of development. (b) The end Result of early embryonic folding

separated from proctodeum by the cloacal membrane). The head, containing the brain, now forms the most cranial part of the embryo and lies above and behind the buccopharyngeal membrane (Fig. 1.19).

1.3.1 The Pituitary Gland (Hypophysis Cerebri) The diencephalon develops a neuroectodermal downgrowth from the hypothalamus and floor of the third ventricle, the ‘neurohypophysis’. This joins an ectodermal upgrowth from the primitive oral cavity (the stomodeum), called the ‘adenohypophysis’ (or ‘Rathke’s pouch’). Together they meet to form the pituitary gland. Thus the gland consists of two distinct parts (1) the adenohypophysis (anterior pituitary) and (2) the neurohypophysis (posterior pituitary). Later, Rathke’s pouch becomes separated from the stomodeum. The anterior wall of Rathke’s pouch at the pituitary then proliferates to form the pars anterior (anterior lobe) of the gland. Its posterior wall remains thin and forms the pars intermedia. Small clefts of Rathke’s pouch often persist as the ‘hypophyseal cleft’, which separates the two parts. Congenital pituitary anomalies can arise from either incomplete migration or growth of the adenohypophysis or neurohypophysis, or from abnormal proliferation of the tissues. 1. Craniopharyngioma (a tumour) develops from the remnants of Rathke’s pouch. Rathke’s pouch normally detaches from the primitive oral cavity during formation of the anterior pituitary (adenohypophysis). In the adult, the original site of attachment of this pouch is in the roof of nasopharynx. However remnants of Rathke’s pouch can form a craniopharyngeal canal, which can sometimes give rise to a tumour (craniopharyngioma). This is seen in the roof of nasopharynx. 2. In some patients, in the event of agenesis of the hypophysis, accessory hypophyseal tissue may be found in the posterior wall of the pharynx. 3. Ectopic neurohypophysis can occur following incomplete downward extension of the diencephalon. This usually presents with growth hormone deficiency and dwarfism, and is often also associated with hyperprolactinaemia.

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The Spinal Cord

The caudal part of the neural tube forms the spinal cord. Here, the cavity of the neural tube is almost like a vertical slit. This will eventually form the central canal of the spinal cord. The wall of the tube becomes subdivided and differentiates into three layers, (1) the inner ependymal, (2) mantle and (3) the outer marginal layers. Rapid growth of the mantle layer in the ventral part of the developing spinal cord, makes this region thicker and reduces the lumen of the tube ventrally. The nerve cells in this layer will become the neurones of the anterior grey column. The axons of these cells leave the spinal cord ventrolaterally and form the anterior (motor) nerve roots of the spinal nerves. Later, a line of demarcation appears in the lateral wall of the tube. This is known as the ‘sulcus limitans’. Neural crest cells collect near the dorsolateral aspect of the neural tube. These will give rise to the dorsal root ganglion and the spinal ganglion.

1.5

The Neural Crest

Neural crest cells play a diverse but critical role in embryonic development. They first appear at the junction of the neural plate with the adjacent ectoderm. This is mediated by regulatory proteins, BMP-4 and BMP-7. As the neural tube closes (neurulation), clumps of neural crest cells break away from the neural folds and aggregate near the midline, dorsolateral to the neural tube. Unlike the neural tissues in the neural tube, neural crest cells migrate widely to distant sites in the developing embryo, including the skull, face, thyroid, dorsal root ganglion, skin and elsewhere. These cells ultimately differentiate into a wide range of cells and structures. The Neural crest plays a key role in the development of the following: 1. Neurones of the dorsal root ganglion 2. Neurones of the sensory ganglion of the cranial nerves V, VII, VIII, IX and X. 3. Neurones of the autonomic (sympathetic and parasympathetic) ganglia (including ciliary, submandibular, sphenopalatine and otic ganglia). 4. Schwann cells 5. Chromaffin cells of the adrenal medulla 6. Melanocytes in the skin 7. Parafollicular ‘C’ cells of the thyroid gland 8. Cells of the leptomeninges (pia and arachnoid mater). 9. Dental papilla, odontoblasts and dentine. 10. The skeletal and connective tissue elements of the branchial (pharyngeal) arches, which ultimately form the bones of the face. Migration of neural crest into the arches is not random, but follows a strict topographical relationship with their site of origin along the neural tube. 11. The vault of the skull. 12. The connective tissue of the thyroid, parathyroid, thymus and the salivary glands 13. The aorticopulmonary septum of the heart.

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As one can imagine, there are many disorders that can occur as a result of neural crest disturbance. Neurocristopathy is the termed used to describe any disorder related to maldevelopment of neural crest cells. These can affect many different organ systems. Neurocristopathies commonly arise from either a defect of migration, differentiation or abnormal proliferation, and in some cases can result in tumours within neural crest-derived tissues. Some of the commoner neurocristopathic tumour syndromes include (1) the phaeochromocytomas, which arise within the tissues of the adrenal medulla (chromaffin cells), (2) the neuroblastomas, which also comprise tumours of the adrenal medulla or autonomic ganglia, (3) the carcinoid tumours involving enterochromaffin cells of the gastrointestinal tract and (4) medullary thyroid carcinomas involving the parafollicular cells of the thyroid gland. The primary neurocutaneous syndromes are also examples of abnormal proliferation of neural crest cells and include neurofibromatosis, tuberous sclerosis and neurocutaneous melanosis (multiple melanotic tumours of the central nervous system and multiple melanotic naevi). The commonest differentiation defect involving neural crest cells is albinism, which leads to a complete or partial absence of pigment in the skin, hair, and eyes. Albinism is also associated with ocular defects such as photophobia, nystagmus, and amblyopia. Neurocristopathic defects involving migration or abnormalities in differentiation can be divided into neural crest cells of the trunk or cranial regions. Hirschsprung’s disease is the commonest defect of trunkal neural crest cells. This leads to congenital megacolon since the terminal part of the colon has no innervation. Cranial neural crest defects include (1) aorticopulmonary septal defects of the heart, (2) defects involving the anterior chambers of the eyes, (3) cleft lip or cleft palate (described later), (4) frontonasal dysplasia, (5) dental abnormalities and (6) DiGeorge syndrome. This latter syndrome results in hypoplasia of the thymus, thyroid and parathyroid glands and is associated with cardiovascular defects of the aortic arch. It is linked to a deletion on chromosome 22, which results in a defect of the neural crest associated with the third and fourth pharyngeal arches and the cardiac outflow tract. A risk factor for developing DiGeorge syndrome is high exposure to retinoids during embryogenesis. CHARGE syndrome is a rare disorder involving defects in both cranial and trunkal neural crest cells. It is an understandable disorder, if the wide distribution of neural crest cell is remembered. Its cause is unknown, but it seems to involve an insult during the second month of gestation, presumably involving the development of the neural crest cells. Key features include (1) coloboma of the retina, lens or choroid, (2) heart defects (tetralogy of Fallot, ventricular septal defect [VSD], patent ductus arteriosus [PDA]); (3) atresia choanae, (4) retardation of growth, (5) genital abnormalities in male infants (e.g., cryptorchidism, microphallus) and (6) ear abnormalities and deafness. Waardenburg’s syndrome is another rare disorder involving defects of both the cranial and trunkal neural crest cells, and arises from mutations in the Pax-3 genes. Patients with Waardenburg’s syndrome exhibit ocular hypertelorism, deafness, cleft palate, and pigmentation defects (commonly a white stripe in the hair and skin anomalies). Patients with type I Waardenburg’s syndrome also have hypoplasia of the limb muscles.

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Ectodermal Placodes

Prior to the completion of neural tube closure, the neural folds contains two different cell types—neural crest cells and neuroepithelial cells. Some of the neuroepithelial cells become incorporated into the surface ectoderm. These areas are then termed ‘ectodermal placodes’. Ectodermal Placodes develop at specific sites and have important roles in the development of the special sensory systems. ‘Integumentary’ placodes are involved with hair follicle development. The sensory placodes contribute to the development of the special senses (vision, hearing and smell). Their initial position on the developing head is significantly different to their final position. They include 1. Adenohypophyseal placode 2. Otic placodes—the first placodes visible on the surface of the embryo 3. Olfactory (Nasal) placodes—these have medial and lateral components which become the olfactory epithelium 4. Optic (Lens) placodes—these will form the lens of the eye 5. Profundal/trigeminal placodes.

1.7

Development of the Face and Neck

Development of the face and neck begins in the fourth and fifth week. “Hox complex” genes have been described, which appear to be play an important role in early development. These control ‘spatial patterning mechanisms’ (i.e. the ‘body plan’) during development in all vertebrates. They are expressed during embryogenesis and control the sequential and orderly development of all the major elements that make up the body. Retinoic acid appears to be important in this regard. This is a derivative of vitamin A, and is particularly important in the normal development of the pharyngeal arches. Lack or excess of retinoic acid can result in striking facial anomalies. With excessive intake, this causes hypoplasia of pharyngeal arches 1 and 2. This is the reason why females taking isotretinoin for acne are required to take contraception and regular pregnancy tests throughout the duration of their treatment. Initially, a forehead prominence appears as a result of the developing brain. This lies just above a depression called the ‘stomodeum’ (the primitive oral cavity). A pericardial prominence (formed by the developing heart) lies below the stomodeum. Within this relatively small area, growth and differentiation of the mesenchymal (connective) tissue results in the formation of a series of expanding arches—the ‘pharyngeal’ (or branchial) arches. This arrangement is referred to as the ‘pharyngeal apparatus’ and consists of four elements; (1) the pharyngeal arches, (2) pharyngeal pouches (3) pharyngeal clefts (grooves) and (4) pharyngeal membranes. This initially small region begins to grow caudally, pushing the developing heart downwards and elongating the developing neck. As previously noted, this explains the long course of the phrenic nerve.

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The pharyngeal apparatus contributes to the formation of the face, neck, mouth, pharynx and larynx. As the arches develop, they are gradually separated from each other both externally, by a number of intervening clefts (the pharyngeal clefts or grooves), and internally, by corresponding invaginations in the lateral wall of the primitive pharynx (the pharyngeal pouches). These indentations do not normally communicate with each other and tissue remains between the two keeping them apart. As a result, the clefts separate the arches on the external (ectodermal) surface, whilst the pouches separate the arches on their internal (endodermal) surface. Each arch will thus come to have its own associated cleft, pouch, cartilage, nerve, muscle group and artery. There are six arches in total. Five of these play a key role in the development of the face and neck. At first the arches are located in the lateral wall of the primitive pharynx. However they gradually grow forwards and merge with their counterparts from the opposite side, in the floor of the primitive pharynx. This results in a stack of U-shaped cylindrical-type bars. Developmental defects arising from the arches can thus take many forms, including hypoplasia of its various tissues, or the development of cysts, sinuses or fistulas. Cystic hygromas are benign growths that are believed to arise from the pharyngeal arches. They are usually multiloculated cysts and occur in the anterior or the posterior triangles. They enlarge with infection and inflammation and can occasionally result in respiratory obstruction or swallowing problems. Usually surgical excision is recommended.

1.7.1 Pharyngeal Clefts These ectodermal clefts appear during the fifth week of development. However most are temporary and only the first cleft remains in the adult, as the external auditory meatus. The second, third and fourth clefts become obliterated by the rapidly proliferating second pharyngeal arch (see the cervical sinus later).

1.7.2 Pharyngeal Arches These are U-shaped cylindrical bars in the lateral and ventral walls of the primitive pharynx. They begin to form during the fourth week. Within each arch a cartilaginous rod develops, providing structural support. Each arch subsequently develops into a specific and predetermined structure within the head and neck. In some arches, part of the cartilage forms permanent bone and cartilage, whilst part of it disappears. In other arches the cartilage disappears, but its perichondrium persists to form a ligament or raphe. There are six pharyngeal arches initially, each consisting of a core of mesenchymal tissue covered on the outside by ectoderm and on the inside by endoderm. However, the fifth arch regresses soon after developing. Each arch is innervated by an its own cranial nerve and artery and has a muscular component, with a skeletal and cartilaginous supporting structure. Understanding these points helps understand the complex anatomy of this region. The arteries are connected ventrally to the ventral aorta, passing around the primitive pharynx (Figs. 1.20 and 1.21).

1  Embryology of the Head and Neck: An Aid to Understanding Our Complex… Lateral view

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Coronal section

Pharyngeal pouches

Outer ectodermal Inner ectodermal Mesodermal core

Pharynx

Embryo

Pharyngeal Clefts

Fig. 1.20  Branchial arches Lateral view

Front view

Forebrain swelling Stomoderm 1 Mandibular arch Pericardial swelling

2 3 4 Pericardial swelling

Fig. 1.21  Branchial arches 2

The nerve of each arch provides motor innervation to its muscles and sensory innervation to its overlying skin and mucosa. Wherever the muscle cells migrate to, they take their associated nerve with them. Strictly speaking morphologically, each pharyngeal arch is supplied by two nerves. One nerve runs along cranial border of the arch and is known as the post-trematic nerve. A second nerve runs along its caudal border and is called the pre-trematic nerve. In humans, the pre-trematic (caudal) nerves disappear from all the arches except the first arch, where it persists as the chorda tympani nerve. Some authorities consider that the tympanic branch of glossopharyngeal nerve and auricular branch of vagus nerve also represent the pre-­ trematic branches of their nerves.

1.7.2.1 The First Arch This develops into two parts 1. An upper maxillary prominence. This will become the future maxilla, zygomatic bone and part of the temporal bone. It is associated with a maxillary cartilage.

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2. A lower mandibular prominence. This will become the future mandible. It is associated with Meckel’s cartilage. The dorsal end of the cartilage lies close to the developing middle ear. This persists and forms the malleus and incus. Ventrally (anteriorly), the cartilage is surrounded by mesenchyme that will form the mandible. Cartilage that becomes trapped within the developing bone degenerates and disappears. The remaining part of the cartilage between the mandible and ossicles also disappears, but its perichondrium persists as the anterior ligament of malleus and the sphenomandibular ligament. The artery of the first pharyngeal arch eventually becomes the terminal portion of the maxillary artery, a branch of the external carotid. The nerve of the arch is the trigeminal nerve (CN V). The arch also gives rise to the muscles of mastication, the mylohyoid, the anterior belly of digastric, tensor veli palatani and tensor tympani. All these muscles are therefore innervated by motor branches of the trigeminal nerve. Sensory branches of the trigeminal nerve supply the skin of the face, the lining of the mouth and nose and general sensation to the anterior 2/3 of the tongue. Anomalies of the first arch can be categorised into two main types 1. Type I anomalies are derived from the ectoderm and include duplication of the external auditory canal, usually located behind the pinna. 2. Type II anomalies involve ectoderm and mesoderm and usually manifest as a fistula along the external auditory canal, middle ear cleft or nasopharynx. These may pass adjacent to the facial nerve and terminate at the level of the anterior border of the sternocleidomastoid muscle. First arch abnormalities can present with congenital unilateral facial palsy. They occur following a lack of migration of neural crest cells into the first pharyngeal arch. Presentation varies and facial anomalies are grouped under the diagnosis of ‘first arch syndrome’. The more important are: 1. Treacher Collins syndrome (mandibulofacial dysostosis): This is inherited as an autosomal dominant trait and occurs in about 1/85,000 births. It presents with malar hypoplasia (due to underdevelopment of zygomatic bones), mandibular hypoplasia, Down slanting of the palpebral fissures and deformed auricles (Figs. 1.22, 1.23 and 1.24). 2. Pierre Robin syndrome: This is an autosomal recessive disorder which occurs in approximately 1/85,000 births. The primary defect is a small mandible. Infants present with a triad of micrognathia (small mandible), cleft palate and glossoptosis (posteriorly placed tongue). 3. Di George syndrome: This is caused as a result of a micro deletion on the long arm of chromosome 22. It results in abnormal development of the neural crest cells, notably with failure of the third and fourth pharyngeal pouches to differentiate into the thymus and parathyroid glands. The syndrome occurs in 1/25,000 births and is one of the most severe pharyngeal arch disorders. Infants lack a thymus and parathyroid glands and have cardiac outflow defects. They also have a “Fish mouth deformity” (shortened philtrum), low set notched ears and an increased susceptibility to infection (Fig. 1.25).

1  Embryology of the Head and Neck: An Aid to Understanding Our Complex… Fig. 1.22 (a) Child with bilateral atresia with a bone-anchored hearing aid mounted on a soft headband. (b) Child aged 6 years, before surgery to insert an auricular prosthesis and boneanchored hearing aid. (c) The same child after placement of a bone-­ anchored hearing aid and bone-anchored auricular prosthesis

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Fig. 1.23  Treacher Collins syndrome; newborn with respiratory distress. (a) Lateral view shows very small and retruded mandible (arrow), and air-way tube. (b) 3D CT image of the skin of a child, lateral view, shows severe micrognathia (arrow). (c) 3D CT image, lateral view of a child, shows absent zygoma (arrow)

1.7.2.2 The Second Arch The cartilage component of this arch is called Reichart’s cartilage. The dorsal end ossifies to become the stapes and more caudally the styloid process. It also becomes the stylohyoid ligament and the upper body and lesser horn of the hyoid bone. The nerve associated with the second pharyngeal arch is the facial nerve (CN VII). This innervates all the muscles derived from the arch, namely the ‘facial muscles’ as well as the stapedius, stylohyoid, platysma and the posterior belly of digastric. Sensation is also conveyed by the facial nerve, notably taste from the anterior 2/3 of the tongue (via the pre-trematic chorda tympani). This arch has two associated arteries 1. Stapedial artery. This connects the embryonic internal carotid, internal maxillary and middle meningeal arteries. It regresses before birth. 2. Hyoid artery—which gives rise to the corticotympanic artery in the adult.

1  Embryology of the Head and Neck: An Aid to Understanding Our Complex… Fig. 1.24 Treacher Collins syndrome; 4-year-old male. (a) 3D CT image of left side of skull shows underdeveloped mandible with antegonial notching and part of zygoma with zygomatic arch absent (arrow); micrognathia with open bite, and small facial skeleton compared to skull. (b) 3D CT image of right side; similar absence of zygoma (arrow) and appearance of mandible as contralateral side, with the exception of a less developed condylar process

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Abnormalities in the development of the second arch are more common that those of the first arch. These are usually unilateral and often present as cystic lesions, located anterior to the sternocleidomastoid muscle. These cysts are usually first noticed in the second decade of life, after puberty (when secretions of the epithelium increase). There are four main types of second arch defect, which can be classified according to location.

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Fig. 1.25 (a) Micrognathia. (b) Pierre Robin syndrome

1. Type I defects are found anterior to the sternocleidomastoid muscle at the junction of the middle and lower thirds. They are usually deep to the platysma muscle. 2. Type II defects are found adjacent to the great vessels and can compress them if they grow large enough. These are common. 3. Type III defects course between the internal and external carotid arteries and extend laterally. They are usually superior to the glossopharyngeal and hypoglossal nerves. 4. Type IV defects are very rare and are located next to the pharyngeal wall. Branchiootorenal syndrome is a second arch syndrome and is seen in approximately 2–3% of all deaf children. Features include deafness, auricular malformations, pharyngeal fistulae and renal problems. Some of the external pinna abnormalities involve tags, microtia and preauricular sinuses. There have also been reports of defects in the facial nerve and ear ossicles. In rare instances, a midline cervical cleft is observed, and is believed to derive from incomplete fusion of the second and third pharygeal arches. It presents at birth and releases a serous discharge.

1.7.2.3 The Third Arch The cartilaginous component of this arch is less complex than the first two arches, giving rise to the lower body and greater horn of the hyoid. Its associated cranial nerve is the glossopharyngeal nerve (CN IX). Its sensory function is to provide taste and general sensation to the posterior 1/3 of the tongue. The third arch also gives rise to stylopharyngeus muscle. The artery of the third pharyngeal arch becomes the common carotid artery and the proximal portion of the internal carotid artery. Defects of the third (and fourth) arches are difficult to delineate and are rare. Most third arch abnormalities manifest on the left side and present either as a neck abscess or as acute thyroiditis.

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1.7.2.4 The Fourth Arch The fourth arch gives rise to all the laryngeal cartilages (thyroid, cricoid, arytenoid, corniculate and cuneiform cartilages) except the epiglottis, which develops from the caudal part of hypobranchial eminence. The fourth arch’s associated nerve is the superior laryngeal branch of the vagus nerve (CN X), which innervates the arch’s muscular derivatives—the pharyngeal constrictors, levator palatini and cricothyroid. Sensation to a small area of the root of the tongue is provided by the superior laryngeal branch. The vascular derivatives of the fourth pharyngeal arch arteries in adults differ between the right and left. 1 . Right—proximal portion of the subclavian artery 2. Left—part of the aortic arch Defects of the fourth arch thus differ on the left and right sides according to these vascular derivatives. Fistulae or sinuses that develop on the right side pass beneath the subclavian artery and between the superior and recurrent laryngeal nerves, whereas on the left, similar abnormalities pass beneath the aorta and posterior to the common carotid artery. Usually sinuses or fistulae developing from the fourth arch will involve the thyroid gland or the cervical oesophagus. These can present with either abscess or stridor due to the pressure effects on the surrounding structures.

1.7.2.5 The Sixth Arch The adult vascular derivatives of this arch also differ between the left and right: 1. Left—ductus arteriosus 2. Right—proximal portion of the pulmonary arteries The associated nerve to this arch is the recurrent laryngeal nerve, a branch of the vagus nerve. As embryonic development progresses, the right and left recurrent laryngeal nerves take different paths within the thorax. On the left, the recurrent laryngeal nerve has a longer course than the right. This is because it hooks under the left arch artery (ductus arteriosus), whist on the right side, neither the sixth or fifth arch arteries persist and so the right nerve is restrained only by the fourth branchial arch artery (subclavian). As the heart descends and the neck elongates, the left nerve is therefore ‘dragged’ downwards into the developing thorax, hooked around the ductus arteriosus. Rarely, the right fourth branchial arch artery does not develop and the right recurrent laryngeal nerve is not restrained by the subclavian artery. It therefore divides from the vagus more superiorly. This anomalous nerve may therefore be damaged during thryoid surgery. The recurrent laryngeal nerves innervate the intrinsic muscles of the larynx (except cricothyroid), which are derived from the sixth arch. Sensation is extensive and includes taste sensation from the epiglottis and pharynx, general sensation from the pharynx, larynx, oesophagus, tympanic membrane, external auditory meatus and part of the external ear. The recurrent laryngeal nerve also provides the efferent limb of the gag reflex and parasympathetic innervation to the viscera.

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1.7.3 Pharyngeal Pouches The pharyngeal pouches separate the pharyngeal arches on their inner (endodermal) surfaces. There are five pairs of pouches, with only four giving rise to adult structures. 1 . First arch pouch—Eustachian tube and middle ear cavity 2. Second arch pouch—Lining of the palatine tonsils (tonsillar fossa) 3. Third arch pouch—the inferior parathyroid glands and the thymus 4. Fourth arch pouch—the superior parathyroid glands and possibly the parafolicular C cells (via the ultimobranchial body—see the fifth arch pouch). 5. Fifth arch pouch (ultimobranchial pouch). This is a transitory structure, like the fifth arch. However, in some lower animal species it develops into the “ultimobranchial body”. In humans this structure joins the fourth pouch to form the ‘caudal pharyngeal complex’. Parafollicular “C” cells of the thyroid may arise from this complex, although some authorities believe that they arise from the neural crest. The term ultimobranchial body should therefore not really be used in reference to humans as it only exists as a true entity in lower animal species. C cells secrete thyrocalcitonin, which stimulates deposition of the calcium in the bones. Persistence of the pharyngeal pouches and grooves may give rise to structural abnormalities later in life, including cysts, sinuses, and fistulas, all of which are lined with epithelium. Cysts are enclosed cavities, whereas sinuses are open at one end and fistulas are open at both ends. The fistula and sinus openings are usually located anterior to the sternocleidomastoid muscle, but the precise location is determined from the structure it originates from. Persistence of the thymus gland may develop from the third pharyngeal pouch, and is usually caused by incomplete descent of the thymus into the chest, or deposition of thymic tissue along its path of descent. Sometimes there is complete failure of the thymus gland to regress. These processes can lead to thymic cysts or a cervical thymus gland. When deposition of thymic cells occurs, there might be a collection of cysts that form along the descent tract. These sometimes contains thyroid or parathyroid cells. The cysts manifest during childhood and grow over time. Respiratory obstruction, mass effects or dysplasia may occur. Some patients can present with myasthenia gravis, a disorder with a known association with thymus neoplasms.

1.7.4 Pharyngeal Membranes There are four pharyngeal membranes (1, 2, 3, and 4), located between the pharyngeal arches. These are initially formed by two layers (1) an inner endodermal lining from the associated pharyngeal pouch and (2) an outer ectodermal lining from the associated pharyngeal cleft. These two layers become separated by a thin layer of

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mesoderm to form three layers. Only the first pharyngeal membranes persist (as the tympanic membrane). The remaining membranes disappear.

1.7.5 Cervical Sinus The mesenchyme of the second pharyngeal arch rapidly expands and grows downward, such that the arch overlaps the second, third and fourth pharyngeal clefts. This later fuses with the epicardial ridge lower down. Thus, the second, third, and fourth pharyngeal clefts get buried under its surface. These join together to become a slit-­ like cavity lined by ectoderm—the cervical sinus. The sinus normally disappears as the neck continues to develops, however failure of the sinus to obliterate can result in the formation of a branchial cyst. This is described further in the chapter on the neck. Rupture of the cyst can result in the development of a branchial fistula. Fistulas may also arise following persistence of the pharyngeal grooves and incomplete closure of the cervical sinus. These may not clinically manifest until puberty, when they then expand as a result of increased epithelial secretions.

1.7.6 Development of the Face The face develops from five ‘facial prominences’ that appear around the primitive mouth in the fourth week. These are derived from the first and second pharyngeal arches. They are composed mainly of mesenchyme derived from the neural crest. 1. The frontonasal prominence is a midline structure. This is formed by proliferation of mesenchyme ventral to the forebrain vesicle and forms the central part of the upper border of the stomodeum (primitive oral cavity). It is derived from nearby neural crest cells, which migrate from the ectoderm as the forebrain develops. These cells invade the adjacent space, becoming the frontonasal prominence. Structures derived from the frontonasal process are supplied by the ophthalmic nerve (V1). 2. The right and left maxillary and mandibular prominences are derived from the first arch. They surround the rest of the developing stomodeum. The maxillary prominence is above and lateral to the stomodeum, while the mandibular ­prominence is below it. These then fuse together. Structures derived from the maxillary processes are supplied by maxillary nerve (V2) whilst those derived from the mandibular processes are supplied by the mandibular nerve (V3) (Fig. 1.26 and 1.27). During this time, nasal placodes develop on the frontonasal prominence within the overlying ectoderm. These thicken and sink in to form nasal pits, which deepen to form the nasal sacs. At the same time, the mesoderm proliferates around the placodes, to form the medial and lateral ‘nasal prominences’. As the maxillary prominences continue to grow they fuse in a ‘zip-like’ fashion with the mandibular

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Fig. 1.26 Development of the face Frontonasal process Stomodeum (primitive mouth)

Max.pr. 1 Mand.pr. 2 3

Pericardial swelling

Pharyngeal arches 4

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Med.nasal fold Lat. nasal

Nasolacrimal ducts Frontonsal process

Fig. 1.27  Development of the face 2

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Fig. 1.28 (a–f) Congenital anomalies of the face and palate

prominences laterally, to form the cheeks. Further growth compresses the medial nasal prominences, resulting in fusion at around the tenth week of development. Thus the bridge of the nose and the ‘intermaxillary segment’ (both derived from the medial nasal prominence) are established. The intermaxillary segment will later develop into the central portion of the upper lip and the premaxilla. The lateral nasal prominence gives rise to the alae of the nose and also fuses with the maxillary prominence, except at the site of the nasolacrimal duct. The lacrimal and nasal bones here are derived from neural crest cells. Facial clefting can occur when there is incomplete fusion between the five facial prominences. This can be partial or total. It can be unilateral or bilateral and is also a common feature in many congenital syndromes. The commonest clefting anomalies are cleft lip and cleft palate, but oblique facial clefting, microstomia, and macrostomia have also been described. Very rarely the two mandibular processes fail to fuse in the midline to cause cleft lower lip (Fig. 1.28, 1.29 and 1.30). Cleft lip is most commonly seen in the upper lip and the incidence is approximately 1  in 1000 births. It is more common in males. The cleft forms when the

38 Fig. 1.29  Tessier clefting system. (a) Soft tissue clefts. (b) Bony clefts. Dotted lines represent uncertain localisation or uncertain clefting. Note that the northbound cranial line has different number than its counterpart southbound facial line. This system is descriptive and anatomic. It avoids aetiology and pathogenic speculation (Tessier P. J Maxillofac Surg 4:69, 1976) [1]

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Fig. 1.30  Child with a right-sided Tessier 7 cleft with macrostomia and ridge in soft tissue of cheek, left-sided Tessier 4 cleft. Note the nostril elevation, absent eyelashes medially and hypoglobus. The cleft involves the maxilla and orbit

maxillary prominence fails to fuse with the intermaxillary processes. Specifically, there are three main types: 1. Unilateral cleft lip—This occurs due to failure of fusion of the maxillary process with the medial nasal process. 2. Bilateral cleft lip: This occurs due to failure of fusion of maxillary processes with the frontonasal process. 3. Central cleft lip/hair lip: This occurs due to failure of development of philtrum of the upper lip from the frontonasal process (Fig. 1.31).

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Fig. 1.31  Cleft lip intact palate

Severity of cleft lip varies considerably. In the most severe cases it completely separates the lateral lip from the philtrum and nasal cavity. Some cleft lips only involve the soft tissues, but sometimes the deformity can extend to the maxillary bone and can lead to dental deformities. Cleft palate is formed when there is a failure of fusion of the palatal shelves along the midline. This is more common in females. This is described further in the chapter on the mouth. Bilateral complete cleft palate occurs if both maxillary processes fail to fuse with the premaxilla. The palate is divided in two by a midline cleft, with an anterior V-shaped cleft separating the premaxilla completely. Incomplete cleft palate is characterised by the presence of a bifid uvula or cleft of the soft palate. Failure of fusion of the palatal shelves may be due to a number of developmental anomalies including poor growth of the shelves themselves, inadequate elevation of the shelves or failure of the shelves to fuse. Oblique facial clefts are rare congenital deformities which occur when the maxillary process fails to fuse with the lateral nasal process. A fissure persists between the inner corner of the eye and the upper lip, with exposure of the nasolacrimal duct.

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Fig. 1.32  Embryology of the oral cavity

Forebrain swelling Ectoderm endoderm Stomedeum

ant-end of foregut

Bucco pharyngeal membrane

Pharynx

Perl cardial swelling

This usually occurs bilaterally. Abnormalities of the side of the mouth can also occur following abnormal fusion between the maxillary and mandibular processes, resulting in lateral facial clefts. The oral commissures (corners of the mouth) are formed at the junction of the maxillary and mandibular processes. Initially they are sited laterally, close to the auricle. During normal development the commissures gradually shift medially as the maxillary and mandibular processes fuse in a zip-like fashion. Excessive fusion results in microstomia (small mouth), whilst failure to fuse fully results in macrostomia (large mouth) (Figs. 1.32 and 1.33).

1.7.7 The Paranasal Sinuses These develop later during foetal life and do not reach adult size until the age of 12. The maxillary sinuses develop from invaginations of the nasal cavities at around birth and undergo rapid growth until the age of 6 years. A second growth spurt from the age of 7 then takes place. Chronic rhinosinusitis in childhood may affect this development, resulting in maxillary sinus hypoplasia. If severe this can also affect the shape of the orbit and ethmoids. The sphenoid sinuses also develop from birth. At the age of 6 the “presphenoid” is pneumatised. By the age of 12 this has extended below the sella turcica and may include the anterior clinoid and pterygoid processes. With extensive pneumatisation the optic nerves can enter the sinus cavity—this is important to remember during endoscopic sinus surgery. The ethmoid sinuses are

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Fig. 1.33 Hemifacial microsomia; 4-year-old male with multiple anomalies including cleft palate and lip. (a) 3D CT image, lateral view, shows left-sided severely hypoplastic mandible and absent zygomatic arch (arrow). (b) 3D CT image, lateral view, shows normal right side for comparison

developed by the time of birth. Initially fluid filled, these become air-filled during the first year. Pneumatisation can vary widely. The frontal sinuses are the last sinuses to develop. These arise when the ethmoid recesses extend beyond the superior orbital rims, usually at the age of 6. In essence the frontal sinus is a variant of pneumatisation of the ethmoid sinuses. Aplasia and hypoplasia of the frontal sinuses is common.

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1.8

Muscles of Head and Neck

The head and neck musculature is also partially derived from ‘somitomeres’ 1–7 in the head and neck region. These also contribute to the formation of the pharyngeal arches. The mesoderm of each pharyngeal arch is thus derived from two sources 1. Paraxial mesoderm (see below) which gives rise to most of the muscles of head and neck region. 2. Neural crest cells which give rise to the skeletal elements and connective tissues of the head and neck region (discussed above) (Figs. 1.34, 1.35 and 1.36).

Ectoderm

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Fig. 1.34  Segmentation of the paraxial mesoderm into somites

Fig. 1.35 Differentiation of the somites

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1st pair or somites 4 occipital 8 cervical 12 thoracic 5 lumbar 5 sacral

42 - 44 somites

8-10 coccygeal

Fig. 1.36  Arrangement of the somites

1.8.1 Myotomes A myotome is defined as a group of muscles that are innervated by a single spinal nerve root. This is clinically useful when determining whether damage has occurred to the spinal cord and if so, at which level. Skeletal muscle development begins with the appearance of somites. During the trilaminar stage, the middle layer (mesoderm) on either side of neural tube divides into three parts. These are the paraxial mesoderm, intermediate mesoderm and lateral plate mesoderm. The part that is directly adjacent to the neural tube is called paraxial mesoderm. From about day 20 the paraxial mesoderm differentiates into segments called ‘somites’. 44 pairs are initially formed, but 13 break down later, leaving 31 pairs of somites. Initially there are 4 occipital, 8 cervical, 12 thoracic, 5 lumbar, 5 sacral and from 8 to 10 coccygeal. Caudal to the occipital region, the number of somites subsequently corresponds to the number of spinal nerves in the region. Thus, there are eventually 8 cervical, 12 thoracic, 5 lumbar, and 5 sacral somites, corresponding to same number of spinal nerves in these regions. Each somites is comprised of a ventral and a dorsal portion. The ventral portion consists of the ‘sclerotome’, the precursor to the ribs and vertebral column. The dorsal portion consists of the ‘dermomyotome’. As the embryo continues to develop the myotomes proliferate and eventually develop into muscle. Most muscles in the upper and lower limbs are composed of multiple myotomes and therefore receive innervation from more than one spinal nerve root. For example, the biceps brachii muscle is innervated by the musculocutaneous nerve, which is derived from C5, C6 and C7 nerve roots. All three of these spinal nerve roots are associated with action of the muscle. With regards to the head and neck: 1. The extraocular muscles develop from three ‘preotic myotomes’, (Somitomeres 1–3), that are arranged around the developing eye. These myotomes are innervated by the IIIrd, IVth, and VIth cranial nerves, hence the extraocular muscles are supplied by IIIrd, IVth, and VIth cranial nerves.

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2. The muscles of the tongue develop from precervical somites called ‘occipital myotomes’. These are innervated by the hypoglossal nerve. As the tongue develops in the floor of pharynx, the occipital myotomes migrate forwards and enter the tissues of the developing tongue to form the majority of its musculature, with the exception of palatoglossus. Thus, the long hypoglossal nerves supply the tongue muscles. 3. The muscles of the pharyngeal arches also develop from mesoderm that is derived from somitomeres. These include the muscles of mastication, facial expression, pharynx, and larynx. They are innervated by the associated nerves of the respective pharyngeal arches. 4. The stylopharyngeus muscle arises from seventh somitomere of the third arch and is supplied by the nerve of the third arch, the glossopharyngeal. 5. The laryngeal muscles are derived from occipital somites 1 and 2. These arise from the fourth and sixth pharyngeal arches and are thus supplied by the branches of vagus. Congenital muscular torticollis is a term that describes a shortened tight sternocleidomastoid muscle, and is thought to be due to fibrosis within the muscle. The aetiology is unclear, but it is thought to be caused by crowding within the uterus, or injury during birth. Physiotherapy during the first weeks of life can help to gradually lengthen the muscles. Aglossia and microglossia are very rare anomalies, often associated with malformations in the extremities, cleft palate and dental agenesis. There develops a rudimentary, small tongue. As a consequence the alveolar arches do not develop transversely and the mandible does not fully develop, resulting a severe facial deformity. The cause is believed to be trauma during the first few weeks of gestation. A completely cleft or bifid tongue is another rare condition due to a lack of mesenchymal proliferation and merging of the lingual swellings. It is often found as one feature of the oral-facial-digital syndrome.

1.8.2 Dermatomes A dermatome is defined as an area of skin that is innervated by a single spinal nerve. Along with myotomes, this is also of great diagnostic importance in determination as to whether there is damage to a cranial nerve or the spinal cord. Dermatomes develop in the third week. Following the development of the somites, the dorsal portion of each consists of the dermomyotome. Each dermatome migrates to form the dermis, taking its respective innervation along with it. Dermatome maps depict the dermatomes according to their segmental distribution. This is a commonly used map in the assessment of spinal injuries.

1.8.3 The Skull Further details of this are described in the chapter on the head. The skull develops from mesenchyme around the developing brain. It is divided in two parts (1) the

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Fig. 1.37  Normal 3D CT bone anatomy of the face and skull; (a–e) 7-month-old, (f–h) 8-year old

neurocranium, that encloses and protects the brain and (2) the viscerocranium, that forms the skeleton of the face. The neurocranium consists of a cartilaginous skull base and a membranous cranial vault. The cartilaginous base of skull is formed by chondrification in the mesenchyme below the brain. It subsequently ossifies. The vault develops from the surrounding mesenchyme, derived from the neural crest cells and paraxial mesoderm. This undergoes membranous ossification to form a number of flat membranous bones, separated by the sutures and fontanelles (Fig. 1.37). Following birth, rapid enlargement and changes in the curvature of the cranial vault occurs in response to further expansion of the brain. The periosteum of the bones contains cells which can differentiate into osteoblasts and osteoclasts. Changes in the shape and size of the calvarium is achieved by remodelling on the

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extracranial and intracranial surfaces. By the age of 2, the brain and cranial vault have achieved about three quarters of their full growth. Most of the enlargement of the cranial vault is completed by around 8 years of age as a result of sutural growth and remodelling. After 8, growth is restricted to thickening of the bones and enlargement of the superciliary ridges. As growth slows and ceases the sutures develop ‘interlocking fingers’ of bone which subsequently makes the cranial vault very strong. Many abnormalities of skull shape related to disturbances in sutural growth have been described. These are known as synostoses. Examples include: 1. Scaphocephaly: Boat-shaped skull due to frontal and occipital expansions. It occurs due to premature fusion of the sagittal suture. 2. Brachiocephaly: Short skull due to premature bilateral fusion of the coro nal suture. 3. Plagiocephaly: This occurs following premature fusion of the coronal and lambdoid sutures on one side only. This results in unequal curvatures of skull. 4. Acrocephaly: Pointed skull due to premature fusion of the coronal suture. 5. Microcephaly: Small skull due to failure of proper development of the brain. 6. Oxycephaly (turricephaly or acrocephaly): A tower-like skull caused by premature closure of the lambdoid and coronal sutures. 7. Kleeblattschädel: This is a clover leaf skull caused by premature closure of all the sutures, forcing the brain herniate and grow through the anterior and sphenoid fontanelles. 8. Crouzon syndrome. This is an autosomal dominant disorder caused by a mutation in the gene that encodes for fibroblast growth factor receptor 2. Clinical features include premature craniosynostosis, midface hypoplasia with shallow orbits, ocular proptosis, mandibular prognathism, progressive hydrocephalus but without mental retardation (Figs. 1.38 and 1.39). 9. Apert syndrome. This is also an autosomal dominant disorder. Clinical features include craniosynostosis leading to turribrachycephaly, syndactyl of hands and feet, various ankyloses, progressive synostoses of the hands, feet, and cervical spine and mental retardation. 10. Pfeiffer syndrome. An autosomal dominant genetic disorder resulting in craniosynostosis leading to turribrachycephaly, syndactyl of hands and feet and broad thumbs and great toes. 11. Schuller-Christan Syndrome: There are large defects in the skull bones (Figs. 1.40 and 1.41).

1.9

Arterial Development

As the pharyngeal arches develop, each receives a specific artery derived from the developing aortic sac. Thus, the aortic sac gives rise to six pairs of aortic arch (pharyngeal) arteries. These have been previously noted. The fifth pair soon disappears along with its corresponding arch. The remaining five aortic arch arteries are numbered I, II, III, IV, and VI.  Each artery is embedded in the mesenchyme of its

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Fig. 1.38  Crouzon syndrome; 2-year-old. (a) 3D CT image, oblique view, shows superior elongation of skull and typically “opened mouth”. The maxilla and zygomas are hypoplastic. (b) 3D CT image, lateral view, shows maxillary hypoplasia (arrow)

Fig. 1.39  Picture of 3D CT skull showing cloverleaf skull (kleeblattschädel deformity)

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Fig. 1.40  Premature unilateral synostosis, 7-month-old male. (a) 3D CT image shows closure of right side of coronal suture but left side open (arrow), as is sagittal suture (large arrowhead). Anterior fontanelle open and metopic suture closed but can be seen (small arrowhead). Asymmetric deformity of anterior part of head. (b) 3D CT image shows evident asymmetry of right and left orbita (arrow) due to the abnormal growth

pharyngeal arch. The major arteries of the head, neck (and thorax) are derived from (1) the aortic (pharyngeal) arch arteries and (2) the aortic sac and its right and left “horns”. Each of these arteries eventually regress to some extent as follows 1. The greater part of the first arch artery disappears, a small part remaining as the maxillary artery. 2. The greater part of second arch artery disappears. Its remaining part forms the hyoid and stapedial arteries in foetal life. 3. The third, fourth and sixth arch arteries open into the aortic sac. Each third arch artery gives off a bud that grows cranially to form the external carotid artery. The sixth arch artery on each side also gives off an artery to the developing lung bud. On the left side, a portion of this remains to form the ductus arteriosus. 4. On the right side, the third and fourth arch arteries arise from the right horn of aortic sac to form the brachiocephalic artery. As a result, the right common carotid artery and right subclavian artery appear as branches of the brachiocephalic artery. Angiogenic factors stimulate growth of these major vessels. These are usually inhibited once the vessels have developed to an appropriate size. If these angiogenic factors fail to be inhibited, this can lead to continued growth of the blood vessels and congenital haemangiomas. Haemangiomas are the commonest tumours of infancy. Haemangiomas tend to grow in proportion with the child’s growth. The vast

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Fig. 1.41  Occipital plagiocephaly unrelated to craniosynostosis; patent lambdoid suture. (a) Baby sleeping supine on one side. (b) 3D CT image shows flat head. (c) Axial CT image shows patent suture (arrow) but left occipital plagiocephaly. (d) Axial CT image shows complete closure of lambdoid suture (arrow) representing true lambdoid craniosynostosis from different patient for comparison

majority remain benign, but occasionally they may differentiate into a haemangiosarcoma. Their location will also determine their clinical significance. Five classes of haemangioma are often described: • Type I—Birth marks such as stork bite and naves flammus • Type II—Formed from capillaries in the dermis, includes salmon patches, port wine stains, and congenital spider angiomas • Type III—Capillary haemangiomas manifesting during childhood including strawberry marks, strawberry haemangiomas, and capillary cavernous haemangiomas • Type IV—arteriovenous fistulas • Type V—arteriovenous malformations and capillary haemangiomas Syndromes involving haemangiomas include Von-Hippel-Lindau disease, Maffucci syndrome, Sturge-Weber syndrome, and Kasabach-Merritt syndrome.

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Hydranencephaly results from bilateral widespread hemispheric infarction secondary to occlusion of the internal carotid arteries in utero. The hemispheres are replaced by hugely dilated cystic cavities. The brain stem and cerebellum are usually spared because the vertebrobasilar circulation is not affected. Other causes of this devastating condition include toxoplasmosis, rubella, cytomegalovirus, and herpes virus.

1.10 Understanding Congenital Anomalies In addition to genetic defects, exposure to chemicals, drugs, viruses and other factors during development can result in a wide variety of anomalies. In severe cases early development fails completely and leads to miscarriage. Other severe anomalies may result in a still birth. In other cases exposure during the embryonic period can result in congenital malformations. Vertically transmitted infections can be passed from the mother to the unborn child at any stage of development. Teratomas and other types of tumour are thought to be related to primitive streak remnants, which would ordinarily disappear. In the head and neck a wide variety of disorders are therefore possible as a result of failure of the various processes of proliferation, differentiation, regression and migration (Fig. 1.42). Fig. 1.42 Mouth duplication

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Some of these congenital anomalies are described throughout this book. Cysts include thyroglossal duct cysts, which usually present during childhood in the first decade. These arise from persistence of the thyroglossal duct, which is an epithelial tract formed for descent of the thyroid during development. These cysts are usually soft, non-tender, and are mobile. Classically they move on swallowing. The commonest type is the infrahyoid type, but there are five other types based on its location in the midline of the neck (suprahyoid, juxtahyoid, suprasternal, intralaryngeal, intralingual). Sometimes these cysts may become infected and lead to abscess, which can cause respiratory obstruction if severe (Fig. 1.43). Ectopic thyroid tissue is another relatively common abnormality, and can arise from the median “anlage” (precursor) or less commonly, the lateral anlage. The thyroid tissue may sometimes produce thyroid hormone, but could also be inactive. The commonest position for ectopic thyroid tissue is the tongue—this is important to remember if excising tongue lesions. Fig. 1.43  Thyroglossal cyst

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Cervical teratomas are rare lesions that present at birth. They usually extend in the midline from the thyroid gland and can obstruct the airway. Usually these teratomas arise from the thyroid gland, but sometimes they can develop from other parts of the neck. There is a risk of malignant degeneration so these tumours are usually excised as early as possible. The commonest teratomas of the cervical region are dermoid cysts which are derived from ectoderm, but can contain cells from all three germ lineages.

1.10.1 Teratogenic Agents These are chemicals or substances that can cause birth defects when present during embryonic development. They include a wide array of drugs, chemicals, and infectious, physical and metabolic agents which can adversely affect the intrauterine environment of the developing foetus. Whist the first 2 weeks of life (prior to organogenesis), appear to be a relatively safe time for the embryo regarding teratogenic exposure, the next 45 days are especially dangerous. This is the period that most organs develop. Thus, most major malformations, such as amelia (absent limbs), cleft lip/palate, microtia and congenital heart anomalies, arise during the first 60 days of embryonic development. One notable exception is alcohol, which can result in malformations during the entire pregnancy. Craniosynostosis and hearing loss for example appear to develop after 60 days of conception. The pathogenic mechanisms for teratogens are diverse, but ultimately produce alterations in form and function as well as cellular or embryonic/foetal death. The same teratogen can result in different defects depending on the times of exposure. For example, exposure to thalidomide around the 33rd day causes microtia and facial palsy, but later exposure results in aplasia of the arm bones. Exposure to rubella after the 55th day causes hearing loss and retinopathy but earlier exposure can cause cataracts and congenital heart anomalies. Most, but not all, teratogens have a threshold dose below which no malformations occur. However above the threshold dose, many teratogens exhibit a dose–response effect (Fig. 1.44). Fig. 1.44  Rubella cataract

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1.10.2 Classification of Congenital Malformation of Brain Congenital anomalies of the brain are extremely complex. A number of classification systems have been proposed, but a simplified classification of brain malformations is as follows: 1. Disorders of Organogenesis • Neural tube closure • Diverticulation and cleavage • Sulcation/cellular migration • Cerebellar hypoplasia/dysplasia 2. Disorders of Histogenesis • Neurocutaneous syndromes (Phakomatoses) 3. Disorders of Cytogenesis • Congenital vascular malformations • Congenital neoplasms of brain 4. Disorders of Myelination • Leukodystrophies

1.10.3 Craniofacial Deformations Congenital deformations of the head and neck are common, but most resolve spontaneously within the first few days following birth. These usually arise from intrauterine constraints with severe foetal crowding. Deformations can occur in the nose, ear and mandible. Torticollis, nonsynostotic plagiocephaly, craniosynostosis may also result. The Potter sequence (oligohydramnios sequence) is used to describe a series of compression deformities of the face and limbs, pulmonary hypoplasia, wrinkled skin, and growth restriction resulting from any pathologic condition that leads to oligohydramnios. The Amnion rupture sequence can result in three types of anomalies—disruptions, deformations and malformations. Disruptions are caused by adhesions, by tearing and constriction by amnionic bands. These can interfere with normal embryogenesis, resulting in malformations. In the head and neck they include bizarre facial clefting, encephaloceles and pseudoanencephaly. Deformations result from oligohydramnios and intrauterine crowding, as previously noted. Other malformations from the amnionic rupture sequence cannot be explained by these mechanisms but may include craniofacial disruptions, clefts and neural tube defects.

1.10.4 Congenital Lumps These are common in the head and neck and make take various forms 1. Epidermoid cysts are of ectodermal origin and are therefore lined by stratified squamous epithelium. Dermoid cysts also include the dermis and therefore may

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contain skin appendages, such as hair follicles, sebaceous glands and sweat glands. Both cysts arise from the inclusion of the elements of the developing skin during the fusion of adjacent tissue processes. When the central nervous system is involved, this occurs between the third and fifth week of development during closure of the neural tube. Such cysts then tend to be located in the midline and can be associated bone and skin defects with communications with the central nervous system. Dermoid cysts in the head and neck are estimated to account for about 10% of all dermoids. Common sites include the orbit, floor of the mouth and nose, with the rest found in the lip, palate, neck, frontal and occipital regions. Intracranial dermoids are uncommon are often occur in the midline of the posterior fossa, to involve the vermis and fourth ventricle. Epidermoid cysts may involve the skull vault, cerebellopontine angle and middle cranial fossa. 2. Hamartomas are localised growths of tissues indigenous to the site of origin. These are very uncommon but have been reported in the eye; sinuses; nasal cavity; pharynx; mouth; larynx; trachea and thyroid, parathyroid, and parotid glands. Hamartomas often contain a variety of tissues such as epithelium, vascular tissue and glands. Cartilaginous containing tissues can also occur in the larynx and trachea and secretory hamartomas in the upper respiratory tract. Whilst most are benign and do not need treatment, some may be sited in more critical places, such as the hypothalamus, which can predispose to seizures. 3. Teratomas are true neoplasms composed of multiple tissues, not normally found at their site of origin. At least two germ cell layers are present. The tissues contained may show varying degrees of differentiation. Teratomas are well described in the central nervous system (e.g. pineal region and sacrococcygeal), but are rare outside the skull in the rest of the head and neck. However they can occur in the nasopharynx, orbit, larynx, and tongue. The ‘epignathic’ teratoma is a rare type that may be discovered before during antenatal screening and which poses a threat to the airway. Other rare sites include the pharynx, middle ear and mastoid. Teratomas in adults are more likely to be malignant than those that occur in childhood. 4. Heterotopia, ectopia and aberrant tissues (choristomas) are developmental abnormalities in which mature tissue arises in an abnormal location. In the head and neck the two most common examples are ectopic thyroid and parathyroid glands. More unusual examples include gastric mucosa in the tongue and heterotopic salivary tissue found in many sites including the nose and middle ear. Rests of ectopic salivary tissue can also be found in the tonsils, lymph nodes, larynx, hypopharynx, neck, external auditory canal, middle ear, and thyroglossal duct. In some cases cystic development can occur, rarely neoplastic change (e.g. pleomorphic adenoma in any of these structures or ectopic thymoma in the thyroid). 5. Proliferative haemangiomas and vascular malformations are complex deformities that may present at or shortly after birth, or later in life. These are primarily a vascular developmental problem which can bleed, thrombose, become inflamed or infected. Proliferative haemangiomas are benign neoplasms that grow faster than the child in the postnatal period but then most often slowly involute. By contrast, malformations grow at the same rate as the patient although they can

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increase in size under the influence of hormones during puberty and pregnancy. Deep sited lesions may affect the airway or interfere with the eye, swallowing, speech and hearing. Proliferative hemangiomas and malformations commonly arise in the skin, but can involve the mucosa of the nose, mouth, tonsil, palate, tongue and the neck. Parotid haemangiomas are a common cause of parotid swellings in children. Laryngeal subglottic vascular malformations need careful evaluation. Some malformations may be part of a more widespread syndrome (e.g. sturge-weber).

