Textbook of Otitis Media: The Basics and Beyond 3031409485, 9783031409486

Citation preview

Marcos V. Goycoolea · Sady Selaimen da Costa · Christopher de Souza · Michael M. Paparella   Editors

Textbook of Otitis Media The Basics and Beyond

123

Textbook of Otitis Media

Marcos V. Goycoolea  •  Sady Selaimen da Costa Christopher de Souza  •  Michael M. Paparella Editors

Textbook of Otitis Media The Basics and Beyond

Editors Marcos V. Goycoolea Department of Otolaryngology Clínica Universidad de Los Andes Santiago, Chile, USA

Sady Selaimen da Costa Otolaryngology Federal University of Rio Grande do Sul Porto Alegre, Rio Grande do Sul, Brazil

Chris de Souza Department of Otolaryngology Tata Memorial Hospital Mumbai, Maharashtra, India

Michael M. Paparella Paparella Ear Head & Neck Institute University of Minnesota Minneapolis, MN, USA

ISBN 978-3-031-40948-6    ISBN 978-3-031-40949-3 (eBook) https://doi.org/10.1007/978-3-031-40949-3 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 This work is subject to copyright. All rights are solely and exclusively licensed 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 Paper in this product is recyclable.

Preface

The First International Symposium on Recent Advances in Otitis Media was held in May 1975 in Columbus, Ohio. At the time I was a first-year resident—26 years old—in Otolaryngology at the University of Minnesota, with two previous years in General Surgery. I was doing research in otitis media in cats and “my cats made it to the meeting.” As a coauthor of Michael Paparella and Steve Juhn, that was my first paper ever. At that symposium I was one of the youngest if not the youngest participant. The meeting in Columbus was organized by Doctors Ben Senturia, Charles Bluestone, David Lim, Michael Paparella, and Steve Juhn, among others. From then on, every 4 years and for many years I participated as a member of the Minnesota team and eventually as a member of the Chilean team. There were many groups at the time. Our group was led by Michael Paparella and Steve Juhn and all of us residents including Tim Jung and myself. Other groups were the Pittsburgh group of Charles Bluestone and Sylvan Stool, the Swedish group of Dr Inglested that included, among others, Sten Hellstrom, Karin Prellner, Margaretha Casselbrandt, and Ann Hermannsonn, the Danish group of Mirko Tos and Jans Thomsen, the Finish group of Tauno Palva and Pekka Karma, the Japanese groups with Drs Mogi, Honjo, Ogra, and many others, including the group in Israel led by Jacob Sadé. All these groups kept participating every 4 years and bonds of friendship developed over time. In between the Swedish group organized the middle inner ear interactions meeting in Umea with unforgettable pre- and post-congress meetings with the leadership of Sten Hellstrom, Jan Wersall, Matti Anniko, Claude Laurent, and others. Over time we became staff, and our fellows became incorporated to the group. That was the case of Marcelo Hueb, Sady Selaimen da Costa, Carlos Ruah, and Chris de Souza, who became prominent otolaryngologists, many of them presidents of their national societies and members of the Collegium. At the first Symposium in 1975, we were the young members and Doctor Senturia—a wise, kind, and encouraging man—was gradually fading (as heroes often do over time). I will never forget unique moments at these multiple reunions such as the Swedish group dancing and singing “the frog” at a farewell party, Goro Mogi fishing in Tromso, Norway, presenting himself as: “Goro Mogi a great fisherman from Japan,” Dr Lars Eric Stenfors talking about the flying penguins of Norway and trying to convince us that the meat we were eating was whale, David Lim in Jukasjarvi (the town of the midnight sun in summer and the Ice Hotel in winter) telling me: “Marcos look how far otitis media has taken you,” Ann Hermannson in northern Sweden teaching us about the Hundras and the beliefs of the northern people (I still keep the bone box with the magic power of northern Sweden), Sten Hellstrom organizing a pre-meeting competition of picking berries and mushrooms in the Umea forest, etc. During these unforgettable meetings we learned a lot about otitis media but more importantly we learned about life and friendship, and my wife and I are thankful and feel privileged to have participated and to have met all of them and consider them our friends. We were scientists but at the same time human beings and friends who enjoyed not only science but, more importantly, friendship. These were meetings that taught us to help and treat people, persons, far beyond the important use of statistical significance, xi square, and computerized evidence. The last International Symposium on Recent Advances in Otitis Media was held in June 2021, and there I was, presenting, 46 years later. Only that, this time, the difference was that I was one of the oldest if not the oldest participant, and one of the very few originals of 1975. v

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Preface

However, the difference was that at this last meeting the one that was gradually fading was me, just like Dr Senturia at the first meeting. Many of our mentors and pioneers like Michael Paparella—our honored co-editor and co-author in this book—Steve Juhn and others, just like the old heroes, are fading away. However, although they physically fade away, those that remain and had the privilege to have lived, worked, and learned from them will keep them alive in their hearts and in their concepts because they have become an integral part of the “otitis media family” forever. At this stage in my professional career, I was not about to edit another book on otitis media; however, I accepted as an exception only to lead this book in honor of our pioneers who so generously encouraged us, taught us, and introduced us to the subject of otitis media. In this spirit, and before fading away myself, I accepted to lead a book in honor of their memory and to give the torch to the young ones on my team and in other teams, who are in the same position that I was in 1975. God and life have been good to me and my family (it has not been free), and I feel that I should make this last otitis media effort and personally contribute with concepts in structure, function, and pathogenesis which are current and essential for the understanding of this multifactorial disease. At the same time, I wanted to contribute by transmitting the energy that was given to us in 1975 and transmit it modified and improved to the new generations, which will in turn modify and improve it in a constant enrichment that will contain the concepts and the spirits of the “otitis media family” for eternity. Santiago, MN, USA Porto Alegre, Rio Grande do Sul, Brazil Mumbai, Maharashtra, India Minneapolis, MN, USA

Marcos V. Goycoolea Sady Selaimen da Costa Chris de Souza Michael M. Paparella

Contents

1 Definitions, Terminology, and Classification �����������������������������������������������������������   1 Marcos V. Goycoolea, Sady Selaimen da Costa, Chris de Souza, and Michael M. Paparella 2 Otitis  Media: Basic Concepts and Fundamentals ���������������������������������������������������   5 Sady Selaimen da Costa and Rafael da Costa Monsanto 3 Otitis  Media and Human Efforts to Deal with It Through Time���������������������������  21 Marcos V. Goycoolea and Mario Castro 4 Development  and Anatomy of the Human Middle Ear�������������������������������������������  29 Charlotte M. Burford, Hannah L. Cornwall, Matthew R. B. Farr, Claudia M. Santoni, and Matthew J. Mason 5 Normal  Histology of the Eustachian