2

Initial Assessment of the “Head and Neck” Patient Ishita Basu and Michael Perry

Attendance to an emergency department is often an unpredictable event and the beginning of a (sometimes lengthy) hospital journey. For many patients this can be quite an upsetting process. For the attending clinician, managing such patients sympathetically can be difficult but is a good opportunity to build rapport and for the patient to gain confidence. This is especially important in children. Whilst ideally, a thorough and detailed history and examination is often necessary in order to make a correct diagnosis, in a busy emergency department setting, or with very sick patients this is not always practical or possible. Patients therefore need to be triaged quickly so that they can be appropriately managed in accordance with their clinical need. Triaging patients is a common process and often becomes necessary whenever demand outstrips the resources required to make a detailed assessment in a timely fashion (usually within 15 min or less). Unfortunately a “one size fits all” approach is not possible in all patients. However, with experience, questions can quickly become tailored towards recognising ‘key’ symptoms or signs, which in the head and neck may indicate significant or serious pathology, or the presence of serious complications following injury. Knowing what to ask and what to look for when faced with an injury, infection, or distressed patient, significantly helps speed up the triage process. Many useful indicators exist. For example, the presence of neck stiffness in any patient with a severe headache should raise concerns regarding the possibility of meningitis or subarachnoid haemorrhage. Similarly, difficulty swallowing in a patient with a neck abscess is also a ‘red flag’ symptom, implying potential airway issues. With practice and experience we can learn which questions are the more important and therefore should be specifically asked. Today, a number of algorithms have been developed which can be used to rapidly sort and prioritise patients. This is usually done by an experienced member of the I. Basu (*) Oral & Maxillofacial Surgery, Northwick Park Hospital, London, England M. Perry London Northwest University Hospital, Harrow, Middlesex, UK © Springer Nature Switzerland AG 2021 M. Perry (ed.), Diseases and Injuries to the Head, Face and Neck, https://doi.org/10.1007/978-3-030-53099-0_2

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clinical team. Triage should be ideally be undertaken within 15 min of the patients arrival in the emergency department, although this may not be practically possible. Determining clinical urgency is usually based on the patient’s presenting complaints and a few important and measurable physiological parameters, notably temperature, pulse, blood pressure, respiratory rate, pain score and level of awareness. These can all be assessed within a relatively short period of time following arrival. However whenever a rapid history is being taken, care is required not to assume too much on the basis of a few questions alone. This initial assessment will form the foundation on which a differential diagnosis will be made, the patient triaged and investigated, and treatment planned. Omissions of key questions from the history, or inadequate assessment can therefore result in misdiagnosis, unnecessary investigations and ultimately a delay in treatment. It is traditionally taught that 90% of the diagnosis comes from the history. Whilst that is true for many conditions, in the emergency department setting, examination and simple investigations play an equal or sometimes more important role, particularly in the triage process. The presence of absence of a fever may make all the difference in the management of a patient with a headache or a neck swelling. Early Warning Scores (EWS) for both adults (NEWS) and children (Paediatric Early Warning -PEWS) have now been developed to help in the early identification of the unwell and deteriorating patient. These were originally designed for use on the wards but have since been adopted for use in emergency departments. The scores derived from these algorithms also provide a baseline from which deterioration or improvement can be measured. If those patients that require urgent surgery the initial assessment must also include relevant aspects of the pre-operative assessment. Not only must we make a diagnosis, but we must also quickly determine the severity of the condition, identify any need for urgent treatment and minimise the risks of anaesthesia and surgery, by identifying and quickly optimising co-morbidities. If the patient has had previous hospital admissions or previous treatments then obtaining hospital records can provide valuable information regarding pre-operative, anaesthetic or prior post-­ operative problems.

2.1

Taking a ‘Focused’ History

Most medical students are usually taught at some point during their undergraduate training that “90% of a diagnosis comes from a good history”. Whilst the precise percentage varies and the original source of this apocryphal saying has been attributed to a number of imminent physicians over the years, research has shown that this statement is, in the main, correct. However, when dealing with the critically ill or injured patient, time constraints can sometimes preclude taking a lengthy and detailed history. There may be times when the patient is unable, or even unwilling to give a history (e.g., they are unconscious, intoxicated, or confused), in which case it is important to try to speak to family members, friends, paramedical staff, or any witnesses who may be able to provide useful information. Be sure to document

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clearly from whom the information has come from and why the patient is unable to speak. Efficient history taking and the art of asking pertinent questions in a busy Emergency department is a useful skill that needs to be learnt and which requires practice. In most cases it usually commences by establishing the identity of the patient and how he or she would like to be addressed. Basic demographic details, such as name, age, address and occupation may also be taken at this time. Patients must then be allowed to relay their chief complaint and concerns in their own words, rather than being asked to confirm what we think is going on. Depending on the circumstances, this may involve sensitive and personal issues (for example injuries that have resulted from abuse or domestic violence). In some cases, the patient may need to divulge information which may not be normally shared, even with close contacts (for example circumstances resulting in an injury, alcohol/recreational drug usage/sexual contacts/HIV risk etc). As clinicians we must therefore be sensitive to this and take into account the patient’s body language when approaching such topics. A useful starting point is often to treat patients as we would want to be treated if we were patient. With these considerations in mind patients should ideally be assessed in privacy and in a quiet setting. However, in such situations it is also important to make sure that necessary precautions to safe guard oneself are taken. Patients can be unpredictable, especially following alcohol or substance abuse. If necessary, include another member of staff as a chaperone, especially if the patient is female or a minor, and the clinician male. If this is not possible then leave the door or curtains of the bed or bay area partially open. In other cases there may also be cultural issues to consider, or a language barrier. Ideally an interpreter should be requested, but in the emergency setting a friend or family member may have to suffice. Caution is always required when using ‘friends and family’ however, as many issues can arise if the friend/family dynamics are unknown and possibly adversarial. As clinicians our overriding duty is to the patient first and we must make all efforts to ensure that any communication through a third party ensures this. There are many anecdotal instances where this has not been the case and communications have been ‘interpreted’ differently, with friends or family conveying different meanings between the patient and staff. Nevertheless, despite this caution the absence of a hospital translator should not compromise or delay urgent treatment. If the patient is to undergo emergency surgery and time allows, then consent must be obtained in detail with an interpreter so that the patient is fully aware of the procedure and its risks. The interpreter should also be available for any anaesthetic assessment and until anaesthesia is given. Patients can refuse treatment at any time. Clear and detailed documentation of the history is also essential with regards to any medico-legal implications of injuries. A significant proportion of injuries to the head, neck, face and teeth that are seen in the emergency department are liability-­ related accidents, or “alleged assaults” occurring as a result of interpersonal violence. Police reports may need to be written at a later date. Therefore, be careful what you write and try to note as much detail as possible. It is important to stick to the facts, ie what the patient or witnesses tells you, and to avoid speculation (eg

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“patient was drunk”). Whatever is written in the notes is usually accepted as an accurate account of events and anything further based on memory may be inadmissible unless a witness testifies to it. In cases of alleged clinical negligence, it is very difficult to defend oneself in a court of law in the absence of documentation—“If it’s not documented, it didn't happen”. Hand-drawn pictures and measurements or wounds are also very helpful. Photographs are ideal, but can be difficult to take in an emergency department and are becoming increasingly difficult to obtain as a result of data protection legislation. If these are taken, make sure that the patient has consented in writing to these if possible. If not, get the consent in retrospect. On a more practical note, legible writing ensures that colleagues who continue the patient’s care can read what you have written.

2.1.1 The History A detailed account of the events leading up to presentation, or the mechanism of the injury, is very valuable in the early stages of assessment and can often provide clues to occult problems. For example, a history of a fall or minor head injury, weeks or months previously, may suggest the possibility of a chronic subdural haematoma in an elderly patient presenting with intermittent confusion. Previous toothache, or treatment at a dentist, may suggest the underlying cause of a newly developed neck abscess. Enquire also about the patient’s general health. This is important in order to assess their fitness, should surgery be required. It may also modify treatment.

2.1.1.1 The Presenting Complaint There are many reasons why patients attend their doctor or emergency department. Some are genuinely urgent, others less so. These will be discussed in more detail in the relevant chapters, but common problems include: Pain (headaches, neck pain, TMJ discomfort, toothache etc) Injuries (lacerations, abrasions, contusions, fractures, organ or visceral injury) Bleeding (epistaxis, otorrhoea, bleeding gums, and following injuries or recent surgery) Lumps or swellings (discrete lumps or diffuse and sometimes rapidly spreading swelling) Rashes and ulcers (typically involving the skin, oral mucosa and occasionally the eyes) Trismus (limitation of mouth opening secondary to muscle spasm) Social related problems (alcohol and substance abuse, domestic abuse and occasionally child-abuse) Other, less common concerns may include (1) Facial Asymmetry from progressive bony or soft tissue enlargement, (2) Jaw symptoms (commonly stiffness and locking) (3) Altered sensation or weakness involving the face and (4) the development of dysfunction in and important structure (e.g. loss of hearing, reduced vision, or change in the bite)

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Some complaints and their underlying causes are more common in specific age groups. Visual impairment and glaucoma or temporal arteritis, for instance generally occur in the elderly. These and other conditions becomes more recognisable with experience. However rare or unusual the condition may still present to the emergency department and it is important to avoid making a diagnosis too prematurely. To elicit information about the presenting complaint, start by using an open question, for example: ‘What is the problem?’ or ‘Tell me about the problem?’. Patients should be encouraged to describe their complaints and concerns in their own words and this should be carefully documented. The patient should then be asked more specific details about his or her symptoms, starting with the most important first. These will vary, depending on the initial presentation. It is important to concentrate on symptoms and not on diagnosis to ensure that no information is missed. Direct questioning can then be used to ask about the progression of events, the current situation and any other symptoms that might be present. Negative responses are also important, especially during triage. Assaults/Injuries (See also Chapter on the Injured Patient) Assaults are common in many urban areas, and injuries have many accidental causes. Because of the potential for serious injury, assessment must be expedited and is described elsewhere in this book. For less urgent trauma (typically the “walking wounded” patient) the following can be questioned. Time and place. This is important not only in the triage process but also from a medico legal perspective. Mechanism of injury. This important concept is discussed in the chapter on the injured patient. Very often the mechanism of injury can provide useful clues in the diagnosis of hidden (occult injuries). For example, a blow to the chin can result in fractures around the TMJ (condyles). Grinding machinery can result in intra ocular foreign bodies. Deceleration injuries are particularly worrying, particularly when they involve the chest or abdomen. Bungee jumping, which can result in huge deceleration forces, has been reported to result in stroke and retinal detachment. Was there any loss of consciousness? This is a potentially significant symptom as it may indicate potential brain injury. However reduction of consciousness has many causes, most notably alcohol intoxication, hypoxia and hypoglycaemia. What happened immediately after the injury and how did the patient get to hospital (walk, ambulance or other transport)? This information is also helpful for the triage process and in establishing higher cerebral function. What are the effects of the injury ? (notably any affects on the vision, bite or ability to breath through the nose) Are there any other injuries apart from those on the head/face? Often facial injuries and scalp lacerations are very obvious and these may divert attention away from other perhaps more important injuries. Following assaults and explosions, consider the possibility of piercing or penetrating injuries. Blood on the clothes is a useful clue. Sometimes the entry wound can be quite small and easily overlooked.

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Ask if the police are involved ?—if so it is important to get consent from the patient so that you can speak to them if they arrive later. Otherwise patient confidentiality will prevent your providing useful information. Does the patient have any previous injuries ? (for example the ‘broken nose’ may be and old injury and cannot be simply manipulated back into position. Missing teeth may also be long-term). Possessing Pain This is one of the common causes for attendance to an emergency department. Acute pain serves as both a protective function and indicates the presence of an injury or illness. Often, the physiological signs elicited, occur as a result of the body’s response to pain. Other factors such as the patient’s cultural background, emotions, and psychological or spiritual well being may also contribute to their perception of pain. Pain has many possible causes and can be easily misdiagnosed. Pain within the head and neck region can originate from local pathology, nearby pathology and even distant sites. Jaw pain during a myocardial infarct, otalgia from a throat infection and headaches from glaucoma, carbon monoxide poisoning or a hypertensive crisis, are just a few examples. When assessing pain consider the following The site of the pain and any radiation—This must be precisely recorded, noting any trigger points and/or referred pain. Does the cross the midline? (indicating it is not dermatomal) Ask the patient to describe the onset of pain—was it sudden, or has it developed gradually? Describe the character of pain, using quality/sensory descriptors for example, sharp, throbbing, burning. Neuropathic pain descriptions include shooting, burning, stabbing, allodynia (pain associated with gentle touch). Sometimes the description of the pain may give an indication of the underlying pathology. Throbbing pain is often vascular based (inflammation/infection). Deep-seated or gnawing, unrelenting type pain may indicate an erosive-type inflammatory, infective or malignant condition. Duration of the pain—how long does it last, such as minutes, days or weeks? Is it continuous or intermittent? Are there any aggravating and relieving features—is there anything that makes it better or worse? Has anything to date improved the pain? Associated symptoms—when the pain occurs, does anything else happen with it, such as nausea, vomiting, headache, swelling, dysfunction, numbness or dysaesthesia ? Is there pain anywhere else? Note also the affects of the pain on activities, for example, mobility, sleep. Is the pain constant in intensity or does it fluctuate? Severe unrelenting pain can sometimes indicate deep-seated and infiltrative pathology (for example malignant otitis externa) Frequency and periodicity—has the patient had this before? Influences—does anything affect the pain e.g. trigger-sensitive points, movement, heat, or cold.

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Pain assessment can be particularly difficult in elderly patients, due to cognitive impairment and sensory-perceptual deficits. Underreporting of discomfort is common because the patient does not wish to complain. Pain may also mask other newly developing physical or cognitive disabilities. Chronic pain is often defined as any pain lasting more than 12 weeks. Whereas acute pain is a normal sensation that alerts us to possible injury, chronic pain is different. Chronic pain may arise from an initial injury, such as a neck sprain, or there may be an ongoing cause, such as illness. However, in many patients there may be no clear cause. Other problems, such as fatigue, sleep disturbance, decreased appetite, and mood changes, often accompany chronic pain. Chronic pain may limit a patients activities, which can lead to disability and despair. Bleeding (Non-traumatic) The assessment of a patient presenting with acute blood loss can be conveniently divided into three phases—(1) recognition that blood loss has occurred. This may be obvious, for example in epistaxis, or implied if there are unexplained, easily caused bruises or petechiae. Ongoing assessment of the site and extent of blood loss continues in parallel with resuscitation. (2) The second phase of the assessment is localising the source or sources of blood loss and their control. (3) estimation of the amount of blood loss to enable appropriate replacement. In trauma, some guides exist, but these cannot be fully relied on. Unfortunately visual estimates of blood loss are usually inaccurate. In some studies, the amount of blood estimated to have been lost by inspection alone has been half the actual measured loss. For example, clinicians typically underestimate postpartum blood loss by 30%-50%. Patients are equally unreliable in their assessments. As in obstetrics, haemorrhage in the head and neck may be concealed. The four “W’s”, of who, when, where and what are helpful in identifying causes of spontaneous blood loss. Who: who is the patient, sex, age, race and family history? When: when did the bleeding occur, i.e. onset of bleeding? Is it related to drug ingestion or any underlying disorder? Did it develop after surgery or trauma? Where : sites of bleeding, nose, gums, skin, muscle etc. What: description of the type of bleeding (fresh, or old). More specific questions should enquire about the following The type and sites of bleeding—whether it involves the skin or mucous membranes (i.e. petechiae, purpura, bruises), epistaxis, gingival bleeding, or other sites such as menorrhagia and/or haematuria which would suggest a platelet and/or vascular abnormality. Bleeding into deep tissues, joints and muscles suggests a coagulation factor defect. Is the bleeding spontaneous or does it follow trauma? Usually a history of easy bruising or bleeding excessively after injury suggests an inherited bleeding problem. The duration of bleeding and whether symptoms have been lifelong (since childhood) or of recent onset. Any childhood history of epistaxis, or abnormal bleeding episodes suggest inherited bleeding disorders. Any previous history of bleeding during or after surgery including tooth extractions, should also be noted.

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Current medication should be noted. This is important since a wide variety of drugs can affect haemostasis (drug induced thrombocytopenia). Any family history of abnormal bleeding in both parents, maternal grandparents, aunts, uncles, and siblings should be taken. This will guide the direction and extent of laboratory investigations. Inherited bleeding disorders are found in a significant number of women with menorrhagia. The key features of initial assessment are thus to assess the site and severity of bleeding, identify any systemic illness, local anatomical defect, or a haemostatic disorder (vascular defect, platelet abnormality or coagulation disorder). Investigations can then be directed accordingly. Lumps and Swellings Whilst the neck is a common site for lumps, these can occur throughout the entire head and neck region and consequently have a diverse range of pathologies. In most cases the nature of a lump is self evident from the examination. Nevertheless a proper history should be taken, as occasionally examination can be misleading. The assessment of neck lumps is described in detail in the chapter on the front of the neck. A general approach to other lumps includes the following questions. When did you first notice it? How did you notice it? Has it changed since you first noticed it? Has it ever completely disappeared since you noticed it? Any other lumps elsewhere? What do you think caused it? What are the symptoms related to the lump? Is there loss of body weight? Ask how long the lump has been present (days, months or years). Recent swellings, a few days old are usually inflammatory in nature, commonly abscesses or local infections. Swellings that have been present for months should be regarded as neoplastic. Thus, any unexplained neck lump which persists for more than six weeks should be referred urgently. Ask how the lump initially developed (spontaneously or following trauma, surgery and insect bite, or some other cause). Lumps that develop following trauma may be haematomas. Skin swellings that occur after insect bites or minor injuries may be infective. Dental abscesses can present as swellings anywhere on the face and upper neck. Determine how the lump has progressed, making note of any sudden increase in size. If the size has rapidly increased (over minutes or hours) this may suggest infection or bleeding into the lump. Less rapid increase in size indicates malignancy. Sarcomas tend to grow faster than carcinomas. If a swelling is getting smaller, this may be a resolving infection. Lumps which fluctuate in size over a short period of time, or when stooping, laying or bending, probably contain fluid (blood, or cystic fluid). The features of the lump itself may also indicate its nature. Infections and abscesses are painful; the pain is typically “throbbing” in nature. Neoplastic

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swellings are typically painless. If the swelling is discharging, this may be an abscess or sebaceous cyst. Ask the patient is what they think has caused the lump. They may have had an injury beforehand, or a similar lump previously removed. Some aspects of the past medical history may be helpful. Infective conditions are more common in diabetics. A past history of cancer, surgery or trauma may suggest metastasis, epidermal inclusion cyst or a keloid. Radiation to the neck increases the risk of some thyroid cancers. Associated symptoms should also be noted, particularly weight loss, night sweats, loss of appetite, pain, dysphagia/odynophagia, difficulty breathing, chronic cough, sore throat, change in the voice and otalgia. The patient’s personal history may also be relevant. The risk of malignancy increases with age. Asian patients with enlarged neck nodes have a higher incidence of metastatic nasopharyngeal cancer or tuberculosis. Occupational exposure to asbestos, nickel and wood dust and a history of smoking and heavy alcohol consumption are associated with an increased risk of certain head and neck cancers. Recent travel abroad may suggest unusual infections. Disturbances in Sensation or Weakness Neurological symptoms, notably altered sensation or facial weakness can have many causes and often indicate significant pathology. However in some patients the cause may never be found. This is discussed elsewhere in this book. Possible causes of numbness and weakness in the head and neck include Nerve irritation (cervical disc herniation, trauma, infections such as shingles, tumours, AV malformations etc). Metabolic conditions affecting calcium, potassium, sodium, vitamin B12 and other vitamin Toxins, such as lead, alcohol, tobacco, and from chemotherapy Medical conditions—Diabetes, migraine, multiple sclerosis, seizure, stroke The key points to establish from the history are exactly where the numbness is, its progression, any other associated neurological symptoms and possible predisposing causes. Weakness is less variable in distribution and tends to involve the face. However a weak shoulder or weak tongue can sometimes be secondary to accessory or hypoglossal palsies respectively. The history in the patient with “numbness” is especially important. Firstly, it is important to determine what the patient means by “numbness”—loss of sensitivity (anaesthesia or hypesthesia), or distorted sensations (paresthesia). True loss of sensitivity is more likely from damage to sensory pathways, whilst paraesthesia has a much wider range of causes. Dysesthesia (unpleasant sensation) and allodynia (painful stimuli) may result from damage to a nerve or an underlying painful condition. Note the onset and duration of any numbness and whether this has been continuous or intermittent. Nearly instantaneous symptoms (seconds or minutes), suggest ischaemia or trauma. Hours to days suggests infectious or toxic-metabolic. Days to weeks: Infectious, toxic-metabolic, or immune-mediated. Weeks to months: Neoplastic or degenerative

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Note also if there has been any change in colour or temperature of the affected skin. “Red flag” symptoms include (1) sudden onset over a few hours or days, (2) progressive dyspnoea, (3) confusion or loss of consciousness, (4) slurred speech, (5) change in vision, (6) loss of bladder or bowel control and limb weakness. Any history of cancer or risk factors for cancer should be enquired about. Risk factors for stroke, diabetes and thyroid disease are also relevant as are occupational and drug histories. The distribution of numbness should be carefully noted paying particular attention to whether it crosses the midline or not. Numbness over the face is a relatively common benign and sometimes psychological presentation, especially with perioral paraesthesia. Symptoms do not follow known anatomical nerve distributions and may appear at times of particular stress. Numbness that corresponds to a dermatome, or terminal nerve branch (mental nerve, infraorbital nerve, supraorbital nerve etc) is highly suggestive of nerve irritation or infiltration. Trauma, infections and tumours should be considered. If both the face and body are affected, but on opposite sides, this may suggest a brainstem lesion. If they are affected on the same side this suggests an upper brain stem, thalamic, or cortical lesion Associated neurologic symptoms (eg, paresis, dysesthesias, sphincter dysfunction such as incontinence or retention, dysphasia, visual loss, diplopia, dysphagia, cognitive decline) should be noted. The presence of a fever and/or rash may suggest infectious neuropathy and brain infection, Headache may indicate a tumour, stroke, or encephalopathy. Diabetes and some infections (HIV, syphilis, or Lyme disease) can predispose to neuropathy. The family history should include information about any familial neurologic disorders. Drug and social history should include use of all drugs and substances and occupational exposures to toxins. Assessing Infections These form a diverse group ranging in site, severity and causative organism. Questions must therefore be tailored accordingly. The various specific infections involving the head neck are discussed in their relevant chapters throughout this book. However in general terms questions are designed to (1) identify the cause, (2) determine its severity and (3) identify any predisposing or underlying conditions. How long an infection has been present and its site of origin will help to determine urgency and need for referral. Symptoms and signs of systemic upset may require urgent referral and admission, particularly with bacterial infections and infections involving critical sites (such as the airway, central nervous system and eyes) Rashes and Ulcers The assessment of rashes and ulcers is discussed elsewhere in this book (see chapters on the mouth and skin). Rashes are mostly confined to the skin, but can occur within the mouth where they are typically described as red or white “patches”. Technically these are not rashes, but the patient may present describing them as such. Ulcers are commonly seen in the mouth but can also involve the skin, eyes and

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other mucus membranes, including the nose and ears. Of note, all non-healing ulcers without an obvious cause should be regarded with suspicion of malignancy. With rashes a full dermatological history is usually required and is discussed in the chapter on the skin. Mouth and ocular ulcers are discussed in their relevant chapters. Key considerations include any obvious underlying cause (notably chronic irritation from dentures etc), the presence of associated vesicles or blisters and risk factors for malignancy (notably smoking and alcohol). Painless ulcers are more worrying than painful ulcers, but a malignant ulcer can be painful, particularly if it is invading deeper structures, involving nerves or become secondarily infected. Multiple ulcers are rarely malignant and tend to suggest non-neoplastic or systemic causes. Therefore further enquiries should be made regarding ocular/genital/GI and joint symptoms. The drug history is also important, particularly nicorandil—this can induced the formation of malignant looking ulceration not only within the mouth, but also in anal and penile mucosa. These usually resolved quite quickly following cessation of the drug. Trismus Trismus has a specific definition—strictly speaking, it is limitation in mouth opening secondary to muscle spasm. However the term is often used to describe any cause of limitation of mouth opening. These commonly include Infection; Trauma; Dental treatment; Temporomandibular joint disorders Tumours; Radiotherapy Congenital problems; Miscellaneous disorders (tetanus and myasthenia gravis). Whilst there are many causes of limitation in mouth opening, most causes of trismus are essentially traumatic, infective and neoplastic in nature. Trismus is therefore a potentially serious clinical sign. Important questions to consider in history include The onset, duration and progression of trismus. Painless limitation of opening from muscle spasm is unusual as the spasm is usually in response to irritation. Usually there is some degree of discomfort. If the patient has recently had dental treatment, limitation of mouth opening maybe secondary to a inferior alveolar nerve block and localised haematoma in the muscle. This can become infected. Associated symptoms should also be enquired about, notably symptoms of infection (toothache, wisdom teeth problems and a sore throat) and malignancy (including risk factors). In severe cases difficulty swallowing and breathing should be assessed urgently. If you present urgent referral is required.

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2.1.1.2 Other Important Information A thorough medical history is also important to highlight any co-morbidities that may complicate or contraindicate treatments, or surgery. Names and doses of medication should be documented as well as any over-the-counter or herbal remedies. Contrary to popular belief that all herbs and dietary supplements are safe, research has shown that some of these products carry the same dangers as prescribed medications. Interactions may occur between prescription drugs and over-the-counter compounds. Such interactions involve mainly inhibition or induction of cytochrome P450 enzymes and/or drug transporters. This can increase risks in patients taking drugs with a narrow therapeutic range (e.g. warfarin, cyclosporin and digoxin). Anticoagulants are also of particular relevance following trauma or if surgery is required, and chronic steroid usage is important when managing infections. If the patient states they have an allergy, it is important to determine whether this is a true allergy, or drug intolerance e.g. diarrhoea with penicillin. The type of allergic reaction should be noted. Determining whether it is a true allergy, or drug intolerance e.g. diarrhoea with penicillin is important in infections when antibiotics are required. Many patients use the term ‘allergy’ inappropriately. Following trauma, the patients tetanus status should also be questioned. Some diseases are considered familial. A family history can therefore reveal risk for example, with cerebrovascular disease or dementia. Start with an open question such as: ‘Are there any illnesses in the family?’, notably immediate family (parents and siblings). For each affected individual ask about their specific diagnosis and the age of onset and (if appropriate) age and cause of death. Some inherited conditions may affect anaesthesia and surgery, for example blood dyscrasias and acute porphyrias. Patients should be asked about a history of malignant hyperpyrexia, porphyria and, if of non-European decent, sickle cell disease. Certain inherited muscle diseases (such as central core disease and multiminicore disease) are associated with the risk of malignant hyperthermia. If the patient is severely unwell and it is not possible to carry out such a detailed history, focus on information regarding cardiac disease, hypertension, diabetes, asthma, allergies and ethnic origin. Social factors can also influence management and surgical outcomes. The family situation, living conditions, smoking, coffee and alcohol consumption are notably important. Social circumstances with regard to home support may affect the patient’s discharge. This is especially important for discharge planning in the elderly or head injured patients. The patient’s home circumstances may also affect discharge if there are safe-guarding issues from possible abuse or domestic violence. Patients may have a history of alcohol abuse or use of recreational drugs. They may therefore experience withdrawal symptoms as inpatients. Although not a substance of abuse, this may also include excessive coffee and tea (caffeine) intake, which may later manifest as severe headaches and minor irritability. The potential for drug withdrawal therefore needs to be taken into consideration during admission, anaesthetic assessment and post-operatively on the ward. With such patients, hospital alcohol and drug liaison services should be a part of the admission process

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and work-up for surgery, to pre-empt and prevent withdrawal. Patients may also be malnourished and this can effect wound healing. Any smoking history and use of betel quid should also be documented. It is important to sensitively ask about religious beliefs in certain circumstances. Some medications and implants contain human and animal derived content, and this may be in conflict with some religious codes, such as porcine (Muslim patients) or bovine (Hindu patients) products. It is therefore important to document a patient’s religion and beliefs and gain consent from patients when using products such as these. Jehovah’s witnesses will not accept blood transfusions. This has significant implications following trauma, or if urgent surgery is required. It is also a complex issue medico-legally, especially in the unconscious patient.

2.1.2 P  ractical Application of Information from the Medical, Drug and Social History Previous treatments and surgery can alert us to potential risk factors that may affect surgical planning and the suitability for general anaesthesia. In the very ill, or multiply injured patient this may not be possible and a more limited ‘AMPLE’ history is often taken in the early stages of assessment. This is discussed in the chapter on the injured patient. However more detailed assessment should be possible in most ambulant patients and the ‘walking wounded’. Either way, the focus is to identify those factors that may have an immediate impact on diagnosis and management, including general anaesthesia. Postoperative complications are also more likely in patients who are medically compromised, but many complications can be prevented or minimised with careful pre-operative assessment, monitoring and support during and after surgery. Although chronic medical conditions are unlikely to be significantly improved prior to emergency surgery, liaising closely and early with anaesthetic colleagues is advised to minimise risks. Important conditions and co-morbidities includes:

2.1.2.1 Age Care should be taken in assessing the very young and elderly patients following injury or if they require general anaesthesia and surgery. This applies to all aspects of trauma and surgery, not just in the head, neck and face. Both age groups have a reduced physiological reserve and are thus more susceptible to the adverse affects of injury and diseases, notably blood loss and infections. Patients are particularly at risk following blood loss which can quickly lead to physiological decompensation. Careful fluid replacement is necessary as fluid overload can also occur. Evidence suggests that these extremes of ages also recover more slowly from general anaesthesia. Elderly patients often have a number of co-morbidities and medications and these may need optimisation prior to surgery. Many elderly patients are on antiplatelet agents or anticoagulants, which can complicate the management of injuries, notably head injuries. Delayed presentation following head injury is common. In many hospitals, patients 65 or over undergoing major elective surgery require full

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blood count (FBC), biochemistry, chest X-ray and ECG as baseline investigations. At the other end of the age range, the very young pose considerable anatomical and physiological challenges and are notably susceptible to heat loss and fluid/electrolyte imbalances. Fluids must be administered with caution. For this reason, neonates and infants require highly specialised care and possibly transfer to a specialist unit. Many hospitals have a ‘cut off’ age or weight, below which a child should be transferred.

2.1.2.2 Pregnancy The possibility of pregnancy should be considered in all female patients of child bearing age (some recommended guidelines suggest between the ages of 10 and 50). Urine or a blood sample should be obtained as soon as possible for βhCG testing. Pre-operative assessments also include a check for possible pregnancy. Understandably this has the potential to be a very sensitive issue. If a patient is known to be pregnant and requires surgery, advice from the obstetric team should be requested as early as possible. The stage of pregnancy and condition of both the mother and foetus may affect the choice of local anaesthesia and medications. Even a simple manoeuvre such as laying the patient flat may result in fainting as the gravid uterus can reduce venous return to the heart (by compressing the inferior vena cava). In a multiply injured patient, the most effective treatment for the foetus is resuscitation of the mother. Care must also be taken with prescribing in pregnancy as a number of drugs are potentially teratogenic, can affect foetal maturation (closure of ductus arteriosus), or the onset of delivery. Although often a cause for concern, radiographs (including CTs) of the head and neck actually carry very little risk to the foetus. Radiation travels in a straight line and XRays beams are focused away from the pelvic region. Together with the use of protective lead aprons the risk in reality is minimal. Nevertheless, most hospitals will usually restrict XRays to those regarded as essential (eg assessment of potentially serious injuries and infections). 2.1.2.3 Ischaemic Heart Disease Pain from cardiac ischaemia can have a range of presentations. This can include chest, arm, shoulder pain, face or jaw pain. While sudden chest pain radiating into the arm is the ‘classic’ presentation, cardiac ischaemia can occasionally present with tooth, jaw, or facial pain as its sole symptom. This is due to convergent mechanisms and neural pathways in the trigeminal complex. Visceral cardiac afferent fibres join with the somatic afferent fibres of the upper extremities, chest and cervical region. The majority of the cardiac innervation passes through the first five thoracic roots, thus pain can be perceived in the chest and arms. However connections between cardiac afferents and the trigeminal nucleus also exist, and this can result in pain in the face and jaw. Other communications include the upper cervical roots C2 and C3. Cardiac ischaemia can thus present as anterior neck pain, a painful jaw, or masquerade as “toothache”. This is usually bilateral, the most frequent locations being the throat and jaw. When this occurs, misdiagnosis leads to unnecessary dental

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treatment or, more significantly, a delay in cardiac treatment and the patient subsequently experiencing acute myocardial infarction. Cardiac pain should therefore always be considered if an obvious cause for the pain cannot be found. The clue is in the history—typically the pain occurs during exertion and is relieved by rest or nitrate medication. Nicorandil is a popular vasodilator prescribed for angina. This can occasionally cause ulceration of the oral cavity (also reported in the anus and penis). The ulcer is often large and can be easily confused with malignancy. However, in contradistinction to malignant ulcers, they usually resolve quickly following cessation of the drug (within a few weeks). Nevertheless, biopsy or close follow up/referral is advised to ensure a tumour is not missed. Patients may also be taking prescribed anticoagulants, or anti platelet agents from their own doctor (see later). Peri-operative cardiac events following surgery are not uncommon and carry significant morbidity and mortality. Risk factors include smoking, diabetes, hypertension, a family history of ischaemic heart disease, obesity and hypercholesterolaemia. Assessment of a patient’s cardiac risk involves a relevant medical history, including a family history of cardiac disease and exercise tolerance, physical examination and an ECG. Congestive cardiac failure is considered to be the most significant risk factor for peri-operative cardiac events, and optimisation whenever possible may include close fluid monitoring and the use of inotropes or vasodilators. A history of a myocardial infarction within the previous 6 months is also associated with an increase chance of post-operative cardiac events (estimated at 20–50% risk of a further infarction and death). Local anaesthetics containing adrenaline should be avoided. Patients with stable angina require careful monitoring of fluid balance, electrolytes and analgesia. Patients with unstable angina or worsening angina are at high risk of peri-operative cardiac events and death and may require HDU/ITU admission before surgery for optimisation. It is now generally accepted that there is no clear evidence that antibiotic prophylaxis significantly reduces the risk of infective endocarditis in potentially susceptible patients. Current guidelines in the UK and elsewhere state that antibiotic prophylaxis for infective endocarditis need not be prescribed. Nevertheless, patients with a past history of rheumatic fever are predisposed to valvular heart disease, which can lead to heart failure or infective endocarditis.

2.1.2.4 Hypertension Hypertension is common and patients with severe hypertension have a higher chance of peri-operative myocardial infarction and dysrhythmias. Currently there are no definitive guidelines regarding delaying surgery to optimise blood pressure as there is no clear evidence that this reduces the overall cardiac risk. However, a Systolic BP >200 mmHg or diastolic >100 mmHg may require urgent admission and pre-operative treatment, especially if symptomatic. Hypertensive “crises” in which the BP is extremely high, can present with neurological symptoms, commonly headaches and drowsiness. Patients need urgent treatment as they are at risk of stroke.

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2.1.2.5 Pulmonary System Respiratory complications are a major cause of post-operative morbidity in surgical patients and occur more frequently than cardiac complications. Post-operative respiratory complications include atelectasis, pneumonia, pneumothorax, bronchitis and hypoxaemia. Any general anaesthetic longer than 2–3 h increases the chances of post-operative respiratory complications. Asthma and chronic obstructive airways disease (COAD) are common conditions and patients may need to be optimised prior to a general anaesthetic. Current guidelines for COAD suggest “targeted” oxygen therapy, with the aim of keeping oxygen saturations between 88–92%, without increasing the PaCO2 or worsening any acidosis. Patients often require regular nebulisers and chest physiotherapy. In severe or worsening COAD, the patient may require ITU or HDU admission for IV bronchodilators or non-invasive/invasive ventilation. Patients allergic to aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) can develop bronchospasm— aspirin-­induced asthma or NSAIDs-exacerbated respiratory disease. NSAIDS and aspirin should therefore be avoided in asthmatic patients. These drugs inhibit cyclooxygenase (COX) and reduce prostaglandin synthesis, hence their use in fever and relieving pain and inflammation. However, inhibition of the COX pathway also activates the lipoxygenase pathway, leading to increased leukotriene synthesis and increased risk of bronchospasm. Not all patients are sensitive to NSAIDs and so their use is not absolutely contraindicated. If prescribed, patients should be reassessed or advised about possible worsening of their asthma. Regular use of steroid inhalants on the oral mucosa can result in the development of acute pseudomembranous candidiasis (oral thrush). This is because of fungal overgrowth in an area of localised immunosuppression. Tuberculosis although uncommon, is still seen in developed countries. This is prevalent among the homeless and deprived inner city areas where poverty and over-crowding contribute to its persistence. It is also one of the differential diagnoses for neck lumps. 2.1.2.6 Diabetes When patients initially present, their blood glucose may be significantly deranged secondary to infection, trauma or reduced oral intake. Patients are often hyperglycaemic, which can result in diuresis, dehydration and ketoacidosis. Intravenous rehydration, with correction of sodium depletion (beware pseudohyponatraemia) and potassium supplementation is usually required together with an infusion of short acting soluble insulin. Regular monitoring of blood glucose, sodium, potassium and acid-base balance is important. When rehydration is underway and some correction of acidosis and hyperglycaemia has been achieved, any urgent surgery may then be carried out. Careful planning is required in all diabetic patients who require surgery and need to be fasted. The main source of nutrition to the brain is glucose, but persistently high levels predispose to infections, poor wound healing and ketoacidosis. The aim of management is therefore to minimise gross fluctuations in blood sugar by ensuring an adequate glucose, calorie and insulin intake. The best way to manage these patients is to enlist the advise/help of a diabetic specialist.

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Guidelines continue to evolve and what follows is a general overview of management. When managing patients it is always best to refer to local hospital protocols, rather than textbooks, which can quickly become out of date. Nevertheless, current guidelines at the time of writing suggest that prior to surgery a variable rate intravenous insulin infusion (VRIII) is commenced. In many hospitals this has now replaced the ambiguous term ‘sliding scale’- a continuous IV infusion of insulin (sometimes subcutaneously). Patients with a planned short starvation period (no more than one missed meal in total) should be managed by modification of their usual diabetes medication, avoiding a VRIII wherever possible. If a patient is expected to miss more than one meal a VRIII should be commenced. However, patients who are diet controlled or on once daily metformin, should only be started on VRIII if their BM>12 mmol/L on two consecutive occasions. Long acting insulin and long acting oral hypoglycaemics should be stopped the night before. Blood urea, electrolytes, creatinine and eGFR should also be checked to exclude renal disease. Effective glycaemic control in the post-operative period in diabetic patients significantly improves morbidity. It is also essential in the resolution of severe infections, notably cervico-facial abscesses. All patients admitted with a cervico-facial abscess should have a blood glucose recorded on admission. 1 in 70 people in the UK have undiagnosed Type II diabetes mellitus, with an abscess being the first manifestation. Hospital attendance is therefore an opportunity for diagnosis. A useful checklist for Pre-operative Management includes: 1 . Record blood sugar on admission and regular monitoring as inpatient 2. Maintain good pre-operative glycaemic control 3. Check renal function and potassium 4. Liaise with the diabetic team especially if poor glycaemic control 5. Stop long acting insulin/oral hypoglycaemics 12–24 pre-operatively 6. Whenever possible place patients first on the operating list 7. Sliding scale for IDDM patients 8. Post operatively sliding scale should be continued until normal oral intake Hypoglycaemia should always be excluded in confused, agitated or head injured (and non-head injured) patients, even if they appear to be intoxicated. Clinicians should also be aware of undiagnosed hypoglycaemia in sedated post operative patients that take longer to recover than anticipated.

2.1.2.7 Anti-coagulation Patients with injuries to the head and neck region who are taking anti-coagulants are at an increased of intracranial bleeding and are presumed to have a higher risk of bleeding into easily distensible or friable tissues (notably the floor of mouth, the neck, orbit and globe). This can result in space occupying haematoma, which in addition to local pressure effects, are at risk of secondary infection if not drained. Head injured patients taking anticoagulants often require admission for observation. In the elderly, repeat CT scan maybe prudent. If a patient has suffered extensive

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facial injuries, or comminuted fractures of the mandible, the soft tissues of the face, mouth and throat can occasionally swell significantly and may even require airway protection. With widespread injuries control of haemorrhage can often be difficult as bleeding occurs from multiple sites which can be difficult to tamponade. Similarly, trauma to the airway whether direct or indirect places the anticoagulated patient at risk of losing their away. This may be seen following blunt trauma to the front of the neck (look for fractures of the hyoid bone). All penetrating injuries, especially penetrating injuries to the neck require careful assessment. Some specialists recommend avoidance of nerve blocks in case the artery adjacent to the nerve truck is punctured by the needle. This can theoretically result in significant haemorrhage. Common anti-coagulants include: Warfarin  This inhibits the production of Vitamin K dependent clotting factors II, VII, IX and X. Patients taking warfarin should have their INR checked as soon as possible. Most patients are usually aware of their target INR, and may have their anti-coagulation booklets with them, with their target range and recent INR values recorded. For atrial fibrillation the target range is usually 2–3 and 3–4 for patients with metallic heart valves. An INR up to four is generally considered safe to proceed with many surgical procedures, but this depends on the surgical site and duration of the procedure. Lower values may be necessary when operating around the spinal cord, brain or eye. At other sites local measures such as the suturing of wounds and carboxymethylcellulose packs should be routinely used to ensure adequate haemostasis. In those patients who require major emergency surgery, vitamin K or prothrombin complex concentrate can be used to reverse the coagulopathic state. However, re-establishment of effective coagulation afterwards is then very difficult. Whenever possible, advice from the haematology team should be sought. For major elective surgery, warfarin may be stopped 3 days prior to surgery and bridged with LMWH. Following surgery, Warfarin can then be restarted and LMWH continued until the INR is within its desired range. Clopidogrel  This is a commonly prescribed drug which irreversibly blocks ADP receptor on platelets preventing aggregation. Regular use of clopidogrel even at low doses (75 mg) can produce 40–50% inhibition of ADP-induced platelet aggregations. Platelet function gradually recovers 3–5 days after it is stopped and the guidelines are to stop 7–10 days prior to elective surgery. Unfortunately, there are no useful tests to monitor the drug’s activity and there are no specific reversal agents. In the acute setting therefore, a platelet transfusion may need to be administered (ideally after discussion with the haematology team). Aspirin  This irreversibly inhibits the thromboxane A2 stage of the COX pathway responsible for degranulation of platelets. If patients are taking aspirin for secondary cardiovascular prevention they should continue taking it throughout the

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p­ eri-­operative period. Evidence suggests that for the majority of surgical procedures the risk of peri-operative bleeding while continuing aspirin is minimal, and withdrawing it may be associated with increased thromboembolic complications. However, there are some procedures that aspirin may be stopped for. These include patients undergoing spinal surgery, extensive head and neck surgery, as well as intracranial, middle ear and posterior ocular procedures. Dabigatran, Rivaroxaban, Apixaban and Edoxaban are newer anticoagulants which may be prescribed instead of Warfarin for people with non-valvular atrial fibrillation. Unlike Warfarin these new oral anticoagulants do not require regular international normalised ratio measurements. Dabigatran  This is a thrombin inhibitor that is now more commonly used for atrial fibrillation, prevention in stroke and DVT. Current guidance for stopping dabigatran is related to creatinine clearance: >50 ml/min—stop 1–2 days prior to procedure 75 years). Low dose rivaroxaban may also be used in combination with aspirin or clopidogrel following acute coronary syndrome. Rivaroxaban does not require routine anticoagulant monitoring and INR values are unreliable in monitoring it. It has a similar half life as dabigatran, but is not as dependent on renal clearance. Similar guidelines are followed as for stopping dabigatran. Apixaban  Apixaban is also a highly selective and reversible direct inhibitor of free and clot bound factor Xa. It has no direct effect on platelet aggregation, but its inhibitory effect on factor Xa indirectly decreases clot formation induced by thrombin. It has a similar half life as dabigatran, but is not as dependent on renal clearance. Similar guidelines are followed as for stopping dabigatran. Edoxaban  Edoxaban is the most recent oral Xa inhibitor to be licenced in the UK. 50% is excreted renally and it’s half life is 10–14 h. The guidelines recommend that it should be discontinued at least 24 h prior to surgery.

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Unfortunately, there are no specific reversal agents for Dabigatran, Rivaroxaban or Apixaban or Edoxaban. Routine monitoring of these agents is not undertaken to assess the efficacy of treatment. This brings specific problems in all patients requiring surgery and therefore close liaison with a haematologist or pharmacist is recommended whenever possible.

2.1.2.8 Bleeding Disorders Clotting disorders (haemophilia, platelet disorders etc) predispose patients to the same risks and complications as those patients taking anticoagulant medication. Leukaemia patients are at increased risk of developing severe infections and can sometimes develop infiltrating masses in the orbit. Sickle cell disease is a group of blood disorders which are usually inherited. The most common variant is sickle cell anaemia. This results in an abnormality in haemoglobin, which in itself results the red blood cell becoming sickle-shaped and less mechanically flexible under low oxygen conditions. Thus, patients with this disease require care during administration of general anaesthesia. Thrombosis in the inferior alveolar artery is uncommon but has been reported and can present acutely as severe pain in the mandible. This can result in significant diagnostic confusion. The undiagnosed presence of blood dyscrasias and other causes of delayed clotting should be considered whenever there is prolonged bleeding following apparent minor injury or minor surgery. The commoner problems include haemophilia A, haemophilia B, Von Wille- brand’s disease, liver disease and patients on anticoagulants. Patients with known or suspected bleeding problems need to be fully assessed by an appropriate specialist. With appropriate prophylactic measures, (e.g. local measures, tranexamic acid, DDAVP, factor replacement or adjustment/reversal of medication) urgent surgery can usually be safely carried out. Opinions vary considerably as to what is an “acceptable” INR for surgery, although this depends on the site (superficial v deep/within a cavity or superficial). 2.1.2.9 Deep vein Thrombosis (DVT) Deep vein thrombosis (DVT) occurs when a blood clot (thrombus) forms in one or more of the deep veins, usually in the legs. Risk Factors include 1. Previous history of DVT or pulmonary embolism 2. Age 3. Obesity 4. Extensive trauma 5. Congestive heart failure 6. Malignancy 7. Diabetes Mellitus 8. Prolonged immobilisation 9. Length and type of operation 10. Type of anaesthetic 11. Oral contraceptive 12. Female sex

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1 3. Pregnancy and puerperium 14. Varicose veins 15. Some drugs Deep vein thrombosis (DVT) is generally uncommon following isolated head and neck problems or their management. However, it can occur following prolonged immobilisation. Head injured patients are particularly at risk, made worse so by the reluctance to provide prophylactic anticoagulation. DVTs can be especially difficult to diagnose in the unconscious or unresponsive patient and those with spinal-cord injuries, who cannot report any discomfort. Clinical diagnosis is often difficult and it is well known that a significant number of patients can have very few symptoms despite the presence of a large thrombus. Symptoms if present, include pain, swelling, redness, or warmth of the affected limb. Whilst this is usually the lower limb, the upper limb can also develop DVTs, particularly if it has been damaged or there has been injury to the brachial plexus or subclavian vessels. Malignancy, pacemakers and central lines can also predispose to upper limb DVTs. Paget-Schroetter syndrome (PSS) is a condition sometimes seen in young athletes who use their arm for sports like baseball, swimming, or tennis. Repetitive motion is believed to irritate the veins in the neck and shoulder, which can result in thrombus formation. “Silent” thrombi can occur in both the upper and lower limbs and are a particular concern as the thrombus remained undetected until it detaches and sudden fatal pulmonary embolism occurs. For this reason all patients admitted to hospital are now assessed for risk factors and if identified appropriate preventive measures taken. Today a D-dimer test may be used in the diagnosis of DVT, which is then confirmed by ultrasound of the suspected veins. Many hospitals have their own protocols which should be followed whenever possible. Currently, prevention is directed towards elimination of stasis in the veins, or reducing the tendency to clot in the patient. Measures include: • Routine DVT assessment in all surgical admissions • Full length anti-embolism (TED) stockings • Intermittent pneumatic calf compression—Intraoperative calf compression is recommended during prolonged surgery. • Low voltage electrical calf stimulation • Early mobilisation—most “head and neck” patients should be able to mobilise soon after treatment • Aspirin • Heparin/low molecular weight dextrans, warfarin. Heparin is currently available as “fractionated heparin” and low molecular weight (LMWH). These are reported to be more effective but are more expensive. Low dose subcutaneous heparin significantly reduces the incidence of DVT. Low molecular weight heparins may be given once daily, which is more convenient for both the staff and the patient. More recently new oral anticoagulants (such as apixaban, dabigatran and rivaroxaban, Edoxaban) have become available. These also carry risks of haemorrhage but with these drugs there is no specific reversal agent available.

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2.1.2.10 Steroids in Surgery and “Steroid Cover” Patients on long-term, or high dose steroids are at risk of adrenocortical suppression if these are suddenly reduced. Furthermore, following surgery, trauma or infections, patients are unable to mount a normal “stress response”. This is a very complex process which includes (1) the maintenance of appropriate fluid, electrolyte, osmolar and glucose balance, (2) metabolic homoeostasis including catabolic and anabolic processes, (3) the ability to fight infection and (4) wound healing. In the early stages, lack of a stress response can result in metabolic disturbances and occasionally circulatory collapse, similar to that seen in Addison’s disease. Steroid supplementation may therefore be required in the peri-operative period, commencing in the emergency department or on induction of anaesthesia and then continued post-­ operatively (with or without a reducing dose). Usually a doubling of their normal dose or conversion to IV is sufficient to ensure reliable administration. However, it is always best to follow local protocol. Patients who have been on long-term steroids should never have them discontinued abruptly, but rather they should be reduced gradually over a few days. For most nil by mouth (NBM) patients one regime might be Major surgery—Hydrocortisone 100 mg IM or IV with the premedication and then qds for three days after which return to previous medication. Minor surgery—prepare as for major surgery, except that hydrocortisone is given for 24 h only. However protocols may vary, depending on the anticipated stress, its duration and the doses of steroids already prescribed. Chronic steroid use also predisposes the patient to the risks of infection, poor wound healing, osteoporosis and a diabetic potential, each with their own attendant problems. Patients who are on chronic glucocorticoid therapy produce less subcutaneous collagen and other extracellular proteins by fibroblasts. This lack of collagen and other proteins results in a tendency of patients with Cushing’s syndrome to bleed and to bruise easily. There may also be defects in the walls of small blood vessels, resulting in defective constriction during bleeding. Wound healing and scar formation are also impaired. Stable patients with chronic inflammatory disease who are receiving low-dose glucocorticoid therapy can usually withstand dental care and other minor procedures. 2.1.2.11 Stress Ulceration Stress ulceration, sometimes referred to as ‘stress-related mucosal damage’ (SRMD) is the term used to describe a spectrum of acute, erosive, inflammatory changes to the upper gastrointestinal tract which occur in association with critical illness or extreme physiologic stress. Findings may vary from asymptomatic superficial lesions found incidentally during endoscopy, to occult gastrointestinal bleeding resulting in anaemia, to overt and significant gastrointestinal bleeding. Suggested mechanisms underlying SRMD include reduced gastric blood flow, mucosal ischaemia and reperfusion injury, all of which occur frequently in critically ill patients. Stress ulceration may also be referred to as stress-related erosive syndrome, or stress -related gastritis. It is classically seen following extensive burns, major trauma and multiorgan failure. Patients undergoing surgery for head and neck cancer may

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similarly be “stressed” post-operatively, particularly if their recovery is complicated. Gastrointestinal ulceration can result in fatal haemorrhage. Guidelines recommend the use of stress ulcer prophylaxis in patients with severe sepsis who have known risk factors, one of which is need for mechanical ventilation > 48 h. Several drugs/techniques have been described to reduce the incidence of SRMD, including sucralfate, histamine-2 receptor blockers (H2RBs) and proton pump inhibitors (PPIs). Sucralfate acts by adhering to epithelial cells, thereby forming a cytoprotective barrier at the ulcer site. This protects the gastric mucosa from the effects of acid and pepsin. However sucralfate can impair the absorption of enteral feeds and oral medication. H2RBs competitively inhibit histamine binding to gastric parietal cells, which reduces acid production. PPIs inactivate the H+/K+ ATPase enzyme in the parietal cell, inhibiting the secretion of H+ ions and thereby increasing the pH of the gastric contents. There is also some evidence to suggest that early feeding may reduce the likelihood of stress ulceration.

2.1.2.12 Hepatitis and HIV These pose risks of cross infection. Hepatitis can affect liver function, therefore it is important to check the patient’s liver function tests (LFTs) and clotting status. Infection with human immunodeficiency virus (HIV) is now a well recognised chronic disease that results in severe immunosuppression and acquired immunodeficiency syndrome (AIDS). This with a variety of oral and pharyngeal lesions including ulceration, gingivitis, hairy leukoplakia and tumours (notably Kaposi’s sarcoma). These are discussed in the chapters on the mouth and throat. With improved treatments patients with HIV now live for many years, with partial restoration of their immunocompetence. It is therefore important to be aware of some of these oral presentations of HIV. For many patients, these may be the first clinically detectable features. 2.1.2.13 Epilepsy Epilepsy has no identifiable cause in about half of sufferers, however fitting can occur following head injuries, especially in children. It can also run in families, where it is believed that specific genes can make a person more sensitive to environmental conditions that trigger fits. Other causes and associations include (1) CNS conditions (brain tumours or strokes—a leading cause of epilepsy in adults over 35) (2) Infections (meningitis, AIDS and viral encephalitis) (3) prenatal injury (infection, poor nutrition or oxygen deficiencies) (4) developmental disorders (autism and neurofibromatosis). Fitting after head trauma makes assessment difficult. Status epilepticus is a state of continuous seizure activity lasting more than five minutes or frequent recurrent seizures without regaining full consciousness in between. Following head injury this can aggravate secondary brain injuries (as a result of wide variations in blood pressure and hypoxia). Consequently patients with status epilepticus have an increased risk of permanent brain damage and death. Intubation, ventilation and transfer to ICU/ITU is required if seizures cannot be controlled. Sudden unexpected

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death in epilepsy (SUDEP) has also being reported to occur in a small number of patients. The cause for this is unknown, but some research has suggested it may occur secondary to heart or respiratory complications. Patients who suffer from frequent tonic-clonic seizures or whose seizures cannot be controlled by medications may be at higher risk of SUDEP.  About 1% of people with epilepsy die of SUDEP.

2.1.2.14 Previous Injuries The presence of old facial fractures, particularly the nose, zygoma or mandible, can make diagnosis of a new injury difficult, especially if the patient denies any previous trauma. Unfortunately some patients will use a more recent injury as an excuse to attempt to get total correction of the pre-existing deformity. This is not possible with fractures of the facial bones, which would then require more complex procedures. Previous injuries to the eye may result in long-standing or permanent reduction in vision acuity. This needs to be differentiated from an acute change. Acute chest and head injuries preclude the use of Entonox (a mixture of nitrous oxide and oxygen). This is particularly helpful in providing temporary pain relief (such as when reducing dislocations of the mandible or shoulder). The inhaled gas can rapidly expand, resulting in pressure effects within the body cavity. 2.1.2.15 Tetanus Status This should be considered in all wounds, whether they be lacerations, bites, abrasions or other penetrating wounds. Tetanus is a potentially life threatening disease, caused by a neurotoxin produced by Clostridium tetani. This organism is ubiquitous in the environment. Tetanus is acquired following inoculation of a wound with tetanus spores. In the absence of immunity, even comparatively minor wounds can become fatal. In many countries, tetanus has become increasingly rare due to the success of the national immunisation programs. Wounds can be classified as tetanus prone or non-tetanus prone. Tetanus prone wounds, including those classed as high risk are a comparatively common presentation to Accident and Emergency departments. Tetanus prone winds should be considered when (1) wounds or burns that require surgical intervention are more than 6 h old, (2) wounds or burns that show a significant degree of devitalised tissue, (3) puncture wounds and animal bites, particularly when there has been contact with soil or manure, (4) wounds containing foreign bodies, (5) open fractures, (6) wounds or burns in patients with systemic sepsis. Depending on the patient’s immunisation history and status a booster, full course, or immunoglobulin may be required. 2.1.2.16 Drug Interactions Many commonly prescribed drugs used in the emergency setting (notably antibiotics, NSAIDs, opiates and sedatives) have the potential to interact with already prescribed medication that the patient may already be taking. Often overlooked, these drugs also include over-the-counter herbal medicines (such as St John’s Wort, Ginkgo Biloba, Echinacea and even high doses of Garlic). Systems involved in drug metabolism, such as the cytochrome P450 have been reported to be particularly

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vulnerable to modulation by some of the active constituents of herbs resulting in important clinical and toxicological consequences. Cytochrome P450 enzymes, form a superfamily of enzymes found mainly in the liver, which are involved in the metabolism of a wide range of drugs. Consequently many herbal products often carry the same risks as prescribed pharmacologically active compounds.

2.1.2.17 Bisphophonates Bisphosphonates are a commonly prescribed drug in patients with osteoporosis, hypercalcaemia and metastatic bone disease (commonly breast, prostate and multiple myeloma). By reducing bone turnover they offer a protective effect against bone loss. The drug binds to the minerals in bone and inhibit osteoclastic function. Osteoclastic mediated bone resorption and bone turnover are therefore severely disrupted. Because the drug is not metabolised, high concentrations will remain in the bone for a long period of time. Unfortunately these can affect bone healing in the jaws following trauma or dental extractions—Bisphosphonate-Related Osteonecrosis of the Jaw (BRONJ). The term MRONJ (medication related osteonecrosis of the jaw) is now increasingly being used. This commonly affects the mandible. Appearances can be quite dramatic, raising concerns of malignancy. Management is difficult and is described in the chapter on the lower jaw. Bisphosphonates are often used to treat bone pain, and bone metastases in advanced 2.1.2.18 Alcohol Intake Acute alcohol intoxication is a common problem in many emergency departments. In some studies up to thirty percent of emergency department admissions are related to an alcohol misuse. When consumed to excess it can result in agitation, drowsiness and even unconsciousness. Loss of protective airway reflexes and vomiting can occur which may be disastrous in the supine and unattended patient. For this reason restrained patients (on a spine board) should always be supervised until immobilisation is released. In the head injured patient alcohol intoxication also makes assessment difficult, notably their Glasgow Coma Scale. It is important not assume that a drowsy inebriated patient is that way simply due to too much alcohol. Chronic alcoholics are often malnourished, self-neglected and at an increased risk of bleeding (notably chronic subdural haematoma) and infections. A number of brief screening instruments have been developed for identifying at risk patients. Alcohol withdrawal symptoms can be extremely dangerous. These include hand tremors (‘the shakes’), sweating, tachycardia, nausea, anxiety, confusion, irritability, visual hallucinations and in severe cases seizures. Alcohol withdrawal syndrome (AWS) is the name for the symptoms that occur when a heavy drinker suddenly stops or significantly reduces their alcohol intake. In patients where it is anticipated they will not be able to drink alcohol for a significant period (usually during admission) it is important to consider the effects of acute withdrawal and seek help in providing appropriate treatment. This may include high potency vitamins B and C (Pabrinex), benzodiazepines and close observation for withdrawal symptoms. Wernicke– Korsakoff syndrome (WKS) is the combined presence of Wernicke encephalopathy (WE) and alcoholic Korsakoff syndrome. This is due to thiamine (vitamin B1)

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deficiency which can occur secondary to chronic alcohol abuse. Wernicke encephalopathy is characterised by the presence of ophthalmoplegia, confusion and ataxia

2.1.2.19 Home Circumstances These are important for a number of reasons. If a patient with a head injury is well enough to go home there must be a responsible adult who can look after the patient for the next 24 h. If no one is available then the patient may need to be admitted. Similarly, if the patient lives a long way from the hospital in a remote area and bringing them back to hospital quickly would be difficult, it may be better to admit them. Elderly patients and children who attend on a regular basis should have enquiries about their home circumstances. It is important not to overlook domestic abuse. In the UK, if there are concerns regarding home circumstances professional support may be possible, from social services. 2.1.2.20 Occupational History Traditionally, the link between occupation and disease has been difficult to establish. Nevertheless it is known that people in certain occupations may be exposed to hazards which can produce respiratory disease. These include cancers (e.g. asbestos workers), infections (e.g. bird breeders), asthma (e.g. painters), pneumoconiosis (e.g. coal miners), allergic alveolitis (e.g. farmers). Animal husbandry workers in warm humid areas can become infested with nasal myiasis. The occupational history can be used on four levels: (1) basic (a knowledge of the patient’s current occupation and implications of their present illness), (2) diagnostic (to investigate an association with the present illness), (3) screening and (4) comprehensive (to investigate complex problems in depth, usually in consultation with other occupational health professionals). Any history of travel abroad, for either work or pleasure is important to note. This can occasionally result in unusual infections which in the head and neck can sometimes present as cervical lymphadenopathy. Patients requiring emergency surgery are among the sickest patients in the emergency department. They are often elderly, frail and have significant co-morbidity, placing them at risk of death or serious complication. Every effort must therefore be made to make the patient as fit as possible prior to surgery. Metabolic disturbances and clotting abnormalities are particularly important. Whilst some injuries and diseases affecting the head and neck can be considered as true emergencies, fortunately these are relatively uncommon. Examples include airway obstruction, airway threatening injuries or abscess, massive ongoing haemorrhage, large intracranial haematoma and retrobulbar haemorrhage. These require immediate intervention. Management of the majority of remaining conditions described in this book can usually be safely delayed for at least a few hours so that the patient’s general status can be optimised. This will significantly improve their outcomes. In these patients it Is important to get senior and experienced advice at an early stage. If surgery is anticipated it is important to involve the anaesthetic team as soon as possible. In some patients, if very unwell, a brief period of intensive management in a high dependency unit (HDU) may help to improve their physiological status and lower the risks of general anaesthesia. Assessment needs to be methodical, not only of the cardiovascular and respiratory systems, but also risk

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factors, taking into account the disease or injury, the treatment required and the likely recovery period. With this in mind, a useful checklist may help. This includes 1. The patient's age 2. Smoking history, past and present. Smoking is well known to be an important risk factor in both anaesthesia and wound healing 3. Any history of alcohol abuse. This may result in problems in the post-operative period and patience may be malnourished. 4. Ischaemic heart disease 5. Respiratory disease (notably COAD and asthma) 6. The presence of diabetes. Not only does this increase the risk of ischaemic heart disease, but the development of microangiopathy predisposes the patient to poor wound healing. Poorly controlled diabetes can also adversely affect the function of white blood cells. Thus diabetics are at risk of complications following surgery, especially if they also smoke. 7. Malnutrition and nutritional support. Malnourished patients are also at risk of poor wound healing and infection 8. Blood disorders (haemophilia, sickle cell anaemia). This can affect the patient in various ways, notably bleeding tendencies, the presence of anaemia, and risks of infection. 9. A history of trauma. Injuries may be overlooked, particularly in the multiplet injured patient. This is discussed further in the chapter on the injured patient. 10. Fluid balance. Patients may present with significant dehydration, especially if they are disease or injury involves the mouth and throat or neck. They may have been unable to drink fluids for several days, prior to attendance. 11. Deep vein thrombosis (DVT) and prophylaxis. Many factors can contribute to the risk of developing a DVT. These need to be carefully assessed for and prophylaxis given if indicated. Most hospitals will have DVT risk assessment charts and protocols. They should be followed. 12. Assess the need for antibiotics. These will often be required in infections and injuries. Patients with open wounds should also be assessed regarding the need for tetanus immunisation. 13. Assess the need for steroid cover 14. Provision of pain relief 15. Stress ulcer prophylaxis. This is often overlooked, but sick patients attending the emergency department, who require intensive management and surgery are particularly at risk of developing stress ulcers. 16. Early involvement of appropriate specialists.

2.2

Examining the Head, Neck, Face and Teeth

More detailed descriptions of site-specific examination (including the neck and eyes) are presented throughout the relevant chapters of this book. Here, an overview is presented. Following trauma, examination proceeds differently, initially

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following an “ABC” approach. This aims to quickly exclude life and sight-threatening injuries, but can also be applied to life-threatening diseases as well, such impending airway-threatening conditions, severe epistaxis and agitated/drowsy patients. Life-­threatening head and neck injuries are discussed in the chapter on the injured patient. Once the patient is stable a thorough history can be then obtained. With less urgent conditions a more methodical approach may be necessary, tailored according to the specific symptoms and suspected pathology. This is also detailed in the relevant chapters, but here a simple overview will be presented. Head and neck examination of a patient can be divided into: • General examination • Extra-oral examination • Intra-oral examination As with examination of the body elsewhere, inspection, palpation and auscultation of the head and neck is the cornerstone of clinical assessment. This should be undertaken in a methodical manner. During examination any anomalies or lesions are noted and recorded. A simple checklist includes 1. General demeanour—does the patient look well/unwell, calm/agitated or irritable, orientated/confused? 2. Discolouration and dehydration—does the patient look anaemic/cyanotic/ jaundiced/‘ashen’ ? Dehydration may have occurred following many diseases or injuries to the head, neck face or teeth (stoke, facial fractures, abscesses, malignancy etc), which affect the ability to swallow. Dehydration can be assessed by gently pinching a fold of skin on the forearm, holding for a few moments, and then releasing. With dehydration, the skin turgor is reduced and the skin takes longer to return to its original shape. Caution is required in the elderly, as their skin is usually less elastic. 3. Does the patient look well nourished or malnourished? 4. Vital signs/GCS/Vision 5. Hair and facial skin 6. External eyes (lids, conjunctiva, iris) 7. Ear (external, tympanic membrane) 8. Oral cavity and oropharynx 9. Dental and periodontal tissues 10. Temporomandibular joint 11. Facial muscles 12. Nasal cavity and nasopharynx (endoscopy) Larynx (endoscopy) 13. Major salivary glands 14. Anterior neck (thyroid) 15. Lateral neck 16. Posterior neck 17. Supraclavicular notch 18. Cranial nerve function

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These are tailored according to the suspected pathology and discussed in more detail in the relevant chapters throughout this book.

2.2.1 External Examination of the Head and Face If injuries or unusual pathology are present photographs should be taken if at all possible. If not, it is important to document the external signs carefully and diagrammatically. Wounds should not be repeatedly exposed and examined by different clinicians and inquisitive students if it is clear that surgical repair is necessary. Following alleged assaults, this initial information will be important later if the police are involved. Like any other part of the body, a systematic approach is required for examination. Initial inspection should be undertaken at a distance, from the end of the trolley or bed. Remove all dressings if it is safe to do so and any obscuring clothing, such as caps, scarf, spectacles etc. Remember the back of the head (scalp) should be carefully examined—injuries here can be easily missed, especially in a patient who is lying supine. 1. Look for any obvious asymmetry, swelling, discolouration, lacerations, missing tissue and any gross neurological deficits 2. Assess all cranial nerves, bearing in mind that swelling may impair movement and sensation. 3. Standing from behind the patient and looking from from above (‘birds eye’ view) is useful when assessing the projection of the zygomas, checking for any deviation of the nasal bones and in assessing for proptosis of the eyes. 4. Palpate for bony injury and crepitus systematically. The precise sequence is not important, but often it is best to start from the top and work your way down; • • • • • • • • • • •

Scalp Forehead Supraorbital ridges Zygomatico-frontal sutures Infraorbital ridges Nasal bridge Maxilla Zygomatic body and arch Temporomandibular joints Mandible—the range of movement and occlusion Mandibular ramus, body and lower border

2.2.1.1 Specific Sites Forehead The frontal bone may be fractured following a blow to the forehead. There may be a haematoma, crepitus, a depression or step deformity along the supraorbital rim.

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Assess for subcutaneous emphysema and altered sensation of the supraorbital or supratrochlear nerves—these are useful signs of a fracture. A dural tear should be considered if the posterior wall of the frontal sinus is fractured. If present, look for CSF rhinorrhoea and seek neurosurgical advice. Non traumatic swelling and/or pain may suggest frontal sinusitis or rarely a tumour. Eyes This is discussed in detail in the chapter on the eye. Make sure to assess the visual acuity, presence of proptosis, eye movements, pupils and telecanthus. Foreign bodies can be assessed by everting the eyelids. Referral to ophthalmology may be necessary if any ocular trauma is suspected. Nose Inspect the nose for any obvious deviation. Assess interpupillary distance and telecanthus for nasoethmoid fractures. Look for lacerations, septal haematoma and CSF rhinorrhea. Any obstruction to airflow needs careful evaluation. Many causes exist. Nasoethmoid Fractures These extend from the nose to involve the ethmoid bones and often cause damage to the lacrimal apparatus, canthus, nasofrontal duct and dura. Assess for telecanthus, CSF leaks and an upturned nose. Consider these as head injuries in the first instance, until reviewed by an appropriate specialist. Ears Assess for lacerations, change in hearing, tympanic membrane and CSF otorrhea. Temporomandibular Joints and Mandible Look for bruising and swelling. Palpate for mobility and crepitus and for dislocations. Le Fort Fractures Place one hand on the anterior maxillary teeth and the other on the nasal bridge: Le Fort I—only the maxilla will move Le Fort II—the nasal bridge will also move Le Fort III—patients may have step deformity at the infraorbital margin and a mobile midface. They may also have bilateral ecchymosis and bilateral subconjunctival haemorrhage.

2.2.2 Examination of the Mouth, Teeth and Throat The oral cavity extends from the lips to the anterior pillar of the tonsil. It contains the hard palate, tooth bearing areas (plus the teeth) and the anterior two thirds of the tongue. The oropharynx extends from the anterior pillar to the posterior pharyngeal

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wall, containing the soft palate, anterior and posterior tonsillar pillars, tonsillar fossa, lateral and posterior walls and the base of tongue, down to epiglottis. The nasopharynx is the area superior to the hard palate, deep to the nose, containing the adenoids, communicating with the nasal cavity anteriorly. The eustacian tube tube open into it laterally. Examination requires • A good light source is essential for an intra-oral examination • A tongue depressor or dental mirror is required to fully assess the tongue, floor of mouth, buccal mucosa • Ask the patient to remove any dentures as these may obscure any pathology or injuries • At the same time, assess mouth opening and record a baseline measurement if there is trismus

2.2.2.1 Tongue Several characteristics of the tongue should be noted: 1. Colour—a normal tongue is pink-red on its dorsal and ventral surfaces. The ventral surface may have visible veins, imparting a ‘blueish’ hue. 2. Texture—the dorsal surface is rough due to its papillae. There should be no hairs, or ulceration. Minor fissuring can be normal. 3. Size—the tongue should fit comfortably within the mouth, with its tip against lower incisors. Inspect for lacerations and swelling, any signs of weakness, tingling and note any difficulty swallowing. Note the colour, coating and texture of the tongue. This can give an indication of fungal infections, anaemia, B12 deficiency. Ask the patient to touch the tip of the tongue to the roof of their mouth and inspect the ventral surface. Then ask the patient to protrude the tongue straight out inspecting for deviation, colour, texture, and masses. With gloved hands, hold the tongue with gauze in one hand while palpating the tongue between the thumb and index finger of the other, noting any masses and areas of tenderness. At the same time inspect the floor of the mouth. A sublingual haematoma may indicate a fractured mandible. The floor of the mouth may also be raised in infection and place the patient at a risk airway compromise. The floor of mouth and side of the tongue are also a common sites for oral malignancy, due to pooling of carcinogens. Examination of the oral cavity is not completed until the tissues have been carefully palpated. This ‘golden rule’ applies to both ends of the GI tract and not just the lower (as is commonly taught in medical schools).

2.2.2.2 Teeth Apart from size, the major difference in children’s mouths is related to the dentition. The primary (deciduous) dentition erupts into the oral cavity between the age of 6 months and 2 years. This comprises two incisors, one canine, and two molars in each quadrant, giving a total of 20 teeth. Most of the adult (or secondary) dentition

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erupts between the ages of 6 to 12, replacing the primary teeth. Any combination of primary and secondary teeth is called the mixed dentition. This is found between these ages. Primary incisors and canines are replaced by their permanent successors, but the deciduous molars are succeeded by the adult premolars with additional permanent molars behind them. Following injury, look for obvious dentoalveolar injuries—fractured or avulsed teeth must be accounted for and a chest xray and soft tissue view of the neck may be required if aspiration of teeth is suspected. Check the occlusion—ask the patient if their ‘bite’ feels normal. Teeth can be charted as below, assigning a number to each tooth in the dental ‘arch’: Permanent (“Adult”) Teeth Right 87654321 87654321 Total 32

Left 12345678 12345678

1 + 2 = Incisors 3 = canine 4 + 5 = premolars 6, 7 + 8 = molars Deciduous (“Baby”) Teeth Right edcba edcba Total 20

Left abcde abcde

a + b = Incisors c = canine d + e = molars

2.2.2.3 Gingivae (Gums) and Oral Mucosa Inspect for lacerations, swellings and discolouration of the mucosa overlying the alveolar bone, hard and soft palate and tonsils. Any swelling or collection near to a tooth should be investigated to assess whether it is associated with that tooth. Further back, inspect each tonsil and posterior pharyngeal wall. 2.2.2.4 Pharynx & Larynx Movements of the palate can be assessed by asking the patient to say “aahhh”. The integrity of the hypoglossal nerve can then be assessed by asking the patient to stick their tongue out. A patient’s voice can provide important information. A weak voice with a weak cough may suggest a vocal cord palsy. A hoarse voice may also be due to a vocal cord lesion. Any unilateral, asymmetrically enlarged tonsil should be

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viewed with suspicion. This may be secondary to a neoplasm, or a normal sized tonsil displaced towards the midline by a parapharyngeal mass. Flexible nasoendoscopy may be used to examine the upper aerodigestive tract and is relatively straightforward to perform in an outpatient setting using topical anaesthetic. In experienced hands, the scope can be manoeuvred to visualise the middle and inferior turbinates, nasal septum, osteomeatal complex, Eustacian tubes, adenoids, soft palate tongue base, vallecula, laryngeal inlet and piriform fossa.

2.2.2.5 Salivary Glands/Salivary Flow There are three paired salivary glands. The parotid glands are the largest and produce serous saliva. Their associated ducts (Stensen duct) open adjacent to the upper first molar tooth intraorally. The submandibular and sublingual glands discharge through a papilla in either side of the lingual frenulum on the floor of the mouth. Lumps/stones can be noted by bimanual palpation of the glands. Assess the oral mucosa for the extent of lubrication. The patency of the duct, gland function, and any infections can be further assessed by massaging the glands in an attempt to express saliva or pus.

2.2.3 Examination of the Front of the Neck The structures of the neck that can be seen or palpated during examination include (a) The mastoid process (b) Parotid gland (c) Submandibular gland (d) The sternocleidomastoid muscle (e) The hyoid bone (f) Thyroid prominence (g) Cricoid cartilage (h) Cricothyroid membrane (i) Thyroid gland (j) Trachea (k) Clavicular heads

2.2.3.1 Examination of Neck Lumps and Cervical Lymph Nodes Most of the lymphatic drainage from the aero digestive tract is through the deep cervical chain, which runs alongside the internal jugular vein, deep to the sternocleidomastoid muscle. Lymph nodes are generally palpable when they are greater than 1 cm in size. Palpable nodes in children are likely to be infective or reactive, however cervical lymph nodes in patients over 50 may be secondary to metastatic spread of an aerodigestive SCC and should therefore be treated with suspicion. A history of systemic symptoms should be taken. General malaise, rigors and fevers may suggest an infective cause, whereas loss of appetite, dysphagia and weight loss may suggest a malignancy. There are around 400 or so lymph nodes in the head and neck. These are often grouped into

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1. Pre-auricular 2. Posterior auricular 3. Occipital 4. Submental 5. Submandibular 6. Facial 7. Parotid 8. Upper Jugular 9. Jugulodigastric 10. Retropharyngeal 11. Superficial Cervical (Anterior and posterior) 12. Deep Lateral Cervical and 13. Supraclavicular. A full history should be taken with regard to the duration, change in size, pain, systemic symptoms such as fevers, weight loss and compressive symptoms. Any risk factors such as smoking and betel quid should also be noted. During examination of any lump note in particular Location: midline/anterior triangle/posterior triangle Size—width/height/depth Shape—Is it well defined? Unilocular/Multilocular Consistency—smooth/firm/rubbery/irregular/nodular Overlying Skin—tethered to skin/erythema/ulceration/punctum Pulsatility—suggests a vascular origin such as aneurysm or carotid body tumour Temperature: increased temperature may suggest an inflammatory or infective cause Fluctuance: if fluctuant may suggest it is fluid filled, such as a cyst Trans-illumination: suggests a mass is fluid filled, such a cystic hygroma Auscultation: bruits may suggest a carotid aneurysm Chronic inflammatory masses are often non-tender and rubbery and either mobile or matted. Congenital masses are usually soft, mobile and non-tender unless infected. Vascular masses may be pulsatile or have a bruit. Malignant masses may be hard, non- tender and fixed. Examination of the neck in a non-trauma context is discussed in the chapter on the front of the neck. This should be undertaken carefully, including all the major structures and lymph nodes. It is worth noting that several normal structures are palpable and can be easily confused with pathology. Notably 1. the transverse process of C1 (palpable between the mastoid process and the angle of the mandible) 2. the hyoid bone 3. the carotid bulb (particularly if it is atherosclerotic) and 4. the submandibular salivary glands. Examination should include any lumps themselves, the rest of the neck, the skin of the head and neck and sometimes the chest, ears, oral cavity, nasal cavity,

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nasopharynx, oropharynx, hypopharynx and the larynx. In cases where pathology is suspected in an area that is difficult to examine without specialised equipment, (the nasopharynx, hypopharynx and larynx), patients may need to be referred.

2.2.3.2 Examination of the Thyroid Gland Keep in mind that the thyroid may be congenitally located as high as in the sublingual area or as low as in a substernal position. The thyroid may be palpated from either behind the patient using bimanual palpation or from each side, using one hand with the other offering counter support. Inspection • • • •

Any skin changes—such as erythema Assess for scars—previous thyroidectomy Swellings/masses—the normal thyroid gland should not be visible Ask patient to swallow some water—masses embedded in the thyroid gland will move with swallowing • Ask patient out their tongue—thyroglossal cyst moves on tongue protrusion and swallowing. • Lymph nodes will move very little Palpation—This is best done from behind the patient—the gland usually lies over the 2nd, 3rd & 4th tracheal cartilages. Palpate the thyroid isthmus using the pads of your fingers. Place your fingertips on each side of the Adam’s apple as an initial landmark. work downwards, slightly below the cricoid cartilage where the thyroid isthmus crosses the midline. Palpate each lobe of the thyroid in turn by moving your fingers out laterally from the isthmus. Also palpate whilst asking the patient to swallow to feel for symmetrical elevation of the thyroid lobes. A normal thyroid feels smooth and “fleshy” as would a normal muscle. Increased firmness suggests inflammation or a neoplastic process, asymmetrical elevation may suggest a unilateral thyroid mass. Note the following when palpating the thyroid gland: Size—it is enlarged?—Goitre Consistency—smooth or nodular—eg. Multinodular goiter Symmetry—are the lobes similar in size? Masses—any distinct masses evident? Note the position, tenderness, consistency, mobility, shape. Single or multiple nodule may indicate a toxic nodule of hyperthyroidism, hypersecreting adenomata or autoimmune thyroiditis. Nodules palpated within the parenchyma of the gland usually indicate cysts (both benign or malignant), benign adenomas, local malignant carcinoma, or secondary metastases. The cervical lymph nodes should also be palpated as part of the thyroid examination at this point. Local lymphadenopathy may be from metastatic spread of a thyroid malignancy.

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Percussion: over the sternum—retrosternal dullness can indicate a large thyroid mass extending posterior to the manubrium Auscultation: for thyroid bruits over each lobe. A bruit suggests increased vascularity which can occur in Grave’s disease

2.3

 adiographic Investigations Commonly Used in Head R and Neck Conditions

This is discussed further in the relevant chapters of this book. By way of summary; Assessment of thyroid mass

2.3.1 Plain Films Whilst these are a useful screening tool for many conditions, in other situations it is better to progress straight to more complex modalities, notably CT. This is commonly seen in high energy or complex injuries and infections, where CT more precisely defines the injury or presence of pus.

2.3.1.1 Orthopantogram (OPG) and Posterior Anterior (PA) Mandible The OPG, also known as a panoramic film, is essentially two slightly distorted right and left lateral views placed together. This captures the maxilla, mandible, teeth and surrounding structures and tissues. An OPG can be used to assess: • Dentoalveolar fractures • Dental pathology—infections, impacted teeth • Mandible fractures—should be used with a Posterior Anterior (PA) mandible view for accurate assessment • Cysts in the maxilla and mandibles • Tumours • Temporomandibular joints—dislocations and pathology

2.3.1.2 Occipitomental Views (OM Views) OM views delineate the upper and middle thirds of the face, including the frontal sinuses and maxillary sinuses, orbital rims, zygomatic arches. These views are taken with the film placed on the patient’s chin (mentum) and the radiographic source at the occiput. The name thus indicates the direction of the Xray beam. Depending on the angulation of the beam and the extension of the neck, these views can be 0°, 15°, 30° and 45°. Whilst OMs are commonly used to assess facial trauma, their use is not possible in patients who are unable to extend their neck (ie suspected or actual cervical spinal injuries). The OM 30 view (30° caudal angulation) is the most common view. These can be difficult to interpret, but a systematic approach can help. Consider the following

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1. Is the maxillary sinus clear? Opacification or fluid levels in the sinus are suggestive of a fracture or sinusitis. 2. The sinus and orbital outlines should be approximately symmetrical and there should be no steps in the bony outline 3. Look at the orbital outlines. The height to width ratios should be similar 4. Look for the ‘baby elephant’s trunk’—this is formed by the zygomatic arch and body. 5. The coronoid processes should be symmetric and equidistant from the maxillae and lower borders of the zygomatic arch See text for description (Fig. 2.1) McGrigor-Campbell Lines. Line 1 (red): Look for • Widening of the zygomatico-frontal sutures • Fractures of the superior rims of the orbits • Opacification/air-fluid level in the frontal sinuses Line 2 (orange): Look for • Fractures of zygomatic arch—superior aspect • Fractures of the inferior orbital rims • Fractures of the nasoethmoid bones and medial orbits • Soft tissue shadow of the superior maxillary antrum Line 3 (blue): Look for • Fractures of the zygomatic arch—inferior aspect • Fractures of the lateral maxillary antrum • Opacification/air-fluid level in the maxillary sinuses • Fractures of the alveolar ridge

1 2

2 3

3

Fig. 2.1  Assessment of OM views in trauma—‘McGrigor-Campbell Lines’

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Blowout fractures may occasionally be identified with this view. Weakening of the orbital floor results in herniation of the adjacent orbital contents into the maxillary sinus. This may be seen as a ‘teardrop’ sign in the roof of the maxillary sinus. A ‘fluid level’ in the maxillary sinus (blood) increases the reliability of this finding. Although this sign is not completely reliable, it is often taken as an indication of further detailed imaging (CT). Air in the soft tissues indicates a fracture involving a sinus (usually the maxillary or ethmoid). This is also useful sign, often indicating more detailed assessment with CT.

2.3.1.3 Lateral Soft Tissue Cervical Views Lateral soft tissue views of the neck may show retained foreign bodies in the vallecula at the base of the tongue, pyriform fossa or hypopharynx. In the absence of a foreign body they may show sequelae of trauma with soft tissue gas or a collection in the retropharyngeal region. In some infections, gas within the soft tissues is a worrying sign. This indicates extension of the infection and the presence of gas forming organisms. Anatomically these can rapidly spread downward into the mediastinum. 2.3.1.4 Cervical Spine Imaging This is a complicated topic and is discussed in detail in the chapter on the back of the neck. Clinical findings are particularly important in the context of determining the need for imaging. The Canadian C Spine Rules, stratifies patients into high and low risk and is used in alert, clinically stable patients. The rule is based on three high-risk criteria and five low risk criteria, and the ability of patients to rotate their necks. Other protocols (such as NEXUS) also exist. However, when imaging is being considered it is always best to seek senior help or follow the protocols in your own hospital. 2.3.1.5 Computed Tomography (CT) Both CT and MRI are powerful imaging tools. Their related strengths and weaknesses frequently make them complementary for many suspected pathologies although often only one of the two needs to be used to image most patients. CT is a digital technique that provides ‘slices’ of different thickness, sometimes as thin as 1 mm or less. However CT scans produce high doses of radiation and therefore they should only be conducted if they will alter the management of the patient. If CT does not include the abdomen or pelvis there is negligible risk to the foetus. Nevertheless current practice in many hospitals is to avoid CT during pregnancy if at all possible. The main advantage of CT scanning over other imaging techniques is the third dimension in visualisation that it provides. CT eliminates superimposition of images away from the area of interest. It is particularly useful in trauma patients, especially those who are immobilised. CT images can be viewed in axial, coronal and sagittal views and can reformatted for 3-dimensional views. These scans are essential to fully assess complex facial fractures and plan surgical management. They are commonly undertaken in unconsciousness patients who have suspected, or actual head injuries as well as for suspected frontal sinus and naso-ethmoid fractures, orbital/orbital floor fractures, Le

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Fort fractures, pan facial fractures. Complex mandibular fractures my also need CT imaging, such as condyle fractures to assess the angulation/displacement of the fractures segment, or comminuted fractures. Common indications for head and neck CT in a trauma context include 1. Assessment of the cervical spine 2. Any patient with a suspected head injury 3. Fractures of the frontal sinus 4. Nasoethmoid fractures 5. Middle third fractures 6. Suspected orbital floor/orbital wall fractures 7. Displaced mandibular condyle injuries 8. Pan facial fractures 9. Gunshot wounds 10. Penetrating wounds CT is better than MRI at showing cortical and trabecular bone detail. Aside from trauma, CT of the head and neck has many other uses, such as the evaluation of spreading infection, intracranial bleeding, tumours (bony and soft tissue) and the location of foreign bodies. CT remains the primary examination in the paranasal sinuses, oral cavity, and larynx. With the addition of contrast (CT angiography) the blood supply to a region of interest can also be evaluated. This is useful following penetrating injuries and in suspected AV malformations. CT angiography is a quick and accurate investigation for evaluating penetrating neck trauma to exclude injury to major vessels. It has been shown to be reliable modality in diagnosing and excluding injuries requiring intervention and thus significantly decrease non-therapeutic surgical neck explorations. Calcification on a CT may provide useful clues as to the underlying pathology. For example 1. Drusen (tiny yellow or white accumulations of extracellular material that build in the retina) can mimic papilloedema clinically but can be seen on CT 2. Calcification may occur in association with vasculopathy and choroidal vascular malformations. 3. Calcifications may be seen in association with metabolic bone disease and some arthropathies (such as synovial chondromatosis in the TMJ) and may help narrow the differential diagnosis

2.3.1.6 Cone Beam CT (CBCT) CBCT is a variant type of CT and has become more popular recently in the diagnosis and treatment planning of head and neck surgery. It is based on volumetric tomography. CBCT differs from conventional CT as a cone shaped beam is used with two dimensional detectors, as opposed to a fan shaped beam on one dimensional detectors. The main advantage of cone beam CT is that there is overall less radiation that conventional CT scanning. However, this does result in less definition of images. In facial trauma CBCT is useful with mandibular and orbital fractures.

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2.3.1.7 Magnetic Resonance Imaging (MRI) The two main advantages of this type of imaging is that it does not use ionising radiation and has excellent soft tissue contrast resolution. MRI also has the advantage over CT in being able to detect vascular malformations and hypervascularity in general. MRI is also very good at demonstrating bony structures such as the skull base and mandible when they contain fatty marrow and their cortical surfaces are surrounded by tissue or fluid. MRI is probably more sensitive than CT in demonstrating pathology spreading primarily within the marrow-containing spaces of bones. The main disadvantage is that scan acquisition make take a long time and patients with claustrophobia may not tolerate confinement. MRI is also contraindicated in patients for a variety of well-known reasons (patients with metallic foreign bodies, cerebral aneurysm clips, cochlear implants and pacemakers). Thus emergency MRI is not often available. Instead, CT is commonly undertaken. Critically ill patients can be studied with MRI.  However the logistics of patient monitoring and maintenance of vital functions are more difficult in MRI scanners and at times impossible in very unstable patients. MRI images are either T1 or T2 weighted, and highlight different structures: T1 Weighted

T2 Weighted

Bright signal intensity • Blood (subacute) • Fat

• Water—inflammation, oedema, tumour • Blood (subacute)

Low signal intensity Fibrous tissue—tendons, disc Muscle, calcium air Water—inflammation, oedema, tumour Fat, fibrous tissue

However MRI interpretation requires expertise. Although all imaging systems can generate artefacts, those found in MRI are more numerous and are more likely to be interpreted as pathologic by inexperienced observers. Movement artefacts are far more of a problem in MRI compared with CT. This is mostly a problem extracranially and below the hard palate. However ocular movements can degrade orbital and globe images. Mandibular motion can obscure detail in the oropharynx and oral cavity. Swallowing and laboured breathing degrade laryngeal and hypopharyngeal studies. Airway problems, with partial obstruction, frequent swallowing and coughing can often result in inadequate MRI studies in patients with oropharyngeal, laryngeal and hypopharyngeal cancer, whereas with CT this is less likely. However in the nasopharynx and parapharyngeal space, movement is normally not a problem and so MRI is often the preferred choice of imaging because of its better contrast resolution and depiction of major vessels and nerves. Both

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blood and cerebrospinal fluid flow can also degrade images, hide pathology and result in misinterpretation.

2.3.1.8 Sialography This maybe useful for duct injuries, salivary obstruction and glandular disease. This is rarely undertaken acutely. 2.3.1.9 Ultrasound US is a noninvasive imaging tool of great value when used appropriately in the head and neck region. This is an extremely useful triage tool especially in the children. It is often of greatest use in the head and neck in the assessment of carotid occlusive disease and in thyroid gland, where it has now supplanted much of radionuclide imaging. However it often cannot evaluate the entire extent of pathology or its potential associated findings and therefore is often supplemented with further imaging, such as CT.  Doppler colour flow techniques are very helpful for identifying normal and abnormal vascular structures, vascular masses, and the relationship of neck masses to the normal vessels. Cysts will be seen as homogenous sonolucent lesions with a strong back wall and good sound transmission. Debris and fluid–fluid levels may be seen. Colour flow assessment may help exclude a solid tumour. These usually have a variable and non-specific internal texture depending on their composition and stromal elements and whether calcification or cystic change is present. Vascular malformations are of highly variable depending on the vessels of origin, flow in the vascular space and any feeding and draining vessels. Colour flow analysis is important in evaluation. Abnormal lymph nodes will be enlarged compared to normal and have increased and/or altered colour flow patterns. Focal or extensive cystic necrosis may be present. Care is required in probe positioning—acoustic shadowing from bone and cartilage (larynx and mandible) and air (trachea) can obscure structures of interest. 2.3.1.10 Nuclear Medicine This has important niche roles to play in head and neck disease. Currently, the main application is positron emission tomography (PET) using fluorine-18 2- fluoro-­2-­ deoxy-D-glucose (FDG) is predominantly for tumour imaging. FDG-PET with or without computed tomography (CT) now has an increasing role in the imaging of head and neck cancer. The majority of squamous cell carcinoma primary sites greater than 1 ml can be detected with FDG-PET and PET can now stage lymph node in head and neck cancer with a sensitivity of around 95%. Other radionuclide studies may be used to more assess the likelihood of infection or to monitor treatment effects in selected cases. Unfortunately inflammatory conditions can result in false-positive FDG-PET studies in patients with cancer.

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Chronic Pain

The aetiology of chronic facial pain and headache is varied. It may have its origins as a result of an injury, vascular, infective, neoplastic or some other pathology, or as a result of previous treatments. Establishing its cause is therefore an important part of both diagnosis and management. Not all patients should be managed by analgesia alone. Perception of pain serves as an important and crucial protective response to noxious or harmful stimuli. Any inability to feel pain places the insensate area at risk of injury. Sensory loss is therefore just as important as hyperalgesia and pain. Neuropathic pain can arise as a result of pathological processes within the somatosensory system. This occurs in the absence of normal physiological stimulation of the peripheral nerves. Here, an overview is presented. More detailed accounts of causes, investigations and their treatments are discussed in the relevant chapters throughout this book. Chronic pain is a common problem. For example, following trauma it is reported to occur in up to 50% of patients. For many this can result in significant quality of life issues, with patients describing pain levels as moderate to severe in nature. In addition to the pain, patients may also experience (1) minor sensory deficit with hyperalgesia and (2) hypoaesthesia, with a pronounced deficit in sensitivity to thermal and painful stimuli. Causes of chronic facial pain and headache are multifactorial and can be considered as inflammatory, musculoskeletal, neuropathic and vascular (Table 2.1). The underlying mechanisms (and therefore treatments) are thus, by necessity varied. Diagnostic criteria for headaches and orofacial pain can be found in the classifications published by both the International Association for the Study of Pain (IASP) and in the International Headache Classification. Over 200 causes of headache exist. Ocular, sinus, dental and neurological pathology can also result in chronic pain. Precise diagnosis is therefore essential. Unfortunately treatments have varying success rates. Table 2.1  Causes of chronic facial pain Dentoalveolar

Inflammatory

Musculoskeletal Neuropathic

Vascular

Types Crown fracture with pulp exposure Root fracture Tooth avulsion, Luxation, Subluxation Alveolar fracture Caries Osteomyelitis Sinusitis Foreign bodies Plate infection Fractures of facial skeleton Temporomandibular joint dysfunction (TMJD) Tympanic plate fracture Trigeminal neuralgias TMJ and somatisation Craniofacial pain syndromes Haematoma Intraosseous aneurysm

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2.4.1 Assessing Chronic Pain Precise diagnosis requires a systematic approach. Regarding the nature of the pain itself, this should include (1) timing of pain (onset, duration and periodicity), (2) location and any radiation, (3) quality and severity, (4) relieving and exacerbating factors. Any known or suspected cause should also be noted (injury, recent dental treatment). Any other history of pain (headaches, migraines, chronic pain syndromes, fibromyalgia) is also important. Medication abuse, notably a history of drug dependency (opiods, opiates, barbituates) is common in chronic pain suffers. This includes alternative medical treatments that the person may have obtained or sought. The family history is also important. It has been suggested that in some patients there may be susceptibility to psychiatric illness, pain syndromes (which can have shared genetic factors) and previous family experiences all of which can influence the patient’s perception of pain. Alcohol abuse and smoking should also be noted. Studies have shown an increased dependence on alcohol and smoking in the presence of chronic pain. There is also an increased risk of chronic pain syndromes with smoking and alcohol via shared CNS (corticostriatal) pathways. When taking a history in which chronic pain is the main feature, it is important to qualify what the patient means by pain—it is a subjective sensation. Over the years many attempts have been made to quantify pain for record keeping, to enable pre-treatment baselines, to assess the success of treatments and to help further research. Standardised questionnaires in both assessment and monitoring of treatment have been devised and validated, such as the Brief Pain Inventory, Beck Depression Inventory, Hospital Anxiety and Depression Scale, McGill Pain Questionnaire and the Oral Impacts on Daily Performance Scale. However a simple visual analogue scale is often the easiest to use and allows patient compliance. Any associated headache must be carefully considered. This is discussed in greater detail in the chapter on the head. Headache is a symptom, not a diagnosis. It can arise from of a number of different conditions involving not only the head, but also the neck, face, eyes and beyond. The brain itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by the pain-sensitive structures around the brain. These include the periosteum of the skull, the muscles, nerves, arteries and veins, subcutaneous tissues, eyes, ears, sinuses and mucous membranes. Although most cases of headache are benign and self-limiting, a few are due to serious pathology, which may prove fatal or result in significant disability without prompt diagnosis and treatment. The key is awareness of important causes and eliminate them from the differential diagnosis clinically and by investigation. Worrying features of a headache include (1) Associated fever (2) Sudden onset/Late onset (in over 50s) (3) Nausea or vomiting (4) Stiff neck/Photophobia (5) Changes in personality or mental function/Neurological deficit (6) Change in usual pattern of headache/present on waking (7) Pain that increases with coughing or movement (8) Headaches that get steadily worse (9) Associated painful red eye/pain and tenderness near the temples and (10) Headaches in patients with cancer or impaired immune systems

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Examination of the head and neck in a patient with pain, includes an extraoral assessment looking for swelling, scarring, facial paralysis and/or paraesthesia, tenderness with trigger points, musculoskeletal facial deformity and functional deficits. In all “pain” patients it is important also to examine the cranial nerves and the external ear canal. Intraoral examination should include a comprehensive dental examination, looking for obvious dental pathology (decay, mobile teeth, cracked teeth, exposed pulp, infection, exposed hardware), soft tissue problems (scarring, infection) and the occlusion. Investigations are usually radiological. These look for signs of neurologic pathology within the Central Nervous System (CNS), cranial nerves, peripheral nervous system, evidence of infection and signs of hard tissue pathology, such as infections, tumours, fractures and dental pathology. More recently there have been advances in using Pressure-Specified Sensory Devices in the evaluation of the sensibility of the face. These have previously been used in extremity evaluation. This device can confirm there is a problem with a nerve, and can demonstrate whether it is regenerating or degenerating as well as the degree of axonal loss. If there is loss of axonal function then the underlying cause must be treated (for example decompression at the infraorbital foramen to relieve V2, or the removal of a neuroma).

2.4.2 Common Causes of Facial Pain Following Trauma The many causes of pain in the head and neck are discussed throughout this book. Pain following trauma is a particularly difficult subgroup to diagnose and manage. A brief overview is therefore given here

2.4.2.1 Dentoalveolar One of the commonest causes of inflammation and chronic pain following facial trauma is dental trauma resulting in pulp exposure and eventually periapical infection. The pain may not always be confined to the tooth. It is therefore important to assess the dentition closely to elucidate any crown or root fractures, loss of restorations, pulp exposure, the presence of a sinus, tooth luxation, subluxation and avulsion. Most crown injuries will be detected clinically with probing or air blasting. Root fractures are most frequently seen on imaging. However some root fractures may not be seen unless pressure is placed on the tooth, so as to open the fracture and illicit pain. This can be achieved by getting the patient to bite down on a tongue depressor until it becomes painful. In addition to an OPG, more focussed intraoral imaging is usually necessary to visualise subtle injuries to the teeth. It is also important to check for pulp vitality. Treatment planning may also require other dental specialists, such as endodontists, and restorative experts. In the initial phases, prior to any definite management (restorations, endodontics or exodontia), analgesics will be required. Antibiotics have a role only when there is active infection present or there is a high risk of infection.

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2.4.2.2 Inflammatory Conditions Although not the commonest cause of chronic pain following the management of facial trauma, inflammation and inflammatory conditions have been shown to have an important and often treatable role. Meningitis (reported in up to 30%) and mucocoeles associated with frontal sinus fractures are well known complications which cause severe headache, sometimes with other worrying neurological symptoms (nausea, vomiting, confusion). These symptoms can initially be subtle and therefore often require investigation. In cases where there is a history of frontal sinus fracture, investigations should include routine blood tests. These may demonstrate a raised white cell count (lymphocytosis) and raised inflammatory markers (CRP/ESR), as well as abnormal urea and electrolytes (notably hyponatraemia). Further tests include CT or MRI of the brain (which may demonstrate the inflamed meninges or a mucocoele) and a lumber puncture. Diagnosis following this last test is confirmed with a high polymorphonucleocytes, low glucose (50 mg/dl) and organisms on culture and polymerase chain reaction (PCR). Initial treatment commonly includes broad spectrum antibiotics, as the common organisms are staphylococci, pseudomonas or other gram negative bacteria. Once the inflammation and infection are controlled surgical drainage of the frontal sinus may then be required. Chronic sinusitis is another important inflammatory cause of pain following facial trauma. Midface fractures can result in changes in the normal sinus outflow system and studies comparing this cohort with patients diagnosed with rhinosinusitis show similar scores in quality of life surveys. Symptoms include facial pain or a pressure sensation, runny nose, the ‘need to blow nose’ and a lack of a good nights sleep. Radiological investigations should include an OPT and a CT scan of the sinuses. Cone beam CT (CBCT) if available will give the same detail with less radiation. A blood profile will look for raised inflammatory markers. Management of this condition is both medical and surgical, including a “sinus regime” (decongestants, anti-inflammatories, nasal saline washouts, corticosteroids, antibiotics) and minimally invasive endoscopic procedures (Functional Endoscopic Sinus Surgery, FESS) which is both diagnostic and therapeutic. Antrostomies can drain the congested sinus. Retained foreign bodies following surgical management (IMF screws, plates and screws, wires) or from the trauma itself (glass, metal, grit, vegetation within the wound) can cause long term discomfort from an inflammatory response and often result in infection. Unfortunately some investigations can be misleading. Inflammatory markers may not always be raised and organic material (vegetation) may not be visualised on CT or MRI. A good history is therefore required, especially consideration of the mechanism of injury and management. Management includes both medical (anti-inflammatories, antibiotics) and surgical removal of any foreign bodies found on examination or imaging. Chronic deep-seated pain of long duration associated with symptoms of swelling, general malaise and flu-like symptoms may be a sign of osteomyelitis. This can occur following trauma where the skin or mucosa has been breached allowing the ingress of bacteria. It is usually seen in immunocompromised patients and smokers.

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Clinically the site affected will be tender, erythematous, swollen, with a decreased and painful range of motion. There may be an obvious discharge of pus, but this is not always seen in the chronic phase. Investigations include full blood count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), random and fasting glucose levels and blood cultures. Useful imaging includes plain films (demonstrating mottled bone), CT, MRI and SPECT (Single Photon Emission Computed Tomography) bone scans which demonstrate an increased uptake of the radio-­ isotope marker (hot spots). Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) scans have also been reported to be useful in the diagnosis and followup of patients with osteomyelitis of the mandible. Following comprehensive ­ workup, a bone biopsy should be obtained to determine the exact causative bacteria allowing targeted antibiotic therapy. Surgery also allows any causative agent such as a foreign body or sequestrum to be removed and allows washouts of the area affected. Commonly a 6 week course of Clindamycin is appropriate as this can infiltrate the bone (care with elderly patients as Clindamycin can result in Clostrium Difficile infection).

2.4.2.3 Musculoskeletal Causes Mandible fractures—Chronic bone pain is not typically associated with fractures of the mandible and their subsequent management, although dysaesthesia of the inferior alveolar or mental nerve is a common problem and often associated with litigation. Some studies have suggested that the perception of pain can be associated with the type of treatment or fixation used. For example some evidence suggests that in the management of subcondylar fractures chronic pain is experienced more frequently in the closed reduction and intermaxillary fixation group. This is by far an inconclusive study, but it does highlight the complexity of the nature of perceived pain. The precise mechanisms for this are still unknown. Temporomandibular Pain dysfunction is a common cause of pain following facial trauma. However the complex relationship between this and psychological factors such as stress, sleep disturbance and other aspects of illness behaviour make this a difficult condition to treat. The role of psychological factors in oro-facial pain is well recognised and in some epidemiologic studies patients with elevated somatisation scores and self-rated family stress were more likely to report facial pain. Studies have also shown that around one-third of chronic pain suffers give a history of facial trauma and it has been shown that this factor is independently associated with chronic pain, even after adjusting for psychological factors. Patients with chronic facial pain may benefit from multi-disciplinary management involving non-­ invasive techniques like cognitive behavioural therapy (CBT) for which a large quantity of evidence now exists. Zygomatic Complex—Commonly, chronic pain or dysaesthesia arises following injury to the infraorbital nerve within this area. This nerve, the second sensory branch of the trigeminal nerve (V2), exits onto the soft tissue of the face through the Infraorbital foramen. Following midface, zygomatic or orbital injuries, whether soft tissue or bony, or in combination, the infraorbital nerve is usually injured to some extent. This typically results in a period of paraesthesia which usually resolves.

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However in some cases it can persist and evolve into chronic discomfort. The precise cause of the nerve injury in these fractures remains unclear and may involve traction, pressure, ischaemia, inflammation or some other physical damage. It is also felt that unlike the more common hypoalgesic response, the hyperalgesic response may be associated with inflammation. Localised impacts are more likely to result in chronic neuropathic pain states, suggesting a possible connection between the nature of trauma and persistent infraorbital nerve injury. Pain or dysaesthesia in the distribution of the infraorbital nerve which has objective evidence of nerve compression may benefit from surgical decompression and division of scar tissue. Frontal Sinus Fractures—Although these constitute 5–12% of all facial fractures their management remains controversial. Frequent headaches and complaints of continuing pain are the most common complications experienced by patients (70% incidence in some studies). Often it is difficult to identify the aetiology of the discomfort and in many cases the pain results from the initial trauma and not from its treatment. In all cases it is important to carefully consider mucolcele and infective causes, including osteomyelitis of the frontal bone. Supraorbital neuralgia can be caused by blunt force trauma directly over the nerve. Its progression is usually favourable and it often responds well to symptomatic treatment, most commonly amitriptyline and gabapentin. The indications for surgical decompression are similar to the infraorbital nerve

2.4.2.4 Vascular Conditions These are very rare causes of chronic pain following facial trauma, but occasional cases have been reported in which painful intraosseous haemangiomas have developed following fractures. Longstanding haematomas can become organised and calcify and this may irritate adjacent nerves causing chronic pain or discomfort. Removal of the organised or calcified haematoma is required. 2.4.2.5 Neuropathic Trigeminal Neuralgia—This is a common cause of facial pain following facial trauma. Management is related to the site and type of injury sustained. The trigeminal nerve can be injured either along its intracranial or extracranial positions and various treatment modalities exist for each. “Classical” trigeminal neuralgia (or tic douloureux) is caused by pressure on the trigeminal root and can be successfully treated with carbamazepine in around 60–70% of patients. Carbamazepine and Oxycarbazepine would be considered first line therapy with Lamotrigine and Baclofen as second line treatments. Other medical treatments are third line but the evidence for their efficacy is poor. Radiofrequency gangliolysis is where a percutaneous needle is used to thermally destroy the trigeminal ganglion and root. This is now one of the more established options for the management of severe trigeminal neuralgia. It usually produces an immediate improvement in pain symptoms. Posterior fossa microvascular decompression is also considered by many to be the treatment of choice for recalcitrant chronic facial pain. Results have shown a 90% success rate at 1 year, with 70% retaining long standing relief at 15 years. In the last

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decade the Gamma Knife (Linear accelerator) has become popular with patients who wish to avoid invasive procedures. This is a focussed beam of radiation aimed at the trigeminal nerve root. It has an excellent success rate, although improvement in pain may take several months. Extracranially, the trigeminal nerve can be affected along one or more of its three main branches (V1, V2, V3). The symptoms and signs will always identify the division affected. This cranial nerve changes physiologically as it leaves its central origin and enters the facial skeleton. It becomes and functions as a peripheral nerve, ensheathed in Schwann cells. Therefore it will regenerate when injured. This increases the risk of neuroma formation. Increased exposure also means that the nerve can be divided or crushed. Divided nerves should be repaired if possible thereby decreasing the incidence of axon sprouting, embedding in scar tissue and forming neuromas. Compression of the trigeminal nerve usually results in paraesthesia, but in some patients chronic compression can be experienced as chronic pain. In a partially injured nerve there can be components of both true nerve injury with axonal sprouting, as well as compression. Fractures (either during the trauma itself or their manipulation during repair) can compress the trigeminal branches. 50% patients may still have symptoms related to the infraorbital nerve 6 months following a zygomatic fracture. Treatment for persisting pain may include osteotomy to relieve the pressure at the infraorbital foramen or along the floor of orbit. Neurolysis of the nerve is also required.

2.4.2.6 Neuroma A neuroma can be a reparative sequelae of any injured nerve, whether injured primarily or following surgical repair. Painful neuromas can develop following nerve repair as a result of neuronal regeneration. There are many schools of thought on how to deal with the injured nerve. Currently it is believed that the segment of injured nerve should be resected with a minimal 2 mm margin. Non-tension primary repair should be performed. If this is not possible, grafting should be performed. Recently bioabsorbable nerve conduits have proved successful with some studies showing better recovery than with primary repair or autogenous nerve grafting. When the patient can demonstrate a trigger point to their pain and if this area corresponds to the known anatomy of the trigeminal nerve then it is most likely that a neuroma is present. Diagnosis is aided by performing a local anaesthetic nerve block. A successful nerve block should qualitatively lower a visual analog scale by five units. If there is residual pain then there is either a second nerve conducting the pain, a more proximal second injury on the same nerve, a central cause for the pain, or some other cause (including malingering). Resection of the neuroma is the treatment of choice with either reconstruction of the nerve or not restoring it at all. With the later method the now free proximal nerve end is implanted within innervated muscle to reduce neuroma recurrence. This is relatively uncomplicated in the extremities but difficult to accomplish in the maxillofacial area as the muscles are less bulky.

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Neuromas can also be the cause of TMJ pain following trauma in which the auriculotemporal branch or the masseteric motor branch of V3, innervating the lateral and medial aspects of the TMJ respectively, are injured. Neuroma formation develops within the capsular scar after the trauma or surgery. As these branches can be blocked denervation of the TMJ should successfully treat the pain.

2.4.2.7 The Future As we have gained more knowledge in the anatomical and physiological pain pathways, so too has our knowledge on how to both reduce the risk and subsequently treat chronic pain. Some interesting studies have shown that using intraoperative sub-anaesthetic doses of Ketamine in a variety of surgical procedures may reduce the incidence of chronic pain. However further large scale studies need to be developed. This subject would of course not be complete unless we touched on the role of genetics in chronic pain development. It is very much likely that genetics contributes to the phenotypic variation of acute and chronic pain. Studies suggest up to 30–70% of chronic pain incidence is accounted for by genetic variations. Genes have been identified to be responsible for hereditary sensory and autonomic neuropathies (HSAN) and Erythromelalgia—associated with SCN9A gene mutation. However none of the findings thus far are of benefit to our cohort of patients and it would seem likely that it will be the interaction of multiple genes with the environment that will show the most promise in future understanding. Also many genes affect the metabolism and effectiveness of analgesics eg. polymorphisms of CYP2D6 affect the O-methylation of codeine to more potent metabolites. It will take time before we will be able to calculate the risk of the individual patient developing chronic pain but this knowledge will allow us to customise the treatment for each patient.

2.5

 ome Eponymous Diseases, Clinical Signs S and Special Tests

Aarskog’s syndrome—short stature, abnormal facies, and genital and hand and foot abnormalities. Characteristic features include a round face with a broad forehead, broad nasal bridge, short nose, everted nostrils and hypertelorism. The cornea is also enlarged. Abadie’s sign—seen in exophthalmic goitre. This is characterised by spasm of the levator palpebrae superioris muscle resulting in retraction of the upper lid. The sclera becomes visible above cornea. Achard’s syndrome—brachycephaly, arachnodactyly, widespread dysostoses, receding lower jaw and joint laxity. Despite similarities, the Achard and Marfan syndromes are different conditions. Ackerman’s syndrome—fused molar roots with a single canal (taurodontism), hypotrichosis, full upper lip without a cupid’s bow, thickened and wide philtrum, occasional juvenile glaucoma and entropion of the eyelid.

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Ackerman’s tumour—a rare a slowly-growing, well-differentiated, verrucous tumour that tends to invade local structures and occurs predominantly in older males, on the buccal mucosa and lower gingiva. Tobacco chewing is the principal aetiological agent. Adamkiewicz’ artery- the largest of the medullary arteries which supply the spinal cord by anastomosing with the anterior (longitudinal) spinal artery. Injury to the artery of Adamkiewicz can result in anterior spinal syndrome. Adams–Oliver syndrome (AOS)—a rare congenital disorder characterised by defects of the scalp and cranium (cutis aplasia congenita), transverse defects of the limbs, and mottling of the skin. Cutis aplasia congenita is defined as missing skin over any area of the body at birth. In AOS skin aplasia occurs over the vertex of the skull. These can range from solitary round hairless patches to complete exposure of the cranial contents. There are also limb defects, cardiovascular malformations, cleft lip and/or palate, abnormal renal system and neurologic disorders. Adams-Victor-Mancall syndrome—progressive facial and tongue weakness, speech and swallowing impairment. It is seen in alcoholic or nutritionally deprived patients. Adie syndrome (Holmes–Adie syndrome)—a neurological disorder characterised by a dilated pupil that reacts slowly to light, but briskly to accommodation. This is caused by disruption to the parasympathetic innervation to the eye, often following viral or bacterial infection. Adie-Critchley syndrome—A phenomenon caused by a tumour in a specific area of the frontal lobe. When an object is placed in one hand of the patient, he grasps it, but cannot voluntary release it. Adson-Coffey syndrome—Thoracic outlet syndrome with compression of the nerves and vessels in the outlet of the thorax between the clavicle and the first rib. Symptoms are identical with those of a cervical rib. They include pain in the chest, shoulder, arm and hand, numbness and tingling along the ulnar border of the forearm, skin changes, claudication, diminished pulse, lowered blood pressure on the affected side, and wasting and weakness of the muscles of the hand and forearm. Adson’s test/manoeuvre—for thoracic outlet syndrome. With the patient in a sitting position, with their hands resting on the thighs, they take a deep breath in, hyperextends the neck and turns the head towards the affected side. If the radial pulse on that side disappears this is considered positive. Aeby’s muscle—in the chin region, a labial muscle formed by sagittal fibres running from the skin to the mucous membrane. Aicardi syndrome—a rare genetic malformation syndrome in babies characterised by deficiency in the corpus callosum, retinal abnormalities and seizures. Possibly caused by a defect on the X chromosome. In the H&N, several tumours have been reported in association with the syndrome (choroid plexus papilloma, medulloblastoma, teratoma in the soft palate, parapharyngeal embryonal cell cancer and scalp lipoma). Albers-Schönberg’s disease—excessive calcification of bones causing marble like appearance, increased radiological density and multiple fractures. Associated disorders include poor dentition, visual disorders, hearing disorders, facial

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paralysis, osteomyelitis of the mandible and maxilla, low blood calcium, and elevated serum phosphorus. Albinus muscle II—Musculus scalenus minimus. The smallest of the scalene muscles, a band-like structure occasionally found between the scalenus anterior and the scalenus medius. It originates from the cervical vertebrae and descends to the first rib. Alexander disease—one of the leukodystrophies, a group of genetic neurological disorders caused by defects in myelin. There is destruction of the white matter in the midbrain and cerebellum with formation of abnormal clumps of protein— Rosenthal fibres. Symptoms include mental and physical developmental delays, abnormal increase in head size, and seizures. Alexander disease is a progressive and often fatal . disease.” Alexanders law—spontaneous nystagmus that occurs after acute unilateral vestibular loss (vestibulo-ocular reflex). The fast phase is directed towards the healthy ear. This is made worse when looking towards the healthy ear. Alezzandrini’s syndrome—Developmental anomaly with retinal degeneration, unilateral facial vitiligo, weakness and bilateral deafness. Alibert’s disease—An Trichophyton related inflammatory skin disease affecting males only, involving the hair follicles of the bearded region of the face. Symptoms include eczema and pruritus on the face and burning sensation, followed by painful small pustules or papules, each pierced by a hair. When neglected, the condition may become chronic and the lesions may develop crust and undergo granulomatous changes. Alzheimer’s disease—a chronic progressive neurodegenerative disease. It accounts for about 70% of cases of dementia. Its cause is unknown but may be related to genetics, head injuries and hypertension. Early symptoms include short-­ term memory loss. There is currently no treatment. Although progression can vary, the typical life expectancy following diagnosis is three to nine years. Amsler-Verrey sign—Haemorrhage caused by applanation tonometry and cataract surgery in Fuch’s heterochromic iridocyclitis. Andernach’s ossicles—Small irregular bones found in cranial sutures. Andersch’ ganglion—The inferior ganglion of glassophrayngeal nerve. Anderson’s syndrome—familial syndrome characterised by midfacial hypoplasia, mandibular prognathism, flat nasal bridge, pointed chin, depressed zygomatic bones, calvarial thinning, brachycephaly, hypoplasia of the petrous bone, prominent eyebrows, malocclusion, and large ear lobes. André’s syndrome—Orofacial anomalies of hypertelorism, palpebral slant, low-set ears, cleft palate, retrognathia, promient forehead, Robin’s anomaly, faulty ossification of the cranial vault, broad sutures and fontanels, sinous ribs, long and thin clavicles, flat vertebrae, abnormal bowing and hyperostosis of the long bones, and faulty ossification of the bones of hands and feet. Andogskiy’s syndrome—Chronic eczema, bilateral cataracts that eventually involve the entire lens. and lichenification of the skin in the neck, flexor surfaces of extremities, especially elbows and knees.

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Angelman syndrome—a genetic disorder that mainly affects the nervous system. Symptoms include a small head and a specific facial appearance, severe intellectual disability, developmental disability, speech problems, balance and movement problems, seizures, and sleep problems. Interestingly, children are reported to have a particular interest in water and always happy with hand flapping movements— hence the previous name “happy puppet syndrome”. Anton–Babinski syndrome (visual anosognosia)—a rare symptom of occipital lobe damage usually following a stroke or head injury. Patients are cortically blind, although they feel they are capable of seeing and may confabulate to fill in the missing sensory input. Visual imagery is received but cannot be interpreted. Anvil test—for cervical vertebral disorders. A vertically striking a blow to the top of the head elicits pain in the vertebra(e). Apert syndrome—a congenital disorder characterised by malformations of the skull, face, hands and feet. It affects the first branchial arch. In acrocephalosyndactyly, selective cell death does not occur and thus the skin (and rarely the bone), between the fingers and toes remain fused. Various types of craniosynostosis also occur (commonly brachycephaly). Argyll Robertson pupils (colloquially, “prostitute’s pupils”)—bilateral small pupils that reduce in size when looking at a near object (accommodate), but which do not react to light (light-near dissociation). This is highly specific for neurosyphilis, but can occur in diabetic neuropathy. Asboe-Hansen sign (“indirect Nikolsky sign” or “Nikolsky II sign”)—the extension of a blister to adjacent unblistered skin when pressure is put on the top of the bulla. Avellis syndrome—a neurological disorder characterised by a alternating paralysis of the soft palate and vocal cords on one side with loss of pain and temperature sensation in the extremities, trunk and neck on the other side. It usually results following occlusion of the vertebral artery resulting in lesions in the nucleus ambiguous and pyramidal tract. Horner’s syndrome may be associated. Babinski reflex:—scraping the soles causes toes to pull up (UMN sign). Baller–Gerold syndrome—a rare genetic syndrome that involves premature fusion of the skull bones and malformations of facial, forearm and hand bones. Bannayan–Riley–Ruvalcaba syndrome—a rare autosomal dominant hamartomatous disorder with occurrence of multiple subcutaneous lipomas, macrocephaly and haemangiomas. The disease belongs to a family of hamartomatous polyposis syndromes, which also includes Peutz–Jeghers syndrome, juvenile polyposis and Cowden syndrome. Patients have an increased risk of developing thyroid problems and tumours. Bárány test—nystagmus elicited by hot or cold irrigation of ear canal. A test for vestibular function. Barré–Liéou syndrome—seen in cervical spondylosis. Damage to the posterior cervical sympathetic chain results in headache, neck pain, orofacial pain, otlagia, toothache, tinnitus and nasal congestion. Barrett’s oesophagus—a condition in which the oesophageal lining undergoes metaplastic change, to become similar to the intestine. This is a complication of

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gastroesophageal reflux disease (GORD). Accompanying disorders include hiatus hernia, stricture of the oesophagogastric junction, ulcers, heartburn, dysphagia, vomiting, and gastrointestinal haemorrhage. Bastian-Bruns law—a transverse lesion in the upper spinal cord resulting in loss of tendon reflexes and muscular tone below the level of the lesion Batten disease—a fatal autosomal recessive disease of the nervous system that typically begins between 5 and 10 years of age. One of the neuronal ceroid lipofuscinoses (NCLs—neurodegenerative diseases). Symptoms include gradual onset of vision problems and seizures and later mental impairment, worsening seizures and progressive loss of sight, speech, and motor skills. Battle’s sign (mastoid ecchymosis)—bruising over the mastoid process, usually an indication of fracture of middle cranial fossa. Beck’s triad—a triad of hypotension, distended neck veins and muffled heart sounds. Seen in cardiac tamponade. Becker’s sign (Becker’s phenomenon)—visible pulsation of the retinal arteries, seen in aortic insufficiency or Graves’ disease. Beckwith–Wiedemann syndrome—macroglossia, macrosomia, microcephaly, midface hypoplasia, midline abdominal wall defects, cardiac anomalies, posterior helix pits, neonatal hypoglycemia, Wilms tumour and hepatoblastoma. Most children do not have all of these features. Other features are described. Prognosis is generally good but there is a risk for some cancers Behçet’s disease—a triad of mouth ulcers, genital ulcers and anterior uveitis. The main feature is severe aphthous-like ulceration, which is often the first sign of the disease. Behçet’s is more common in individuals from the Mediterranean and Far East. MAGIC syndrome is a possible variant of Behçet disease—mouth and genital ulcers with inflamed cartilage (relapsing polychondritis). Benjamin Syndrome (Benjamin anaemia)—hypochromic anaemia with intellectual disability, megalocephaly and various other anomalies (external ear, hypogonadism and occasional tumours) Bickerstaff brainstem encephalitis—a rare inflammatory disorder of the central nervous system, presenting with drowsiness, coma, hyperreflexia, ataxia and ophthalmoplegia. It usually occurs following a minor infection, such as a respiratory tract infection or gastroenteritis and is presumed to be an autoimmune disease. Symptoms show similarities with Guillain–Barré syndrome and Miller Fisher syndrome Binswanger’s disease (subcortical leukoencephalopathy)—a form of subcortical vascular dementia with white matter atrophy. It is characterised by loss of memory and intellectual function and changes in mood. Late symptoms include multiple falls, epilepsy, fainting and incontinence Biot’s respiration—abnormal pattern of breathing characterised by episodes of quick, shallow inspirations followed by periods of apnea. It is caused by damage to the pons following strokes or trauma, or from pressure due to uncal or tentorial herniation. It can be seen in opioid abuse. Bitot’s spots—a superficial buildup of keratin in the conjunctiva. These are a sign of vitamin A deficiency and are associated with drying of the cornea.

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Bocca’s sign—absence of a post cricoid crackle (Muir’s crackle), seen in carcinoma of the posterior cricoid. Boeck’s disease (Schaumann-Besnier syndrome)—Sarcoidosis Boston’s sign—spasmodic lowering of the upper eyelid on downward rotation of the eye. Seen in Graves-Basedow disease (hyperthyroidism) with exophthalmos. Bowen’s disease—squamous cell carcinoma in situ (intraepithelial squamous cell carcinoma)—See chapter on the skin. Boyce sign—a gurgling sound on compression of an external laryngocoele. Broadbent apoplexy—cerebral haemorrhage into the ventricular system. Brooke’s epithelioma—a benign skin disease most commonly occurring on the face, around the eyelids and on the scalp around puberty. Lesions are flesh-coloured, translucent papules with slight surface telangiectasia. Regression and rarely malignant degeneration may occur. Brown-Séquard syndrome (See chapter on the back of the neck)—damage to one half of the spinal cord, results in paralysis and loss of proprioception on the same side as the injury or lesion, and loss of pain and temperature sensation on the opposite side Brudziński neck sign—forced flexion of the neck results in reflex flexion of the hips. Seen in meningitis, subarachnoid haemorrhage and encephalitis. It is not very commonly seen. Bruns ataxia (frontal ataxia)—occurs in bilateral frontal lobe disorders. It is characterised by an inability to initiate the process of walking, despite normal power and coordination in the legs. Patients walk with a broad gait and short steps, with a tendency to fall backwards. Occurs with frontal lobe tumours and cerebrovascular disease. Bruns nystagmus—bilateral nystagmus commonly seen in patients with cerebellopontine angle tumours (notably schwannoma). It may be caused by the compression of both flocculi. Bruns’ syndrome—sudden and severe headache, vomiting and vertigo, triggered by abrupt movement of the head. Common causes are cysts of the fourth ventricle and tumours of the midline of the cerebellum and third ventricle. Brushfield spots—small, greyish- brown spots on the periphery of the iris. These are a characteristic feature of Down syndrome (trisomy 21). They occur as a result of the aggregation of normal iris stromal tissue and are much more likely to be seen in children with lightly pigmented irises. Burton line (Burtonian line)—a fine black-blue line along the gingival margin, seen in chronic lead poisoning. A similar line (bismuth line) has been described following ingestion of bismuth compounds. Bywaters’ syndrome (Crush syndrome)—shock and renal failure following severe crush injury to skeletal muscle. Rhabdomyolysis releases myoglobin, potassium and phosphorus, thromboplastin, creatine and creatine kinase, some of which are nephrotoxic Cannon’s disease—White sponge nevus (See the chapter on the mouth). Hereditary leukokeratosis of the mucosa. The condition is harmless, and no treatment is required.

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Cantelli’s sign (doll’s eye sign)—Dissociation between movement of the head and the eyes. Reflex movement of the eyes occurs in the opposite direction to movement of the head, so that if the head is raised, the eyes are lowered. This is often used as a test of brainstem function. Casal collar (Casal necklace)—an erythematous pigmented skin rash in the distribution of a broad collar (dermatomes C3 and C4). Seen in patients with pellagra. Cardarelli’s sign—abnormal pulsation of the trachea that may be found in patients with a dilation or aneurysm of the aortic arch. This can be felt by pressing on the thyroid cartilage and displacing it to the patient’s left, thereby increasing contact between the left bronchus and the aorta. Castleman disease—a group of lymphoproliferative disorders characterised by lymph node enlargement, characteristic histological features and a range of symptoms and clinical findings. The only known cause of Castleman disease is infection with human herpesvirus. Céstan–Chenais syndrome—obstruction of the long circumferential branches of the basilar artery results in ipsilateral ataxia and coarse intention tremor (damage to superior and middle cerebellar peduncle), Ipsilateral paralysis of muscles of mastication and sensory loss in face (damage to sensory and motor nuclei and tracts of CN V), Contralateral loss of sensory modalities in the body (damage to spinothalamic tract and medial lemniscus), Contralateral hemiparesis of face and body (damage to corticospinal tract) may occur with ventral extension of lesion. Chaddock’s sign (external malleolus sign)—extension of the hallux occurs following irritation of the skin in the lateral malleolar region. This indicates lesions of the corticospinal paths (UMN). Chamberlain Line—used to assess craniocervical junction abnormality Charles Bonnet syndrome—visual release hallucinations in a person with partial or severe blindness (from many causes). Patients may describe vivid, complex recurrent visual hallucinations (fictive visual percepts). Cheyne–Stokes respiration—an abnormal breathing pattern with progressively deeper breathes, followed by temporary apnea. This repeats over 1–2  min. This reflects loss in the ability to ‘fine tune’ the respiratory drive. It can sometimes occur during wakefulness or sleep—central sleep apnea syndrome (CSAS). Chiari malformation—a structural defect in the cerebellum resulting in , downward displacement of one or both cerebellar tonsils through the foramen magnum. This can sometimes result in a non-communicating hydrocephalus. Christ-Siemens-Touraine syndrome (Hypohidrotic ectodermal dysplasia)— one of about 150 types of ectodermal dysplasia in humans, resulting in abnormal development of ectodermal structures such as the skin, hair, nails, teeth, and sweat glands. In the H&N there is a sparse amount of hair, hypodontia and malformed teeth. Other facial features include a prominent forehead, thick lips, flattened bridge of the nose, ozena and dark-colored skin around the eyes. Chvostek sign—a clinical sign to detect nerve excitability in hypocalcaemia. Tapping over the facial nerve in front of tragus results in twitching of the facial

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muscles. This also be seen in respiratory alkalosis (hyperventilation causes decreased serum Ca2+) and hypomagnesaemia. Claude’s syndrome—a type of brainstem stroke in which there is ipsilateral oculomotor nerve palsy, contralateral hemiparesis, contralateral ataxia, and contralateral hemiplegia of the lower face, tongue, and shoulder. It occurs following midbrain infarction (the red nucleus) as a result of occlusion or stenosis of a branch of the posterior cerebral artery. Cloquet (canal of)—the embryonic remnant following regression of the hyaloid artery in the eye during the early part of the third trimester. Coats’ disease (exudative retinitis or retinal telangiectasis)—a rare unilateral congenital, nonhereditary ocular disorder, resulting in gradual visual impairment. It is characterised by the abnormal development and breakdown of the blood-retinal barrier, resulting in leakage of blood products containing cholesterol crystals into the retina and subretinal space. Over time an accumulation of proteinaceous exudate thickens the retina, resulting in exudative retinal detachment. Glaucoma can also occur. Clinically, features may resemble retinoblastoma. Patients present with blurred vision and loss of depth perception. Deterioration in vision may be noticed at first in the upper visual field as this corresponds with the inferior part of the eye where blood usually accumulates. Photopsia and floaters are common symptoms. An interesting early warning sign is a yellow-eye during flash photography as light reflects off cholesterol deposits. Diagnosis is made following examination, ultrasonography and sometimes CT or MRI. Laser or cryotherapy may be used to scar the abnormal blood vessels and halt progression of the disease. Very rarely regression or even reversal may occur, but once total retinal detachment occurs, blindness is permanent. Cock’s peculiar tumour—a cyst-like growth that can resemble a squamous cell carcinoma. This usually arises in a trichilemmal cyst of the hair follicle, often on the scalp and scrotum. Chronic inflammation and ulceration result in clinically and histological appearances similar to a squamous-cell carcinoma. The name is a misnomer—this is not a tumour. Cohen syndrome (Pepper syndrome or Cervenka syndrome)—a genetic disorder resulting in craniofacial dysmorphism, obesity and mental impairment. Rare ocular complications include optic atrophy, microphthalmia, pigmentary chorioretinitis, hemeralopia (decreased vision in bright light), myopia, strabismus, nystagmus and iris/retinal coloboma. Micrognathia, a short philtrum and a high palate vault are also described. Cogan syndrome—a rare rheumatic disease characterised by recurrent inflammation of the ears and eyes (cornea). Patients present with inflammation of the cornea, fever, fatigue, vertigo, tinnitus, hearing loss and weight loss. Untreated this can result in deafness or blindness. Vasculitis can also occur further afield with multiorgan impairment. Rarely this can be fatal. The cause is not known, but is presumed to be an autoimmune disorder, possibly related to infection by Chlamydia pneumoniae. Treatment involves steroids and immunosuppression. Collet-Sicard syndrome (glossolaryngoscapulopharyngeal hemiplegia) is caused by a lesion involving cranial nerves IX, X, XI, and XII.  This results in

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paralysis of the vocal cords, palate, trapezius and sternocleidomastoid. There is also anaesthesia of the larynx, pharynx and soft palate. Costen’s syndrome—see TMJDS (chapter on the lower jaw) Creutzfeldt–Jakob disease (CJD)—a fatal brain disorder believed to be caused by a prion protein. It can be familial (fCJD), or sporadic (sCJD). This can be transmitted if exposed to brain or spinal tissue, corneal grafts or dural grafts from an infected person. Cannibalism has also been implicated as a mode of transmission— this caused the disease known as Kuru. Pathologically, progressive neuronal death occurs secondary to the build-up of abnormal protein amyloids. Early symptoms include memory problems, behavioural changes, poor coordination and visual disturbances. Later dementia, blindness and weakness occur. About 90% of people die within a year of diagnosis. The term “spongiform” is often used—spongiform encephalopathy. This refers to the sponge-like appearance of the brain when examined histologically. Cornelia de Lange syndrome—a very rare genetic disorder which presents at birth with a range of signs. These include delayed growth and small stature, microcephaly, thick eyebrows, which typically meet at midline (synophrys), long eyelashes, short upturned nose and thin downturned lips, long philtrum, excessive body hair, low-set ears with hearing impairment, ptosis, nystagmus, high myopia, hypertropia and cleft palate. Other features are present out with the head and neck. Cushing reflex (Cushing reaction, Cushing response)—a physiological response to raised intracranial pressure resulting in a triad of (1) increased blood pressure, (2) irregular breathing and (3) bradycardia. It is usually seen in the late stages of raised intracranial pressure and is taken to indicate imminent brain herniation. Dalrymple’s sign—refers to the abnormal wideness of the palpebral fissure seen in thyrotoxicosis. It occurs secondary to retraction of the upper eyelid, so that the sclera is visible above the cornea. Other less common eye signs include Stellwag’s sign (rare blinking), Rosenbach’s sign (tremor of the eyelids) and Jelink’s sign (hyperpigmentation of the eyelid). Dandy–Walker syndrome—a rare group of congenital brain malformations in which three subtypes are described. All involve the cerebellum and third and fourth ventricles (with complete absence of the cerebellar vermis and enlargement of the fourth ventricle). Features can vary but include raised intracranial pressure, hydrocephalus, macrocephaly and mental impairment. Spastic paraplegia and seizure can also occur. These may present in infancy or childhood. Dandy–Walker syndrome can also be associated with absence of the corpus callosum. Danbolt–Cross syndrome (Brandt syndrome or acrodermatitis enteropathica)— a metabolic transmembrane protein disorder affecting the uptake of zinc. This results in periorificial dermatitis, glossitis and inflammation of the skin in the tips of fingers and toes. Hair loss (scalp, eyebrows, and eyelashes) and diarrhoea are also common. Skin lesions can become secondarily infected. Zinc is important in the function of approximately 100 enzymes in the body. de Musset’s sign—rhythmic nodding or bobbing of the head in synchrony with pulse (aortic regurgitation).

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De Morsier syndrome (septo-optic dysplasia)—one of the milder forms of hypoplastic developmental disorders that can involve brain and orbit. It is associated with incomplete induction of the neural axis during the first trimester. De Quervain’s thyroiditis (subacute granulomatous thyroiditis or giant cell thyroiditis)—a form of thyroiditis. In contrast to other causes of subacute thyroiditis, this is usually painful. Patients develop hyperthyroidism which later becomes hypothyroid as the pituitary reduces TSH production. They may also experience painful dysphagia. Some cases may be viral in origin (such as coxsackie virus, mumps and adenoviruses) and development postpartum has been reported. Management includes beta blockers, aspirin, and NSAIDs (or corticosteroids). Dennie–Morgan fold—an accentuated fold below the lower eyelid that is seen in atopic dermatitis Devic’s disease (Neuromyelitis optica)—inflammation and demyelination of the optic nerve and the spinal cord. This can present as a single episode with permanent remission, or be recurrent. It is thought to be autoimmune in origin. Spinal cord lesions lead to varying degrees of weakness or paralysis in the limbs, loss of sensation and/or bladder and bowel dysfunction. Optic neuritis may present as visual impairment, visual field defects or loss of colour perception. Currently, there is no cure for Devic’s disease, but acute symptoms can be treated with high dosage intravenous corticosteroids or plasmapheresis. Long term immunosuppression may be required. Haematopoietic stem cell transplantation has also been reported. DiGeorge syndrome (22q11.2 deletion syndrome)—a genetic condition which includes congenital heart defects, facial anomalies, velopharyngeal insufficiency and recurrent infections. Renal problems, hypocalcemia from parathyroid dysfuntion, hearing loss and autoimmune disorders can also be associated. Most cases are sporadic but the disorder can be inherited as an autosomal dominant condition. Dix–Hallpike manoeuvre (Nylen–Barany test)—a diagnostic manoeuvre to identify benign paroxysmal positional vertigo (see the chapter on the ear). Dodd’s sign—a crescent of air seen on plain films between a mass and the posterior pharyngeal wall. Donnai–Barrow syndrome—is a genetic disorder resulting in prominent, wide-­ set eyes, coloboma of the iris, dystopia of the lateral canthi, a short bulbous nose with a flat nasal bridge and malposition of the ears. Sensorineural hearing loss can result in deafness. High myopia and retinal detachment can result in progressive vision loss. In almost all patients the corpus callosum is underdeveloped or absent. Other defects may occur (diaphragmatic hernia, omphalocele). Dravet syndrome (severe myoclonic epilepsy of infancy)—a type of epilepsy with seizures that are triggered by hot temperatures or fever. The syndrome usually develops during the first year of life. Treatment includes anticonvulsants and a ketogenic diet. Duane syndrome (Stilling-Türk-Duane or retraction syndrome)- a rare congenital type of strabismus characterised by limitation of abduction of the affected eye. Globe retraction into the socket and narrowing of the palpebral fissure occurs on adduction. Duane syndrome may be associated with other syndromes including Klippel-Feil, Goldenhar syndrome, heterochromia, and congenital deafness. It is

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believed to occur as a result of abnormal innervation of the EOM. In most cases the abducens nucleus and nerve are absent or hypoplastic and the lateral rectus muscle is innervated by a branch of the oculomotor nerve. Three variants are described. Elschnig’s spots—on fundoscopy, black spots surrounded by bright yellow or red margins are seen. These are a sign of advanced hypertensive retinopathy. Emanuel syndrome (derivative 22 syndrome)—a rare congenital disorder associated with multiple anomalies, including preauricular skin tags or pits, hypotonia and heart defects. Intellectual development is often significantly delayed with a small head (microcephaly) and micrognathia. About half of all affected infants have cleft palate. Epstein’s pearls—benign and transitory cystic papules on palate in the newborn Erbs-duchennes palsy—brachial plexus injury at C5-6 results in a characteristic posturing of the arm. The arm hangs by the side the arm is medially rotated, the forearm is extended and pronated due the appearance of this position this is also known as “waiters tip”. Eustachian tube (after Bartolomeo Eustachi)—see the chapter on the ear Foix–Alajouanine syndrome—arteriovenous malformation of the spinal cord with abnormally dilated and tortuous vessels on the surface of the cord. Patients present with limb weakness, numbness and loss of sphincter control. Forbes–Albright syndrome—galactorrhoea-amenorrhoea associated with a pituitary tumour. Forchheimer spots—small red spots on the soft palate, seen in children with rubella. Forsius-Eriksson syndrome—hypoplasia of macula lutea, nystagmus, myopia, and refraction anomalies. Affects only males; females are carriers. Foster–Kennedy syndrome (Gowers–Paton–Kennedy syndrome)—compression of the optic and olfactory nerves with increased intracranial pressure secondary to mass effect, usually a tumour. Other symptoms may include nausea, vomiting, memory loss and emotional lability from involvement of the frontal lobe. Pseudo-­ Foster–Kennedy syndrome is defined as unilateral optic atrophy with papilledema in the contralateral eye but with no mass. Fournier test—This tests for an ataxic gait. The patient is asked to stand quickly from a sitting position and walk around, then stop quickly and turn around quickly on command, noting any unsteadiness. Frey’s syndrome (Baillarger’s syndrome, Dupuy’s syndrome, auriculotemporal syndrome)—a neurological disorder resulting from damage to the auriculotemporal nerve, supplying the parotid gland. Patients complain of facial flushing and sweating from the cheek during eating—“gustatory sweating”. Following surgery (or trauma) to the gland, abnormal neurological pathways develop between the nerves to the salivary gland and the overlaying sweet glands. Fuchs’ dystrophy (Fuchs’ corneal endothelial dystrophy)—a slowly progressing corneal dystrophy that usually affects both eyes. Patients develop central corneal clouding, loss of corneal sensation and blistering of the corneal epithelium. Corneal oedema results in blurred vision worse on waking, which improves during the day. Management includes topical hypertonic saline, the use of a hairdryer

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(directed across the face) to dehydrate the tear film and therapeutic soft contact lenses. In severe cases corneal transplantation may be required. Furstenbergers sign—this is seen when a nasopharyngeal cyst is communicating intracranially. Enlargement of the cyst occurs when the child is crying or following compression of the jugular vein. Gardner’s syndrome—multiple osteomas, sebaceous cysts, multiple supernumerary teeth and colorectal polyposis. Goldenhar syndrome (oculo-auriculo-vertebral syndrome)—a rare congenital defect associated with abnormal development of the first and second branchial arches. In 10% of cases the condition affects both sides. Patients have incomplete development of the ear, nose, soft palate, lip and mandible. Features include facial asymmetry, ocular dermoids, strabismus, microtia, atresia of the external acoustic meatus, preauricular skin tags, deafness and macrosomia. The condition is sometimes referred to as hemifacial microsomia, although there is a subtle difference between the two. Cardiac, renal and lung defects may also occur. Gorlin–Goltz syndrome (nevoid basal-cell carcinoma syndrome, multiple basal-cell carcinoma syndrome, Gorlin syndrome)—an inherited condition resulting in multiple defects in the skin, nervous system, eyes, endocrine system and bones. Patients are particularly prone to developing a basal-cell carcinomas and odontogenic keratocysts. Other features include rib and vertebrae anomalies, palmar or plantar pits, calcification of the falx cerebri and characteristic facial appearances (frontal bossing, hypertelorism and mandibular prognathism). Numerous other features have been described. Graves’ disease (toxic diffuse goiter)—an autoimmune disease involving the thyroid and the most common cause of hyperthyroidism. Features include symptoms of hyperthyroidism, pretibial myxoedema and Graves’ ophthalmopathy. Smoking increases the risk of the disease and may worsen ocular problems. Griffith’s sign—lid lag of the lower eyelid when looking up. Seen in Graves’ ophthalmopathy. Grinker’s myelinopathy (anoxic leukoencephalopathy, delayed post-hypoxic leukoencephalopathy)—a rare disease of the central nervous system in which delayed leukoencephalopathy develops after a severe hypoxic episode. It is often seen following carbon monoxide poisoning or heroin overdose. Following recovery patients begin to develop a wide range of symptoms as a result of demyelination and the degeneration of the cerebral hemispheres and basal ganglia. These include apathy, dementia, Parkinsonism, agitation, urinary incontinence, and pseudobulbar palsy. Magnetic resonance imaging or computed tomography may be required to confirm a decrease in white matter density. Hyperbaric oxygen has been suggested as a possible treatment in the early stages. Grisel’s syndrome—subluxation of the atlanto-axial joint, but not associated with trauma or bone disease. Seen mostly in children in association with pharyngitis, adenotonsillitis, tonsillar abscess and cervical abscess or following ENT procedures (such as tonsillectomy). Due to laxity of the transverse ligament. Symptoms vary and include persistent neck pain and stiffness, mild paraesthesia, clonus or quadriplegia or acute respiratory failure.

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Gower’s sign—abrupt intermittent oscillation of the iris under light stimulus in some stages of tabes dorsalis. Gunn’s sign—On fundoscopy, arteriovenous nicking is seen. Commonly seen in hypertensive retinopathy. Venules form an “hourglass” shape around the arteriole. Hailey–Hailey disease—(familial benign chronic pemphigus)—a genetic disorder characterised by outbreaks of rashes and blisters in the skin, often over large areas of the body. These can become infected. The cause is an enzyme deficiency resulting in malformation of intercellular desmosomes and causing acantholysis. Treatment involves steroids, dapsone, methotrexate, thalidomide and, cyclosporine. Laser resurfacing has been reported to encourage healing. Hallervorden–Spatz syndrome (pantothenate kinase-associated neurodegeneration, neurodegeneration with brain iron accumulation)—a degenerative disease of the brain that can result in parkinsonism, dystonia, dementia and death. An excess of iron progressively builds up in the brain. Hand–Schüller–Christian disease—multifocal Langerhans cell histiocytosis. This is often described as a triad of exophthalmos, lytic bone lesions (often in the skull), and diabetes insipidus (from pituitary stalk infiltration). Hartnup disease (pellagra-like dermatosis)—a metabolic disorder affecting the absorption of amino acids (particularly tryptophan that is important in the production of serotonin, melatonin, and niacin). It effects mainly the brain and skin. Patients present in infancy with failure to thrive, photosensitivity, intermittent ataxia, nystagmus, and tremor. Symptoms may be triggered by sunlight, fever, drugs or stress. Later symptoms include mental retardation, short stature, headaches, unsteady gait and episodes of fainting. Treatment involves a high-protein diet supplementation with nicotinic acid or nicotinamide and avoidance of any trigger factors. Hashimoto’s thyroiditis (chronic lymphocytic thyroiditis and Hashimoto’s disease)—an autoimmune disease affecting the thyroid gland, resulting in gradual destruction. Several autoantibodies have been found to be present against thyroid peroxidase, thyroglobulin and TSH receptors. Patients eventually develop hypothyroidism. Potential complications include lymphoma. The gland may become enlarged and lobulated. Other autoimmune diseases may be associated such as type 1 diabetes, vitiligo, and alopecia. Management includes thyroid hormone replacement. Occasionally transient periods of thyrotoxicosis can arise and rarely patients may develop orbitopathy. Hatchcock’s sign—pressure behind the angle of the mandible results in pain in parotitis but not in adenitis. Heel-knee test. To look for cerebellar signs. Coordinated movements of the lower extremities. The supine patient is asked to rapidly pass the heel of one leg up and down the shin of the other. Hennebert’s sign—pressure induced nystagmus. A false positive fistula test that occurs when there is no evidence of middle ear disease causing a fistula of horizontal semicircular canal. This is seen in 25% cases of meniere’s disease or congenital syphilis. Hennebert symptom- pressure induced dizziness

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Hippocratic facies—the appearance in the face caused by impending death or long illness. It relates to the appearances seen in cachexia. Hirschberg corneal reflex test—a screening test for strabismus. A light is shone in the eyes and observed as to where the light reflects off the corneas. This should be in the same position. Hitzelberger’s sign—numbness of the external auditory canal (supplied by Arnold’s nerve—a branch of the Vagus nerve to ear) as a result of compression, typically by an acoustic neuroma. Hodgkin’s lymphoma—a type of lymphoma in which cancerous cells arise from lymphocytes. Symptoms may include fever (sometimes cyclic—“Pel-Ebstein fever”), pruritis, night sweats, and weight loss. On examination there are often multiple enlarged “rubbery” lymph nodes in the neck, axillae and groin. It is also said nodes can become painful following alcohol consumption. About half of cases are associated with Epstein–Barr virus, other cases may be associated with HIV/ AIDS.  Diagnosis usually requires excision biopsy of a node. Four subtypes are described (Nodular sclerosing, Mixed-cellularity, Lymphocyte-rich and Lymphocyte depleted). Treatment involves chemotherapy, raidotherapy and sometimes stem cell transplant. Hoffman’s Test—used to determine whether the patient’s fingers or thumbs will flex involuntarily in response to certain stimuli. A positive result may be a sign of an underlying condition affecting the central nervous system (corticospinal pathways). This test is sensitive but not specific for cervical myelopathy Holman Miller sign (Antral sign)—seen in angiofibroma, the tumour pushes forward on the posterior wall of the maxillary sinus. Hondousa sign—a radiographic finding, seen in Angiofibroma. There is characteristic widening of the gap between ramus of the mandible and the maxillary body, indicating infratemporal fossa expansion. Horner’s syndrome (Claude Bernard-Horner syndrome)- miosis, ptosis, anhydrosis and enophthalmos. This occurs following injury or disease to the sympathetic trunk in the neck or thorax, including Pancoast lung tumour, Cervical rib, Thyroid carcinoma, Syringomyelia, Multiple sclerosis, Thoracic aortic aneurysm, trauma and following local surgery/nerve blocks. Patients need careful investigation to exclude malignancy. Treatment is aimed at the cause. Hollenhorst crystals—bright-orange atherosclerotic emboli seen on ophthalmoscopy, at the bifurcation of the retinal arteries. These are assumed to be a cause of transient ischaemic attacks of the retina. Horton’s cephalalgia (cluster headache, “alarm clock headache”)—a well described cause of headache which is characterised by recurrent, episodic, severe unilateral pain, usually around the eye, with lacrimation and nasal congestion. Their cause is unknown. (See chapter on the head) Hunter’s glossitis—smooth appearance of the tongue seen in nutritional anaemia (pernicious anaemia). Huntington's disease (Huntington's chorea)—an inherited degenerative CND disorder. Early symptoms are often subtle and include mood or mental changes, followed by lack of coordination and an unsteady gait. Jerky body movements

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subsequently occur and the patient declines with difficulties chewing, swallowing, and speaking and the onset of dementia. Currently there is no cure for Huntington's chorea. Tetrabenazine, neuroleptics and benzodiazepines may help. Today, life expectancy is generally around 20 years following the onset of symptoms. Huntington’s sign—flexion of the thigh and extension of the leg in the paralysed limb, following coughing (in a recumbent patient, with legs hanging over the edge of the table) suggests an upper motor neurone lesion. Hutchinson’s melanotic freckle (Lentigo maligna) melanoma in situ (see the chapter on the skin). This usually progresses very slowly and can remain in non-­ invasive for years. It is normally found in the elderly Hutchinson’s pupil—the pupil on the side of an intracranial mass lesion is dilated and unreactive to light. This is due to compression of the oculomotor nerve on that side Hutchinson’s sign—vesicles on the tip or side of the nose, which precede the development of ophthalmic herpes zoster. These occur because the nasociliary nerve innervates both the cornea and nose. Hutchinson’s teeth (Hutchinson’s incisor)—seen in congenital syphilis. The teeth are smaller, more widely spaced and have notches on their edges. Hutchinson’s triad—congenital syphilis—interstitial keratitis, nerve deafness, Hutchinson’s teeth Irvine–Gass syndrome (pseudophakic cystoid macular oedema or postcataract CME)—a common causes of visual loss after cataract surgery. Pseudophakia refers to replacement of the lens. Following surgery the retinal capillaries dilate and leak fluid into the retina. Irwin Morre’s sign—a positive squeeze test seen in chronic tonsillitis Jackson sign—pooling of saliva in the pyriform fossa as a result of cancer Joffroy’s sign—absence of wrinkling on the forehead in Graves disease. Johanson–Blizzard syndrome—a rare congenital disorder resulting in abnormal development of the nose and scalp and pancreas. Symptoms include mental retardation, hearing loss, pancreatic insufficiency and growth failure. Kaposi’s sarcoma—a cancer of uncertain origin (possibly vascular) that can involve skin, mucosa, lymph nodes and other organs. Skin and mucosal lesions are typically red, purple, brown, or black in colour, varied in morphology and can be confused with pyogenic granuloma, haemangioma or malignant melanoma. They can be isolated or widespread and are often found in the mouth, gastrointestinal tract and respiratory tract. Several sub-types are described- classic, endemic, immunosuppressive related and epidemic and human herpesvirus 8 (HHV8) has now been associated in many cases. Immunosuppresion related can occurs following organ transplantation, but is also an AIDS defining feature. Treatment includes surgery, chemotherapy and radiotherapy. HIV patients may be teated with highly active antiretroviral therapy (HAART). Kartagener syndrome (primary ciliary dyskinesia)—a rare, genetic disorder that results in defects in the function of cilia lining the respiratory tract, sinuses, fallopian tube and the flagella of sperm. This results in impaired mucus clearance from the lungs and susceptibility to recurrent chest infections, sinusitis and otitis

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media. In males, immotility of sperm can result in infertility and fertility in females may occur from dysfunction of the fallopian cilia. Patients may also have situs inversus and dextrocardia. Management is aimed at preventing or treating infections (chest physiotherapy etc) and enhance mucous clearance. Kasabach–Merritt syndrome (haemangioma thrombocytopenia syndrome)—a rare disease usually in infants, in which sequestering of platelets within a vascular malformation results in a reduced platelet count and bleeding problems. It is usually associated with large or are growing rapidly malformations. Patients develop thrombocytopenia, low fibrinogen levels, high fibrin degradation products, and microangiopathic haemolysis. Management focuses on treatment of the underlying vascular malformation and includes surgery, embolisation, corticosteroids, alpha-interferon and rarely chemotherapy or radiotherapy. Kawasaki disease (mucocutaneous lymph node syndrome)—a presumed autoimmune condition of blood vessels which is common in Japan. Symptoms include unresponsive persistent fever, sore throat, diarrhoea, cervical lymphadenopathy, and inflammation/erythema of the genital area, eyes, lips, palms and soles of the feet. Recovery then usually occurs. Rarely coronary artery aneurysm can develop. Treatment may include intravenous immunoglobulin and aspirin Kayser–Fleischer rings—copper deposition in Descemet’s membrane, visible in the cornea. Seen in Wilson’s disease. Kearns–Sayre syndrome—a mitochondrial myopathy resulting in chronic progressive ophthalmoplegia, with involvement of the levator palpebrae, orbicularis oculi and extra-ocular muscles. Patients present with ptosis and ophthalmoplegia plus a pigmentary, “salt-and-pepper” retinopathy and cardiac conduction abnormalities. Ocular symptoms may begin unilaterally but eventually involve both sides. Other symptoms include cerebellar ataxia, proximal muscle weakness, deafness, diabetes mellitus, growth hormone deficiency, hypoparathyroidism, and other endocrinopathies. Currently there is no cure although research is ongoing into muscle fibre regeneration. Kennedy’s disease (Spinal and bulbar muscular atrophy)—a progressive genetic neurodegenerative disorder involving the brainstem and spinal cord, which has. both neuromuscular and endocrine manifestations. Symptoms include weakness of tongue and perioral muscles and gradually increasing weakness of the limbs and respiratory muscles. Bulbar signs include difficulty in swallowing and speech. Endocrine manifestations include gynecomastia, erectile dysfunction, testicular atrophy and reduced fertility. Management is largely supportive. Kernig’s sign—inability to fully extend the leg when the thigh is flexed. Usually indicative of meningeal irritation. Kerr’s sign—Alteration of the texture of the skin below the level of injury in spinal cord lesions. Kikuchi disease (Kikuchi-Fujimoto disease)—a rare self-limiting illness with symptoms that overlap with tuberculosis and Hodgkin’s lymphoma leading to misdiagnosis. Presumed autoimmune or viral in origin. Also known as necrotising lymphadenitis, it can occur sporadically and is common in Japan. Symptoms include fever, lymphadenopathy, skin rashes, fatigue and headache. Diagnosed following

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lymph node biopsy. Treatment is supportive with nonsteroidal anti-inflammatory drugs and corticosteroids. Kimura’s disease—a rare chronic inflammatory disorder commonly seen in Asian males, resulting in subdermal lesions in the head or neck or painless cervical lymphadenopathy. Its cause is unknown but may be related to an allergic reaction or an autoimmune process. Treatment may not be required, or may involve steroids. King–Kopetzky syndrome (Cocktail party effect)—an auditory processing disorder resulting in difficulty in hearing speech in the presence of background noise, but with normal hearing test results. May have multiple causes. Kinsbourne syndrome (dancing eye syndrome, opsoclonus myoclonus syndrome)—a rare neurological condition of unknown cause in early childhood. Possibly autoimmune involving the nervous system. Symptoms include unpredictable, fast eye movements (opsoclonus), strabismus, involuntary twitching, cerebellar ataxia, aphasia, irritability and lethargy. These develop quickly over a few weeks. About half of cases are said to be associated with neuroblastoma. There is no cure for OMS, but treatment may include corticosteroids, immunoglobulins and other immunosuppressive drugs. It has been postulated that some viral infections may play a role in the activation of the disease. Kjer’s optic neuropathy—a mitochondrial dysfunction disease affecting the optic nerves in children, eventually resulting in blindness. Non-syndromic and syndromic forms (with extra-ocular signs) occur. Klippel-Trenaunay-Weber syndrome—venous angiomata of the orbit, kidneys and other viscera Klumpke’s palsy—brachial plexus injury to C8-T1 results in hyperextension at the metacarpophalangeal joints and hyperflexion at the interphalangeal joint resulting in claw hand. Patients can also develop Horner’s syndrome if T1 is involved. This is a poor prognostic sign. Klüver–Bucy syndrome—bilateral lesions of the medial temporal lobe which can result in compulsive eating, amnesia, hypersexuality, insertion of inappropriate objects in the mouth (hyperorality), visual agnosia and docility. Koplik spots—white lesions on the buccal mucosa that appear two to three days before a measles rash is apparent. Korsakoff syndrome—an amnestic disorder involving the limbic system, caused by thiamine deficiency associated with alcohol abuse. When Wernicke encephalopathy is present this is called Wernicke–Korsakoff syndrome. Symptoms include amnesia and confabulation (invented memories, taken by the patient to be true events). Most commonly seen in chronic alcoholism, but can occur in severe malnutrition, hyperemesis gravidarum, mercury poisoning or following chemotherapy. Treatment involves thiamine supplementation although this may not reverse the condition. Krabbe disease (globoid cell leukodystrophy or galactosylceramide lipidosis)— a rare and often fatal lysosomal storage disease that results in progressive deterioration of the nervous system. Accumulation of lipids adversely affects the development of myelin. Symptoms begin around 3 and 6 months with irritability, fevers, limb stiffness, seizures, feeding difficulties, vomiting, and slowing of development.

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Juvenile and adult-onset cases have been described. Bone marrow transplantation has been reported to provide some benefit in early cases, although the prognosis is generally poor. Krimsky Test—essentially the Hirschberg test, but using prisms to quantify the degree of stabismus. Krückmann-Wolfflin bodies (Brushfield spots)—small, greyish-brown spots on the periphery of the iris. These are a characteristic feature of Down syndrome (trisomy 21). They occur as a result of the aggregation of normal iris stromal tissue and are much more likely to be seen in children with lightly pigmented irises. Küttner’s tumour (chronic sclerosing sialadenitis)—chronic inflammation of the submandibular gland, resulting in an indurated neck lump, that may be confused with a tumour. It is now regarded as a manifestation of IgG4-related disease. These are often painful, resulting in surgical excision. Lange-Nielsen syndrome—autosomal recessive deafness, prolonged QT interval and syncopal attacks. This results from mutations in potassium channels. Laugier’s sign—Blood behind the eardrum suggesting a basilar skull fracture Laurence–Moon syndrome—a rare genetic disorder resulting in retinitis pigmentosa, spastic paraplegia, and mental impairment. Leber’s disease—hereditary optic neuropathy which can eventually leads to bilateral optic nerve atrophy. Leichtenstern’s sign—lightly tapping any bone in the extremities causes the patient to flinch suddenly. Seen in cerebrospinal meningitis. Leigh syndrome (subacute necrotising encephalomyelopathy)—a neurometabolic disorder caused by a defect in the mitochondrial enzyme thiamine-­diphosphate kinase. Common in infancy but can occur in adolescence or adulthood. Symptoms may develop after infection or surgery. These include diarrhoea, vomiting, dysphagia, seizures, peripheral neuropathy, hypotonia and dystonia. The eyes are commonly affected resulting in ophthalmoparesis and nystagmus. Hypertrophic cardiomyopathy can cause death. Prognosis varies. Lejeune’s syndrome (cri du chat, chromosome 5p deletion syndrome)—a rare genetic disorder due to chromosome deletion on chromosome 5. Its name comes from the characteristic cat-like cry of affected children which is said to be similar to that of a meowing kitten, as result of developmental problems with the larynx and CNS. Other symptoms include, difficulty in swallowing, excessive drooling, severe cognitive, speech and motor disabilities, microcephaly, micrognathism, low-set ears, hypertelorism, strabismus and epicanthal folds. Cardiac defects and cleft lip and palate may also occur. Lemierre’s syndrome—infectious thrombophlebitis of the internal jugular vein. Can occur following an anaerobic bacterial infection of the throat in otherwise healthy adults. This can result in systemic complications including sepsis and septic emboli. Symptoms commence with a sore throat, but progress to fever, extreme lethargy, rigors and and a swollen and very tender neck. Septic shock can occur. Cranial nerve palsies and Horner’s syndrome are rare, but highly suggestive of the diagnosis. Treatment involves IV antibiotics and drainage of any abscesses.

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Occasionally ligation of the internal jugular vein is required. Even with prompt diagnosis mortality is round 5%. Letterer–Siwe disease—one of several rare syndromes arising from Langerhans cell histiocytosis. It almost exclusively occurs in children under three and is often rapidly fatal. Features include scalp lesions, otorrhoea, lymphadenopathy, osteolytic lesions and hepatosplenomegaly. Leudet’s sign—a clicking sound which can heard through an otoscope while the patient experiences tinnitus. It caused by reflex spasm of the tensor palati muscle and occurs when there is inflammation of the eustachian tube. Lhermitte’s sign—electric-shock like sensation that passes down the body when the patient flexes the head forward. Commonly seen in multiple sclerosis other disorders of the cervical cord. Libman’s sign—severe tenderness (but otherwise painless) following pressure of the mastoid. Lisch nodules—brownish-red spots in the iris. Seen in Neurofibromatosis Lombard reflex—the involuntary tendency of speakers to increase their vocal effort when speaking in a loud environment to enhance their voice. Lowe syndrome (oculocerebrorenal syndrome)—a rare X-linked recessive disorder resulting in congenital cataracts, hypotonia, mental impairment and renal problems. Glaucoma can develop later. Lou Gehrig’s disease (amyotrophic lateral sclerosis, motor neurone disease)— degenerative disorder of upper and lower motor neurones affecting voluntary muscles. Symptoms include hypertonia, muscle twitching, increasing weakness, followed by difficulty speaking, swallowing and eventually breathing. The cause is unknown in most cases. There is currently no known cure. The average survival from onset of symptoms is two to four years. Motor neurone disease is technically a group of diseases which includes amyotrophic lateral sclerosis (ALS), progressive muscular atrophy, progressive bulbar palsy, pseudobulbar palsy and spinal muscular atrophy. Luc’s abscess—a rare but serious complication of acute otitis media, where infection spreads out from the middle ear, resulting in a subperiosteal collection beneath the temporal muscle. Ludwig’s angina—a severe life-threatening cellulitis involving the submental, sublingual and submandibular spaces, bilaterally. Most cases occur as a result of a dental infection. Symptoms include difficulty swallowing saliva and airway compromise. Urgent surgical drainage is required (see chapter on the front of the neck). Lyre’s sign—splaying of the carotid vessels as a result of a carotid body tumour Macewen’s sign—used to diagnose hydrocephalus. Percussion of the skull near the junction of the frontal, temporal and parietal bones will produce ‘cracked pot’ sound, indicative of separation of the sutures. Machado–Joseph disease (spinocerebellar ataxia)—a rare neurodegenerative disease that causes progressive cerebellar ataxia with ophthalmoplegia and lack of muscle coordination of the limbs. This may sometimes be mistaken for drunkenness or Parkinson’s disease.

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Mackler’s triad—chest pain, vomiting and subcutaneous emphysema. Highly suggestive of oesophageal rupture, but is only seen in about 15% of cases. Marburg multiple sclerosis (acute fulminant multiple sclerosis)—one of the multiple sclerosis type disorders (which includes neuromyelitis optica, balo concentric sclerosis and Schilder’s disease). This progresses quickly to death within 1–2 years. Marcus Gunn pupil—Relative afferent pupillary defect (See chapter on the eye) Marfan’s syndrome—a disorder of connective tissue affecting primarily the musculoskeletal system, the cardiovascular system and the eye. Patients have a tall stature, long limbs, with an arm span greater than height. There is laxity of the joints and ligaments, which can affect the TMJ. The face may present an elderly appearance and a high arched palate. The lens of the eye is dislocated and there is a high frequency of glaucoma or retinal detachment. Marshall syndrome—a disorder of the connective tissue which can result in progressive sensorineural hearing loss, myopia, cataracts and detached retina. Joints may become hyper extensible and osteoarthritis may develop in large joints later. Facial features include a flat round midface, the appearance of large eyes and short upturned nose. Marshall-Smith Syndrome—accelerated skeletal maturation (usually starting before birth), respiratory difficulties and mental retardation. Features include dysmorphic facial features, prominent eyes, bluish sclerae, coarse eyebrows, upturned nose and skull abnormalities. Respiratory difficulties, pneumonia and failure to thrive are common. McCune–Albright syndrome—a disorder affecting bone, skin and endocrine systems. Features include fibrous dysplasia, café au lait macules, various endocrine disturbances (notably precocious puberty, hyperthyroidism, excess growth hormone and cushing’s syndrome). McRae Line—used in assessment of the craniocervical junction. Melkersson-Rosenthal Syndrome—a noncaseating granulomatous disease resulting in persistent or recurrent orofacial swelling, facial paralysis and a fissured tongue. Ménière’s disease (endolymphatic hydrops)—a disorder of the inner ear which results in severe vertigo, tinnitus, hearing loss and aural fullness. One or both ears may be affected. Symptoms last a few hours. The cause is unclear but likely involves increased fluid in the labyrinth of the inner ear. Mikulicz’ aphthae—a minor recurrent aphthous ulcers (see chapter on the mouth). Millian’s ear sign—erysipelas is seen to spread to pinna, where as in cellulitis it does not. Miller Fisher Test (CSF tap test) a test used to decide whether shunting of cerebrospinal fluid will help in suspected normal pressure hydrocephalus. 30 mL of CSF is withdrawn via a lumbar puncture. Clinical improvement in cognitive function suggests probable benefit. Möbius sign—an inability to maintain convergence of the eyes. Seen in Graves’ disease.

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Morgagni syndrome—obesity, hirsutism (abnormally excessive hair growth), and Hyperostosis frontalis interna Müller’s Manoeuvre—a reverse Valsalva manoeuvre is performed (attempted inspiration with a closed mouth and nose). At the same time fiberoptic assessment of airway is undertaken, looking for collapse. This may be used to determine the cause of sleep apnea. Müller’s sign—pulsation of the uvula that occurs during systole. May be a sign of severe aortic insufficiency. Munchausen syndrome—a factitious disorder where those affected fake disease, illness, or psychological problems to draw attention. People may fake their symptoms in multiple and creative ways, including self-inflicted injury. Munchausen syndrome by proxy is where attention-seeking behaviour is sought by a caregiver/ parent using those who are in their care. Naffziger sign—Increase in pain or sensory disturbances over the distribution of a nerve root following compression of the jugular veins occurs in the presence of an extruded intervertebral disk or mass. Nikolsky’s sign—formation of bullae after shearing forces are applied to the epidermis or mucosa—commonly seen in pemphigus vulgaris Norrie disease—a hereditary autosomal recessive oculocerebral disease resulting in mental retardation, hearing loss, and bilateral leukocoria of varying degrees of severity. Ocular changes include retrolental fibrosis, intravitreal haemorrhage and microphthalmia. The abnormality is generally bilateral. Oliver’s sign—tracheal tugging, can occur in aortic aneurysms Osler–Weber–Rendu syndrome (hereditary hemorrhagic telangiectasia)—a rare disorder that results in abnormal vessel formation. This can present as recurrent epistaxis, bruising, GI tract bleeding and involvement of other organs. AVMs are associated. Treatment focuses on controlling bleeding from defective blood vessels. Diagnosis is made based on the “Curaçao criteria”. If three or the following are present, the condition is confirmed (1) spontaneous recurrent epistaxis, (2) multiple telangiectasias in typical locations, (3) visceral AVM (lung, liver, brain, spine, (4) first-degree family member with HHT. Paget’s disease (osteitis deformans)—a disorder of boney remodeling. Disorganised new bone formation occurs resulting in deformity, weaken, pain, fracture and arthritis of associated joints. Common sites include the pelvis, femur, vertebrae and skull—with reduced hearing or vision. Rarely malignant change can arise. Treatment involves bisphosphonates and calcitonin. Parinaud syndrome (dorsal midbrain syndrome)—a cause of light-near dissociation (Argyll Robertson pupils). The patient has a vertical gaze palsy associated with pupils that accommodate but do not react. Causes include pinealomas, multiple sclerosis and brainstem infarction. Parinaud oculoglandular syndrome—unilateral granulomatous conjunctivitis, pre-auricular lymphadenopathy and fever. Common causes include tularaemia, cat-­ scratch disease, tuberculosis, syphilis and lymphogranuloma venereum. Parkinson’s disease—a slowly progressive neurodegenerative motor disorder involving the substantia nigra in the midbrain. Initial symptoms include a tremor at

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rest which disappears during voluntary tasks (‘pill-rolling’ in the hand), slowness of movement, ‘cogwheel’ rigidity and difficulty walking. Dementia, depression and anxiety may occur later. The precise cause is unknown but there occurs a build-up of proteins (Lewy bodies) in the neurones. Diagnosis is based on symptoms. Antiparkinson medication includes levodopa (L-DOPA), Dopamine agonists and deep brain stimulation in selected cases. Stem cell transplantation is an active area of research. Parks–Bielschowsky test (head tilt test)—a test to isolate a weakened extraocular muscle (particularly superior oblique muscle) in acquired vertical double vision. Paul Dudley White’s winking ear lobe sign—movement of the ear lobe in time with the pulse suggests tricuspid insufficiency. Pemberton manoeuvre—a clinical test for latent thoracic inlet syndrome. The patient elevates both arm until they touch the sides of the face. A positive Pemberton’s sign occurs when the patient develops facial congestion and cyanosis, and respiratory distress after about one minute. This indicates superior vena cava syndrome (SVC), commonly the result of a mass in the mediastinum, such as a retrosternal thyroid, lymphadenopathy, tumour, or following fibrosis of the mediastinum. SVC syndrome can result from diffuse mediastinal lymphadenopathy following various pathologies such as cystic fibrosis and Castleman’s disease. Peutz–Jeghers syndrome—a genetic disorder characterised by multiple benign gastrointestinal hamartomatous polyps and pigmented perioral macules on the lips and oral mucosa. There is a risk of GI malignancy. Phelp’s sign—the loss of bone between the carotid canal and the jugular canal, seen in glomus jugulare Pickardt syndrome (Pickardt–Fahlbusch syndrome)—a rare form of hypothyroidism caused by obstruction of the portal veins connecting hypothalamus and pituitary. This can arise from tumours compressing the infundibulum, or inflammatory disorders and traumatic brain injury. A congenital variant of Pickardt’s syndrome is sometimes referred to as pituitary stalk interruption syndrome (PSIS). Symptoms include those of hypothyroidism, functional hyperprolactinemia, secondary hypogonadism, reduced growth hormone and secondary adrenal insufficiency. Treatment depends on the cause and if necessary, replacement hormones. Pierre Robin syndrome—refers to a cleft palate resulting from a severe micrognathia (underdeveloped lower jaw). During embryonic development the palate is initially open. With micrognathia there is not enough room for the tongue to descend. This prevents subsequent closing of the palate. Plummer’s disease (toxic nodular goiter)—a multinodular goiter associated with hyperthyroidism. It is the second most common cause of hyperthyroidism (after Graves’ disease) in the developed world (iodine deficiency is the most common cause of hypothyroidism in the developing world). Symptoms include those of hyperthyroidism plus tracheal compression with very large thyroids. Treatment includes antithyroid medications, radioactive iodine and surgery. Plummer’s nail—separation of the nail from the nail bed (onycholysis), seen in patients with thyrotoxicosis.

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Pott’s puffy tumour—a misnomer. A subperiosteal abscess associated with osteomyelitis of the frontal bone. Infection can also spread inwards, with a risk of cortical vein thrombosis, extradural abscess, subdural empyema and cerebral abscess. Management involves surgical debridement and antibiotics. Potocki–Shaffer syndrome—a rare genetic syndrome that results in defects in the heart, kidneys, and urinary tract. The parietal foramina are enlarged resulting in brachycephaly and additional “soft spots” in the skull. Visual and other craniofacial abnormalities can occur. Primrose syndrome—a rare, slowly progressive disorder characterised by ossification in the auricles, hearing impairment, learning difficulties and facial abnormalities. Plummer–Vinson syndrome (Paterson–Brown–Kelly syndrome, sideropenic dysphagia)—dysphagia, iron-deficiency anaemia and oesophageal webs. Today this syndrome is rare, as a result of improvements in nutritional status. It generally occurs in postmenopausal women. Patients have an increased risk of squamous cell carcinomas of the oesophagus and pharynx. Other symptoms include glossitis, koilonychia, cheilitis and splenomegaly. Diagnosis is made following barium oesophagography or videofluoroscopy. Treatment is aimed at correcting any iron-deficiency anaemia. Quadriceps test—for hyperthyroidism. An inability to maintain leg extension at a right angle to the body when sitting. Normal persons can hold this position for at least a minute. Those with hyperthyroidism can maintain it for only a few seconds. Queckenstedt’s sign: Compression of the IJV results in a rapid rise in the ICP. In healthy people, the pressure rises rapidly on compression and then disappears when the compression is released. In those with vertebral canal block, the cerebrospinal fluid pressure is scarcely affected by compression of the veins of the neck, unilaterally or bilaterally. Quincke’s sign—an acutely swollen uvula. This can present with a sensation of fullness in the throat and gagging. The uvula is swollen and appears translucent, sometimes resting on the tongue. May be related to exposure to allergens, or hereditary angioedema. Initial treatment includes antihistamines, nebulised adrenaline and intravenous corticosteroids. Ramsay Hunt syndrome. Three syndromes carry this name. Ramsay Hunt syndrome type 1 (Ramsay Hunt cerebellar syndrome)—a rare form of cerebellar degeneration. Ramsay Hunt syndrome type 2 (herpes zoster oticus)—reactivation of herpes zoster in the geniculate ganglion, resulting in facial weakness, deafness, vertigo, pain and vesicles in the ear. Ramsay Hunt syndrome type 3 (Hunt’s disease or artisan’s palsy) Rathkes pouch—an invagination of endoderm from the developing nasopharynx which will become the anterior pituitary. Raymond Céstan syndrome—obstruction of the long circumferential branches of the basilar artery. Clinical features include (1) Ipsilateral ataxia and coarse intention tremor (superior and middle cerebellar peduncle), (2) Ipsilateral paralysis of muscles of mastication and sensory loss in face (sensory and motor nuclei of CN V), (3) Contralateral loss of sensation in the body (spinothalamic tract and medial

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lemniscus), (4) Contralateral hemiparesis of face and body (corticospinal tract), (5) Horizontal gaze palsy. Refsum disease (heredopathia atactica polyneuritiformis)—an autosomal recessive neurological disorder that results in the over-accumulation of phytanic acid. This results in cerebellar degeneration and peripheral neuropathy with ataxia, Treatment involves a phytanic acid-restricted diet (avoid grass feeding animals and certain fish, such as tuna, cod, and haddock). Plasmapheresis may help. Reiter’s syndrome (reactive arthritis)—an cross-reactivity inflammatory arthritis that occurs following infection elsewhere. This often involves large joints and occurs with conjunctivitis, uveitis and urethritis or cervicitis. Patients can also develop mucocutaneous and psoriatic-like lesions. Common triggers are Salmonella, Shigella Campylobacter and Chlamydia trachomatis. Reye syndrome—a rapidly progressive encephalopathy mostly in children, resulting in vomiting, confusion, seizures and loss of consciousness. Reye syndrome in adults is rare. Death occurs in 20–40% of patients and about one third who survive have significant degree of brain damage. The cause is unknown, but it was mostly associated with ingestion of aspirin, or following a viral infection (such as influenza or chickenpox). For this reason, aspirin is not prescribed in children. Treatment is supportive. Riddoch syndrome (Riddoch phenomenon)—an ability to distinguish static objects which are effectively invisible to the patient. Only moving objects are perceived and even then only poorly. The condition is caused by lesions in the occipital lobe. Riedel’s thyroiditis (Riedel’s woody thyroiditis)—a chronic form of thyroiditis now believed to possibly be a manifestation of IgG4-related disease. The disease is characterised by dense fibrosis of the gland that extends into the neck. The thyroid gland becomes hard and fixed to the adjacent structures. Treatment usually consists of prednisolone and/or surgery. Riesman’s sign—a bruit over the globe of the eye, heard in thyrotoxicosis Riggs’ disease (pyorrhoea, gingivitis expulsiva)—a historical term for periodontitis. Rinne test—a hearing test (see chapter on the ear). Ritter’s disease (staphylococcal scalded skin syndrome, pemphigus neonatorum)—bullous impetigo caused by Staphylococcus aureus. It is most common in children under 6 years, but can be seen in immunosuppressed adults. Widespread formation of fluid-filled blisters occur often involving the face and nappy area. These then rupture resulting in painful erythroderma. The condition is caused by epidermolytic exotoxins produced by S. aureus. IV antibiotics to cover S. aureus should be given (eg vancomycin or clindamycin). Robles’ disease (Onchocerciasis, river blindness)—Onchocerca volvulis infection transmitted by the black gnats of the genus Simulium. It affects individuals who live or work within a few kilometers of the waterways. The disease can involve the skin, lymphatics, eyes and elsewhere. Two forms of infection are recognised—a benign type, produced by adult worms, which affects the subcutaneous lymphatic vessels and a severe type, in which microfilaria invade the eyes. This is a major

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cause of blindness after trachoma. Onchocerciasis is found mainly in Africa and in parts of South America and the Arabian Peninsula. Romberg test—for differentiating between peripheral and cerebellar ataxia. An increase in unsteadiness when the eyes are closed indicates peripheral (spinal) ataxia, but no change indicates cerebellar. Romberg’s sign—unsteadiness and swaying is seen in tabes dorsalis. Rosai- Dorfman disease (sinus histiocytosis) a rare disorder in children, resulting in severe lymphadenopathy (usually the cervical lymph nodes) characterised by the accumulation of histiocytes in the lymph node sinus. Other features include involvement of the skin, kidneys and skeletal system. Symptoms usually subside after around 6–9 months. Diagnosis is based on histology. Treatment is not usually required unless severe, when surgical, chemotherapy or radiotherapy options are considered. Roth’s spots—retinal haemorrhages with pale centres seen in SBE and some systemic vasculitides Rust’s phenomenon—In cancer of the upper cervical vertebrae, the patient supports their head by their hands when changing from the laying to the sitting position or vice versa Sandifer syndrome—gastrointestinal symptoms and neurological features in children, which is associated with gastro-oesophageal reflux. Onset is usually in infancy or early childhood. Symptoms include spasmodic torticollis and dystonia, with nodding and rotation of the head, neck extension, gurgling, writhing movements of the limbs and severe hypotonia. Schirmer’s test—measures tear production. A strip of filter paper is placed inside the lower eyelid for five minutes, and its wetness is measured. Less than 5 mm of wetness is usually indicative of dry eye. Schinzel–Giedion syndrome—a congenital neurodegenerative disease associated with skull abnormalities, midface retrusion, hydronephrosis and other anomalies. Schnederian papilloma—inverted papilloma of nose Schwartze sign—the appearance of a reddish retrotympanic mass from discolouration of the promontory. Is said to be pathognomonic for otosclerosis. Seaver Cassidy syndrome—a very rare disorder characterised by hypertelorism, telecanthus, epicanthal folds, downslanting palpebral fissures, ptosis, broad nasal bridge, malar hypoplasia, thin upper lip, smooth philtrum and low-set, prominent ears. Males may also have an underdeveloped scrotum and cryptorchidism. Skeletal anomalies may also be present. Seidel’s sign—a sickle-shaped scotoma that is a superior or inferior extension of the blind spot. It occurs in some patients with glaucoma. Shabbir syndrome (laryngo–onycho–cutaneous syndrome)—a rare genetic disease in which patients develop abnormalities in the larynx, finger and toenails and skin. Many of these are related to the abnormal growth of granulation tissue. Symptoms in infants include a hoarse cry due to overgrowth of granulation tissue in the larynx. Excess granulation tissue can also block the airway. Granulation tissue can also grow in the conjunctiva resulting in impairment or complete loss of vision.

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Sheehan’s syndrome (postpartum pituitary necrosis)—ischaemic necrosis of the pituitary gland following blood loss during and after childbirth. If severe this can result in hypopituitarism. Since the pituitary controls many endocrine functions, a variety of symptoms may occur (agalactorrhea, oligomenorrhea, hypothyroidism, adrenal insufficiency. In severe cases an Addisonian crisis can develop. Treatment requires life long hormone replacement therapy. Sipple syndrome (Multiple endocrine neoplasia type 2)—a group of conditions associated with tumours of the endocrine system. These may be benign or malignant and commonly involve the thyroid, parathyroid, and adrenals. MEN2 is a sub-­ type of MEN (multiple endocrine neoplasia). Features include musculoskeletal changes, neurofibromatosis, medullary thyroid carcinoma (MTC), pheochromocytoma and hyperparathyroidism. Sjögren syndrome—an autoimmune disease involving the salivary and lacrimal glands. Symptoms include a dry mouth and dry eyes. Dry skin, vaginal dryness, a chronic cough, lethargy are also described. There is an increased risk of lymphoma. Primary and secondary forms exist. Diagnosis is by biopsy of the labial glands and tests for specific antibodies. SS can be associated with several autoimmune or rheumatic disorders, including as coeliac disease and SLE. Spurling test—Compression on the head with extension on the neck causes radicular pain into the arm—a test for cervical foraminal nerve root entrapment. Stankiewick’s sign—this is seen during a FESS, when lamina papyracea is accidentally damaged. Orbital fat protrudes into the nasal cavity on compression of the globe Sturge–Weber syndrome—one of the phakomatoses (a group of neuro-oculo-­ cutaneous disorders involving structures arising from the embryonic ectoderm). Features include a “port-wine” stain of the face, glaucoma, seizures, mental retardation and cerebral vascular malformations. Stargardt disease—a common inherited retinal disease with macular degeneration and progressive loss of vision. Steele–Richardson–Olszewski syndrome (progressive supranuclear palsy)—a neurodegenerative disease. Symptoms include loss of balance, bumping into objects, falls, slurring of speech, difficulty swallowing, and difficulty moving the eyes, particularly on looking up. There is no known cure for SROS and management is primarily supportive. Stevens–Johnson syndrome—an immune based skin and mucous membrane reaction of varying severity, resulting in blistering and inflammation in the skin, mouth and eyes. Complications include dehydration, sepsis and multiple organ failure. The most common cause is following ingestion of some medications, or some infections. Treatment is mostly supportive, but may require steroids. Susac’s syndrome (retinocochleocerebral vasculopathy)—a very rare form of microangiopathy characterised by encephalopathy, retinal artery occlusions and hearing loss. The cause is unknown but may be autoimmune. Symptoms include speech and hearing problems, severe headaches and migraines and impaired vision. These can mimic multiple sclerosis. Treatment includes immunosuppressive agents and corticosteroids

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Swischuk’ s line—alignment of the spinolaminar junction. This is a line which passes along the bases of the spinal process. Angulation of the spinous processes of 11 or more degrees signifies fracture or ligamentous disruption. Sydenham’s chorea (St Vitus dance)—neurological symptoms in acute rheumatic fever. The patient develops choreiform movements and neuropsychiatric symptoms. Presumed to be as a result of neuron-specific antibodies affecting the basal ganglia. Takayasu’s disease (aortic arch syndrome)—an inflammatory vasculitis involving large vessels, resulting in vascular stenosis, thrombosis, and aneurysms. It is commonly seen in young or middle-age Asian women. It mainly affects the aorta and its branches. Obstruction of the left common carotid artery, the brachiocephalic artery and the left subclavian artery, can result in as weak or absent pulses in the arms. Fainting may result from a subclavian steal syndrome or carotid sinus hypersensitivity. Neurological symptoms vary and can range from lightheadedness to seizures. Ocular involvement can result in visual field defects, visual loss or retinal haemorrhage. Stenosis of the renal arteries causes hypertension. A rare complication is coronary artery aneurysm. Diagnosis involves CT angiography, magnetic resonance angiography or contrast angiography to identify “skip lesions” (stenosis and aneurysms alternating with normal vessels). Treatment involves steroids, vascular bypass, angioplasty and stenting. Tapia’s syndrome—an uncommon condition characterised by concomitant paralysis of the vagal and hypoglossal nerves Terson’s syndrome—a rare combination of vitreous haemorrhage with subarachnoid haemorrhage. These are two separate bleeds linked by the increased intracranial pressure related to a subarachnoid haemorrhage. This increased pressure acts on retinal venules, triggering the bleeding Thomsen disease (congenital myotonia, myotonia congenita)—a congenital neuromuscular disorder that affects the skeletal muscles. The hallmark of the disease is the failure of voluntary contraction to relax, often in the hands, face, and eyelids, resulting in rigidity. The condition is sometimes referred to as fainting goat syndrome. Tietz syndrome—an autosomal dominant disorder characterised by profound sensorineural hearing loss from birth, white hair and pale skin. The iris is blue and retinal pigment epithelial cells lack pigment. Tinel’s sign—percussion over a divided or repaired nerve may elicit a tingling sensation in the distal end. This is said to indicate signs of regeneration. Tolosa-Hunt syndrome (cavernous sinus pseudotumor)—an acquired immunebased process without systemic involvement. Probably a variation of idiopathic orbital inflammatory syndrome (IOIS), which involves the orbital apex and cavernous sinus region. Treacher Collins syndrome—a genetic disorder characterised by deformities of the ears, eyes, cheekbones, eyes, teeth and chin. The underlaying problem is a failure of neural crest cells to migrate in to the first and second pharyngeal arches. The most common symptoms are therefore related to structures derived from

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these arches and include underdevelopment of the mandible and zygomatic bones. Complications may include breathing problems, problems seeing and hearing loss. Trail’s sign—the sternal attachment of the sternomastoid muscle becomes more prominent on the side to which a deviated trachea is displaced. Troisier’s sign—an enlarged hard Virchow’s node. Turner syndrome—a condition in which a female is partly or completely missing an X chromosome. Signs and symptoms vary and include a short, webbed neck, low-set ears, low hairline at the back of the neck, short stature, rudimentary ovaries, heart defects, diabetes and low thyroid hormone. Unterberger’s stepping test—used in otolaryngology to assess whether a patient has a vestibular pathology. The patient is asked to walk with their eyes closed. If the patient rotates to one side they may have a labyrinthine lesion on that side. Usher syndrome (Usher-Hallgren syndrome, retinitis pigmentosa-dysacusis syndrome)—a rare genetic disorder resulting in hearing loss and visual impairment. It is responsible for the majority of deaf-blindness cases. Blindness is progressive as a result of retinitis pigmentosa, which commences peripherally and progresses towards the macula. Early symptoms include night blindness (nyctalopia) and loss of peripheral vision. Hearing impairment arises form damaged hair cells in the cochlea. Valsalva manoeuvre—forcible exhalation against a closed glottis—this results in a rapid rise in intrathoracic pressure. Van der Hoeve’s syndrome (Osteogenesis imperfecta, or brittle bone disease). A progressive disorder that occurs in four types. Characterised by blue sclerae, brittle bones, and conductive deafness due to otosclerosis-like changes in the temporal bone. The Ekman-Lobstein syndrome is an adult variant. Vincent’s angina (Plaut-Vincent angina)—tonsillitis caused by an infection from spirochaeta and treponema Vincent’s symptom—numbness of the lip (distribution of the inferior alveolar nerve). Many causes including fractures of the mandible, bony infections and infiltrating tumours. Virchow’s node—left-sided supraclavicular lymph node. These nodes receive lymph vessels from the chest and abdominal cavity, via the thoracic duct. Enlargement may therefore signify cancer within the abdomen (notably gastric, ovarian, renal and testicular). Von Graefe’s sign—lagging of the upper eyelid on looking down, suggesting Graves’ Disease. Von Hippel–Lindau disease (Familial cerebello retinal angiomatosis)—a rare multisystem disease resulting in haemangioblastomas, pheochromocytoma, pancreatic cysts and other benign tumours with the potential for malignant transformation, such as renal cell carcinoma. It is a type of phakomatoses (a group of neuro-oculo-­ cutaneous disorders involving structures arising from the embryonic ectoderm). Several subclassifications exist. Symptoms include headaches, dizziness, visual problems and high blood pressure. Strokes, myocardial infarction and spinal

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haemangioblastomas are also common. Diagnosis is often made based on a family history of VHL disease, and the presence of haemangioblastoma, pheochromocytoma or renal cell carcinoma. Von Recklinghausen Neurofibromatosis (Neurofibromatosis type I)—a complex disorder resulting in numerous tumours arising anywhere in the body, within peripheral nerves. Neurofibromas are derived from Schwann cells. Patients also have Lisch nodules (brownish-red spots in the iris), benign skin tumours (neurofibromas—firm, rubbery lumps), larger plexiform neurofibromas, scoliosis, multiple café au lait spots and epilepsy. The neurofibromas may result in multiple neurological conditions and disfigurement. Neurofibroma of the ID nerve is a very rare cause of a numb lip. Optic gliomas can result in proptosis, strabismus, diplopia and loss of loss. Neurofibromas rarely undergo malignant change. Treatment includes surgery, radiotherapy and occasionally chemotherapy. Von Willebrand disease—a common hereditary blood-clotting disorder. An acquired form can also result from other medical conditions. There is deficiency in von Willebrand factor (vWF), a protein required for platelet adhesion. Deficiency of vWF can also lead to a reduction in factor VIII. Symptoms include easy bruising, nosebleeds and bleeding gums. Women may experience heavy menstrual periods and blood loss during childbirth. Excessive bleeding following dental extractions or ENT procedures should raise concerns. Management includes replacement therapy and antifibrinolytic agents such as epsilon amino caproic acid and tranexamic acid. Waardenburg syndrome—a rare genetic disorder resulting in minor defects in structures derived from the neural crest. Features include hearing loss, pale or blue eyes, heterochromia, or sectoral heterochromia, white hair, broad nasal root, eyebrows that meet in the middle (synophrys) and patches of pale skin pigmentation. Intestinal and spinal defects can also occur. Wackenheim Line (Basil line)—used to asses the odontoid process. Walker-Warburg syndrome—an oculocerebral disease resulting in hydrocephalus; agyria or lissencephaly, retinal abnormalities similar and sometimes encephalocele. Warthin’s tumor (papillary cystadenoma lymphomatosum)—a benign tumour of the salivary glands (often the parotid gland), containing abundant lymphocytes. Usually seen in older individuals (age 60–70 years) and is more common in males and smokers. Waterhouse–Friderichsen syndrome—adrenal gland failure following intra-­ glandular haemorrhage. Commonly caused by severe bacterial infection (notably Neisseria meningitidis) Meningococcaemia results in sepsis, disseminated intravascular coagulation, purpura, organ failure, rapidly developing adrenocortical insufficiency, coma and death. WFS can also occur following severe infection with other organisms such as Pseudomonas, Streptococcus, Staphylococcus, Haemophilus and Mycobacteria. Watson syndrome—an autosomal dominant condition characterised by Lisch nodules, axillary/inguinal freckling, pulmonary valvular stenosis, macrocephaly, and neurofibromas. Weber test—a hearing test (see chapter on the ear)

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Wegener’s Granulomatosis (Granulomatosis with polyangiitis)—a multisystemic vasculitis of unknown cause which results in granulomatosis. It affects smalland medium-size vessels most commonly in the upper respiratory tract and the kidneys. Symptoms include nosebleeds, blocked nose, crustiness of nasal secretions, eustachian tube dysfunction and inflammation of the uvea. Septal perforation and a saddle-nose deformity are typical complications. Involvement of the heart, lungs and kidneys and subglottal stenosis can be fatal. Management involves immunosuppressants such as rituximab or cyclophosphamide in combination with high-­ dose corticosteroids. Wermer’s syndrome (Multiple endocrine neoplasia type 1 MEN-1)—one of a group of disorders that affect the endocrine system. Tumours develop in the pituitary, parathyroid gland and pancreas. Signs and symptoms vary accordingly, depending on extent of involvement (hypercalcemia, nephrolithiasis, hypoglycemia, diarrhoea, steatorrhea and Cushing’s syndrome) Wernicke encephalopathy—neurological symptoms caused by thiamine (vitamin B1) deficiency. It may occur in association with beriberi and alcoholic Korsakoff syndrome (Wernicke–Korsakoff syndrome). Symptoms of Wernicke encephalopathy include ophthalmoplegia, ataxia and confusion. Treatment includes thiamine supplementation. Most symptoms will improve quickly. Wilson’s disease—a genetic disorder in which copper builds up in the body, notably involving the brain and liver. Renal tubular acidosis and cardiomyopathy can also occur. Neurological symptoms include tremors, difficulty speaking, personality changes and hallucinations. Kayser–Fleischer rings are a pathognomonic sign and may be visible in the cornea. These are due to copper deposition in Descemet’s membrane. “Sunflower cataracts” appear as brown or green pigmentation of the anterior and posterior lens capsule. Management involves penicillamine (which binds copper) and dietary advice. Wiskott–Aldrich syndrome a rare disease which includes eczema, thrombocytopenia (low platelet count), immune deficiency, and bloody diarrhoea (secondary to the thrombocytopenia). Patients have increased susceptibility to infections, particularly of the ears and sinuses. Woods sign—a palpable jugulodigastric lymphnode Wyburn-Mason syndrome—a high-flow arteriovenous malformation extending from the orbit and retina along the anterior visual pathways to the midbrain Zenker’s diverticulum (pharyngeal pouch)—a diverticulum of oesophagus, arising just above the cricopharyngeal muscle as a result of spasm and uncoordinated swallowing.

3

The Injured Patient Soudeh Chegini and Michael Perry

3.1

Initial Assessment of the Injured Patient

Trauma is generally recognised as the leading cause of death in individuals under the age of 40. Although there has been greater acceptance and enforcement of traffic safety measures, serious injuries, particularly those resulting from motor vehicle collisions, are still prevalent worldwide with more than one million deaths annually. When assessing the multiply injured patient in many trauma centres and hospitals today, the injury severity score (ISS) is generally regarded as the gold standard for scoring the severity of their injuries, although other scoring systems exist. The ISS is an adaption of the Abbreviated Injury Scale. Scores from the three most severely injured anatomical sites (one injury per body region) are added together, resulting in an ISS that usually correlates well with the overall severity of injury and survivability of the patient. An ISS of 16 or greater is regarded as a critical injury. In many countries today, such patients are assessed and treated in accordance with the American College of Surgeons’ Advanced Trauma Life Support (ATLS) program®. ATLS has now gained widespread acceptance across most of the world and has been validated as an efficient and safe approach in the management of the multiply injured patient. When a patient has multiple injuries it can be easy to become distracted and difficult to decide which injury to treat first. The ATLS system of care prioritises injuries according to their immediate threat to life. In this way injuries compromising the airway (A) are treated first, followed by those likely to affect ventilation and the delivery of oxygen to the blood (B—Breathing). This is then followed by those injuries likely to affect the delivery of the oxygenated blood to the brain

S. Chegini (*) Northwick Park Hospital, Harrow, UK M. Perry London Northwest University Hospital, Harrow, Middlesex, UK © Springer Nature Switzerland AG 2021 M. Perry (ed.), Diseases and Injuries to the Head, Face and Neck, https://doi.org/10.1007/978-3-030-53099-0_3

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(C—Circulation). Head injuries are then evaluated and treated as part of D— Disability. Finally the entire body is exposed to assess for any other injuries and the patient kept warm (E—exposure/environment). This algorithm is not surprisingly referred to as the ‘ABCDE’ approach. Other systems have been designed that continue this alphabetical theme and act as an aide memoire. They include F—foley catheter/Farenheit (temperature), G—gastric tube/ Get vital signs (ECG, Pulse Oximetry), H—Head to toe exam, I—Interventions, Inspect back etc. However, whilst these are useful prompts they are not recognised as part of the ATLS system. Initial assessment in ATLS consists of an initial rapid primary survey to identify and treat immediate life-threatening conditions (based on the ABCDE approach). The exception to this sequence is in patients with an obvious external exsanguinating wound. In these circumstances control of haemorrhage is undertaken before or at the same time as assessing, and if necessary securing the airway. This should only take a few seconds. Following the primary surgery and when the patient is stable, appropriate investigations and a more detailed head to toe examination (secondary survey) can then be performed. Within this context, any head, neck or facial injuries that threaten life (and sight—discussed later) need to be recognised and dealt with urgently during the primary survey. As such, it is important to be especially vigilant towards injuries that can place the airway at immediate risk. This is discussed further, later in this chapter and in the chapter on anaesthesia. Spinal immobilisation is also frequently required with significant injuries above the collarbones, as cervical spine injuries can be fatal (see the chapter on the back of the neck), and this in itself can bring problems in patients with significant facial injuries. Uncontrolled bleeding from the scalp, face and neck can also quickly impair the patient’s circulation, resulting in haemodynamic shock, drowsiness and loss of the anyway. Injuries above the collar bones may also disrupt the cranium or visual system. These must be identified and managed during the disability stage—D and are discussed elsewhere. With regards to facial injuries, most patients usually present without life-threatening complications. So long as the airway is secure and there is no active bleeding from the face, these injuries can be assessed during the secondary survey and should not be allowed to distract us from the primary survey and more serious conditions. At the end of the primary survey patients will undergo investigations such as a ‘pan-scan’ (CT of the head, neck, chest, abdomen and pelvis) or plain X-ray of the chest, cervical spine and pelvis. In many trauma units today, multislice CT (MSCT) now serves as the main imaging technique, due to its high diagnostic precision and speed in obtaining images. Throughout the initial stages of assessment is important to continuously reassess the patient injuries can evolve over time. Once the primary survey has been completed and the patient is stable, facial injuries can then be addressed and treated (Figs. 3.1 and 3.2).

3.1.1 Life-Threatening Injuries to the Head, Neck and Face These are discussed in further detail in the relevant chapters throughout this book. Here an overview will be presented. One of the commonest causes of death following severe facial injury is airway obstruction. This may be because of the tongue

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Fig. 3.1 Obvious facial injuries following a high-speed motor vehicle collision. The brain, eyes, and cervical spine require careful evaluation

Fig. 3.2 Obvious injuries to the face and forehead with exposed brain and rupture of the globe. Remember the cervical spine as part of the assessment

obstructing the hypopharynx in an unconscious patient, massive swelling, or secondary to uncontrolled haemorrhage, effectively drowning the airway. However in many patients a combination of factors contribute to progressive airway obstruction.

3.1.2 Secretions and Bleeding Compromising the Airway The airway is generally considered to be the passage between the nasal and oral cavities, passing down to the tracheal bifurcation. Much of this passage is contained within the head, neck and face and this places the airway at significant risk from injuries above the collar bones. Bleeding and secretions are common and can quickly accumulate, resulting in obstruction. Coughing and clearing of the airway may be impaired and ineffective, especially in supine or drowsy patients. Frequent causes of bleeding and secretions include mucosa lacerations or facial fractures. Obstruction must therefore be anticipated and alleviated early with careful

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examination and gentle suction. Retropharyngeal haematoma, although rare, can occur following spinal injuries. This can also occasionally compromise the airway.

3.1.3 Oedema More insidious compromise can arise from swelling in the adjacent tissues. This may not be present initially, but can develop over time. This emphasises the importance of reassessment, as the patient’s physical well-being can change over time. Swelling can be particularly troublesome following midface and mandible fractures, as a result of generalised oedema or the development of haematoma. In such patients early consideration should be given to formal intubation and ventilation, especially if transfer to another hospital is anticipated. More sinister swelling can occur rapidly following inhalation injuries and smoke exposure and from high energy impacts, including facial gunshots. These patients can quickly develop massive airway compromise. This will be difficult to manage if it is not anticipated on arrival. These cases are almost always advised to undergo early intubation, as airway obstruction will inevitably occur. Circumferential burns of the neck will also cause significant swelling and restriction of the airway (Fig. 3.3).

3.1.4 Other Causes of Blockage of the Airway The tongue is supported within the oral cavity via its attachments to the mandible. Displaced anterior fractures can disrupt this support causing the tongue to flop backwards into the oropharynx if the patient is supine. Similarly, displaced midface fractures can physically reduce the space within the oropharynx, especially if fracture fragments are mobile and accompanied by bleeding and swelling. Foreign bodies may also block the airway passage. This may include avulsed teeth, dentures and external objects such as broken glass from a windshield (Figs. 3.4, 3.5 and 3.6). Fig. 3.3 Progressive facial swelling following isolated midface fractures. The mandible is intact. This patient is being nursed on her side but will require very close observation for the next 24 h

3  The Injured Patient Fig. 3.4 “Bucket handle” or comminuted fractures of the mandible place the airway at risk. The tongue is attached to the central mobile fragment(s) (a). If the patient is supine, any displacement can allow the tongue to fall back and obstruct the upper airway (b). Snoring is a sign of impending obstruction

Fig. 3.5  This patient received a localised blow to the face when the door of a lorry swung round and struck him. He was walking around at the scene with significant facial bleeding, when the paramedics arrived. A good example of “primum non nocere”— if he had been placed supine his airway could have obstructed

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Fig. 3.6  This patient was kicked in the face by a horse, sustaining comminuted fractures of the mandible. He developed airwaythreatening swelling over the next few hours, which required urgent intubation and placement of a temporary (percutaneous) tracheostomy, prior to repair

3.1.5 Cervical Spine Injuries These are discussed in greater detail in the relevant chapter of this book. As part of initial airway management, the cervical spine is simultaneously immobilised to prevent or exacerbate cervical cord injuries. Unstable injuries to the cervical spine that move can result in spinal cord haemorrhage, oedema, or direct neuronal injury, resulting in severe and permanent disability. The innervation to the diaphragm is derived from levels C3, C4 and C5 (discussed in the chapter on embryology). Any paralysis of the diaphragm will quickly compromise the patient’s ability to breathe and therefore adversely affect ventilation and oxygenation. The cervical spine is therefore protected very early, during assessment of the airway, either manually (inline immobilisation), or using a hard cervical collar, blocks and straps/tape (Figs. 3.7, 3.8 and 3.9).

3.1.6 Haemorrhage Together, the head, neck and face comprises one of the most vascular regions of the body. The brain receives 25% of the total cardiac output, all of which passes through the carotid and vertebral vessels and returns to the heart via a number of large veins. Due to its proximity, the face also receives a considerable amount of

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Fig. 3.7  A vertical split in a thoracic vertebra following a crush injury. This patient required spinal immobilisation and certainly would not have been able to sit up if coexisting facial injuries were obstructing the airway. This would have required urgent intubation

this high blood flow. The neck is therefore a highly vascular structure, with many vessels carrying blood from the heart to the brain (and upper limb), as well as to a multitude of organs and tissues within the face and neck itself. Penetrating injuries to the head, neck and face can therefore lead to circulatory collapse if not treated promptly. Damage to the carotid or internal jugular vessels can be devastating, due to their high output. Many patients will arrest at the scene of injury, unless bleeding can be immediately controlled. In the limbs, haemorrhage will often slow due to localised and generalised vasoconstriction. However in the head and neck, the blood supply is maintained at a high pressure to maintain perfusion of the brain. Therefore unless head and neck haemorrhage is stemmed by first responders, paramedics or the resuscitation team, it will not arrest spontaneously. A well known example of this is the patient with a slowly bleeding scalp laceration. These can be easily overlooked, but will continue to bleed until the patient develops haemodynamic shock. Blood loss from injuries to the external carotid artery and its branches can also cause circulatory compromise. These vessels are smaller than those passing to and from the brain and can therefore also be overlooked. A common injury is to the temporal artery. Vessels such as this

142 Fig. 3.8  This elderly patient was seen as an outpatient, having tripped and fallen flat on her face. In addition to her facial injuries she was also complaining of some mild weakness in her right hand. MRI confirmed a central cord syndrome. The clue is the mechanism of injury, which resulted in hyperextension of the neck

Fig. 3.9 Devastating injury, incompatible with survival

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have a superficial path and can be easily damaged by simple lacerations around the temple and forehead. Midface fractures can sometimes be associated with rupture of the venous plexus systems around the skull base. It is not possible to see the bleeding source directly. These will present with profuse bleeding around the oro and nasopharynx. If these fractures are not reduced promptly, blood loss will continue.

3.1.7 Head Injuries (Brain Injuries) These are also discussed in greater detail in the relevant chapter of this book. The brain is the most important organ within the body. Any injury above the clavicles should raise suspicion of the potential for a head injury. However, patients can sustain head injuries without any obvious signs of trauma to the head or face. This can occur following rapid deceleration (e.g. high speed vehicle collision or bungee jumping). Therefore careful assessment is important to avoid overlooking occult injuries. The risk of injury to brain can be assessed based on the mechanism of injury, the patient’s symptoms and following neurological examination. Head injury should be suspected if the mechanism of injury involves a high energy impact or rapid deceleration, such as a fall from height or motor vehicle collision. Patients with head injuries can present with vomiting, retrograde amnesia or impaired consciousness. Neurological examination should always include the Glasgow Coma Scale. If there is any concern, the patient should undergo an urgent CT of the head (and neck).

3.2

Understanding the (Rapid) Primary Survey

Through its various steps and techniques, the ultimate aim of the primary survey is to ensure delivery of adequate oxygen to the vital organs of the body, notably the brain. To fully understand how this process is applied, it is important to appreciate the steps that enable oxygen from the air to reach is destination—the cells and organs.

3.2.1 Providing Oxygen Normal air has an oxygen concentration of around 21%. This meets the needs of most uninjured persons. However, in the trauma setting the body’s oxygen requirement increases substantially. This can often be met by providing a higher concentration of inspired oxygen. The greater percentage of inspired oxygen increases the oxygen saturation of the blood perfusing the alveoli of the lung. This helps compensate for any reduced respiratory effort, structural lung damage or impaired circulation.

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3.2.2 Airway Patency Inspired oxygen must have a clear passage to the alveoli (i.e. a patent airway). Following trauma and in some diseases this can become blocked by distorted anatomy (such as an unsupported tongue), foreign bodies, swelling, secretions or blood. If the airway is completely blocked the patient will only have a few minutes to survive. This is why airway care is the first system in the ATLS algorithm. At the same time the cervical spine is protected.

3.2.3 Breathing (Ventilation) Within the lungs, the main gasses that are exchanged between the alveoli and blood are carbon dioxide and oxygen. Carbon dioxide (CO2) is primarily dissolved within the plasma. This must effectively pass from the blood into the alveoli and be expelled. If it is not, CO2 retention can quickly result in acidosis and adversely affect the intracranial pressure (and cerebral perfusion). Oxygen in turn, passes from the inspired air within the alveoli, into the blood and is transported principally bound to haemoglobin within the red blood cells. The amount of oxygen that is bound to haemoglobin can be estimated with the oxygen saturation. Breathing must therefore be adequate, that is to say, exchange of oxygen and CO2 must be adequate within the alveoli. This exchange process is known as ventilation. Passage of oxygen into the blood is known as oxygenation. Injury to the lungs can result in poor gas exchange and inefficient ventilation. Outwith the lungs, the thorax (rib cage) and diaphragm are also essential to normal breathing. The diaphragm is the chief muscle responsible for breathing at rest. Nerves from cervical spine levels C3, C4 and C5 provide its motor supply. This is remembered using the phrase ‘C3, 4, 5, keeps the diaphragm alive’. Protection of this neuronal pathway from the cervical spine is thus essential to life. This is achieved primarily by triple immobilisation, discussed elsewhere. Immobilisation occurs during ‘A’ and is maintained throughout. This and other measures will optimise the integrity of neurological outflow from the cervical spine, even in the presence of cervical spinal injury (Fig. 3.10).

3.2.4 Circulation (Haemorrhage Control) Oxygenated blood has to circulate to the vital organs, most notably the brain. This requires the heart to effectively pump the blood as well as an adequate circulatory volume. Both can be compromised if there is any damage to the heart, or following significant haemorrhage. The average 70 kg man requires around 5 L of blood in their circulating volume. However following trauma, fluid requirements may be

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Fig. 3.10  Multiple rib fractures resulting in a “flail chest”. Not only is respiration inefficient, but it is also very painful. In some trauma centres the rib fractures maybe surgically repaired, to reduce painful movements

higher. This is partly due to the systemic response to trauma. In addition to blood loss, the presence of damaged tissue causes the release of vasoactive chemicals. This increases systemic capillary permeability and the leakage of fluid and electrolytes from circulatory system into the extra and intracellular spaces. Clinically this appears as oedema and swelling. Furthermore, depending on the type of trauma (notably muscle damage), toxins such as myoglobin (rhabdomyolysis) and electrolytes (potassium) may also leak into the circulation. These need to be excreted as they are toxic to the heart and kidneys. The ability of cells to metabolise the delivered oxygen at a cellular level is chiefly a product of the integrity of each cell. This can be disrupted by a number of process and toxins such as cyanide (a problem following inhalation of fumes and smoke).

3.2.5 Disability The brain itself must be sufficiently vital for meaningful function. This requires structural integrity, neurotransmitter balance and adequate perfusion with oxygen and nutrients. This can be compromised with significant parenchymal injury or following intracranial swelling or haemorrhage. The presence of these is investigated with an urgent CT of the head. Severe or focal injuries such as haemorrhage will require neurosurgical intervention and intensive care. This is discussed further in the chapter on the head.

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3.2.6 Critical Steps in the ABCDE Algorithm Based on the understanding of trauma and the pathophysiology of cerebral hypoxia, a number of critical steps in the management of the injured patient have thus been developed. 1. The first step is to evaluate the airway, by eliciting a coherent verbal response and by visual confirmation. When necessary removal of foreign bodies from the anterior oral cavity and/or suction of blood and secretions may be performed. Airways adjuncts may also be required. Sometimes subtle signs, such as abrasions on the neck, or a change in the voice may indicate potential airway compromise and the need for early intubation. At the same time the patient’s cervical spine is also immobilised until injury to the cervical spine has been evaluated. 2. All trauma patients are provided with high flow oxygen. This should be through a non re-breathable mask to prevent inhalation of expired gases. At this stage any obvious chest injuries are identified and treated. 3. Assessment of the circulation involves assessment of both the circulatory volume and cardiac function. Injuries to the heart must be treated urgently. These include penetrating injuries and cardiac tamponade. At the same time the ­circulation is supported by IV fluids and if necessary, with blood. Multiple large bore intravenous cannulas are placed. 4. Disability assesses the level of consciousness (Glasgow coma score) and pupils (localising signs in the unconscious). 5. The final step in the primary survey is exposure and environmental control. This involves inspection of the entire patient (including their back), to identify any injuries. Examination of the back must be undertaken with controlled movement of the patient if spinal cord injury has not yet been ruled out. This involves log rolling the patient. Log rolling enables safe movement of the patient whilst maintaining the spine in a neutral position. During all this time, the patient is kept warm with blankets and if necessary overhead heating. Care must be taken to avoid hypothermia. This is often overlooked. In the presence of hypothermia, essential circulatory proteins, such as clotting factors, fail to perform. This can further exacerbate ongoing haemorrhage. The ABCDE algorithm is typically applied in this order, based on the time frame in which each threat to life can kill. However, recent experiences in the Iraq and Afghanistan wars have suggested a slightly more flexible approach may be required. In some circumstances, massive external haemorrhage is quickly addressed with pressure before continuing with the ABCDE algorithm. This has led to the development of the acronym MARCH (Massive haemorrhage, Airway, Respiration, Circulation, Hypothermia). Today, most trauma victims are managed by a trauma TEAM. This allows for each member to be allocated a role, such that multiple steps can often be completed simultaneously. A designated team leader oversees and coordinates management. Team leaders generally are not given a ‘hands-on’ role in this manner

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Fig. 3.11 Severe trauma to the face and head, potentially affecting all the elements of the primary survey

to allow him/her to supervise the complete management of the patient and direct each team member (Fig. 3.11).

3.2.7 History Taking in Trauma: The “Ample” History In general medicine, the usual approach in the assessment of patients, starting first with a detailed history and then examination, is not appropriate for the acutely injured or unwell patient. Nevertheless, a simple but relevant history is still needed, in order to quickly collect vital information. Often, the pre-hospital team obtains and shares this either during the pre-alert call, or on arrival at the emergency room. Ambulance and paramedic colleagues usually ask standardised questions when they arrive at the scene of an accident, but they also have the advantage of being able to see the environment where injuries have occurred. They therefore often have a better appreciation of the mechanism of injury and the likely forces that the patient may have been subjected to. This can be very helpful in the initial assessment. In other circumstances, the history may be collected from relatives or witnesses. Searching the patient’s personal property may also identify medication, medical devices or medical alert documentation. The acronym AMPLE is a useful guide to obtaining the relevant information. This stands for—Allergies, Medications, Past medical history, Last meal and Events.

3.2.7.1 Allergies This refers to any medications that are known to cause anaphylaxis in the patient. Anaphylactic reactions can be life-threatening and in the shocked patient can go unrecognised and complicate resuscitate. Patients with

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anaphylactic reactions often wear a medical alert bracelet or necklace. They may also carry a medical alert card or Epipen. Beware of descriptions of drug side effects. This is different to an allergy and side effects should not contraindicate the use of life saving medication.

3.2.7.2 Medications It is important to obtain a list of prescribed and non prescribed drugs. This includes recreational and herbal medications, both of which can affect the body’s physiology and interact with administered drugs. Despite widespread public perception that herbs and dietary supplements are safe, research has shown that some of these products carry the same dangers as prescribed medications. Interactions may occur between prescription drugs and these over-the-counter compounds. Such interactions involve mainly inhibition or induction of cytochrome P450 enzymes and/or drug transporters. This can increase the risk in patients taking drugs with a narrow therapeutic index (e.g. warfarin, cyclosporin and digoxin). Potential interactions can occur with the herbal medicines black cohosh, garlic, Ginkgo, goldenseal, kava, milk thistle, Panax ginseng, Panax quinquefolius, saw palmetto and St John’s wort. Ginkgo biloba extract, for example, has been reported to cause spontaneous bleeding and can interact with anticoagulants and antiplatelet agents. Salvia miltiorrhiza may enhance anticoagulation and bleeding among people taking warfarin. St. John’s wort may have monoamine oxidase–inhibiting effects and can increased levels of serotonin, dopamine and norepinephrine. It should not be used with prescription antidepressants. Ephedrine-containing herbal products have been associated with adverse cardiovascular events, seizures and even death. A list of all medications should therefore be obtained. Such a list may also provide clues to the patient’s baseline health and past medical history. 3.2.7.3 Past Medical History This refer to the patient’s co-morbidities, which is discussed in the chapter on general assessment of patients. With an increasing number of patients living to older age, accumulation of co-morbidities is common. This includes chronic organ failure (notably heart, lung and renal). Beware patients with chronic organ failure who are compensating. They may appear ‘well’ to their relatives, but should be considered at high risk of rapid deterioration. Once stabilised there should be a low threshold to transfer these patients to high dependency or intensive care settings. 3.2.7.4 Last Meal This is important to the timing of non-emergent surgery. Timing will depend on the urgency of the injury versus the safety of anaesthesia. During induction of anaesthesia and intubation patients may reflux and aspirate stomach contents. This is more likely if the stomach is full, in which case surgery is deferred or (if clinically urgent) rapid sequence induction can be performed with cricoid pressure to reduce the risk of aspiration. Recent consumption of water is of less significance.

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3.2.7.5 Events These include the mechanism of injury and the circumstances in which the patient was found (environment). The mechanism of injury will help estimate the forces that have been applied to the patient. This sets the threshold of suspicion for injuries, patterns of injury and their severity. For example, a patient who has fallen from the top of the stairs is more likely that have cervical spine injury than a collapse in the street. They type of surface onto which the individual has fallen is also important. Not all injuries come from impacts and deceleration injuries can result in severe mediastinal bleeding (the ‘Bell clanger’ effect). In broad terms, mechanisms of injury are considered as (1) blunt impacts, (2) rapid deceleration (such as motor vehicle collisions and falls) or (3) penetrating injury, such as shooting or stab wounds. Less common mechanisms include (4) burns and (5) explosive injuries. Each mechanism can produce a different pattern of injury and the amount of force involved in the injury will then dictate the severity of injuries suffered by the patient. If the mechanism involves a single blow, the risk of injury is usually localised to the associated anatomical region. In the head and neck for example, following a neck stabbing, we need to know how long the blade was, which direction the assault was from (above/below, in front/behind) and whether the blade broke. In this situation, pelvic, abdominal and lower limb injury is unlikely, although chest, head and upper limb injury are all possible. In such a confined anatomical space there is also the potential for airway, cervical spine, breathing and circulatory problems, all from a single wound. Other mechanisms may be more complex (MVC, fall from a height, explosion). With MVCs cases speed of impact, seat belt usage, vehicle deformity, and injuries sustained by others (notably fatalities) are useful clues. A pedestrian struck by a vehicle travelling at 20 mph has a 5% chance of sustaining fatal injuries, compared to someone struck by a vehicle travelling at 50 mph, who has an 85% chance of being killed. Infants and children have more elastic bones than adults. This can result in significant soft tissue and organ injury with relatively little bone deformity. Some important mechanisms of injury and related sequelae in head and neck trauma include A. Head on vehicle collisions can result in head and scalp injuries, facial injuries from impact with the steering wheel, dashboard or windscreen and flexion/ extension injuries to the cervical spine B. A fall or jumping from a height of 10 feet or more is likely to result in calcanial and other lower limb fractures depending on how the patient lands and what they landed on. If they land on their feet, the energy transfer can progress axially, resulting in hip, pelvic and spine fractures, and even skull base fractures. C. Falling from a bicycle is a common cause of orbitofacial injuries in children, typically resulting in ocular blunt trauma. Penetration of the orbit by a bicycle brake handle is a rare but devastating injury. Traumatic globe subluxation and skull base fractures may occur. D. Explosions can result in penetrating injuries and retained foreign bodies. Occasionally the entry wound seems innocuous and can be easily under appre-

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ciated. Many cases of foreign bodies in the middle third of face, notably the antrum and nasal cavity, have been reported in the literature. E. Whenever children hold objects in their mouths, oral injury is likely. Penetrating injuries of the palate have been reported with pens, screwdrivers and even chopsticks. Carotid injuries have been reported. Organic material may be difficult to identify on CT or MRI. F. Anterior–posterior directed impacts to the forehead or face can result in hyperextension injuries to the neck, resulting in ligamentous and possibly spinal cord injury. This is particularly common in the elderly. G. Strangulation/hanging type injuries can fracture the hyoid/larynx and avulse the trachea. H. A high-velocity projectile can penetrate both the eye and the brain. Cavitation can occur anywhere along the path of the projectile. This can be permanent or temporary depending on the amount of energy transferred and the elasticity of the tissues involved. Temporary cavitation can be easily overlooked as the structures involved return to their original position once the energy has been dissipated. Untreated, this can lead to significant tissue destruction and sepsis. I. Blunt trauma to the forehead can result in blindness, even in the absence of fractures. At the moment of impact, energy is transferred to the orbital apex, resulting in injury to the optic nerve. J. Fractures following an impact to the bridge of nose can extend deep to involve the skull base and orbit (with risks of CSF leaks and blindness) K. Successful airbag deployment has been reported to result in ocular injury. L. Compressed air or blast injuries can result in massive surgical emphysema in the face, neck, and chest. Pneumothorax can also occur. These can result in pressure fracture on adjacent structures, and can expand. Positive pressure ventilation carries significant risk if this involves the thorax. M. Rapid deceleration (for example seen in bungee jumping) has resulted in retinal haemorrhages, whiplash, carotid dissection, and stroke. N. Rapid deceleration (for example seen in MVCs) can result in torn cerebral blood vessels, brain stem contusions and spinal cord contusion or transection. Common injuries include subdural haematoma, diffuse axonal injury, whiplash, detached retina, or traumatic optic neuropathy. O. Rebound injuries, which occur due to recoil following deceleration, can include spinal fractures and contra-coup injuries to the brain. P. A blow directly on the chin can result in a ‘guardsman’s fracture’ (an anterior mandibular fracture, together with bilateral condyle fractures). Alternatively, if the mandible does not break, energy can be transferred directly to the brainstem resulting in serious injury. Q. Prolonged hypotension (from any cause) has been reported to result in blindness R. Because of the plastic nature of bone, localised impacts can temporarily or permanently deform the facial skeleton. Blows to the cheek can result in isolated orbital floor “blowout” fractures, with no associated fractures of the cheek.

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S. Crush injuries to the face (as unusual mechanism) can result in significant elastic deformation of the bone with little in the way of displaced fractures. In more extreme cases craniofacial dysfunction can occur. T. Widespread (“Panfacial”) fractures are associated with bleeding, swelling and airway compromise. However these complications can also occur in the absence of any fractures, in patients taking anticoagulants or with clotting abnormalities. Swelling worsens when supine, from elevated venous pressures and reduced lymphatic drainage. U. Hypertension during resuscitation may precipitate intraocular bleeding. In the elderly patient a dilated pupil may precipitate ocular problems. Acute angle closure glaucoma can be precipitated by drugs and general anaesthesia—this should be considered in any tense, painful, red eye. In many countries, the most common mechanism of injuries are motor vehicle collisions and falls. Before the introduction of in-car safety features, drivers and passengers suffered vehicle ejection through the front windshield or head collision onto the dashboard. Mid-face fractures were thus common following traffic accidents. These have now been vastly reduced by the use of vehicle safety features. However, beware of deceleration injuries. Seat belts and air bags will cause rapid deceleration in the patient which can result in shearing forces and avulsion of vessels with significant bleeding.

3.3

Airway Management

The airway is best considered as consisting of a collapsable, partly muscular tube, which requires muscle activity and neurological stimulation to maintain its patency. In this way deformity within the walls of the tube can occur from swelling, haematoma or from external displacement (facial fractures). The air passage within the tube itself can be obstructed by foreign material such as teeth, secretions or blood. Any loss of consciousness can result in loss of muscle tone, both within the wall and surrounding it. Snoring can be an early sign of this. It is important to remember that the status of the airway can quickly change over time and should therefore be reassessed regularly. Talking patients are considered to have a patent airway at the time of their assessment. But this can change. Vocalisation of appropriate dialogue shows that there is free passage of air to the lungs in an alert patient. Sensible speech also confirms the absence of confusion and neurological integrity. A normal sounding voice shows that there is no significant deformity of the passage. A ‘hot potato’ voice is associated with swelling around the oropharynx and tongue base (often noted in Ludwig’s angina). Snoring implies either loss of tongue or pharyngeal wall support. Noisy breathing and stridor are usually associated with deformity around the larynx and vocal cords. Confused or drowsy patients in the supine position lack the ability to

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keep their tongue out of the pharynx. They are also unable to coordinate effective swallowing and prevent aspiration. In such cases careful consideration must be made whether to intubate these patients early. When assessing the airway following facial trauma several key questions need to be considered. A. Is the patient conscious? If so, sedation should be avoided if possible and analgesics should be given cautiously B. Is the patient breathing spontaneously? If so, this allows time to call for help, transfer the patient to the operating room if immediate surgery is required and manage the airway under the best possible conditions, by the most experienced personnel. Failed attempts at endotracheal intubation by inexperienced clinicians in complex injuries will compound the problem, especially if the patient has a coexisting head injury. C. What is the extent of the injury? Fractures of the mandible and midface, particularly if they are highly mobile and associated with bleeding and swelling, will make all aspects of airway care difficult. Mask ventilation may not be possible as it may be difficult to achieve an effective seal. Aggressive ventilation via a tight fitting mask may also result in progressive surgical emphysema. If there are fractures of the cribriform plate, high-pressure ventilation by bag may also force air intracranially. D. Is there a limitation in mouth opening? If so, is this mechanical or as a result of pain. If secondary to pain analgesia and sedation will improve opening during anaesthesia. Assessment of the airway is often divided into the three steps of Look, Listen, and Feel. If detailed examination is essential (following a localised facial/anterior neck impact), the patient’s mouth must be sufficiently open and the neck adequately exposed to allow you to inspect for injury. This can be difficult if the patient has been fully immobilised with a collar, blocks and tape. In such cases, it is permissible to release the collar, so long as manual immobilisation is continued by someone else. Releasing the front half of the hard collar will also enable a clear view of the front of the neck and allow the patient to fully open their mouth. The anterior neck is an important anatomical site—clinical signs here can signify problems not only to the airway but also in the chest. Bruising, swelling, surgical emphysema, distended, bubbling wounds and laryngeal distortion or crepitus should all be assessed for. There should also be free movement of the thyroid cartilage prominence on swallowing (Figs. 3.12 and 3.13). At the same time the oral cavity and pharynx should be inspected. This is also an important guide to airway status. The uvula should be central, the pharynx should be symmetrical and the soft palate should move symmetrically with swallow. Ask the patient to ‘stick out’ their tongue. If this is freely mobile, the floor of the mouth is probably undamaged. When examining the oral cavity note the presence of secretions and fresh blood. If these are present they may need careful suctioning. Monitor the patient for active bleeding. If active bleeding is evident it is important to identify

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Fig. 3.12 When diseases and injuries involve the face, mouth and anterior neck, assessment of the airway requires more than just talking to the patient. The mouth must be fully open and carefully inspected

the source and if possible control it. If severe this may require formal intubation. Be mindful of blood trickling down the nasopharynx from the nose. In the awake patient this can be easily overlooked as the patient swallows the blood. Any foreign bodies should also be noted and removed taking care not to push these further backwards. Mobile teeth that appear imminently at risk of avulsion should also be noted, but if they are still attached do not attempt to remove them—this will be painful, often difficult and can lead to further bleeding. In the awake patient with facial injuries, oral secretions may need regular suctioning. However it is important to avoid sucking too deep and touching the soft palate or pharynx with the suction tube. This may elicit a gag reflex which can agitate the patient and lead to vomiting. A common mistake is to pass the suction tube blindly into the oropharynx. This can cause discomfort, distress, push foreign bodies deep and elicit vomiting. Suctioning should always be performed carefully and under direct vision. It is also important to listen and note the quality of sound of the patient breathing. This may be difficult in a noisy resuscitation room, but if the patient is unconscious

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a

b

Fig. 3.13  Nasal packing using a urinary catheter. This technique requires good access to the oral cavity and pharynx (a). In an emergency, the hard collar will need to be unfastened and the head supported by an assistant (b)

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or asleep any sounds may provide useful clues. Noisy breathing or stridor suggests airway restriction and impending obstruction. An abnormal voice can also be a precursor to airway compromise. A hoarse voice suggests poor mobility of one or both vocal cords. In the unconscious or asleep patient feel also for airflow from the mouth and nose. This may be the only sign of airway patency in a comatose patient. Finally, feel the neck for surgical emphysema. The larynx, thyroid cartilage, cricoid cartilage and trachea should all be central and in-line. Any steps in continuity may suggest laryngeal fracture or tracheal avulsion. Displacement of the trachea suggests tension pneumothorax or an expanding haematoma in the neck. If the patient is already intubated and being ventilated, look specifically for surgical emphysema (arising from a chest injury). This may indicate the need for a chest drain and possibly a tracheostomy. Air will continue to expand as a result of the raised airway pressures, which if unreleased can result in mediastinal compression.

3.3.1 The ‘Difficult Airway’ in Facial Trauma Complete obstruction of the airway in facial trauma rarely occurs. More often, partial obstruction arises as a result of a combination of factors. Each in itself may not be significant, but when combined these can rapidly compound and escalate the problem. Agitation of a patient suggests hypoxia, whilst obtundation suggests hypercarbia. Cyanosis suggests hypoxemia, secondary to inadequate oxygenation. Contributing factors that make an airway ‘difficult’ include . Bleeding from the nose or oral cavity A B. Swelling around the lower jaw, neck, floor of mouth, pharynx and soft palate. This can continue to progress over 24 h. Swelling over the cheeks and upper face generally does not have a significant impact on the airway. C. Trauma to the front of the neck. It is always important to look for evidence of injury to the larynx and trachea. Clinically the patient may have noisy breathing, snoring, gurgling, or croaking. Hoarseness, subcutaneous emphysema and a palpable fracture are very suggestive laryngeal fracture. Check that the trachea is central. D. Loose or foreign bodies in the mouth (teeth, fillings, dentures etc.). If obstruction is significant and prolonged, the patient will soon become obtunded. This will then allow passage of a laryngoscope to check there is no foreign body, such as denture impacted in the vocal cords. If present this should be removed with a Magill’s forceps. If the foreign body cannot be removed quickly it should be left and a surgical airway performed. If no foreign body is visible an endotracheal tube should be inserted. E. Mobile fractures of the mandible or midface. In comminuted or bilateral fractured mandible, the central portion of the mandible with its attached tongue may fall backwards obstructing the airway. Pulling the anterior part of the mandible forward may clear the airway, but if the patient cannot sit up it is likely that an

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endotracheal tube will need to be passed. In severe midface fractures the maxilla may be collapsed backwards causing obstruction. This will need to be pulled forward to disimpact the fracture. F. Alcohol or recreational drugs G. A reduced level of consciousness H. A full stomach. All trauma patients should be considered as having a “full stomach”, since there has been no time for stomach emptying prior to intubation. In addition, patients with facial injuries often swallow blood which accumulates in the stomach, with the risk of regurgitation and aspiration. Evacuating stomach contents via a naso-gastric tube is ideally done, but insertion of a tube in a confused, uncooperative, sometimes intoxicated patient may by itself, trigger vomiting. I. A restrained patient in the supine position. Conscious patients with maxillofacial injuries are usually more comfortable sitting upright as this allows blood and secretions to drain out of the mouth. J. Patients on anticoagulants. K. An anxious patient L. Inability to bag-valve-mask ventilate a patient. This is a contraindication to administering a muscle paralysing agent (used during rapid sequence induction). Whilst many of these factors may be obvious in patients following facial trauma, others are not. For this reason all supine, restrained patients should never be left unsupervised. As can be seen, obstruction has many potential causes. The more common of these are secretions, blood and solid material, such as loose teeth and extraneous fragments such as gravel, dirt etc. Loose dentures can inadvertently fall back into the oropharynx. Material that is easily visible can be retrieved with fingers or blunt forceps. Magill’s forceps have a right angle shape that makes them ideal for this. However do not chase after material that you cannot see directly. Blindly poking around in the back of someone’s throat carries a high risk of pushing this further down and inducing vomiting. The patient won’t thank you either. Bleeding from the nose and nasopharynx can often go undetected in the supine patient. An awake patient will often be able to swallow this safely. This is particularly a problem for the immobilised patient who cannot sit up. Similarly, a drowsy patient will have a weakened swallowing reflex. These patients need close observation and ideally should be allowed to sit up as soon as other significant torso injuries (notably the spine and pelvis) have been excluded. Disrupted anatomy can occur following high impact injuries, resulting in comminuted or displaced fractures. Midface fractures can collapse into the nasopharynx and restrict the oropharyngeal space. These injuries are usually quite apparent as patients are either very swollen, or bleeding significantly from the face. Bilateral anterior mandible fractures (‘bucket handle’ fracture) can sometimes result in loss of tongue support. This will allow the tongue to flop back into the oropharynx in the supine patient. Occasionally it can lead to airway obstruction if the patient has reduced consciousness. These fractures require urgent temporary support (bridle wire fixation) which is discussed elsewhere. Sublingual haematoma (following mandibular fracture) can further displace the tongue.

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Progressive swelling is perhaps a more worrying concern. Swelling may not be immediately apparent, or significant, when the patient first attends. However this can progress over the next 36 h, by which time the patient may be on the ward and unsupervised. The face does not have a deep fascial layer, like the rest of the body, which is why swelling can be so extensive. The concern however is more with internal swelling (around the airway) rather than around the midface and eyes. The airway is a relatively small space and only a small amount of swelling is required to impact on its patency—much like sucking through smaller diameter straws. Any trauma involving the floor of mouth, pharynx or larynx can lead to oedema and quickly compromise the airway. For this reason comminuted mandibular fractures are more of an immediate concern than midface fractures, although the latter can still result in significant swelling and bleeding. The combination of both midface and mandibular fractures is therefore an indication to seek senior advice and urgent anaesthetic input. It is important to anticipate this early and reassess the patient regularly. Once the airway has been compromised it will be much harder to intubate the patient. Injuries to the soft palate and base of the tongue, inhalation burns and midface fractures will all lead to localised airway oedema. Fractures of the upper cervical spine can sometimes results in bulging of the posterior pharyngeal wall secondary to bleeding (retropharyngeal haematoma) and swelling. Vomiting is another potentially severe problem in all traumatised patients who remain supine. It is therefore important to have an agreed plan of action within the trauma team on how to manage vomiting should it occur. If you are on your own, tilting the trolley head down tilting is a safe approach. This will allow vomitus to flow out of the mouth, which can then be suctioned away. Any continuing risk to the airway may require intubation and a definitive airway. When there is a question regarding the need for intubation, there should be a low threshold for securing the airway. Blind intubation, either orally or nasally, carries with it a risk for exacerbating an already delicate situation.

3.3.2 The Front of the Neck This is a key anatomical structure which is often overlooked both clinically and in many texts. Minor injuries can very quickly become life-threatening, due to the many vessels and delicate structures confined to this tight space. It is useful to divide the anatomical structures of the neck into five major functional groups, as an aide memoire to comprehensive assessment. These are . Airway—pharynx, larynx, trachea, lung. A B. Major blood vessels—carotid artery, innominate artery, aortic arch, jugular vein, subclavian vein C. Gastrointestinal tract—pharynx, oesophagus. D. Nerves—spinal cord, brachial plexus, cranial nerves, peripheral nerves. E. Bones—mandibular angles, styloid processes, cervical spine.

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Fig. 3.14  Penetrating neck injuries—what structure are at risk?

The platysma is an important anatomical landmark. This separates the superficial and the deep structures of the neck. Wounds that do not penetrate the platysma, are not significant penetrating neck injuries. Bleeding may still be profuse, but is usually easily controlled by direct pressure or simple ligature. The sternocleidomastoid muscle divides the neck into the posterior triangle (which contains the spine and muscles), and the anterior triangle (which contains the airway, vasculature, nerves, oesophagus and salivary glands) (Fig. 3.14). Pathologically, three mechanisms are reported to be responsible for the consequences of the blunt anterior neck trauma, (1) external haemorrhage, (2) soft tissue haematoma resulting in airway obstruction and (3) impaired cerebral circulation. Injuries include direct blows during sports, ‘clothes-line’ type injuries, fast moving soccer balls, hockey pucks and in rare cases strangulation. Signs and symptoms arising in the front of the neck may indicate a number of serious problems involving many different systems. This structure should therefore be closely assessed, particularly if the patient has sustained an impact or deceleration injury to the chest. Many vital structures traverse the neck. These are all at risk of injury from these mechanisms. Only a thin layer of skin only protects these structures, unlike other internal organs which are relatively sheltered. Trauma to the larynx and trachea can results in significant surgical emphysema and haematoma which can compress the airway. Signs include ecchymosis, swelling, tenderness, and a change in voice. Crepitus on palpation of the neck may suggest airway injury or communicating pneumomediastinum. Laryngotracheal separation is rarely seen but should be thought of following strangulation-type injuries. Fractures of the hyoid bone can destabilise the airway although this is unusual. The hyoid is part of the supporting mechanisms for both of the larynx and tongue. Fractures can sometimes be seen on lateral cervical spine film. Deep to these midline structures is the oesophagus. Whilst this is rarely damaged following blunt trauma, injuries to the oesophagus can occur from penetrating or explosive injuries. These injuries are very difficult to recognise clinically, yet the consequences of a missed oesophageal rupture and mediastinitis are serious (Fig. 3.15).

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Fig. 3.15  Dog bite to anterior region. The hyoid bone was fractured

A number of important vessel pass through the neck. The larger arterial vessels such as carotids are relatively deep, but are still at risk from penetrating injuries. Bleeding is often profuse and is almost immediately life threatening. Smaller vessels such as the branches of the external carotid can also lead to life threatening haemorrhage, but are often easier to control. Veins tend to bleed more slowly and this can sometimes be mistaken for a minor ooze. Distended veins may indicate raised intra thoracic pressure (tension pneumothorax) or cardiac tamponade. Care should always be taken when investigating any active bleeding. This often requires general anaesthesia. Until then, firm pressure should be applied (being careful not to occlude the internal carotid). In the case of a small penetrating injury it should be assumed that the injury is deep until imaged or formally explored. Consider also the possibility of a growing haematoma. The presence of spreading ecchymosis or a pulsatile swelling with an audible systolic bruit should arouse suspicion of traumatic pseudoaneurysm and needs further investigations. If the patient is stable CT and MRI are useful in diagnosis. US and Colour Doppler are also helpful diagnostic tools, but CT angiography remains the gold standard. Early endovascular or surgical intervention is often required. Rigorous spinal precautions should not be maintained at the expense of managing life-threatening airway or vascular injuries. “Hard” clinical signs mandating immediate exploration of the neck include A. Uncontrollable haemorrhage B. Rapidly expanding haematoma C. Palpable thrill or audible bruit D. Focal neurological compromise E. Absent or decreased pulses in the neck or upper extremities Many important nerves also traverse the neck. Damage to these, although rarely life-threatening, can result in significant morbidity. These include branches of the

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facial nerve, hypoglossal nerve, accessory nerve, phrenic nerve and vagus. It is also important to remember that there are a number of important glands and organs contained within the neck and whilst injury to these is quite rare, the consequences can be serious. These include the thyroid gland, parathyroid gland and carotid bodies. Injuries to the salivary gland are usually not serious.

3.3.3 Clearing the Cervical Spine This is discussed in greater detail in a chapter on the back of the neck. Although clearance of the cervical spine is often recorded, it is important to appreciate that the entire spine needs to be cleared, not just the neck. This usually requires initial imaging followed by clinical examination. The most appropriate time to clear the spine depends on the clinical circumstances, other injuries and suspicion of spinal injury in the patient. Although clearance may not be an immediate priority (since the spine is being protected) it is well known that prolonged immobilisation can result in the development of pressure sores. Patients are also easier to manage once they are giving freedom to move and sit up. This especially applies to patients with facial injuries (Fig. 3.16). For these reasons the spine should be cleared as soon as is practically possible. Patients can sometimes be combative against spinal restraint. Even for a well patient, the simple action of being restrained onto a hard spine board with interventions being performed on them can be quite distressing. This anxiety will be heightened if compromised from anxiety, pain, intoxication, drugs or hypoxia. Every effort should be made to correct these problems early. Providing the patient with continuous reassurance is vital. Fig. 3.16 Infectious, chronic, non-healing scalp pressure ulcer in the right parietal area. Note the purulent dressing

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3.3.4 Airway Procedures Facial trauma often presents problems with mask ventilation and difficult intubation. The injuries may disrupt the normal anatomy with oedema and bleeding in the oral cavity. Consequently masks cannot fit closely with loss of effective mask ventilation. An injured airway may also prevent efficient transference of gases to and from the lungs. Intubation is difficult if the vocal cords cannot be seen. The oral cavity, pharynx and larynx may be filled with blood, secretions and debris, all of which preclude good visualisation of the cords. This is all made worse by the presence of a possible C-spine Injury. Definitive airway management is highly specialised and usually undertaken by anaesthetists or other appropriately trained specialists. In the first instance however there are a few simple techniques we can all do to initially maintain an airway.

3.3.4.1 Simple Manoeuvres and Adjuncts The chin lift and jaw thrust are commonly known techniques that manually open the oropharyngeal space. However, the chin lift places the patient’s neck in a hyperextended position and therefore should not be undertaken if the patient is in a hard collar or the neck has not been cleared. Alternatively, the jaw thrust manipulates the mandible forwards, lifting the tongue base out of the oropharynx. This technique is only effective if the mandible is not fractured and the attachments of the tongue are intact. Nevertheless, it is safe to perform whilst awaiting anaesthetic support. At the same time, suction may be applied. This should be available at the bedside for all immobilised patients. Suction can be applied via a large bore Yanker sucker. Smaller size Yanker suckers are available for children. In some patients suction can also be applied (cautiously) via the nasal passages using a fine bore flexible catheter. When applying suction to clear the airway remember to only suck what can be seen with the naked eye. Never pass the suction blindly into a space. This can displace foreign material. Remember also that touching the soft tissues beyond the anterior palatine pillars (innervated by the glossopharyngeal nerve) can elicit a gag reflex and can cause vomiting. If there are mobile jaw fractures impeding the airway, these are can sometimes be temporarily stabilised using wires. The bridle wire technique involves passing a wire around teeth either side of the fracture to reduce and then hold mandibular fragments together. This is best done with fine wires which are easy to manipulate, although a heavy suture may also suffice. In an awake patient be aware that manipulating fragments will be painful. Administration of local anaesthetic into the fracture area will help if there is sufficient time to allow this. Once the fragments are stabilised, the patient will be much more comfortable. Clearly this is not definitive management of the fractures, but it does buy time and provides comfort for the patient. It is mostly used in anterior fractures. The oropharyngeal airway is a curved plastic device which can be placed into the oropharyngeal cavity. The curvature of the device acts as a hook in the vallecula to support the base of tongue. This prevents it from falling back into the oropharynx and obstructing the airway. This device can often be used to augment and

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sometimes replace the jaw thrust. However in a conscious patient this will elicit a gag reflex. Any patient who can tolerate an oropharyngeal airway is unable to protect their airway independently. These patients need to have a definitive airway established early. With conscious patients a nasopharyngeal airway may be placed. This is a small caliber flexible tube which is passed through one or both nasal passages to provide a patent nasal airway as far back as the nasopharynx. This should not elicit a gag reflex but can be difficult to place if the nose has been previously injured. It can also be uncomfortable for the patient. Other concerns relate to the possibility of anterior skull base fractures, although in reality safe passage of a nasopharyngeal airway should still be possible.

3.3.4.2 Definitive Airways Placement of a definitive airway, that is intubation of the patient, should only be undertaken by clinicians who have received appropriate training and experience. The term ‘definitive airway’ is often used to refer to the placement of a cuffed tube within the trachea (with the cuff then inflated). Placement of the tube into the trachea ensures an uninterrupted passage for gasses and affords a degree of protection against aspiration (although this is not guaranteed). The balloon helps seal the airway tube but it is not always an absolute barrier. Foreign material, especially liquids can still leak slowly pass it. This leakage is believed to be the cause of hospital acquired pneumonia that is commonly experienced by intubated patients in intensive care. The laryngeal mask airway, although not a definitive airway, may also have a role in trauma, in selected cases. This is a tube with a mask like end which sits over the epiglottis and vocal cord complex. There are multiple mask designs. This provides some protection of the airway from aspiration, however it is not a tight seal and if applied incorrectly is prone to dislodge. The main advantage of this technique is the ease of placement. It does not require direct visualisation of the larynx. Practitioners can also be easily trained to perform this technique. It has now become a standard airway technique to be achieved by Advanced Life Support Providers. Patients with complicated airways such as those with facial fractures and oedema may not tolerate placement of a laryngeal mask airway. In this case a smaller device may be used. Alternatively, inflatable laryngeal masks are now available which can bypass the area of difficult anatomy. All these devices should be regarded as temporary measures only, to be used if intubation is not possible. They do not fulfil the criteria of a definitive airway, long term ventilation is unreliable and they provide significantly less protection from aspiration. Tracheal intubation is the most common technique for airway provision in trauma. This can be placed via the mouth or nose, although in the acute stages of assessment the nasal route is generally avoided. This is technically much more difficult and maybe contraindicated in patients with signs of head or facial injuries. Both techniques require direct visualisation of the vocal cords and therefore should only be undertaken by an appropriately trained and experienced practitioner. Direct visualisation of the vocal cords can be difficult if the patient has poor mouth opening or altered pharyngeal anatomy. In these circumstances, video assisted

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laryngoscopic devices and flexible fiberoptic nasendoscopy may be used. Flexible fiberoptic intubation under local anaesthesia may be possible in selected cases but can be difficult in the presence of some facial injuries. Blood, vomitus and secretions in the patient’s airway may preclude visualisation of the cords. Accomplishing effective local anaesthesia may also be difficult and relies on the patient’s cooperation. The Glidecope is a video-assisted laryngoscope which enables indirect visualisation of the epiglottis. Extubation of the patient with a difficult airway requires careful consideration and planning. This is also at high risk of complications. As a result of the injuries themselves, or their repair, the soft tissues and mucous membranes will be swollen and oedematous for several days. These may place pressure on the airway, which is held patent by the endotracheal tube. The neck only has a limited amount of expandability and therefore only a small amount of bleeding or swelling in the region is required to result in airway compromise and potentially raise intracranial pressure. In patients with coexisting facial trauma, extubation should be deferred until all swelling has settled and the vocal chords can be clearly visualised. During and after extubation the patient should be monitored closely and staff should be prepared for the possibility of urgent re-intubation. Alternatively, if prolonged intubation is anticipated a tracheotomy may be placed.

3.3.4.3 Surgical Airways If intubation but becomes difficult, there should be a low threshold to move onto surgical access. Multiple failed attempts can lead to unnecessary prolonged periods of hypoxia, which is extremely detrimental to the injured brain. Surgical airways are therefore occasionally required. This can be difficult. Placement can be challenging without manipulating the neck. Unless the neck has been cleared all movement should be avoided. The anterior half of the hard collar will need to be removed and therefore help is required to maintain manual immobilisation. Needle cricothyroidotomy is commonly described as a simple temporary measure that can provide oxygenation for 30 min (although the lack of ventilation will result in an increase in CO2) build-up. However it is probably simpler to progress immediately to placement of a surgical cricothyroidotomy. Most emergency departments will have the necessary equipment as part of their resuscitation kit (Fig. 3.17). Surgical cricothyrotomy refers to the technique in which the cricothyroid membrane is incised with a scalpel and a tracheostomy tube or modified ET tube is passed to maintain the airway. Most anaesthetists, surgeons and ATLS providers are now trained in this technique. Compared to a tracheostomy, cricothyrotomy is simpler to perform, does not require neck extension, and is less likely to encounter significant bleeding. However the stoma opening is closer to the larynx and this technique has therefore been reported to be associated with a higher risk of causing laryngomalacia. For this reason many specialists argue that it will need to be replaced by a tracheostomy at the earliest opportunity (although this is a little uncertain). The cricothyroid membrane is a fibro-elastic membrane located anteriorly and midline in the neck. It lays between the thyroid cartilage above and the cricoid cartilage below. Laterally, the membrane is partially covered by the cricothyroid

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a

b

c

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Fig. 3.17  Needle cricothyroidotomy in an awake patient. (a) Local anaesthesia is infiltrated first. (b, c) Placement of the cannula. (d, e) The cannula is secured and “jet insufflation” commenced

muscles, but the central portion is subcutaneous and often easily palpable, making it ideal for accessing the airway in an emergency. This may be identified by locating the prominent “Adam’s apple” (thyroid cartilage) superior to it. This is more pronounced in men but can be difficult to identify in fat necks of if there is swelling. The tissues overlying the cricothyroid membrane are relatively avascular and do not contain any significant anatomic structures. The isthmus of the thyroid gland usually overlies the second and third tracheal rings, although rarely an aberrant

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pyramidal lobe may extend just superior to the cricothyroid membrane. Following identification of the cricothyroid membrane the area is cleaned and local anaesthetic is infiltrated. An incision is then made with a scalpel, through the skin and ligament into the airway. This is dilated to allow the passage of a size 6 tube. In an emergency situation a tracheostomy tube may not be available. The insertion of a size 6 endotracheal tube is then an adequate alternative. Care should be taken not to insert the tube too far down the trachea. It should then be secured with sutures and tape. Complications include A. Bleeding B. Incorrect or unsuccessful tube placement C. Subcutaneous emphysema D. Obstruction E. Oesophageal perforation F. Pneumothorax, pneumomediastinum G. Vocal cord injury H. Laryngeal disruption I. Subglottic or glottic stenosis J. Tracheoesophageal fistula (Fig. 3.18) a

Thyroid cartilage notch Cricothyroid membrane and skin incision

T. C. SCM

Cricoid

Sternal notch

Incision in cricothyroid membrane

Fig. 3.18  Surgical cricothyroidotomy. (a) The cricothyroid (C-T) membrane passes between the thyroid cartilage (Adam’s apple) and cricoid ring. It is usually covered by a relatively thin layer of skin and subcutaneous tissues, making access to it relatively simple. (b) Case 1. The patient is positioned supine and the thyroid cartilage is gently grasped from above (c). Some surgeons describe its contour like the keel of a boat, with the membrane at the lower end. The C-T membrane is then palpated by the index finger. It has a slightly “bouncy” feel to it. (d, e) Initial skin incision. (f, g) The skin and subcutaneous tissues are bluntly dissected to expose the C-T membrane immediately below. (h, i) The membrane is then incised. Some surgeons insert the handle of the scalpel blade and gently twist it to open up the hole. (j, k) The incised membrane is opened with either the handle of the scalpel or a spreader. (l, m) The tracheostomy tube (or endotracheal tube) is then placed under direct visualisation. (n, o) Case 2. In experienced hands this procedure can be done in 10–20 s. It is very rapid and provides a safe secure (but relatively small diameter) airway

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Fig. 3.18 (continued)

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j

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Fig. 3.18 (continued)

Alternatively, and if time allows, a percutaneous cricothyrotomy may be undertaken. This uses the Seldinger technique to place a tracheostomy tube over a guidewire. Most prepackaged commercial kits come with a 6-mL syringe, an 18-gauge needle with an overlying catheter, guidewire, tapered dilator, and airway catheter in lieu of a tracheostomy tube. For this technique the cricothyroid membrane must be easy to identify because no initial skin incision will be made. Anatomic distortion can therefore make locating the membrane difficult. The procedure is contraindicated if the neck is highly vascular or the thyroid gland cannot be avoided. This is often undertaken by anaesthetists but is rarely undertaken in the acute trauma

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setting. In many units, surgical tracheostomy is not an emergency procedure. The mortality from this can be as high as 1% and much higher in unfavourable circumstances. Therefore it is generally recognised that only a trained surgeon with adequate light, haemostasis facilities and with assistance should perform this.

3.3.5 Breathing and Ventilation On arrival (if not before), all patients should be given 100% oxygen through a non-­ rebreathing reservoir and mask. This allows every breath to contain 100% without mixing of inhaled and exhaled gasses. Once the patient’s saturation is measured, the oxygen supplied can be titrated appropriately. Assessment of patient’s breathing should be undertaken quickly and includes inspection, palpation, auscultation, percussion and investigations. Inspection is best undertaken at the end of the bed or trolley. Signs of respiratory compromise include use of accessory muscles of respiration. This may appear as the patient bracing themselves, movement of shoulders and neck with breathing and pursed lips. The inability to complete sentences is a concerning sign. An increased respiratory rate is a non specific indicator of abnormal physiology. It does not necessarily relate to respiratory problems and can occur in shock. Nevertheless it should be noted. The chest can also be palpated to determine symmetrical chest movement and the position of the trachea. Asymmetrical position of the trachea is often an indicator of chest pathology. Auscultation with a stethoscope confirms equal air entry into each lung. Resonance on percussion is perhaps less commonly undertaken in trauma but can detect increase air or blood in the chest such as pneumothorax or haemothorax. Pulse oximetry is a noninvasive method of continuously measuring the oxygen saturation of arterial blood. An oxygen saturation of 95% or greater using pulse oximetry is good evidence of adequate peripheral arterial oxygenation. However this measures haemoglobin saturation only, not ventilation and should therefore not be relied upon totally in the assessment of respiratory sufficiency. It should not be regarded as a substitute for arterial blood gases, as it provides no information on base deficit, carbon dioxide levels, blood pH, or bicarbonate. Falsely reassuring readings are also possible—in severe anaemia, the circulation will have less total oxygen, despite a haemoglobin saturation being high 100%. Erroneously low readings can be caused by hypoperfusion of the extremity, poor sensor placement or movement (shivering). A false reading will also occur if haemoglobin binds to something other than oxygen (notably carbon monoxide and cyanide). Methaemoglobinemia, from a variety of causes, can result in low readings. Nevertheless, changes in oxygenation can occur rapidly and may not be detected clinically. For this reason all patients should have continuous pulse oximetry. A number of conditions can significantly affect ventilation. In the context of the head and neck trauma, loss of consciousness and damage to the phrenic nerve (spinal-­cord injuries) would be the two most important conditions. With facial injuries, breathing problems may occur following aspiration of teeth, vomit, dentures and other foreign bodies. If teeth or dentures have been lost, a chest X-ray and soft

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tissue view of the neck should be taken to exclude displacement into the pharynx or lower airway. These must be viewed carefully—acrylic, from which most dentures are made, is not very obvious on a radiograph. All foreign bodies in the airway need urgent referral (Figs. 3.19, 3.20 and 3.21). Within the chest itself there are a number of specific injuries which should be considered. If you are a member of the “ATLS Fan Club” then you will have a useful pneumonic to remember life threatening problems in the chest (mostly “B” problems). A. Airway B. Tension pnuemothorax—A one way valve effect results in air becoming trapped in the pleural space. As the cavity expands, the lung is compressed and eventuFig. 3.19  Tooth in lung. These can easily be missed on a plain film. With the newer adjustable digital images this is less likely

a

b

Fig. 3.20  Foreign bodies in the upper airway (a, b). Often there is a history of loss of consciousness, but the absence of this is no safeguard

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Fig. 3.21  Further examples of teeth in the upper airway. A chest radiograph alone is inadequate

ally collapses. This increase in chest pressure will further restrict air entry into the lungs and reduce the venous return to the heart. This leads to hypoxia and circulatory collapse. The classical signs are distended neck veins, hyperresonant percussion, reduced air entry on auscultation and respiratory distress. Treatment requires urgent needle decompression followed by formal placement of a surgical chest drain.

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C. Large (massive) haemothorax—The collecting blood causes compression of the lungs. This is alleviated with placement of a surgical chest drain. The blood loss should also be replaced with a transfusion. D. Sucking chest wound (open pneumothorax)—This is similar to a tension pneumothorax but air passes in and out of the pleural space. It therefore does not lead to circulatory collapse. However efficiency of oxygenation is compromised. Treatment is by placing a three sided dressing initially, followed later by a chest drain. The dressing will allow air to escape the pleural space but not re-enter on inspiration. E. Flail chest—This is caused by multiple rib fractures. The loss of coordinated chest movement and restricted breathing secondary to pain reduces the patients ability to move air in and out of the lungs. Treatment depends on the degree of respiratory compromise and ranges from simple analgesia, to nerve blocks and urgent ventilatory support F. Cardiac tamponade—This is caused by blood entering the pericardial space. As this increases, the heart becomes compressed and compromised. Treatment requires drainage, analgesia, monitoring and ventilatory support Initial management of breathing is to ensure adequate oxygen enters the lungs. The airway should therefore be clear and the patient should be able to breathe oxygen enriched air. If the patient is unable to self ventilate effectively this will need to be augmented following intubation. Intubation is also indicated if the patient’s airway is at risk from oedema or aspiration. Initial management of serious blunt chest injuries will, in part, be guided by the injuries seen on an initial antero-posterior (AP) chest X-ray. Although other investigations are available to assess thoracic injury (computed tomography, angiography, magnetic resonance imaging and pleuroscopy), in the very early stages resuscitation in most cases will be determined by clinical assessment and standard radiography. Chest ultrasonography (US) is also gaining more attention in the critical care and emergency medicine literature. This has been used recently in the evaluation of pneumothorax and other lung pathologies. Several early trials have been supportive of its potential in the diagnosis of pneumothorax, but mediastinal evaluation is poor and widespread usage is currently not undertaken.

3.3.6 Circulation and the Control of Bleeding Hypovolaemia is the commonest cause of preventable death following trauma. Rapid blood loss leads to a depression of organ and immune function that, if prolonged, quickly progresses to the sequential failure of multiple organ systems. Reported incidences have it shown that acute blood loss accounts for approximately 40% of all deaths following trauma. This is most notably seen following penetrating injury or high velocity impacts, in which patients can rapidly lose significant amounts of blood into several large body cavities (chest, abdomen, pelvis), or externally. Life-threatening blood loss can also occur following injuries to the neck and

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Fig. 3.22 Angiogram demonstrating a tear in the aorta. This occurred following a deceleration injury. Rapid deceleration can result in lifethreatening mediastinal injuries

face, although this is less common. Blood loss in children is more significant than in adults (Fig. 3.22). Timely diagnosis, surgical control of on-going loss and physiologically directed fluid replacement are the cornerstones of management. Any injured patient who is cold to the touch and has a rapid pulse should be regarded as being in hypovolaemic shock until proven otherwise. The degree of hypovolaemia is usually classified based on the patients pulse rate, blood pressure and perfusion. These are all indicators of cardiac function and its effectiveness. When the patient first arrives, the simplest way to assess perfusion is by examining their skin colour, capillary refill time and conscious status. As soon as shock is recognised treatment can be initiated, whilst more definitive and precise tests are being arranged. Urinary output is also a good indicator of renal perfusion but requires a catheter and so cannot be assessed immediately. The earliest sign of blood loss is tachycardia. Blood pressure is a poor guide and will not identify all trauma patients who are in shock. Compensatory mechanisms prevent a significant decrease in systolic BP until the patient has lost around 30% of their blood volume. Attention should therefore be paid initially to the pulse, respiratory rate, and skin perfusion. However caution should be taken when interpreting the pulse rate, particularly with children, the elderly, athletes and patients taking medication which affects cardiac function (beta-blockers). These patients do not

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respond physiologically to blood loss in the same way as other patients and therefore a normal pulse rate is no guarantee that the patient is not shocked. Whilst haemorrhage is usually the presumed cause of shock in all injured patients, it must be distinguished from other possible causes. These include cardiac tamponade (check for muffled heart tones, distended neck veins), tension pneumothorax (check for deviated trachea, asymmetrically reduced breath sounds) and spinal cord injury (check for warm skin, normal or slow pulse rate and neurological deficits). Once tension pneumothorax and cardiac tapenade have been excluded, all hypotensive trauma patients should be considered to be in severe hypovolaemic shock until proven otherwise (ATLS). Arterial blood gases are essential in the evaluation of shock. A negative base excess and raised lactate (lactic acidosis), are good indicators of ischaemia and reduced tissue perfusion. Changes in these are also very reliable in indicating the patients recovery or demise, compared to other measurements. Bleeding patients should also be investigated for coagulopathy. They should be kept warm to allow the proteins of the clotting cascade to function optimally. To aid the arrest of haemorrhage, it is now advised to administer tranexamic acid intravenously in some patients. Drugs causing coagulopathy such as warfarin should be reversed as per local protocol with vitamin K or prothrombin complex concentrate, depending on the clinical circumstances. All trauma patients should be provided with good intravenous access and blood taken for cross match. Initially warmed fluids (this varies in different units) may be infused and the patient’s response reassessed. However which fluid to use and how much to give are still being evaluated and therefore may depend on where you work. It is important not to just give the ‘standard’ 2 L of Saline—rather, find out what your local protocol is—fluid administration may be different (smaller boluses) and will vary depending on the patient’s response. Resuscitation often depends on the clinical circumstances and should be tailored accordingly. Some specialists advocate 250 ml boluses of warmed crystalloid—hypotensive resuscitation. The problem with early and aggressive fluid administration is that it may result in (1) dislodgement of blood clots (by increasing blood pressure), (2) dilution of coagulation factors and (3) hypothermia. Thus the concept of ‘permissive hypotension’ has been developed in which the blood pressure is maintained at lower physiological levels (but enough to maintain cerebral perfusion), until haemorrhage is controlled. During this time a rapid search is undertaken to identify any sites of significant blood loss. Sources of major blood loss are usually A. External wounds B. Chest C. Abdomen D. Retroperitoneum E. Pelvis F. Limbs G. Face

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3.3.6.1 Damage Control This term interestingly is derived from naval warfare. Following damage to a ship, only repairs necessary to enable it to complete its mission were undertaken. All other repairs were completed on return to port. Acute blood loss can result in a combination of acidosis, hypothermia and dilution of clotting factors, sometimes referred to as the “the lethal triad”, which physiologically results in a “first biologic hit”. The severity of this significantly affects the prognosis for survival. Over the years, damage control resuscitation and surgery has gained popularity in the management of severely injured patients. This focuses on rapidly stabilising and improving the patients adverse physiological and biochemical changes that have arisen. Comprehensive anatomical and functional repair of all injuries is deferred until the patient is in a better condition. Damage control surgery involves techniques such as rapid control of haemorrhage and contamination, temporary wound closure, and rapid stabilisation of fractures. Patients are then transferred to the ICU for further resuscitation, with delayed re-exploration and definitive repair of their injuries following restoration of their normal physiology. These principles have been applied successfully in abdominal, thoracic and orthopaedic trauma and have similarly been applied following trauma to the head and neck. Severe maxillofacial and neck trauma, both blunt and penetrating, may be sustained in various military and civilian circumstances. Major haemorrhage from the head and neck area is however uncommon and is usually quite apparent when the patient arrives. The scalp and face are highly vascular regions and may be associated with significant blood loss. It is however, extremely difficult to estimate the volume of bleeding from these sites and other lacerations due to blood loss at the scene and en route to the hospital. External blood loss requires careful visual inspection. The chest, pelvis and limbs can be quickly assessed clinically and then radiographically. Ideally a chest and if necessary pelvic X-ray, should be performed within 10 min of the patients arrival. The abdomen is a difficult region to examine, especially in the unconscious patient and this often requires further investigations (ultrasound or CT). Even a single long-bone fracture can result in up to 10–30% loss of total blood volume. This is usually evident from swelling due to haematoma formation. In some patients surgical intervention or embolisation may be required very early to control bleeding—therefore surgeons/radiologists should be involved in management early. They need time to set up. Rapid immobilisation of limb/pelvic fractures (and when necessary a laparotomy), should all be regarded as part of “C” and therefore not be delayed. In any a patient who fails to respond to fluid replacement, it is important to think of other causes of shock, especially following injuries to the upper torso (myocardial contusion, tension pneumothorax, cardiac tamponade, spinal injuries and sepsis). Injuries are not mutually exclusive and therefore one or more of these may present in the same patient. Rapid assessment is the key to success. CT is increasingly being used in the overall evaluation of otherwise stable patients—a “pan scan”. Other investigations may include

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A. Chest X-ray—look for pneumo/haemothoraces, mediastinal widening, rib fractures, tracheal disruption. B. Echocardiography—this is used to rapidly diagnose a pericardial effusion C. FAST scan. This is commonly used in the emergency department to identify free fluid in abdomen and visualise solid organs (spleen, liver and kidneys). D. Pelvic X-ray—fractured pelvis

3.3.7 Blood Loss Following Head, Neck and Facial Trauma Significant blood loss from the head, neck and face can occur following penetration, rupture or tearing of the major vessels. This may present as an expanding mass under a penetrating wound. Not all bleeding from this area is massive. Rather, patients tend to continually ooze from a wound, which may not be recognised at first. Bleeding from a broken nose or from an occipital scalp laceration in the supine patient are two good examples, which can result in significant blood loss. Whilst greater bleeding from facial fractures can occur, it is usually self-evident as soon as the patient arrives. This is common following high energy midface fractures. Control of haemorrhage can be difficult and may require early intubation to enable access in and around the mouth. At first, active bleeding should be controlled by pressure until the airway and breathing have been stabilised. Once the airway is secured, direct pressure and aggressive packing of open bleeding wounds will control all but the most major haemorrhages. If time permits and the patient is stable wounds should be cleaned first with sterile water and gauze applied. Generalised oozing from a wound can be controlled by firm pressure. Clamping obvious spurting vessels with a blunt artery clip can arrest bleeding if this is localised. The vessel can then be tied off using a suture tie. Needless to say, know your anatomy. Blindly clamping vessels deep in the neck is not to be recommended. Only clamp those that are small and superficial, when all else fails. Bleeding from a “hole” (following a gunshot or stabbing injury) can sometimes be controlled by placing a urinary catheter in the hole and inflating it. Obviously be careful and consider carefully what structures may be in the depths of the hole before attempting this. Very small superficial vessels can be arrested by application of sliver nitrate. This is often useful in epistaxis. Heavy bleeding from extensive scalp or neck wounds where the bleeding vessels cannot be identified can be controlled with the application of sealants such a Celox. This can be in a powder of gel form. It is applied directly over the wound and will accelerate clotting. Compression bandaging can then be applied (be aware of possible injuries underneath this). External fixation of unstable anterior mandibular fractures using available means (orthopaedic pin fixators, wire ligatures etc.) may help protect the airway, as well as reduce bleeding, pain and morbidity. Bleeding may also stem from the base of the skull. This is often an ominous sign. Once the patient is stabilised, angiography may be necessary, with embolisation if possible.

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3.3.7.1 Midface Bleeding The midface extends between the eyebrows and upper teeth and contains the air-­ filled paranasal sinuses. The bones are mostly thin and lined by mucosa. Fractures here can result in profuse bleeding from terminal branches of the maxillary artery. Ocular injuries, vascular injuries, and intracranial penetration are also commonly associated injuries, especially following penetrating trauma. Midface bleeding rarely results in massive blood loss. Nevertheless, following high impacts displacement of the bones can tear soft tissues and rupture the venous plexus around the pterygoid plates. This can lead to significant blood loss and shock. Ongoing bleeding from the palate or into the pharynx will suggest this. The patient may also describe the need to swallow frequently and a feeling of liquid in the back of the throat. Such bleeding needs to be arrested at the earliest opportunity, at first by manually reducing the midfacial bones (gently lifting the maxilla back up and against the skull base). This is then held in place using bite blocks as far back as possible between the teeth. If bite blocks are not available, several gauze swabs or stacked wooden tongue depressors can be tied together and placed. If bleeding continues, posterior nasal packs should be inserted. Needless to say, all this requires a cooperative patient. Ideally the patient should be sitting up, but depending on the mechanism of injury this may not be permitted. If control is not easily attainable, or if the patient is combative, it may be necessary to anaesthetise them and secure the airway. With high energy impacts to the face this will probably be necessary anyway, as the face is likely to swell significantly over the next few hours. It is therefore important to anticipate this and get senior help early (Figs. 3.23 and 3.24).

a

b

Fig. 3.23  Temporary reduction of midface fractures to control haemorrhage

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Fig. 3.24  This patient initially presented with hypovolaemic shock, but only minor facial bleeding. There were no significant injuries below the clavicles. It was only when his systolic pressure was restored that profuse bleeding from the face became apparent. This should have been anticipated in view of the extensive fractures

Fig. 3.25  Epistaxis balloons. Passing catheters, balloons and packing of the nose does carry a risk of intracranial intubation in the presence of skull base fractures, as shown here. Nevertheless, if a patient is pouring blood from the nose and mouth something clearly needs to be done. The actual risk of intracranial intubation is probably very low in experienced hands. Only pass these if you are trained to do so and know what you are doing. If not then get urgent help

3.3.7.2 Epistaxis Bleeding from the nose can be considered as anterior or posterior. This can often be seen with good lighting and with suction. Bleeding from visible vessels (commonly septal) can be cauterised with silver nitrate. This should only be performed under direct vision. Cauterisation of both sides of the septum should be avoided to prevent necrosis of the septum. If bleeding is significant or there is inadequate time to investigate, it should be controlled by nasal packing. Multiple nasal packing materials are now available. Many are self-expanding nasal packs that gradually fill the nasal cavity and provide light compression. These should be inserted parallel to the palate. Other nasal packing systems require inflation with air (Fig. 3.25).

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Alternatively, the anterior nasal space can be packed using ribbon gauze. This requires long thin forceps such as Tillie’s. The gauze is soaked in saline for comfort. Preparations such as adrenaline or tranexamic acid can also help with achieving haemostasis. BIPP (Bismuth iodoform paraffin paste) infused gauze has antibacterial action. Following packing, the pharynx should then be carefully examined. If bleeding is still visible, the source may be from the posterior nasal space. This requires posterior nasal packing (which will require removal of the anterior nasal packs). Posterior nasal packing can also be achieved using proprietary devices, such as the Rapid-rhino. These are often in the form of ‘double balloons’, one for the nasopharynx, the other for the nasal cavity. Alternatively, a perhaps more historical technique, is to use two Foley catheters. Each catheter is inserted through the nose parallel to the palate. The tip with balloon should be observed as it passes behind the soft palate into the oropharynx. The balloon can then be inflated and then gently pulled back into the nasopharynx. This can then provide compression of the posterior nasal passage. Care should be taken to inflate the balloon under direct vision only. The catheter should be secured to avoid falling back into the pharynx and the anterior nasal cavity lightly packed (Figs. 3.26, 3.27 and 3.28). Contrary to popular belief, even in the presence of basal skull fracture posterior nasal packs can still be inserted. The likelihood of intracranial packing is negligible if this is done with due diligence and care. A patient should not be allowed to continue to bleed (and possibly exsanguinate), based on a perceived risk of intracranial complications. It is of course important to pass the catheter or pack parallel to the palate and ensure visual confirmation of its entry into the pharynx. Patients should be reviewed to ensure that the bleeding has stopped. Nasal packs can remain in place for over 24 h and therefore there should be no rush to remove them. Patients will usually require antibiotic prophylaxis. If all these measures fail the patient may require surgical ligation of the sphenopalatine artery. This is located in the posterior nasal space and is the main source of blood supply to the nasal mucosa. This procedure is performed under general anaesthesia. Nasal packing should be kept in place to temporarily stop or slow down the bleeding. With more widespread injuries, blood may also come from the sinuses rather than the nasal mucosa. This will be secondary to fractures of the sinus walls. Bleeding often presents later, where the blood may be slightly darker and usually resolves spontaneously.

3.3.7.3 Oral Bleeding Bleeding from the mouth can appear profuse. This is commonly from lacerations of the tongue, lips, inner cheeks or from the sockets of avulsed teeth. Unless the patient has abnormal clotting, this should quickly settle with compression. Bleeding sockets can be addressed by replacing the avulsed teeth (if they are available) or with gauze and local pressure. Sockets can also be packed with surgicel. If the patient is otherwise stable, consideration should be given to suture the sockets and lacerations. Occasionally these measures are inadequate and there may be a need to use whiteheads varnish or bone wax. Only an appropriately trained professional who is familiar with managing bleeding sockets should undertake this (Fig. 3.29).

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a

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Fig. 3.26  Nasal packing using a urinary catheter (case 1). (a, b) Control of epistaxis using a urinary catheter. The hard collar is unfastened and the head supported by an assistant (c). The catheter is then passed backwards through one nostril, parallel to the palate and its end grasped and withdrawn out the mouth (d). (e, f) This is then repeated on the other side so the ends of both catheters are visible. (g, h) The catheters are then inflated with sterile water or saline. (i) The water-filled balloons are then gently guided back into the mouth and gently wedged in the nasopharynx. The catheters are then put on gentle traction and the hard collar replaced. (j) The nasopharyngeal balloons act as a stop and now enable the nose to be packed without the pack slipping into the pharynx. This technique is really only required in severe or protracted cases of bleeding when other measures have failed. Careful traction is required. If too heavy, the balloons can be pulled out through the nostrils. Also protect the nasal tip from pressure necrosis by the tube. (k) The nasal cavity is then packed in a layered arrangement. This is often easier said than done. The nasal cavity should now be almost water tight. If skull base or orbital fractures are suspected, this needs to be packed lightly

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Fig. 3.26 (continued)

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Fig. 3.27  Nasal packing using a urinary catheter. Packs are usually left in situ 24–48 h. Consider the use of antibiotics during this time (risk of toxic shock syndrome and sinusitis). With extensive fractures, bleeding may continue from the mouth. The oral cavity can also be packed (this patient has been intubated). At this stage, consider acquired coagulation defects, if this has not already been considered

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Fig. 3.28  Overpacking of the nose when the surrounding fractures are unsupported can lead to displacement. Be careful Fig. 3.29  Use of a tongue suture to facilitate intubation. A large deep tongue laceration is also being rapidly closed. Bleeding from it was preventing a clear view of the vocal cords

3.3.8 Urgent Surgical/Radiological Intervention in Bleeding The measures described above are primary measures that can be undertaken in the emergency room. These should temporarily arrest or slow down bleeding and allow completion of the primary survey and stabilisation of the patient. After this, bleeding may have resolved as a result of the body’s own coagulation cascade and localised vasoconstriction. However large, extensive or deep sources of bleeding, or the presence of coagulopathy may prevent this from taking place. Ongoing bleeding in patients with a normal clotting profile, may require surgical intervention to arrest haemorrhage. These patients should be urgently prepared for transfer to the operating room. Surgical intervention will often involve making surgical incisions or access via existing lacerations. This will allow exploration of the damaged tissue to identify and ligate/cauterise bleeding vessels. Similarly, bleeding from comminuted fractures can be arrested by surgical reduction and fixation. Alternatively, supra

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selective embolisation may be undertaken by an interventional radiologist in certain cases. Bleeding may be recognised following CT angiography. This may be followed by image guided interventional embolisation of feeding vessels to the site of haemorrhage. This can only be performed once the patient has been resuscitated and is reasonably stable (Figs. 3.30, 3.31 and 3.32). a

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Fig. 3.30  External carotid artery ligation. (a, b) The skin is incised parallel to the anterior boarder of the sternomastoid muscle. Red line represents the incision. (c, d) The muscle is retracted and the surrounding tissues quickly (but gently) opened up. The common carotid artery is identified by palpation. (e, f) Dissection proceeds superiorly along the artery to identify the bifurcation into the internal and external carotid arteries. The external carotid artery is then identified (it gives off further branches—the superior thyroid is usually just above the bifurcation). This needs confident identification; otherwise there is a risk of ligating the internal carotid artery. (g, h) A tie is then passed around the vessel and secured. (i) Ligated vessel. This procedure may need to be repeated on the other side. Remember the head cannot be turned to improve access unless the neck has been cleared. Therefore this is a very difficult procedure

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Fig. 3.30 (continued)

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Fig. 3.31  Anterior ethmoidal artery ligation (cadaver dissection). A small curved incision is made just in front of the medial canthus (a, b). Subperiosteal dissection rapidly finds the vessel. Depending on the extent of exposure and associated injuries, the medial canthus may be disrupted (c, d)

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Fig. 3.32  Preliminary angiography prior to embolisation. (a) Initial angiogram showing the external carotid artery and some of its branches. (b, c) Digital subtraction techniques have considerably improved identification

3.3.9 Disability Head (more precisely brain) injuries are a common cause of morbidity and mortality following trauma. It has been estimated that 3.2 million people are living with long-term disability related to traumatic brain injury (TBI). This is the leading cause of morbidity and mortality between the ages of 1 and 45 years. Teenagers and the elderly are most at risk, although the causes vary demographically. Motor vehicle crashes are a main cause of head injuries in most ages, whilst falls are most common in people aged 65 or older. Head injuries may be classified as primary (occurring at the time of the traumatic episode), or secondary (occurring later, as a result of reduced perfusion, inadequate oxygenation or raised intracranial pressure—ICP). Secondary injuries can develop hours or days after the initial trauma and may be a major factor in prognosis. The two most common causes of secondary injury are intracranial mechanisms (e.g., haematoma and elevated intracranial pressure [ICP]), and systemic mechanisms (e.g., shock and hypoxaemia) (Figs. 3.33 and 3.34).

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Fig. 3.33  Severe brain trauma following a high energy impact. The CT shows multiple pathophysiological processes. Note how the fractured skull fragment is displaced outwards as result of raised intracranial pressure

Fig. 3.34 Large extradural haematoma, resulting in raised intracranial pressure

Moderate to severe traumatic brain injury can result in prolonged or permanent changes in a patient’s state of consciousness, awareness or responsiveness. These may be classified as A. Coma. The patient is unconscious, unaware of anything and unable to respond to any stimulus. This usually results from widespread damage to all parts of the brain. B. Vegetative state. The represent widespread damage to the brain. Although the patient is unaware of their surroundings, he or she may be able to open their eyes, make incomprehensible sounds and move.

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C. Minimally conscious state. Here, there is a severely altered level of consciousness but with some signs of awareness of self and the environment. This is often a transitional state D. Brain death. There is no measurable activity in the brain and brainstem. This is irreversible. Assessment of these levels of neurological function (following initial ABC management) involves the Glasgow Coma Scale (or AVPU) and pupillary responses. AVPU is a more succinct assessment classifying patient responses to Alert, Vocal, Pain and Unresponsive. However this is somewhat crude and gives no indication of cause or prognosis. The GCS is more structured and is discussed further in the chapter on the head. It provides a practical method for assessment of impairment of conscious level in response to defined stimuli. However, it is important to appreciate that the GCS cannot be relied upon until A, B and C have been normalised. Hypoxia, in the absence of a head injury can result in drowsiness, as can hypovolaemia. Nevertheless, the Glasgow coma scale (GCS) is universally used as a quick and simple method to determine the level of consciousness. It is well known to be reliable and predictive of outcomes. Changes in the patients score over time are more significant than individual measurements. A decrease by two or more points, especially if associated with a dilated pupil, indicates a severe brain injury, usually from raised intracranial pressure. This requires immediate management. A GCS of eight or less (from whatever cause) requires the placement of a definite airway. Hypoglycemia, alcohol and drugs can also alter the patient’s level of consciousness and should be active considered. Nevertheless, a reduced level consciousness following trauma should always be considered secondary to brain injury unless proven otherwise. Hypoxia (PaO2  130 mm Hg. IV nicardipine is titrated according to the response. 3. Oral nimodipine. For the first 10  days following subarachnoid haemorrhage, patients are at risk of intense vasospasm. Nimodipine reduces this risk and accompanying ischaemic complications. Dosage needs to be balanced against the patient’s BP (which ideally should be between a mean arterial pressure of 70–130  mm Hg) and a systolic pressure of 120–185  mm Hg. It limits vessel spasm that can occur in response to the haemorrhage. 4. Analgesics and anti-emetics are prescribed. Bed rest is essential to avoid sudden increases in BP. Restlessness and headache are treated symptomatically as necessary. Stool softeners are given to prevent constipation, which can lead to straining.

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5 . Anticoagulants and antiplatelet drugs are contraindicated. 6. If clinical signs of acute hydrocephalus occur, drainage of CSF should be considered. Excess fluid and blood can be removed using either a lumbar drain inserted into the subarachnoid space of the spinal canal, or a ventricular drain catheter, which is inserted directly into the ventricles. 7. If a cerebral aneurysm is identified on angiography, this can be occluded by either surgical clipping or endovascular techniques to reduce the risks of rebleeding. In many centres today, endovascular coils can be inserted through minimally invasive angiography to occlude the aneurysm. Alternatively, if the aneurysm is accessible surgically, a clip may be placed around it’s neck. This however it requires extensive surgery, which is not without risk. The decision as to which treatment is undertaken is usually made by a multidisciplinary team consisting of a neurosurgeon, neuroradiologist, and other health professionals. An important consideration in deciding between clipping and coiling is the location of the aneurysm, its size and the status of the patient. Aneurysms of the middle cerebral artery and its related vessels can be technically difficult to reach endovascularly and are amenable to clipping. Those of the basilar artery and posterior cerebral artery are hard to reach surgically but are more accessible for endovascular techniques. If surgery is indicated, many neurosurgeons prefer to operate within the first 24 h to minimise risk of rebleeding and other complications. After 24 h surgery may be deferred until 10 days have passed. This allows for any cerebral oedema to settle, although there is a risk of further bleeding during this period. 8. In some cases AVMs may be excised, embolised, or treated with high dose, localised radiation (stereotactic radiosurgery). Radiosurgery results in gradual obliteration over several years. 9. If no structural cause is found following angiography, the patient can be reassured that they are not at risk of further bleeds.

7.8

Complications of SAH

SAH is a complex disease that can involve multiple types of neurological injury and systemic organ dysfunction. Well-established risk factors for mortality include poor clinical grade at presentation, older age, aneurysm rebleeding, large aneurysm size and cerebral infarction from vasospasm. Vasospasm, the direct effects of the primary haemorrhage and rebleeding are the most frequent causes of mortality. Cerebral oedema, intraventricular haemorrhage and medical complications also contribute to poor outcomes. Despite advances in medical and surgical management, SAH remains a major cause of premature mortality. Recovery and prognosis are highly variable and largely dependent on the severity of the initial SAH. In general, one-­third of patients will survive with good recovery; one-third will survive with a disability or stroke; and one-third will die. Complications include 1. Intracerebral haemorrhage (ICH). This can occur following direct rupture of aneurysm into the brain parenchyma. This commonly occurs with internal cerebral artery (ICA), pericallosal and anterior cerebral artery (ACA) aneurysms.

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Secondary rupture of a subarachnoid haematoma into the brain can also occur later. Intraventricular haemorrhage has been reported in up to one third of patients. This is a significant predictor of poor neurological outcome. Subdural haematoma (SDH) is rare following aneurysmal SAH, possibly as a result on tearing of the arachnoid at the dome of the aneurysm and bleeding into the subdural space. 2. Vasospasm. Delayed cerebral ischaemia (DCI) is the most important and preventable morbidity cause after subarachnoid haemorrhage. Blood is an irritant and following a subarachnoid haemorrhage the surrounding vessels can go into intense vasospasm. This can lead to impaired cerebral autoregulation and may progress to cerebral ischaemia and infarction. Often, the terminal internal carotid artery or the proximal portions of the anterior and middle cerebral arteries are involved. Severe cerebral ischaemia can be fatal in 15% of patients. At day 7, up to 70% of patients will have angiographic vasospasm, although this is only clinically manifest in 20–30%. The pathophysiology is not completely understood but the risk is increased following a heavy bleed. In patients who develop vasospasm, hypertensive therapy is often instituted when the aneurysm is secured. This involves an inotrope infusion. If delayed ischaemia does not improve with medical treatment, angiography may be attempted to identify the sites of vasospasm and intra-arterial nimodipine is administered directly into the artery. Continuous EEG (cEEG) has been reported as a possible way to monitor patients for delayed cerebral ischaemia (DCI) and seizures 3. Hydrocephalus. This occurs in about one quarter of patients. Blood in the CSF can result in hydrocephalus by 2 mechanisms: (i) immediate obstruction to the CSF outflow through the sylvian aqueduct, fourth ventricular outlet, basal cisterns, and subarachnoid space (acute, obstructive, noncommunicating type) and (ii) scarring of the arachnoid granulations (delayed, nonobstructive, communicating type). Intraventricular blood is a high risk factor in the development of acute hydrocephalus. A ventriculo-peritoneal shunt may be required. 4. Rebleeding. This can occur in about 20% of patients, usually in the first 2 weeks. Rebleeds in the first few days are thought to be related to an unstable thrombus, later bleeds occur from lysis of the clot. Hypertension, agitation and seizures make rebreeding more likely. 5. Seizures have been reported in 5–10% SAH patients. 6. Electrolyte disturbances. Low sodium can occur as a result of ‘cerebral salt wasting’—that is, the development of extracellular volume depletion due to a renal sodium transport abnormality (in patients with intracranial disease and normal adrenal and thyroid function). This rare phenomenon can also occur in head injuries. It is treated by adding sodium orally or intravenously using 1.8% saline. Fluid restriction is dangerous as this may precipitate vasospasm. 7. Myocardial infarction. ECG rhythm changes can occur in >50% of SAH patients. Troponin elevations may also occur. Left ventricular systolic dysfunction is associated an abnormal sympathetic innervation, possibly following excessive release of norepinephrine from the cardiac sympathetic nerves.

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8. Pulmonary oedema can occur as a result of the sympathetic discharge following SAH and a raised ICP. 9. In those patients that survive, varying degrees of neurological deficit may persist. These include (i) Speech and language deficits and limb weakness, (ii) visual problems (iii) seizures, (iv) fatigue (v) headaches and problems with higher ­cerebral functions (short-term memory loss, loss of concentration, changes in perception and personality)

7.8.1 S  pontaneous Intracerebral haemorrhage (ICH): Cerebrovascular Accident, or Stroke The term “cerebrovascular disease” includes all disorders that result in damage to the blood vessels supplying the brain, thereby producing neurologic damage. “Stroke” and “cerebrovascular accident” (CVA) are used to describe an acute neurologic injury resulting from a severe interruption in the flow of blood to the brain. Complete cessation of the flow may render an irreversible cerebral infarct within a period of 3 or 4 min. General symptoms following stroke include variable motor paralysis, sensory loss, visual difficulties, and speech impairment. Approximately 80% of strokes are associated with atherosclerosis, which leads to embolism, cerebral ischaemia and infarction. Deposition of atheromas in arterial walls predisposes the patient to the development of thrombosis and embolus formation, which can result in infarction of the area of the brain supplied by the occluded vessel. The remaining 20% of cases are caused by cerebral haemorrhage following rupture of a vessel. Clinically these are indistinguishable and it is only following imaging (CT) that the underlying cause can be determined. Nevertheless the distinction between ‘haemorrhagic’ stroke and ‘ischaemic’ or ‘embolic’ stroke is important as treatment differs. Computed tomography (CT) is commonly used in the urgent diagnosis of acute cerebral infarction. With the use of thrombolysis, early signs of ischaemia must be reliably identified, to correctly select patients eligible for thrombolytic therapy or clot removal.

7.8.2 Ischaemic Stroke Carotid atheroma predisposes patients to thrombosis and cerebral embolus, with infarction of the tissues supplied by the occluded vessel. Atheroma commonly develops in the branching portions of the arterial system, notably at the origin of the internal carotid artery. If this is identified, early referral to a vascular surgeon maybe indicated. Other important sites of thrombus formation include the vertebral, basilar, and middle cerebral arteries. Lacunar infarcts are small lesions that occur in the basal ganglia, pons, cerebellum, internal capsule, and deep cerebral white matter. These are associated with hypertension and diabetes and may be occasionally picked up on CT. Symptoms of lacunar infarcts include unilateral motor or sensory

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deficit which may progress over 24–36 h. If these are identified and treated early the prognosis is generally good, often with partial or complete resolution of symptoms over the following 4–6 weeks. Cerebral infarction usually occurs following ischaemic necrosis in one of the cerebral hemispheres as a result of embolism. Thrombosis within an intracranial vessel may also result in stroke. The resulting neurological deficit depends on the particular vessel involved and the extent of any collateral circulation. Carotid artery atherosclerosis, for example, commonly result in infarction in that part of the brain supplied by the middle cerebral artery. This results in contralateral signs such as facial weakness, flaccid hemiparesis and hemisensory loss. Cerebral infarction can also occur as a complication of other diseases. Emboli can arise from thrombi that have formed in the left side of the heart (following myocardial infarction, atrial fibrillation, or rheumatic heart disease). Hypertension is an important risk factor in the development of thrombosis, particularly at the carotid bifurcation. It has been estimated that the risk of stroke increases approximately sevenfold in patients who have uncontrolled hypertension. Septic emboli are relatively uncommon but may be seen following bacterial endocarditis, particularly when the mitral valve has been involved. Rarer causes of ischaemic stroke include severe hypotension, thrombocytosis, anaemia and cavernous sinus thrombosis. Stroke caused by embolism develops suddenly. It is usually not preceded by transient ischaemic attacks, but rather the stroke evolves rapidly when a clot suddenly obstructs a cerebral vessel. The resultant infarct may subsequently enlarge over several days as a result of cerebral oedema. These strokes are sometimes referred to as either ‘stroke in evolution’ or ‘completed’. Stroke in evolution indicates that the symptoms are still progressing and as such there is to some extent a potentially reversible element. This should therefore be regarded as a medical emergency. Treatment should commenced immediately. This involves 1. controlling severe hypertension (>185/110). Decreasing mild hypertension may increase infarction in a patient with acute thrombosis, as this may reduce cerebral perfusion. 2. Urgent CT to distinguish ischaemic from haemorrhagic stroke. 3. Thrombolytic agents may decrease the severity of a stroke in carefully selected patients. However any coexisting intracranial haemorrhage is a contraindication to thrombolysis. 4. Endovascular clot retrieval has recently been shown to improve survival and outcomes in selected patients. 5. Anticoagulants (such as heparin) or antiplatelet therapy with aspirin may also be used. Low doses of aspirin taken daily is recommended to decrease the incidence of thromboembolic strokes. A completed stroke evolves slowly and the full extent of any neurological deficit may take hours or days to emerge. This commonly includes hemiplegia, aphasia, and hemisensory loss as well as speech and swallowing difficulties. Any recovery is dependent on a good collateral circulation. Significant clinical improvement may occur after

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3 weeks, when the cerebral oedema has subsided. After a completed stroke, treatment focuses on the prevention of further neurologic damage, through the reduction of underlying risk factors and rehabilitation, including speech and physical therapy.

7.8.3 Cerebral Haemorrhage Intraparenchymal haemorrhage (IPH) is one form of intracerebral bleeding in which there is bleeding within the brain parenchyma. Bleeding into the ventricles—intraventricular haemorrhage (IVH), can also occur. The commonest cause is hypertension. Bleeding disorders, arteriovenous malformations (AVMs), aneurysms, tumours, and venous hypertension secondary to central venous thrombosis, can also result in intracerebral haemorrhage. Clinically these may all present with signs and symptoms indistinguishable from ischaemic stroke. Urgent imaging is therefore essential (Figs. 7.10 and 7.11). Clinical features include the following, but not all may be present: • Headache • Loss of consciousness • Focal neurological deficit—if present, the nature of this can often be used to determine the site of the haemorrhage. Causes of intracerebral bleeding include 1. Hypertension 2. Arteriovenous malformation (Fig. 7.12) 3. Aneurysm rupture 4. Trauma 5. Intracranial neoplasm 6. Coagulopathy 7. Sympathomimetic drug abuse eg cocaine, amphetamines 8. Sickle cell disease 9. Eclampsia or postpartum vasculopathy 10. Infection 11. Vasculitis 12. Neonatal intraventricular haemorrhage 13. Cerebral amyloid angiopathy In younger patients, vascular malformations (AVMs) are more common. In the elderly, hypertension and amyloid are more common. Cerebellar strokes are uncommon. Patients present with ataxia, ipsilateral facial weakness, gaze paresis, miosis, and decreased level of consciousness. A potential complication of this type of stroke is obstructive hydrocephalus due to compression of the fourth ventricle. Initial management of a stroke patient commences with resuscitation with IV fluids. Intracranial haemorrhage should be treated as a medical emergency and

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may require airway protection with transfer to an intensive care unit. The blood pressure should be maintained at around 140/90. Clotting studies are urgently requested. An urgent CT scan is then required to distinguish between ischaemia and haemorrhage. One of the early CT signs is the loss of gray-white matter interface. CT should be performed as soon as possible after the onset of symptoms, especially if the patient is unconscious or SAH is a possibility. Lumbar puncture in confirmed stroke victims is unnecessary and potentially dangerous. Angiography might also be performed, especially if a clot is close to the Circle of Willis or

Fig. 7.10  Haemorrhage due to hypertension

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Fig. 7.11 Intracerebral haemorrhage due to AVM

Fig. 7.12 Catheter angiography of occipital AVM

Sylvian Fissure, (indicating a possible aneurysmal cause), or in a younger nonhypertensive patient (suggesting a possible AVM), or if surgical evacuation is being considered. In severe cases neurosurgery may be required (craniotomy and clot evacuation) if the patient is deteriorating due to a raised ICP and the clot is superficial. Deep seated haematomas are not amenable to evacuation eg basal ganglia or thalamus. In those patients that survive, stroke rehabilitation will be necessary. Carotid duplex will also be required later if the patient makes a good recovery. This helps determine whether there is any atherosclerosis of the carotid arteries and further risk.

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7.8.4 Intraventricular Haemorrhage This is bleeding into the brain’s ventricular system. It can occur secondary to significant trauma or as part of a stroke. About one third of cases are primary and confined to the ventricular system. These are commonly caused by trauma, aneurysm, vascular malformations and tumours. The remaining two thirds are secondary, arising from an intraparenchymal or subarachnoid haemorrhage. Symptoms are similar to other causes of stroke and include the sudden onset of headache, nausea and vomiting, together with an alteration in the mental state and/or level of consciousness. Focal neurological signs are usually minimal or absent. Diagnosis is confirmed on CT with the presence of blood inside the ventricles. Generally speaking, the prognosis is usually poor when IVH occurs as a result of intracerebral haemorrhage, especially if hypertension coexists and hydrocephalus develops. Intraventricular blood can block the flow of CSF, resulting in obstructive hydrocephalus. This will quickly result in raised intracranial pressure and death unless treated. This type of haemorrhage is common in premature infants or those of very low birth weight. If appropriate, management focuses on the treatment of any underlying causes and monitoring and control of the intracranial pressure via an intraventricular catheter and medication.

7.8.5 Transient Ischaemic Attack (TIA) A transient ischaemic attack (TIA) is a sudden but transient and reversible neurological deficit that lasts from a few minutes to up to 24 h. It is caused by temporary ischaemia of the brain, spinal cord or retina. However this is not severe enough to result in infarction. TIAs generally have the same underlying cause as strokes which result in a disruption in the cerebral blood flow. As such, they are sometimes referred to as ‘mini-strokes’. The severity of TIA varies considerably, from multiple daily attacks over an prolonged period, to a few attacks shortly before a fully blown stroke occurs. Approximately one third of patients with a history of TIA will ultimately go on to develop a stroke within the next 5-years. Diagnosis is therefore important to allow preventive measures to be instituted. TIAs occur as a result of small (often platelet) emboli. The source of these may be an atherosclerotic plaque in the heart, aorta or internal carotid artery. Haematological causes include polycythemia, sickle cell disease, and other conditions resulting in hyperviscosity of the blood. Risk factors include a family history of stroke or TIA, age >55, male sex, high blood pressure, diabetes and smoking. Treatment of TIAs should be initiated as soon as the diagnosis is established. However it is not always immediately possible to tell the difference between a small CVA and a TIA. Most patients are therefore usually investigated and admitted as stroke patients, until TIA has been diagnosed. Treatment should initially be directed towards the correction of the immediate problem, with prevention of further episodes. Any

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predisposing medical conditions should be treated, notably hypertension, diabetes and any coagulopathy. Anticoagulant therapy is often used, but there is little convincing evidence that anticoagulant drugs are of value in the acute stages. Treatment with aspirin or clopidogrel however, significantly reduces the risks of future TIAs and stroke in highrisk patients. According to local protocols, patients should be referred to a vascular surgeon for consideration of endarterectomy if they are found to have carotid stenosis.

7.8.6 Locked-in Syndrome (LIS) This is a condition in which there is complete paralysis of nearly all voluntary muscles in the body except for the eyes. Unfortunately, the patient is still completely aware of their surroundings but cannot move or communicate. In some cases the eyes are also paralysed. This condition is also known as cerebromedullospinal disconnection or pseudo-coma. Causes include: • • • • • • •

Poisoning/neurotoxins Motor neurone disease/Amyotrophic lateral sclerosis (Lou Gehrig’s disease) Brainstem stroke Multiple sclerosis Rapid correction of hyponatremia Traumatic brain injury Lesions in the brain-stem

In children, the most common cause is a stroke of the pons. Diagnosis can be very difficult. Patients present with quadriplegia and an inability to speak. Only blinking or moving their eyes maybe possible. Locked-in syndrome may therefore mimic loss of consciousness and if respiration is affected it can even resemble death. Imaging is required to exclude other causes. If suspected, EEG can indicate that the patient is not unconscious. Treatment is generally supportive and the prognosis is often very poor. It is extremely rare for any significant motor function to return.

7.8.7 Pituitary Apoplexy Pituitary apoplexy is bleeding into the pituitary gland. This usually occurs when there is a tumour present. Sheehan’s syndrome (Simmond’s syndrome or post partum pituitary necrosis) is another form of pituitary gland necrosis which can occur following hypovolaemic shock during childbirth (the gland is hyperpastic during pregnancy with an increased blood supply and is therefore sensitive to ischaemia). In both cases there is major disruption to the blood supply to the pituitary gland resulting in hypopituitarism. In pituitary apoplexy patients present with sudden onset of headache, which may be associated with a rapidly worsening visual field defect and/or ophthalmoplegia. This is followed in many cases by the symptoms of adrenal insufficiency (Addisonian

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crisis), with hypotension, hypoglycaemia and low cortisol levels. Diagnosis is made following CT or MRI and blood tests. These include a complete blood count, urea and electrolytes (notably sodium and potassium), liver function tests, coagulation testing, and a hormonal panel (growth hormone, prolactin, luteinizing hormone, follicle-stimulating hormone, thyroid-stimulating hormone, thyroid hormone). Prolactin is particularly important as prolactinomas will often respond rapidly to medical therapy and do not require surgery. Initial urgent treatment requires intravenous fluids and correction of hormone deficiencies (particularly cortisol). Patients are usually very unwell and will require admission and intensive management. Following recovery, the patient will require follow-up by an endocrinologist to monitor long-term consequences. Long-term hormone supplementation is usually required.

7.9

Intracranial and Related Infections

Many intracranial infections present with similar features. Patients are usually unwell with a fever, headache, nausea and altered level of consciousness. Clinically it may not be possible to distinguish the different types of infection from each other. From an emergency perspective this is perhaps less important. Rather it is more important to establish that an intracranial infection is present and requires urgent referral. Initial treatment may be commenced on clinical grounds only, to avoid delays. Nevertheless it is important to obtain appropriate specimens as soon as possible to confirm the diagnosis and determine bacterial sensitivities to antibiotics if these are present. Not all infections present with a pyrexia. Children and the elderly especially can present atypically, sometimes with apparently innocuous symptoms at first. It is therefore very important to maintain a high index of suspicion in any patient presenting with and a unusual headache and signs of cerebral irritation, or an altered level of consciousness. Urgent CT is often the first line of investigation. Lumbar puncture may be required, but this can be contraindicated if there is raised intracranial pressure.

7.9.1 Diffuse Infections in the CSF: Meningitis Meningitis is an acute inflammatory condition of the meninges usually as a result of infection of the cerebrospinal fluid (CSF). Patients can deteriorate extremely rapidly, making this a medical emergency requiring immediate treatment. Young children often develop nonspecific symptoms, such as irritability, drowsiness, or poor feeding. Therefore it is important to consider meningitis in any irritable child, especially with a rash (non-blanching and petechial). Infection may be caused by viruses, bacteria or other micro-organisms. Bacterial and viral meningitis are contagious and can be transmitted through respiratory droplets during close contact. Viral meningitis can be spread through faecal contamination. Less commonly, certain drugs can result in meningeal inflammation. In most cases the infective pathogen is a virus. Bacterial pathogens need to be quickly isolated, identified and then treated. Bacterial meningitis can result in serious long-term consequences, including deafness, epilepsy, hydrocephalus and cognitive functional deficits if it is not treated quickly.

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Some infective causes are preventable with immunisation (meningococcal, mumps, pneumococcal, and Hib vaccines). The term aseptic meningitis refers to cases of meningitis in which no infection can be found. This is usually caused by viruses but it can also be due to a bacterial infection that has already been partially treated. Rarer infections include spirochetes, borrelia, malaria and amoebae, and these therefore need to be specifically considered if initial investigations fail to identify a cause. Immunosuppressed patients are at risk of fungal infections (cryptococcal sp., Coccidioides sp., Histoplasma sp., Blastomyces sp., and Candida species). Bacterial meningitis can occur spontaneously. It can also arise following trauma (especially skull fractures), surgery and following insertion of specific devices (e.g. CSF shunts for hydrocephalus). Spontaneous meningitis may be difficult to diagnose, as initial symptoms are indistinguishable from many viral infections (malaise, lethargy, fever, anorexia). Patients with immune deficiencies are particularly susceptible to TB meningitis, fungal, viral, and treponemal infections. Cryptococcal, varicellazoster virus, cytomegalovirus, and neurosyphilis should therefore all be considered. The most common symptoms of meningitis are fever, headache and neck stiffness. ‘Nuchal rigidity’ refers to the inability to flex the neck forwards passively due to severe spasm of the neck muscles. This is a very important clinical sign which should be specifically looked for in any patient with severe headache and a fever. Beware any patient who presents with a high fever, altered mental status and nuchal rigidity. If none of these are present, acute meningitis is unlikely, but if all three are present meningitis is probable. A list of meningitis symptoms and signs could include the following: 1. fever 2. Headache 3. Vomiting 4. Photophobia 5. Irritability 6. Confusion 7. Lethargy 8. Hypersensitivity to loud noises 9. Rash (in over half of cases) 10. Seizures (20% of patients at presentation and an additional 10% of patients within 72 h) 11. Tachycardia/tachypnoea/shock 12. The “jolt accentuation manoeuvre” may help determine meningitis in those reporting fever and headache. This is a variant of nuchal rigidity. The patient is asked to rapidly rotate the head. If this does not make the headache worse, meningitis is unlikely. 13. Kernig’s sign. This is very indicative of meningeal irritation. The patient is placed in the supine position, with the hip and knee flexed to 90 degrees. Pain is then induced following passive knee extension, while the hips remain fully flexed. This manoeuvre places traction on the meninges via the sciatic nerve.

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14. Brudzinski’s sign occurs when flexion of the neck causes involuntary flexion of the knee and hip. It is important to also look for a rash. If one is present, this may indicate a particular type of meningitis. Neisseria meningitidis (“meningococcal meningitis”) typically causes a rapidly spreading, non-blanching, petechial rash, which may precede other symptoms. This can be seen on the trunk, lower extremities and mucous membranes. Diagnosis in children can be difficult as they do not present with the same features as adults. Small children may only be irritable and appear to be unwell. The presence of a rash in any unwell child should therefore raise urgent suspicion. Age can sometimes be a guide to the underlying cause. In premature babies and newborns, common causes are group B streptococci, Escherichia coli and Listeria monocytogenes (meningitis in the newborn). Children under five may be infected by Haemophilus influenza (if not vaccinated). Older children are more commonly affected by Neisseria meningitidis and Streptococcus pneumoniae. In adults, Neisseria meningitidis and Streptococcus pneumoniae cause about 80% of bacterial meningitis. Staphylococci, Pseudomonas, and other Gram-negative organisms may infect devices, such as cerebral shunts or extraventricular drains. Tuberculous meningitis is more common in countries in which tuberculosis is endemic, but is also seen in immunosuppressed patients such as AIDS. The most important test in confirming meningitis is analysis of the cerebrospinal fluid following lumbar puncture (if not contraindicated). Urgent imaging is initially required to assess the status of the ventricles prior to lumbar puncture. This is because obstructive hydrocephalus or an intracranial mass is a relative contraindication to this procedure. If a lumbar puncture is undertaken in such patients, coning can occur. CT may also show evidence of increased attenuation in the basal cisterns and sulci as a result of high concentrations of inflammatory cells. This must not be confused with subarachnoid haemorrhage. Other manifestations of meningeal infection (necrotising panarteritis, septic thrombophlebitis, ischaemic injury and cerebritis) may be detected with diffusion MR imaging, but this is rarely undertaken urgently. Imaging also plays an important role in the detection and management of less aggressive forms of meningitis. TB meningitis, for example, can be difficult to diagnose in patients presenting with headache and cranial neuropathies. Management of acute meningitis depends on the causative organisms. Bacterial meningitis needs urgent treatment with antibiotics and more recently in some reports, corticosteroids. This helps to ensure recovery and reduce the risk of complications, such as brain swelling and seizures. In one study adjunctive use of dexamethasone decreased pneumococcal meningitis mortality from 30% to 20%. Patients need immediate admission to hospital. Whilst in hospital, other treatments, procedures and investigations will be carried out depending on the patient’s condition. Antibiotics are not effective against viruses although, they may be started because the cause of meningitis is not known. Once viral meningitis is confirmed they are usually discontinued. Key elements in management include.

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1. If the patient is alert and in a stable condition, oxygen should be administered, intravenous (IV) access established, and immediate admission arranged. It is essential to begin treatment as early as possible. Any delay may contribute significantly to morbidity and mortality. 2. Aggressive resuscitation with IV fluids. This may be necessary the patient is in shock or hypotensive. Crystalloid should be infused until the patient is well hydrated. 3. Monitoring of electrolytes. Hyper or Hypo-natremia can occur in bacterial meningitis as a result of dehydration, inappropriate secretion of antidiuretic hormone (SIADH), or following aggressive intravenous fluid resuscitation. 4. Antibiotics should be given as soon as the diagnosis is suspected and continued until the CSF white cell count is normal. The antibiotic or combination of antibiotics depends on the type of bacteria causing the infection. The penicillins, certain cephalosporins (i.e., third- and fourth-generation agents), carbapenems, fluoroquinolones, and rifampin provide high CSF levels. However it is important to discuss the most appropriate choice of antibiotic with a microbiologist or appropriate specialist. Often these are commenced before bacterial sensitivities are determined. They may therefore need to be adjusted at a later date. 5. Intrathecal antibiotics may be considered in patients with hospital acquired meningitis (for example following neurosurgery or placement of an external ventricular catheter) that does not respond to IV antibiotics. 6. The use of corticosteroids (dexamethasone, 0.15 mg/kg every 6 h for 2–4 days) is controversial but has been reported to improve outcomes by minimising the detrimental effects that can occur secondary to the patient’s host defenses (inflammation). However, the anti-inflammatory effects of steroids reduce blood-brain barrier permeability and can therefore impede penetration of antibiotics into the CSF. 7. If the patient’s mental status is altered, seizure precautions should be considered, seizures should be treated according to the usual protocol, and airway protection should be considered. 8. A throat swab should be taken for polymerase chain reaction (PCR). This helps to identify the likely organism. 9. Blood is taken for culture and Gram’s stain. 10. Computerised tomography (CT) or magnetic resonance (MR) scans of the head may show swelling or inflammation. Computed tomography (CT) of the head should also be performed a before LP is undertaken. If there is no mass effect, LP can be safely performed. X-rays or CT scans of the chest or sinuses may also show infection in other areas that may be associated with meningitis. 11. If there are no contraindications, a lumbar puncture (LP) for cerebrospinal fluid (CSF) examination are indicated to identify the causative organism and in bacterial meningitis determine antibiotic sensitivities. 12. Signs of hydrocephalus and increasing intracranial pressure (ICP) should be closely watched for. Fever and pain should be managed, straining and coughing controlled, seizures prevented and systemic hypotension avoided.

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13. Contact Tracing—for single cases it may be necessary to treat close contacts (‘kissing contacts’). Usual regimes include rifampicin 600 mg twice daily for 2 days and ciprofloxacin 500 mg as a single dose Untreated meningitis is often fatal. Systemic complications in those that can still occur and can be severe. These include 1. Gangrene of the limbs (requiring amputation) 2. Systemic inflammatory response syndrome 3. Waterhouse-Friderichsen syndrome—haemorrhaging into the adrenal glands (which is often fatal). 4. Hyponatremia (syndrome of inappropriate antidiuretic hormone secretion) 5. Cerebral oedema and herniation 6. Hydrocephalus 7. Seizures 8. Cardiac arrhythmias and ischemia 9. Cranial nerve palsies (especially eye movements, facial muscles and hearing). 10. Cerebral venous thrombosis, with weakness, loss of sensation, or abnormal movements

7.9.2 Tuberculous Meningitis (TBM) This is the most commonly seen in children and adolescents. TBM develops when a meningeal, subpial or subependymal tuberculous focus (Rich focus) ruptures into the subarachnoid space or into the ventricular system. Clinical features include 1. Basal exudates 2. Progressive hydrocephalus 3. Vasculitis and Infarction 4. Cranial neuropathies Formation of a thick, gelatinous exudate occurs, initially confined to basal subarachnoid areas. This rapidly extends to involve the basal cisterns, sylvian fissures, cerebral convexities and the ventricles and choroid plexus. Communicating hydrocephalus is caused by obstruction to CSF flow by thick gelatinous inflammatory exudates within the basal cisterns, over the brain convexities and in the cerebral aqueduct or fourth ventricular foramen. Basal exudates localised to the circle of Willis also result in a vasculitis, with spasm or thrombosis of the vessels and infarction. The vessels at the base of the brain are most severely affected, including the terminal segment of common carotid artery and proximal segment anterior, middle and posterior cerebral arteries. Cranial nerve palsies occurs in about 20–40% of patients. These can be the first clinical feature of TB meningitis. The most commonly affected nerves are II, III, IV, VI, VII. Tubercular encephalopathy is a diffuse cerebral disorder characterised by convulsion, stupor and coma, without signs of meningeal irritation or focal

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neurological deficit. It is almost exclusively seen in infants and children receiving antitubercular treatment. It is believed to be an allergic delayed type IV hypersensitivity reaction due to cell mediated immunity to tubercular protein. Isolated calvarial tuberculosis is a rare condition, commonly seen secondary to haematogenous spread from a primary focus elsewhere. The frontal and parietal bones are most commonly involved. This presents as a subgaleal swelling (Pott’s puffy tumor) with a discharging sinus. Bony lesions are usually osteolytic, and appear as well defined “punched out” defects.

7.9.3 Non-infectious Meningitis Non-infectious causes of meningitis may result in diagnostic confusion and inappropriate treatment. Causes include microscopic spread of cancer to the meninges (malignant or neoplastic meningitis), drugs (notably non-steroidal anti-­ inflammatory drugs, antibiotics and intravenous immunoglobulins), sarcoidosis (neurosarcoidosis), connective tissue disorders (systemic lupus erythematosus), and some vasculitides (such as Behçet’s disease). Epidermoid cysts and dermoid cysts have also been reported to result in meningitis following rupture into the subarachnoid space.

7.10 Encephalitis and Meningoencephalitis This is acute inflammation of the brain. Encephalitis is distinct from meningitis although patients can sometimes present with both. Cerebritis, is an area of unencapsulated inflammation which can develop into a collection of necrotic pus—a brain abscess. Encephalitis can have both infective and non-infective causes. In some patients viral infection can be transmitted via an insect vector (notably ticks and mosquitoes). Rabies virus is transferred following an infected animal bite. Brain inflammation can also occur as a complication of viral infections with measles, mumps, chicken pox. Once it has passed across the blood brain barrier the virus enters neural cells resulting in destruction of function, haemorrhage and a diffuse inflammatory response. Encephalitis can also occur in autoimmune disorders such as multiple sclerosis or Rasmussen’s encephalitis. Although Creutzfeldt-­Jacob disease (CJD) is due to a prion (which is not an infectious agent in the strictest sense), this is included as part of the differential diagnosis. Herpes simplex virus, poliovirus, measles virus are common pathogens. Herpes simplex virus deserves special mention. This can initially present with widespread oral ulceration and be erroneously confused with Stevens Johnson’s syndrome. If high-dose steroids are given, the patients may develop herpes simplex virus encephalitis. For this reason severe oral ulceration of the mouth should be treated with caution.

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Other rare types of encephalitis include Japanese encephalitis, rabies and equine encephalitis. Bacterial encephalitis may occur following meningitis. Parasitic or protozoal infestations, such as toxoplasmosis, malaria, or amoebic infection, can also cause encephalitis. Cryptococcus neoformans can occur in immunocompromised patients. Whatever the cause, common symptoms include headache, fever, confusion, drowsiness and fatigue. Seizures, tremors, hallucinations, and memory problems suggest advanced disease. Adults usually present with acute onset of fever, headache, confusion, and sometimes seizures. However children or infants may present with non-specific symptoms such as irritability, drowsiness and fever. In all cases it is important to always check for a stiff neck—this indicates the presence of meningitis or meningoencephalitis. Several subtypes of this disease exist. Limbic encephalitis is a particular form the disease in which the inflammatory process is confined to the limbic system of the brain. Patients therefore present with disorientation, disinhibition, memory loss, seizures, and behavioural problems. Autoimmune encephalitis presents with catatonia, psychosis, abnormal movements, and autonomic dysfunction. Encephalitis lethargica presents with high fever, headache, delayed physical response and lethargy. Patients can also develop upper body weakness, muscular pains, and tremors. Meningoencephalitis is the simultaneous infection of meningitis and encephalitis. Causative organisms are the same as those previously described and include viruses, bacteria and protozoans. Specific infections include: Bacterial • • • • • • •

Listeria monocytogenes Neisseria meningitidis Rickettsia prowazekii Mycoplasma pneumoniae Tuberculosis Borrelia (Lyme disease) Leptospirosis Viral

• • • • • • • • • •

Mumps, a common cause of meningoencephalitis Tick-borne meningoencephalitis West Nile virus Measles Epstein-Barr virus Varicella-zoster virus Enterovirus Herpes simplex virus type 1 Herpes simplex virus type 2 HIV, a very small number of patient develop meningoencephalitis at the early stage of infection.

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Fungal Cryptococcus neoformans Protozoal Primary Ameobic meningoencephalitis can mimic a brain abscess, aseptic or chronic meningitis, or CNS malignancy • Trypanosoma brucei • Toxoplasma gondii Investigations are along the same lines as the previously described intracranial infections. A complete blood count (CBC) with differential should be performed, although findings are often within the normal range. Serum electrolyte levels are usually normal unless dehydration is present (syndrome of inappropriate secretion of antidiuretic hormone occurs in 25% of patients with some types of encephalitis). CT scan should be undertaken if there are focal symptoms or signs, and to exclude brain swelling, raised intracranial pressure, obstructive hydrocephalus, or mass effect. A Head CT also helps exclude brain haemorrhage or infarction as a cause the patients illness. Magnetic resonance imaging is reported to be more sensitive than CT scanning in demonstrating early abnormalities. If there is no evidence of raised intracranial pressure a lumbar puncture can then be undertaken. This should be performed on all patients suspected of having a viral encephalitis. CSF analysis usually shows increased amounts of protein and white blood cells with normal glucose. Specific diagnosis can sometimes be made by the detection of antibodies on polymerase chain reaction. Subsequent MRI imaging can help determine the presence of inflammation and identify other causes. Serological tests may show high antibody titres. EEG may also show characteristic patterns. With the exceptions of HSE and varicella-­zoster encephalitis, the viral encephalitides are generally not treatable beyond supportive care. Specific treatments for T gondii and cytomegalovirus (CMV) encephalitis are also available. Patients should initially be resuscitated and referred urgently. Any hydrocephalus or increased intracranial pressure should be treated immediately. Supportive treatment (intravenous fluids/sedation/mechanical ventilation) should be commenced and anti-viral agents administered if the diagnosis is suspected. Systemic complications include hypotension and shock, hypoxemia, hyponatremia,and exacerbation of pre existing chronic diseases. Corticosteroids may also be used to reduce brain swelling, but as previously discussed their use is controversial in the presence of an acute infection.

7.11 Focal Infections with the Potential for ‘Mass Effect’ 7.11.1 Brain Abscess Brain abscess is caused by intracranial inflammation with subsequent abscess formation. Infection can enter the intracranial compartment directly or indirectly via 3 routes (i) Contiguous suppurative focus (Direct extension—45–50% of cases), (ii)

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following trauma (10% of cases) and (iii) Haematogenous spread from a distant focus (25% of cases). Subdural empyema, sinusitis and middle ear infections are a common cause of brain abscesses, with direct spread intracranially. Haematogenous spread of infection from elsewhere can also occur. Well recognised sites include infective endocarditis and dental abscess. However, In around 15% of cases, no source can be identified. The brain abscess initially begins as a discreet region of inflammation that quickly progresses to form a pus-filled cavity. Common sites are (i) frontal-temporal, (ii) frontal-parietal, (iii) parietal, (iv) cerebellar and (v) occipital lobes (Figs. 7.13, 7.14, 7.15, 7.16 and 7.17). Clinical features are similar to the other causes of intracranial infection. Headache, nauseas, vomiting, and deterioration in the conscious level are all common. With cerebral irritation the patient may develop focal neurology or seizures. However pyrexia may be absent. Nuchal rigidity and papilloedema are seen in about one quarter of cases, so should be routinely looked for. Untreated, additional localised neurologic signs will eventually be found in most patients. These are due to local pressure/inflammatory affects (for example Cerebellar abscess— Nystagmus and ataxia, Brainstem abscess—Facial weakness, dysphagia and hemiparesis and Occipital abscess- Neck rigidity). Any suddenly worsening headache, followed by emerging signs of meningismus, is often associated with rupture of the abscess. Investigations are similar to the other causes of intracranial infection, but it is important to note that the white cell count and CRP can be normal, especially if

Subdural empyema Epidural abcess Dura mater (Attached to skull)

Dura mater (Peeled off skull)

Lateral ventricle Brain parenchyma Brain abcess

Pyoventriculitis

Falx cerebri Subdural space

Cranial bone Superior sagittal sinus

Fig. 7.13  Different types of intracranial suppurative collections

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Fig. 7.14  Left temporal abscess due to mastoiditis

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Fig. 7.15  Large frontal brain abscess

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Fig. 7.16  Case 6.5. (a–d) Axial cranial post-contrast CT scan showing extensive frontoparietal and interhemispheric subdural empyemas on the right side (arrows). Note bilateral maxillary sinusitis (stars)

there is no primary source. Serological tests should be taken for some pathogens (CSF polymerase chain reaction for Toxoplasma). An urgent CT scans should be undertaken. This usually shows a ring enhancing lesion with surrounding oedema. In contrast to tumours, abscesses are usually perfectly circular with a wall of uniform thickness. They can also be multiple. As with subdural empyema a lumbar puncture should not be performed due to the risk of cerebral herniation (coning). Diagnosis is therefore usually suspected on the basis of an enhancing circular lesion on a CT scan of a patient with an infection elsewhere. Many specialists now consider MRI to be the best diagnostic test in the diagnosis of brain abscess. This is reported to have better sensitivity and specificity.

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a

b

c

d

Fig. 7.17  Case 6.4. Axial post-contrast CT scan (a). T1-weighted images without (b) and with (c) gadolinium injection, and a T2-weighted image (d) show multiple supratentorial (right side) and infratentorial (left side) subdural empyemas mimicking intraparenchymal brain abscesses

Early diagnosis is essential. Patients who have only had symptoms for a week or less tend to respond well to medical treatment, although they will require a long course of antimicrobial treatment. However, many patients require urgent surgical drainage. Generally speaking, large abscesses will need to be evacuated or aspirated, whilst smaller ones may be aspirated for diagnostic purposes only. Before the abscess becomes encapsulated, antimicrobial therapy may be beneficial. Once the abscess

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has fully formed, surgical drainage combined with prolonged antibiotics (4–8 weeks) is required. Some neurosurgeons prefer to completely evacuate the abscess, while others advocate repeated aspirations. If the patients consciousness is deteriorating, they should be fully resuscitated and steroids and mannitol should be considered prior to transfer. The use of steroids is controversial, however they may be indicated if there is significant mass effect seen on CT, or evidence of significant cerebral oedema. Complications of brain abscesses are partly related to their location. These include hemiparesis, cranial nerve palsies, hydrocephalus, ataxia and optic atrophy. Recurrent seizures may develop in about a third of cases. With early treatment, mortality has been significantly reduced, but since this condition is commonly seen in immunocompromised patients the mortality rate remains around 10–15%.

7.11.2 Subdural Empyema This is is a collection of pus between the dura mater and the underlying arachnoid. About 95% of subdural empyemas are located within the head, often around the frontal lobe. 5% involve the spine. Most cases are secondary to sinusitis or a middle ear infection. Patients initially present with an illness similar to meningitis, but usually develop a hemiparesis due to cortical venous thrombosis. Seizures are common. The infection has a tendency to spread quickly through the subdural space until it reaches a boundary (falx cerebri, tentorium cerebelli etc.). They are therefore usually unilateral. With progression, the empyema can expand resulting in an increase in intracranial pressure and invasion of the cerebral parenchyma. Cerebral oedema and hydrocephalus can also occur as a result of disruption of the cerebral circulation and normal flow of cerebrospinal fluid. Thrombosis of the cortical veins can result in cerebral infarction. Cavernous sinus thrombosis can also occur. Infection usually enters through the frontal or ethmoid sinuses. Less frequently it enters through the middle ear, mastoid cells, or sphenoid sinus. Rarely, it occurs by haematogenous spread from distant foci, most commonly the heart or lungs. Common causative organisms are anaerobes, aerobic streptococci, staphylococci, Haemophilus influenzae, Streptococcus pneumoniae, and other gram-negative bacilli. Initial investigations and management are similar to meningitis, with the exception of a lumbar puncture. This should be avoided due to the risk of coning. MRI is now the imaging study of choice, being superior to CT scan in defining the extent of the subdural empyema and demonstrating a collection. However CT scan is usually the modality of choice if the diagnosis is uncertain, or if the patient is comatose or critically ill and MRI is not possible. This will also show a thin subdural collection, with pus along the falx. Patients usually require immediate neurosurgical drainage via a craniotomy, which enables good exposure for adequate washout and drainage. Alternatively stereotatic burr hole placement with drainage and irrigation may be undertaken in selected cases. The source of infection should also be identified and treated accordingly (lungs, sinuses).

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7.11.3 Other Focal Infections 7.11.3.1 Neurosyphilis This is an infection which can involve both the brain and spinal cord. It is caused by the spirochete Treponema pallidum. Infection usually occurs in people with long-­ standing and previously undiagnosed (and untreated) syphilis. In such cases the initial infection may have been acquired decades ago. There are four distinct types of neurosyphilis (i) asymptomatic, (ii) meningovascular, (iii) tabes dorsalis and (iv) general paresis. In rare cases neurosyphilis can been mistaken for Alzheimer’s disease. The main symptoms of neurosyphilis include visual impairment, confusion, changing personality, disorientation and an abnormal gait. Patients can sometimes present with seizure. An Argyll Robertson pupil may be present, in which bilaterally small pupils constrict focusing on near objects but not to light. This has been attributed to a dorsal midbrain lesion that interrupts the pupillary light reflex pathway but spares the more ventral pupillary near reflex pathway. Neurosyphilis can be difficult to diagnose, partly because it is not often considered in the differential diagnosis. Blood tests involve the Venereal Disease Research Laboratory test (VDRL), Fluorescent treponemal antibody absorption (FTA-ABS) and other serology tests (including HIV testing). CT/MRI and samples of cerebrospinal fluid may also be required. Management involves high-dose penicillin.

7.12 Raised Intracranial Pressure (Intracranial Hypertension) Raised intracranial pressure is not a specific diagnosis, but has many causes. It usually occurs as a result of intracranial pathology. However, in some patients a cause is not found. Causes include: 1. Generalised brain swelling. This has many causes both intrinsic and extrinsic to the brain. Generalised swelling can occur following trauma, prolonged hypoxia (prolonged seizures), severe electrolyte disturbances and infections such as encephalitis. Systemic disease can also result in wide spread cerebral oedema, for example acute liver failure, hypertensive encephalopathy and any condition resulting in hypercarbia 2. Space occupying lesions, such as tumours, haematoma or abscesses. When these grow slowly the intracranial pressure can be compensated for as previously discussed (monroe Kellie doctrine). However when this compensation process becomes exhausted intracranial pressure will rise 3. Obstruction to CSF flow (Aqueduect stenosis, Chiari malformation, meningeal disease) 4. Increased CSF production. Although uncommon a tumour of the choroid plexus can result in overproduction of CSF, which is produced in excess of that which can be resorbed

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5. Increase in cerebral venous pressure (venous sinus thrombosis or stenosis, heart failure or mediastinal obstruction) 6. Craniosynostosis—premature fusion of the sutures prevents skull expansion as the brain grows. Depending on the number of sutures involved the extent of elevation of the intracranial pressure varies. Some of these conditions are discussed in the chapter on embryology 7. Idiopathic—this is discussed further below Worldwide, the most common causes of raised intracranial pressure are (i) subarachnoid haemorrhage, (ii) trauma, (iii) cerebral tumours (iv) stroke (v) meningoencephalitis, and (vi) Hydrocephalus. In many cases, the underlying cause is self-evident and raised intracranial pressure is anticipated as part of the clinical course. Investigations are directed them accordingly to establishing the underlying diagnosis and monitoring the intracranial pressure. Symptoms of raised intracranial pressure are varied and include headaches, vomiting, nausea, loss of concentration, drowsiness, irritability, changes in personality and blurred vision. Vomiting and headaches that occur first thing in the morning, or wake the patient is an important clue to the diagnosis. Because the patient has been laying down the intracranial pressure has risen even further. Symptoms often relieve on getting up. It is perhaps worth noting that caffeine withdrawal can also result in early morning headaches. Management of raised intracranial pressure is directed at the cause. In some cases CSF diversion may be required.

7.12.1 Hydrocephalus Hydrocephalus is a disturbance of CSF physiology. Secretion of CSF by the choroid plexus is a metabolically active process involving ion pumps and enzyme systems similar to those found in the distal tubule of the kidney. In hydrocephalus there is an abnormal accumulation of cerebrospinal fluid (CSF) within the brain. CSF secretion continues at a constant rate (about 20 mL/h in adults), regardless of intracranial pressure (ICP), so long as the choroid plexus and the brain itself are perfused. This often results in raised intracranial pressure. CSF reabsorption is a purely passive process driven by the pressure differential between the subarachnoid space and the venous circulation. With the rare exception of choroid plexus papilloma (a tumour of the choroid plexus that causes excessive CSF secretion), the diseases that cause hydrocephalus do so by interfering with CSF reabsorption. Symptoms often include headaches, double vision, ataxia, vomiting, sleepiness and mental impairment. In babies there may be a rapid increase in head size, a tense bulging fontanelle and ‘sunsetting’ of eyes. Hydrocephalus can occur as a result of a birth defect (e.g. neural tube defects and those that result in aqueduct stenosis), or it can be acquired, secondary to trauma, intracranial haemorrhage, meningitis and brain tumours. Depending on the underlying drainage mechanisms, hydrocephalus can be classified into communicating and non- communicating (obstructive). Both can be congenital or acquired.

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7.12.2 Communicating Communicating (non-obstructive) hydrocephalus occurs as a result of impaired cerebrospinal fluid reabsorption, but there is still free flow of CSF between the ventricles and subarachnoid space. This type of hydrocephalus is believed to be due to functional impairment of the arachnoid granulations in the superior sagittal sinus (where CSF is normally resorbed into the venous system). Causes of obstruction include subarachnoid and intraventricular haemorrhage, meningitis and congenital absence of arachnoid villi. Scarring and fibrosis secondary to bleeding or infection can also prevent delayed resorption of CSF.

7.12.3 Non-communicating Non-communicating (obstructive) hydrocephalus, is caused by obstruction to the flow of CSF within the brain. As a result CSF cannot reach the subarachnoid space and builds up within the ventricular system. In this group of patients it is not safe to do a lumbar puncture. These patients are at high risk of coning if this is done. Obstruction to CSF flow can occur at the following sites 1. Foramen of Monro—obstruction may lead to dilation of one or both lateral ventricles. 2. The aqueduct of Sylvius. This can be obstructed by a number of conditions including congenital atresia, haemorrhage, or a tumour. This results in dilation of both lateral and the third ventricles. 3. Fourth ventricle—obstruction here (from a posterior fossa mass) results in dilation of the aqueduct as well as the lateral and third ventricles. 4. The foramina of Luschka and Magendie. These may be congenitally obstructed (e.g. Dandy-Walker malformation).

7.12.4 Common Causes of Hydrocephalus (Figs. 7.18, 7.19 and 7.20) Prematurity (post haemorrhagic hydrocephalus) Myelomeningocele Other congenital or developmental conditions affecting the brain • • • • •

Dandy-Walker malformation Arachnoid cysts Interhemispheric cysts Aqueductal stenosis Encephalocele

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Fig. 7.18  CT scan showing congenital hydrocephalus

Brain tumour Traumatic brain injury. Post-traumatic hydrocephalus (PTH) can complicate decompressive craniectomy after traumatic brain injury (TBI). Aneurysmal subarachnoid haemorrhage Congenital or developmental conditions affecting the skull • Crouton • Pfeiffer syndromes • Achondroplasia

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Fig. 7.19  Obstructive hydrocephlaus on T2 MRI due to pineal region tumour

Fig. 7.20  CT scan showing hydrocephalus in an adult

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Meningitis. In many countries today, screening for hydrocephalus is undertaken during pregnancy and shortly after delivery. Routine prenatal ultrasound may detect hydrocephalus during pregnancy in the developing foetus. After birth, the head of the baby is measured regularly. Any abnormalities in head size, especially if accompanied with tense fontanelles require further investigation. Symptoms of hydrocephalus vary with age, disease progression, and individual differences in tolerance by the patient to the condition. For example, an infant’s ability to compensate for increased CSF pressure and enlargement of the ventricles differs from an adult’s. This is because the bones on the infant skull have not fully ossified and the sutures have not yet closed. The cranial cavity can therefore expand to accommodate the buildup of CSF.  In infancy, the most obvious indication of hydrocephalus is often a rapid increase in head circumference or an unusually large head size. Other symptoms may include vomiting, sleepiness, irritability, downward deviation of the eyes (also called “sunsetting”), and seizures. In advanced cases spasticity may occur in the lower limbs. Older patients present with symptoms of raised intracranial pressure. These may include headache followed by early morning vomiting, nausea, blurred or double vision, urinary incontinence, lethargy, drowsiness, irritability, or other changes in personality or cognition. Neck pain should be regarded with suspicion. This may indicate tonsillar herniation. Blurred vision maybe secondary to papilloedema or optic atrophy. Diplopia may arise secondary to CNVI nerve palsy. Symptoms of normal pressure hydrocephalus include, problems with walking, impaired bladder control leading to urinary frequency and/or incontinence, and progressive mental impairment and dementia. Many of these symptoms may be confused with dementia or Alzheimer’s disease. Parkinsonism may also occur. Investigations usually involve CT scan. This will typically show ventricular dilatation. Ultrasonography, magnetic resonance imaging (MRI), and pressure-­ monitoring techniques may also be undertaken in borderline or uncertain cases. The fourth ventricle is usually dilated in communicating hydrocephalus, but may be small in non-communicating hydrocephalus. MRI may also be necessary if a third ventriculostomy is being considered, to visualise the basal cisterns and local anatomy. It can also look for Chiari malformation or cerebellar or periaqueductal tumours. In infants, ultrasound through the anterior fontanelle may be undertaken.

7.12.4.1 H  ydrocephalus Is Most Often Treated by Surgically Inserting a Shunt These consist of three parts (i) a ventricular catheter, (ii) a valve, and (iii) a distal catheter. The ventricular catheter passes from the ventricle of the brain through the skull, where it joins the valve. The valves prevents excessive drainage of CSF. Most include a reservoir that can be punctured with a needle for diagnostic purposes and to remove CSF. The valve is also connected to a distal catheter that carries the CSF to another part of the body, where it can be reabsorbed back into the venous circulation. Common sites include the peritoneal cavity, pleural cavity, right atrium, and the

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internal jugular vein. Shunt systems thus divert the flow of CSF from the CNS to another area of the body where it can be absorbed as part of the normal CSF circulatory process. This will hopefully control the intracranial pressure. Whenever possible the underlying cause is also corrected. Complications of shunts include mechanical failure, infections, obstructions and the need to lengthen or replace the catheter. If these occur, the shunt system usually requires replacement. Shunt systems require monitoring and regular follow up. In patients with normal pressure hydrocephalus a lumbar puncture maybe undertaken to determine the suitability of a shunt. Following removal of CSF from the puncture, if symptoms improve (gait, or cerebral functions), then placement of a shunt will probably help. Repeated lumbar puncture may also be indicated in patients with hydrocephalus secondary to intraventricular haemorrhage. This particular type of hydrocephalus can resolve spontaneously. Treatment of hydrocephalus has changed in recent years with better imaging and introduction of endoscopic procedures as well as enhanced shunts. Third ventriculostomy creates an internal bypass by creating a stoma between the floor of the third ventricle and the basal cisterns. Endoscopic third ventriculostomy (ETV), with or without with choroid plexus cauterisation (CPC), is an emerging technique that provides restoration of cerebrospinal fluid flow and a shunt-free option for hydrocephalus children. In severe cases external ventricular drainage may be required. This can be done at the bedside. CSF drains via a manometer into an external collecting system. This may also be performed if there is infection or bloodstained CSF preventing shunt insertion.

7.12.5 Shunt Assessment It is important to know how to assess a shunt. If a shunt becomes blocked the intracranial pressure can rise very quickly and patients can become very unwell. Consider shunt blockage in any patient known to have a shunt who begins to act erratically, becomes confused or becomes drowsy. If the patient is severely unwell and unresponsive a diagnostic aspirate may be taken from the reservoir. If this improves the patient’s clinical condition a blockage in the distal catheter is likely to be the problem. If fluid cannot be aspirated a blockage in the ventricular catheter may be the cause (commonly from the choroid plexus). In other patients if time allows, diagnosis of shunt blockage can be made following CT scan. However CT imaging requires careful interpretation, depending on the underlying pathology. Neuroendoscopy techniques can also be used to reveal the cause of shunt obstruction. Plain films of the whole of the shunt (Shunt series) may be helpful if there are concerns regarding the distal catheter, which can break, disconnect, or migrate.

7.12.6 Shunt Infection Infection is a common complication of ventriculoperitoneal shunt (VP) placement, reportedly occurring in nearly 10% of patients. Patients with hydrocephalus secondary to IVH or meningitis are especially at risk as well as those receiving a shunt

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under 1 year of age. This may be due to the poorly developed immune system in infants under 1 year of age, the immaturity of the skin barrier in early infants, and the characteristics of the bacterial flora in this age group. Infection generally develops within the first 2 months after surgery, with Staphylococcus epidermidis being the most common cause. However, P. aeruginosa and Klebsiella and other multi resistant gram-negative bacteria have also been reported, making this a very difficult problem to treat. Candida is an incredibly rare but serious cause of ventriculoperitoneal (VP) shunt infections. Contamination most likely occurs at the time of placement or soon after. Breakdown of the wound and dehiscence over the shunt account for most infections. Shunt infections usually occur within a few weeks of surgery and are mostly secondary to contamination from skin bacteria. An infected VP shunt will often become secondarily obstructed by omentum, localising the infection. Patients present with symptoms of a blocked shunt accompanied by a fever. Meningism is uncommon. Infected Ventricular-Atrial (VA) shunts usually will not block and so the infection may continue undetected for a long period. Symptoms of an infected VA shunt include vague ill health and a lowgrade temperature. When a shunt infection is suspected, percutaneous needle aspiration of the shunt reservoir is usually diagnostic. CSF is sent for microscopy and culture. The preferred treatment of CSF shunt infections involves intravenous antimicrobial therapy, surgical removal of the infected shunt, installation of an external ventricular drainage (EVD) device, and insertion of a new shunt once the CSF is sterile. Prophylactic antibiotics have not been shown to prevent shunt infections.

7.12.7 Shunt Overdrainage Occasionally a shunt will excessively drain CSF, so that the patient develops low-­ pressure headaches. This may cause persistent low-pressure headaches, subdural collections, collapse of ventricles, bleeding or in cases of lumbo-peritoneal shunt, downward shifts of the brain resulting in herniation. In these cases, headache complaints are minimal when the patient is lying down but become more severe when the patient sits up or stands. In some patients if the ventricles are very large, any sudden change in pressure can cause them to collapse, tearing the delicate cortical veins and resulting in subdural haematoma. Low-pressure headaches are treated with reassurance and advising a high fluid intake. Caffeine has been reported to be helpful. The shunt can be revised if symptoms persist. Low-pressure headaches can also occur in up to a third of people who have had a spinal tap, usually hours to a day or two afterward—cerebrospinal fluid sometimes continues to leak out of the puncture site.

7.13 Idiopathic (Benign) Intracranial Hypertension (IIH) Idiopathic intracranial hypertension (IIH), sometimes called benign intracranial hypertension (BIH) or pseudotumor cerebri (PTC), is a neurological disorder in which there is increased intracranial pressure, sometimes in the absence of an obvious cause. It can occur in all age groups, but is most common in women aged 20–40.

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It is often associated with obesity. Whilst this is called ‘benign’, this is a misnomer. Untreated it can result in visual loss. The condition occurs in about one per 100,000 people. Symptoms include early morning headaches, nausea, and vomiting. Headaches are often made worse by any activity that increases the intracranial pressure further, such as coughing and sneezing. There may also be pulsatile tinnitus, cranial nerve deficits and visual symptoms. Physical examination is usually normal apart from the presence of papilloedema. Diagnosis therefore relies on a careful history and a high index of suspicion. Cranial nerve palsies may be noted (the patient may have a squint secondary to a third, fourth, or sixth nerve palsy). If the condition has been longstanding, the visual fields may be constricted. Longstanding papilloedema can result in optic atrophy. The cause of the raised intracranial pressure in this condition is unknown. Three theories exist (i) an excess of CSF production, (ii) increased volume of blood or brain tissue, (iii) obstruction of the veins that drain blood from the brain. Congestion of venous blood may result from a generalised increased in venous pressure, which has been linked to obesity. Other causes of raised intracranial pressure must be considered and excluded. Venous sinus stenosis can be treated by endovascular stenting if appropriate. Medications including high-dose vitamin A derivatives (e.g. isotretinoin for acne), long-term tetracyclines and hormonal contraceptives have also been reported to increase intracranial pressure. Other rare conditions include obstructive sleep apnea, systemic lupus erythematosus, chronic kidney disease, and Behçet’s disease. IIH is diagnosed following CT or MRI.  These usually appear to be normal, although slit-like ventricles and an “empty sella sign” (flattening of the pituitary gland due to increased pressure) may be noted. An MR venogram may be performed to exclude the possibility of venous obstruction or cerebral venous sinus thrombosis. Lumbar puncture is often required to measure the CSF pressure, as well as to obtain a sample of CSF to exclude other possible causes. If the pressure is significantly increased, some CSF may also be removed to reduce symptoms. In some cases it may be necessary to monitor the ICP. Diagnosis is often made using the Modified Dandy criteria 1. Symptoms of raised intracranial pressure (headache, nausea, vomiting, transient visual obscurations, or papilloedema) 2. No localising signs with the exception of abducens (sixth) nerve palsy 3. The patient is awake and alert 4. Normal CT/MRI findings without evidence of thrombosis 5. LP opening pressure of >25 cmH2O and normal biochemical and cytological composition of CSF 6. No other explanation for the raised intracranial pressure

7.13.1 Management Aims to Prevent Visual Loss and Symptom Control. Measures Include 1 . Weight loss, including bariatric surgery 2. Lumbar puncture. In some cases, this may be sufficient to control symptoms, and no further treatment is needed. The procedure can be repeated if necessary.

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Repeated lumbar punctures are sometimes required to control the ICP urgently if the patient’s vision deteriorates rapidly 3. Acetazolamide (Diamox) reduces CSF production. Furosemide (Frusemide) may be used as an alternative if acetazolamide is not tolerated 4. Occasionally surgery may be offered if medical therapy fails or if it is not tolerated. This includes optic nerve sheath fenestration (to reduce the pressure locally) or placement of a shunt 5. If venous sinus stenosis is diagnosed, venous sinus stenting may be performed

7.14 Intracranial Thrombosis Cerebral venous drainage is comprised of two systems, the superficial and the deep venous systems. Draining blood passes into the major dural sinuses—Superior sagittal sinus (SSS), inferior sagittal sinus (ISS), lateral sinus (LS), cavernous sinus and straight sinus, and then to the internal jugular vein (IJV). Many anastomoses can be found between these two cerebral venous systems. Clinically the dural sinuses are divided into posterior superior (P-S) and anterior inferior groups (A-I). P-S comprises the SSS, ISS, LS, straight sinus, and occipital sinus. The A-I group comprises the superior and inferior petrosal sinuses and the cavernous sinus. Inside of dural sinuses are found the Pacchioni’s or arachnoid granulations, which play an essential role in the cerebrospinal fluid (CSF) physiology. SSS is located anatomically in the attached margin of falxcerebri, and drains almost all cerebral cortex. The LS drains the cerebellum, brain stem and the posterior portions of brain hemispheres. In the skull base are also the cavernous sinuses, through which the oculomotor, trochlear, abducens, the ophthalmic and maxillary branches of the trigeminal nerves pass. Thrombosis within any of these sinuses can have devastating consequences. Several types can occur. They can arise following a number of predisposing conditions. Trauma, hyperviscosity syndromes and tumours need to be urgently identified.

7.14.1 Dural Venous Sinus Thrombosis Venous sinus thrombosis can affect any age and either sex, but most commonly affects young and middle-aged females. It is a sporadic cause of headache, with an unpredictable prognosis. Diverse aetiologies have been reported to play a major role in the development of this condition. Thrombosis can arise following trauma over the sinus, or tumours nearby and in relation to nearby infections from paranasal sinusitis, otitis, mastoiditis, meningitis and intracranial abscess. It may also occur following neurosurgical procedures. Maxillary sinusitis has been reported as a rare cause. When thrombosis occurs, the venous pressure rises, impeding CSF absorption. This can result in raised intracranial pressure. Patients present with symptoms of raised pressure, notably headaches, especially in the morning, visual disturbances and papilloedema. In severe cases, venous infarction of the cerebral cortex can occur resulting in severe focal neurological deficits. Thus, this condition should be considered in all young women who percent with an unusual and

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progressive headache accompanied with focal neurological signs. Diagnosis is usually made following CT or MRI scans which usually show some degree of brain swelling and in some cases haemorrhagic infarctions (Fig. 7.21). The ‘delta’ sign is a triangular filling defect in the sinus on a CT scan with contrast. Other useful signs include the ‘string sign’ and the ‘dense triangle sign’. MRI and CT venography are also useful imaging modalities. Management aims to control or resolve the underlying cause, control any intracranial hypertension, treat or prevent seizures or focal neurological deficits resulting from cerebral oedema or infarction. Seizures can occur in around one third of cases. Anticoagulation either with heparin or other oral anticoagulants is usually required in most cases, whilst in others, endovascular administration of thrombolytic agents maybe indicated. In selected cases endovascular and other surgical techniques have been used to remove the clot. In extreme cases decompressive craniectomy maybe necessary. Prognosis is highly variable, but recurrence of thrombosis is particularly high inpatients with known risk factors.

7.14.2 Cavernous Sinus Thrombosis This is a rare infective disease. It continues to have a high mortality, despite widespread availability of antibiotics. Significant morbidity includes residual cranial nerve palsies and blindness. Early diagnosis is essential and the possibility of CST should be considered in any patient who presents with sudden proptosis, accompanied by erythema, chemosis, diplopia and a headache. The cavernous sinus is trabeculated and as such acts as a sieve, filtering bacteria and thrombi from diverse sources (such as the maxillary sinus, midface and orbits) CST is a

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Fig. 7.21  CT brain of Left temporo-parietal ICH and CT venogram demonstrating occlusion of left sigmoid sinus by thrombus

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most commonly a septic (infected) thrombosis that develops within the cavernous sinus. This may result from any infection of the tissues drained by the cavernous sinus, such as the face, tonsils, soft palate, teeth and ears. The commonest reported organism is methicillin-resistant Staphylococcus aureus (MRSA), followed by MSSA. However various streptococci, other staphylococci, oral anaerobic flora, and gram-negative organisms have also been reported. Fungal infections (Aspergillus fumigatus) are rare but are seen in immunocompromised patients, such as diabetes, haematological malignancies, those taking immunosuppressants, or patients who have had a bone marrow transplant. Not surprisingly prognosis is poor in this immunocompromised group. Most commonly infection arises from an initial focus of infection in the face (usually the orbital, notably orbital cellulitis), but can also arise from paranasal sinus infection (ethmoiditis). At these sites (i.e. the central midface) the venous drainage communicates directly with the cavernous sinus. Infected emboli can freely pass into the sinus, since the facial, angular, ophthalmic and pterygoid plexus of veins do not possess valves. Thrombosis can then spread into other venous sinuses resulting in subdural empyema or meningitis. Infective endocarditis and extension of thrombosis to the internal carotid artery (which passes through the sinus) are rarer causes. Clinical features include 1 . Systemic upset: fever, tachycardia and sweating 2. Facial or peri-orbital pain 3. Signs of Venous obstruction—eyelid oedema, chemosis, dilated conjuncti val vessels 4. ‘Pulsating exophthalmos’ a transmitted carotid pulse with periorbital oedema (Fig. 7.22) 5. Blindness with papilloedema and retinal haemorrhages 6. Ophthalmoplegia: classically CNVI first followed by CNIII and IV Imaging studies, such as contrast enhanced computed tomography (CT) and magnetic resonance imaging (MRI) have had a significant impact on the diagnosis of CST in recent decades. High-resolution contrast-enhanced CT or MRI is useful in the assessment of suspected cavernous sinus thrombosis. This may reveal the primary source of infection, thickening of the superior ophthalmic vein, and irregular filling defects in the cavernous sinus. However, MRI is more sensitive than CT in the detection of septic CST because it can visualise the blood vessels better. Blood tests include inflammatory markers and coagulation studies. These patients are generally very unwell and the prognosis is often quite poor. The current consensus on treatment is that it should include high-dose intravenous antibiotics directed at the most likely pathogens together with surgical drainage of the original source of infection (usually the paranasal sinuses). Antibiotics should be continued for at least 2 weeks beyond the time of clinical resolution. This has been suggested to be necessary because the bacteria sequestered within the thrombus may not be killed until the dural sinuses start to recanalise. The role of corticosteroids and anticoagulants in treatment is unclear. Surgery to the cavernous sinus itself is difficult and not recommended.

410 Fig. 7.22 (a, b) Cavernous sinus thrombosis from methicillinresistant. Staphylococcus aureus (MRSA). The patient was a previously healthy man who suffered a minor injury to the skin next to the right nostril 3 days earlier. (a) Examination showed bilateral ophthalmoplegia, proptosis, and a right nasal skin lesion. (b) Magnetic resonance imaging (MRI) demonstrated enhancement of the cavernous sinuses and prominence of the right superior ophthalmic vein, suggesting early thrombus formation. Reproduced from Munckhoff et al., with permission from John Wiley and Sons

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7.15 Intracranial Tumours A large number of CNS tumours and cysts exist which are both benign and malignant in nature. Even ‘benign’ tumours (ie non-metastasising) can be life-threatening by virtue of their mechanical pressure effects within a confined space. Commonly tumours present with one or more of three symptoms: • Raised intra-cranial pressure • Progressive neurological deficit • Epileptic fits

7.15.1 Primary Tumour Types • Gliomas including astrocytoma, glioblastoma (Fig. 7.23), oligodendroglioma • Pituitary adenoma

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Fig. 7.23 Intracerebral tumour

• • • • • • • •

Craniopharyngioma (Figs. 7.24 and 7.25) Meningioma Acoustic neuroma Choroid plexus (Fig. 7.26) Pineal region (Fig. 7.27) Colloid cyst Primary CNS lymphoma (Fig. 7.28) Haemangioblastoma

In the presence of unexplained neurological symptoms urgent investigations are indicated. MRI scan is now the definitive investigation of choice, but CT scan, with and without contrast, is usually the first line investigation acutely. Malignant tumours are seen as irregular enhancing cystic or solid lesions, which usually show some degree of mass effect and surrounding oedema. The three commonest tumours are: • Metastases. These are often identified as small round ‘cannon ball’ lesions. They are usually multiple and at the grey-white matter junction, most commonly in the MCA territory. Suspicious lesions require further investigation (CT chest/abdomen/pelvis). Sometimes it is easier to biopsy the primary source, rather than the metastasis (so long as the clinical evidence in favour of malignancy is strong).

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Fig. 7.24  Craniopharyngioma: 7-year-old female with history of longstanding headache. (a) Sagittal T1-weighted MRI shows a large lobulated sellar/suprasellar mass extending upwards to third ventricle and posteriorly into prepontine cistern (arrows). Most cysts show hyperintensity. (b) Axial T2-weighted MRI shows extension into cerebellopontine angles more to left (arrows) with left parasellar extension (arrowhead) and encasement of basillar artery (small arrowhead). (c) Axial CT shows eccentrically located calcification within a hyperdense lobulated mass at suprasellar region (arrow)

• Gliomas. These are primary neuronal tumours and usually appear as large irregular lesions with indistinct margins. Several grades of malignancy are described. Generally the prognosis is poor in high grade gliomas. • Meningiomas. These arise from and are attached to the dura. Although usually benign if left untreated they can result in focal pathology and mass effects. They appear homogeneous on contrast enhancement.

7  The Skull, Brain and Associated Structures: Part II The Patient with a Headache Fig. 7.25  Sagittal T1 MRI with gadolinium of craniopharyngioma

Fig. 7.26  T1 axial MRI showing choroid plexus tumour

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414 Fig. 7.27  t1 axial and sagittal MRI showing pineal region tumour

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Chordomas are uncommon, but malignant tumours that arise from the remnants of the embryonic notochord (see chapter on embryology). Most occur in the sacrococcygeal region, but around one-third occur in the skull base. These are found in the region of the spheno-occipital synchondrosis. Aberrant notochordal rests can occur in the clivus, vertebral bodies, nasopharynx, pharynx and spine. Thus chordomas can arise in any of these sites. There is still some debate about whether some chordomas

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Fig. 7.28  t1 axial MRI showing primary CNS lymphoma

are chondroid variants of chordoma or true chondrosarcoma. Ideally these should be resected, but this is not always possible and multiple recurrences are common. Proton beam stereotactic guided radiosurgery has greatly improved survival. Conventional external beam radiation is not as effective. Management of other cerebral tumours depends on their site, size and specific pathology. The age and general health of the patient is also a key determining factor. Some tumours are deep seated and effectively incurable. In such cases heroic treatments may leave the patient with significant morbidity and with little benefit. In other cases tumours may be small, superficial and detected early. Surgery and/or chemoradiotherapy may then be indicated. Management principles include 1. Urgent neurosurgical referral. Whenever possible, excision of the tumour is the preferred treatment. However, this may not be possible due its site, extent or nature, or because the patient is too frail. In these cases a biopsy or debulking may be performed, or a palliative course of management may be indicated. 2. Steroids to reduce oedema—typically dexamethasone 4 mg, four times daily is prescribed, with gastric protection (proton pump inhibitor). Rarely, if the patient is rapidly deteriorating, intravenous mannitol and megadose dexamethasone should be given pending neurosurgical transfer and emergency surgery. 3. Anticonvulsants should be prescribed if the patient has a history of fits. Some neurosurgeons advocate prophylactic anticonvulsants even in the absence of seizures. 4. In high grade malignant tumours, patients will usually require adjuvant therapy with radiotherapy with or without chemotherapy. Currently ongoing advances in this field are based on molecular profiling of tumours. 5. More recently, Gamma Knife radiosurgery (GKRS) is being considered as a first line of treatment in a number of malignant and benign intracranial diseases, including some astrocytomas. This has shown promising results and can avoid the need for risky neurosurgical resections with deep-seated tumours and toxic side effects of chemotherapy. Morbidity is often less then 5%. However, the effectiveness of GKRS is not known for all tumours.

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7.15.2 Meningiomas Meningiomas are a diverse group of tumours arising from the arachnoid cells of the meninges (Fig.  7.29). They account for up to a quarter of all intracranial tumours. Many produce no symptoms at all and if discovered by chance require no treatment other than follow-up and serial CT scanning. Although these are usually benign in nature, a small percentage of meningiomas can become malignant. Surgery is still the treatment of choice in symptomatic cases, particularly when the tumour infiltrates the skull base or vascular structures. However complete resection may not be possible without significant morbidity and mortality. Debulking may then be indicated for symptomatic cases (e.g. proptosis following orbital infiltration). Meningiomas may be discovered purely by chance when the patient undergoes a head CT scan or MRI of the head for some other reason. The most common ones originate along the cerebral convexities. However patients may present with 1. Focal seizures 2. Progressive weakness or sensory disturbance 3. Aphasia 4. Raised intracranial pressure 5. Diplopia or unequal pupils Fig. 7.29  T1 MRI with contrast showing sphenoid wing meningioma

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Some tumours can invade into the adjacent bone (intra osseous meningioma). This commonly occurs in the orbital region (greater wing of sphenoid), resulting in diplopia, orbital dystopia and vision-threatening proptosis. Similar symptoms can occur with cavernous sinus meningiomas (Fig.  7.30). Involvement of the orbital apex can also result in pressure on the optic nerve with eventual loss of sight. Meningiomas arising entirely outside of the CNS are rare. However extracranial meningiomas can occur in the calvarium, scalp, orbit, nose, paranasal sinuses, middle ear and infratemporal fossa. Lesions of the cheek, neck, and parotid have even been reported. Most extracranial meningiomas are simply extensions of the intracranial component, such as those arising from the skull base. Others occur as a result of growth along nerve sheaths, such as the optic sheath meningioma. Rarely some are metastases from malignant varieties. Ectopic extracranial meningiomas can arise in the nests of arachnoid cells which were deposited in extracranial sites during the early stages of neural tube closure. Such ectopic clusters may be found along the optic nerve, trigeminal nerve and where cranial nerves III, VII, and IX–XII penetrate the dura. Most involve the orbit, basal skull and upper sinonasal region. The causes of meningiomas is not known. Most cases are sporadic, although some are familial. Radiation and a history of head trauma appear also to be predisposing factors. Patients with neurofibromatosis type II have a 50% chance of developing one or more meningiomas, suggesting a genetic basis to the disease (possibly chromosome 22q). Although predominantly intracranial, meningiomas may also occur in the spinal canal.

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Fig. 7.30  T1 MRI with contrast showing cavernous sinus meningioma

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Diagnosis is usually made the following contrast CT or MRI. The WHO classification system grades meningiomas as. 1 . Benign (Grade I) 2. Atypical (Grade II)—this includes brain invasion. The mean survival is approximately 12 years 3. Anaplastic/malignant (Grade III). Mean survival is approximately 3 years. In many cases treatment is not required if there are no symptoms and the patient can be kept under follow-up with regular imaging. However this is generally not recommended if the tumour is causing symptoms, or there are concerns regarding its precise nature. Many tumours can be removed surgically, if their location and size is favourable. Although many are confined to the dural region, intra osseous meningioma can infiltrate the bone widely, making total resection impossible. Radiation therapy may then be indicated with, proton-beam or fractionated external beam radiation. This may also be indicated in small tumours which are surgically inaccessible, or in patients who are unfit for surgery. Radiation may also be considered if there has been incomplete resection of a tumour or recurrence of a high grade tumour.

7.15.3 Astrocytoma (glioma) Astrocytomas (also referred to as gliomas) originate in the glial cells, or astrocytes. They are the commonest glioma and can occur in most parts of the brain. They rarely arise within the spinal cord. Several subtypes exist, but these are often simply referred to as low or high-grade, the latter carrying the worst prognosis. Astrocytomas can develop at any age and do not metastasise. Low- grade tumours are more often found in children or young adults, while high-grade tumours are more common in adults. Astrocytoma causes symptoms as a result of compression, invasion and eventual destruction of the brain parenchyma. Secondary symptoms may be caused as a result of mass effects or obstruction to CSF circulation and raised intracranial pressure. Tumours are usually identified following CT scan or MRI, both of which may be required to define the size, location, vascularity of the lesion, and any secondary effects on the ventricles. These are important in planning surgery. Most tumours will require a biopsy to confirm the diagnosis and determine the grade of lesion. The World Health Organization (WHO) grading system is based on four histological grades from I to IV, with I being the least aggressive (Fig. 7.31) and 4 (Fig. 7.32) being the most aggressive. High grade astrocytoma (grade IV) is the most common primary nervous system cancer and the second most frequent brain tumour, after cerebral metastasis. Management of astrocytomas often requires surgery and radiotherapy. With low grade astrocytomas, excision of the tumour may allow patients to survive for many years. In some reports, the 5-year survival has been around 90%. However this often

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comes with a risk of residual neurological deficit, depending on the location of the tumour and the amount of brain tissue resected. Complete resection of high grade astrocytomas is often not possible due to their widely infiltrative nature. These inevitably recur following treatment (both surgery or radiotherapy). Glioblastoma (WHO grade IV) is the most malignant type of tumour. It is the most common primary brain tumour and typically affects the older age group, with a slight male predominance. These tumours are sometimes divided into primary and secondary, depending on whether they arise de novo (primary), or start out as a less malignant tumour (secondary). These tumours are commonly found in the Fig. 7.31  T1 sagittal MRI with gadolinium showing a cerebellar pilocytic astrocytoma

Fig. 7.32  CT with contrast of left peri-sylvian glioblastoma

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sub-­cortical white mater but they can also spread through the corpus callosum and present as a “butterfly glioma”. Current treatment follows the ‘Stupp protocol’ which was published in 2005. This includes a maximal safe surgical resection followed by conformal external beam radiotherapy with adjuvant temozolamide. However there is no consensus on the treatment of recurrent Glioblastoma with clinical trials currently in progress. Immunotherapy may have a role.

7.15.4 Pituitary Adenoma The pituitary gland (hypophysis), is an endocrine gland about the size of a pea. It is located at the base of the brain, just behind the optic chiasma. The gland rests in the midline hypophyseal fossa of the sphenoid bone (sphenoid fossa or sella turcica) in the middle cranial fossa. The anterior pituitary (adenohypophysis) regulates several important physiological processes (including stress control, growth, reproduction and lactation). The posterior pituitary gland (neurohypophysis), produces ADH (antidiuretic hormone). All these hormones are important in growth, maintenance of blood pressure, functioning of the sex organs, thyroid glands and metabolism, as well as many aspects of pregnancy and childbirth. They also control water/salt concentration within the kidneys, temperature regulation and pain relief. Not surprisingly then, disturbance of the gland can result in a wide range of complex disorders. Pituitary tumours are relatively common and are mostly adenomas (Fig. 7.33). These are benign, slow-growing tumours, which originate from one of its specialised cells. If the tumour produces an excess of one or more hormones, it is called a “functional” adenoma. Examples include (i) prolactinoma, (ii) growth hormone secreting tumour (resulting in acromegaly in adults or gigantism in children), and (iii) cortisol secreting tumours resulting in Cushing’s disease. Nonfunctioning adenomas can also occur.

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Fig. 7.33  Sagittal and coronal T1 MRI with gadolinium of pituitary macroadenoma

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Microscopic pituitary adenomas are reported to occur in about one in five adults. These are often discovered following MRI of the head for some other reason. However, the majority of these will never grow or cause symptoms. Rare tumours include (i) Atypical pituitary adenoma, which grows quickly and is more likely to recur (ii) Pituitary carcinoma, a malignant variant which can metastasise (iii) Multiple endocrine neoplasia type 1 (MEN 1), which is characterised by simultaneous tumours of the pituitary, pancreas and parathyroid glands. Pituitary adenomas develop in 25 percent of patients with MEN 1. Clinical features can be considered as a result of mechanical effects and whether hormones are secreted. They can therefore vary. Large tumours can compress the optic chiasm, resulting in bitemporal hemianopia. Hormone-producing adenomas can produce symptoms related to the hormones released (notably Prolactin, Growth hormone, ACTH, TSH). Very large tumours can compress the remaining gland resulting in pituitary failure. This can present as decreased sexual drive, impotence, loss of body and facial hair, infertility, hypothyroidism, fatigue, low blood pressure, electrolyte abnormalities. If severe, this can be fatal. Diagnostic tests include hormone assays and imaging (MRI). Treatment depends on several factors, including: 1 . Hormone production by the tumour 2. Tumour size 3. The extent that the tumour has invaded surrounding structures 4. Patient’s general health Hormone-producing adenomas can sometimes be treated medically. Prolactinomas may not require surgery. Medication also plays an important role in managing the symptoms of Cushing’s disease and acromegaly. Surgical management now involves minimally invasive endoscopic techniques. Tumours are removed endonasally. Very large tumours may require a craniotomy. Radiotherapy is reserved for large, non resectable or high grade tumours. Ectopic pituitary tissue is rare and related diseases are also rare. Because the anterior lobe of the pituitary develops as an invagination of endoderm from the developing nasopharynx (Rathkes pouch), residual cells can deposit along its path of migration. This can result in functioning glandular tissue or tumours anywhere from the nasopharynx to the suprasellar cistern. Cystic change can also occur and is normally asymptomatic, being discovered by chance. This is usually found in the mucoperiosteum of the roof of the nasopharynx, where the vomer attaches. Pituitary adenomas sited within the nasopharynx are usually downward extensions of lesions arising in the pituitary fossa. Invasive pituitary adenomas can occasionally invade the nasopharynx, ethmoids and nasal cavity. Others can extend to the cavernous sinus. If very invasive, these these can involve much of central skull base. Pituitary carcinomas also show locally invasive features, but will also metastasise. Treatment may be surgical resection and/or chemoradiotherapy, depending on the nature and extent of the lesion.

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7.16 Sudden Disturbance in Cerebral Function Like lethargy, a sudden disturbance in cerebral function can have many causes, many arising outwith the CNS.  This can take many forms, such as changes in behaviour and the development of an acute confusional state (‘delirium’)—characterised by an acute fluctuating impairment of cognitive functions and inattention. Delirium may be the result of a variety of systemic or cerebral diseases or from drug intoxication or withdrawal. Investigations may include a full blood count, biochemistry (serum sodium, potassium levels and blood sugar), liver, renal and thyroid functions, arterial blood gas analysis, chest X-ray, ultrasound abdomen, CT brain and cerebrospinal fluid (CSF) analysis. Further details of the assessment of an acute confusional state fall outside the scope of this book, but it should be noted that some (such as hypoglycaemia and alcohol withdrawal) can be fatal if not treated. Treatment is directed towards the underling cause, some of which have been previously discussed. From a more ‘intracranial perspective’ sudden disturbances in function can arise form a temporary or permanent disruption in neural physiology. Perhaps the best examples of this are CNS infections, stroke, epilepsy and concussion, although other causes exist. Acute confusional migraine has also been described. This is a migraine variant that manifests with acute confusion, agitation, disorientation, altered mental status, speech difficulties and memory deficits.

7.16.1 Epilepsy Seizures (‘fits’) can result from wide variety of disorders, some of which are intracranial in nature, whilst others are extracranial. Epilepsy is a type of seizure but is not a single condition. It is characterised by abnormal, recurrent, and excessive neuronal discharges within the central nervous system, which can be precipitated by a variety of causes. The seizures often occur spontaneously, usually resulting in loss of consciousness, with sensory and motor deficits. Underlying causes include a genetic predisposition, structural or metabolic problems. Common causes of seizures include • • • • • • • • • • •

Genetic and various rare syndromes Brain tumours Stroke Head injury Toxic ingestion/Chronic alcohol abuse/withdrawal Metabolic disorders Infections of the central nervous system such as meningitis/encephalitis Cerebral arteriovenous malformations Tuberous sclerosis Autoimmune encephalitis Hypothalamic hamartomas.

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In many cases the cause is not found. Although the disease can occur at any age, the age at the time of onset of seizures is often associated with specific causes. 1. Infants—complications during birth, anoxia, intracranial injury, metabolic disorders, and congenital malformations. 2. Children and adolescents—trauma and febrile infections. 3. Young adults—alcohol or drug abuse. 4. Older adults—cerebrovascular disease and tumours. Various classifications exist, but a descriptive classification is the most useful. Seizures are divided into generalised and those that affect only part of the brain (partial seizures). Simple partial seizures originate from a discrete area of the brain. Typically they do not result in loss of consciousness. However, complex partial seizures (referred to as temporal lobe or psychomotor) are associated with impairment in consciousness. The majority of generalised seizures are either ‘absences’ (petit mal) or tonic-clonic seizures—(‘grand mal’). The remaining seizures (myoclonic or infantile, and clonic, tonic, and atonic) usually occur in childhood. These have a poorer prognosis with regards to childhood development. “Status epilepticus” refers to recurrent seizures without recovery between them. This is a medical emergency. All seizures are at risk of progression to status epilepticus. Clinically, nonspecific symptoms such as headache, a change in mood or lethargy may herald the onset of an impending seizure. These are distinct from the aura that occurs just before a generalised seizure. The most common type of seizure is the tonic-clonic, or grand mal seizure. About 90% of epileptics experience this at some point during their illness. This begins with an ‘aura’—an emotional feeling or hallucination (hearing, vision or smell) which is quickly followed by sudden unconsciousness and spasms. This is the ‘tonic’ phase, which lasts about 30 s. Because of the muscle spasm, the patient usually falls to the ground and becomes cyanosed. The tonic phase is then followed by a clonic phase, in which the patient undergoes jerking movements (convulsions), incontinence and tongue biting. This can last a few minutes. Following this, a postictal state develops, during which the patient slowly recovers. The patient may be confused, lethargic and occasionally develop a focal but temporary neurological deficit. Petit mal or ‘absences’ are the second most common type of seizure. These occur mostly in children and often resolve during their teen years. A typical seizure lasts just a few seconds. There is no aura, or tonic-clonic phase. Instead the patient loses awareness, becomes ‘vacant’ and appears to stare into space. Many continue normal activities immediately after the seizure has finished, unaware it has occurred. Petit mal attacks may occur several times a day. Severe cases may interfere with school and social activities. Around 50% of patients develop tonic-clonic seizures at puberty. Diagnosis of epilepsy is usually made based on the description of the seizure. More than one is necessary to make a diagnosis. Following a first seizure of any kind, all patients should be referred to a specialist for investigation. Patients should be screened for acute problems such as low blood glucose, metabolic conditions,

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sepsis, toxins, withdrawal states, and stroke. Blood glucose, electrolytes, calcium, thyroid hormone, electroencephalography and CT or MRI may all be required to rule out metabolic or structural causes. Brain lesions commonly associated with epilepsy include cortical malformations, gliosis, vascular disorders, and small tumours. In addition, magnetic resonance spectroscopy (MRS), functional MRI (fMRI) and Diffusion MRI may be used to measure metabolic activity and involved visualise key areas. Positron emission tomography (PET) and single photon emission computed tomography (SPECT) can also help map physiochemical brain processes and brain perfusion patterns. Once fitting has been controlled management involves investigations for underlying treatable causes and prevention of further seizures. During a seizure, rolling the patient onto their side and into the recovery position helps prevent aspiration and injury. If a seizure lasts longer than 5 min this should be considered as status epilepticus. The airway should be protected and midazolam or a suitable alternative given. Once the patient is stabilised treatment then involves use of anticonvulsant medication, preferably under the supervision of a specialist. A number of medications are available (such as phenytoin, carbamazepine and valproate). The choice of drug depends on the type of seizure to be treated. Drug treatment is continued until there have been no further seizures for at least 3 years. In some patients surgery may be indicated to control persistent focal seizures. Mesial temporal lobe epilepsy (MTLE) is a common cause of medically intractable epilepsy. This may be treated with temporal lobectomy. Gamma Knife stereotactic radiosurgery is an alternative to surgery. This appears to be quite promising. First seizures should be reported to the Driver and Vehicle Licensing Agency (DVLA) in the UK or the equivalent body internationally. Currently in the UK, if the first seizure is unprovoked, investigations are normal, and no neurological deficit is present, driving can usually be permitted after 6 months. Otherwise, driving is usually permitted after 12 months of being seizure free. Commercial licences are subject to more stringent regulation.

7.16.2 Vertigo Vertigo is the subjective feeling that one is moving when they are not, often described as spinning or swaying. This may be associated with nausea, vomiting and unsteadiness. It is typically worsened when the head is moved. The condition is classified into peripheral or central, depending on the location of the underlying dysfunction. Common causes are benign paroxysmal positional vertigo, Ménière’s disease, and labyrinthitis. These are described in the chapter on the Ear. Less common central causes include stroke, brain tumours, trauma, multiple sclerosis, and migraine. Rare causes may include carbon monoxide poisoning, alcohol and aspirin.

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7.16.3 Central Vertigo Vertigo that occurs as a result of a disorder within the brainstem or cerebellum is called central vertigo. Vestibular migraine is the association of vertigo and migraines. The cause of this is not known, but it has been suggested to arise as a result of stimulation of the trigeminal nerve in migraine sufferers. Other possible causes include imbalanced vestibular nuclei activity in the brainstem, or vasospasm of the central vestibular pathway vessels. CNS infarctions/haemorrhage, cerebellopontine angle tumours, epilepsy, cervical spondylosis, degenerative disorders, migraine, multiple sclerosis and parkinsonism can all result in central vertigo. Patients may also have accompanying neurologic deficits (such as slurred speech and double vision), and nystagmus. Central vertigo can last along time. In some patients it may not resolve. If a central cause is suspected CT or MRI is indicated, to identify strokes and tumours. Treatments include anticholinergics, anticonvulsants, antihistamines, beta blockers and corticosteroids.

7.16.4 Multiple Sclerosis (MS) This a chronic inflammatory autoimmune demyelinating condition which affects the myelin sheaths of the nerves in both the brain and spinal cord. Onset is usually during young adulthood. Due to its random distribution of CNS involvement, this gives rise to a wide range of neurological signs and symptoms. The disease is classified into several clinical types. 1. Primary progressive—in this form symptoms steadily get worse. 2. Progressive relapsing—This is characterised by a steady functional decline with later superimposed acute attacks. 3. Relapsing remitting—This is the most common form (85% of cases). Patient’s are affected in distinct episodes which completely resolve. In between attacks, patients have no worsening of symptoms. 4. Secondary progressive—here the symptoms only partially resolve. There are no acute attacks. The primary cause of MS is inflammation of central nervous system. Both T cells, and B cells and their products appear to be involved in the pathogenesis resulting in loss of oligodendrocytes. Where myelin is lost, a neurone can no longer effectively conduct electrical signals. Autopsy studies have shown multiple, discrete pink or grey rubbery plaques within the white matter. These are composed of areas of myelin and oligodendrocyte loss, with infiltrates of inflammatory cells and scar tissue. Relative preservation of the axons and neurones themselves within these lesions helps to differentiate MS from other disorders. What precipitates this is unknown,

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although genetic, environmental and infectious agents have been suggested. A 40-fold increased susceptibility among first degree relatives of MS patients has been reported, possibly related to chromosomes 6p21, 10p15, 5p13, and 1p36. Sunlight exposure, deficiency in vitamin D, human herpes virus type 6, Epstein Barr virus, and mycoplasma pneumoniae have also all been implicated, although the mechanisms by which they act are still unknown. Proposed mechanisms include the hygiene hypothesis and the prevalence hypothesis. 1. The hygiene hypothesis—exposure to certain infectious agents early in life is protective, the disease being a response to a late encounter with such agents. 2. The prevalence hypothesis—the disease is due to an infectious agent more common in regions where MS is common and where in most individuals it causes an ongoing infection without symptoms. Diagnosis should be suspected whenever two distinct episodes of neurological symptoms are separated by both anatomy and time. Common symptoms include changes in vision (unilateral visual loss, diplopia), weakness, dyscoordination, sensory loss or distortions, or changes in bowel and bladder function. Less common symptoms include cognitive change, fatigue, and mood disturbance. Progression of MS can eventually result in severe disability. Plaques of demyelination can be seen on MRI scans. No single diagnostic test exists for MS. Evidence for a viral cause include the presence of oligoclonal bands in the brain and cerebrospinal fluid of affected individuals. Currently to make a diagnosis of MS there must be 1. evidence of damage in at least two separate areas of the CNS (brain, spinal cord, and optic nerves). 2. Symptoms must last for more than 24 h. 3. evidence that the damaged areas developed at least 1 month apart. 4. exclusion of all other possible diagnoses. 5. MRI evidence (the most sensitive imaging test for MS). 6. a positive spinal tap for oligoclonal bands. Treatment aims to prevent relapses and progression. Medication in relapsing forms targets different parts of the immune system to avoid further inflammation. However they do not cure the disease or reverse existing damage. These include interferon β analogs, monoclonal antibodies, cytotoxic drugs and steroids. Other drugs are undergoing phase II and III trials.

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The Skull, Brain and Associated Structures: Part III Neil Simms and Jonathan Poots

8.1

Head Injuries

8.1.1 Terminology in Head Injuries: Traumatic Brain Injury (TBI) A “head injury” is one of the most common reason for attendance to the emergency department, particularly at weekends. Traumatic brain injury (TBI), a more precise term, represents a wide spectrum of severity. It has been estimated that 3.2 million people are living with long-term disability related to traumatic brain injury (TBI). This is the leading cause of morbidity and mortality between the ages of 1 and 45 years. Teenagers and the elderly are most at risk, although the causes vary demographically. Motor vehicle crashes are a main cause of head injuries in most ages, whilst falls are most common in people aged 65 or older. Whilst the majority of attendances are relatively minor, it is nevertheless important not to overlook the patient with a potentially serious intracranial injury. They can rapidly deteriorate. Other causes of an altered conscious level should also be considered in any agitated, confused or obtunded patient. Alcohol excess, drugs, hypoxia, hypotension, hypoglycaemia and other metabolic disturbances should always be considered. A systematic approach to the head injured patient should therefore always be followed, even in those with an apparent isolated head injury. This is discussed in the chapter on the injured patient. Traumatic brain injury (TBI) can be either primary or secondary. “Primary” brain injury occurs at the time of the trauma. This is caused by impacts or inertial forces to the head that deform the intracranial tissues. Impacts usually produce focal injuries such as skull fractures, contusions and extradural/subdural haematomas.

N. Simms (*) · J. Poots Royal Victoria Hospital, Belfast, UK e-mail: [email protected]; [email protected]; jonathan.poots@ belfasttrust.hscni.net © Springer Nature Switzerland AG 2021 M. Perry (ed.), Diseases and Injuries to the Head, Face and Neck, https://doi.org/10.1007/978-3-030-53099-0_8

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Inertial forces can occur without any impact to the head. These arise as a result of sudden acceleration or deceleration, translational and/or rotational forces, which can cause focal or diffuse brain injuries, such as subdural haematomas and contre coup contusions. Diffuse injuries commonly occur following rotational or angular acceleration. From a management perspective there is nothing that can be done about these instantaneous injuries. By the time medical assistance arrives the primary injury is completed and secondary brain injury is rapidly developing. Prevention is the only way to reduce their incidence and severity. “Secondary” brain injury occurs after the initial event and arises as a result of complicating factors such as hypoxia, hypercarbia, hypotension, raised intracranial pressure (haematomas or cerebral oedema), cerebral herniation or, later on in the patient’s recovery, infection. Secondary injury can develop hours or days after the initial trauma and may be a major factor in prognosis. Whatever the underlying problem, these all essentially result in the development of either hypoxia or inadequate cerebral perfusion. The focus of head injury management is therefore to prevent these complicating factors from causing secondary brain injury. By doing so it is hoped that recovery from the primary brain injury will occur through natural processes. Whether head injury management is successful or not is dependent on both the extent of primary brain injury and the ability to control and reverse confounding factors.

8.1.2  Primary Injuries to the Brain Injury to the brain can be caused by external forces to the head that strain the tissues beyond their structural tolerance. These forces can be classified as contact or inertial. Contact or impact forces usually produce focal injuries (such as skull fractures, contusions and extradural or subdural haematomas). Inertial or acceleration/deceleration forces can occur without any impact. These can result in focal or diffuse brain injuries—without any external signs of head trauma. As a result of all these different forces, primary brain injury can take the form of:

8.1.2.1 Cortical Lacerations (Burst Lobe) This is mechanical disruption to the substance of the brain, commonly caused by a penetrating injury or pushed-in bone fragment following a skull fracture. A laceration may also occasionally occur following severe shearing forces unassociated with fractures. In most cases, it usually results in significant bleeding and is thus commonly seen in association with an acute subdural and cerebral haematoma. Other brain injuries are frequently seen, including contusions and diffuse axonal injury. Lacerations are particularly common in the inferior frontal lobes and the poles of the temporal lobes. Soon after injury the affected brain usually swells significantly. Patients therefore usually present with a significantly reduced Glasgow coma scale. Craniotomy is therefore often urgently indicated in order to evacuate the subdural haematoma and/or debride the damaged brain. The prognosis is usually poor due to the extent of primary brain damage. A cerebral laceration associated

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with large amounts of blood on CT imaging is generally regarded as an indicator of poor prognosis.

8.1.2.2 Cerebral Contusions/Haematoma These occur when the brain strikes the inner table of the skull. Haemorrhage within the brain substance occurs after very severe TBI. This is usually associated with contusions of the surrounding tissue. “Coup” contusions arise from the skull bending or fracturing, which subjects the underlying cortical and pial vascular network to excessive strains. This can cause bleeding at or near the brain surface. Damage is likely to occur when the skull is “rebounding” from the impact and the vessels are experiencing tensile strain. “Contrecoup” contusions are thought to occur as a result of cavitation effects and inertial loading. As the brain moves towards the impact site it creates an area of negative pressure directly opposite the point of impact. This negative pressure may cause damage by exceeding the tensile strength of the tissues or by causing small gas bubbles to appear within the parenchyma. The return to normal pressure in the brain then causes the small bubbles to collapse—hence the term cavitation. Duret’s haemorrhage (small lineal areas of bleeding in the midbrain and upper pons), is thought to result from disruption of the arteries at the time of downward displacement of the brainstem. This is usually seen in patients with severe herniation for 12–24 hours prior to death. Its presence thus often indicates a grave prognosis. Contusions are most common in the inferior frontal cortex and the anterior temporal lobes. These are composed of areas of punctate haemorrhage, oedema and necrosis. They can evolve over time and may therefore not be obvious on an initial CT scan. Depending on their size and location, they may cause significant mass effect, with midline shift or herniation. 8.1.2.3 Diffuse Axonal Injury This refers to punctate contusions at the interface between the grey and white matter, with widespread disruption and shearing of axon sheaths. It usually occurs following high energy impacts, particularly when there has been a rotational or deceleration element. Unlike brain trauma that occurs as a result of a direct impact to the brain, DAI is the result of shearing forces that occur when the head is rapidly accelerated or decelerated. This may be seen following vehicle collisions, falls, and assaults. It can also occur as the result of child abuse such as in shaken baby syndrome. The effect is disruption of axons. CT imaging in diffuse axonal injuries can be normal, but often shows a tight, swollen brain, with or without petechial haemorrhages. The degree of brain swelling usually increases over the first 48 hours post injury. The prognosis for diffuse axonal injury is poor and surgical options are limited. It is seen in about half of patients with severe TBI and in a third of those who die. It is also a common cause of a persistent vegetative state. 8.1.2.4 Concussion This is a transient impairment of consciousness following a minor or moderate head injury. It is probably a mild form of diffuse axonal injury.

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Secondary Injuries to the Brain

This can occur as a result of varying processes, many of them ultimately resulting (directly or indirectly) in ischaemia to a part of, or all the brain. These include (i) Hypotension (systolic blood pressure [SBP]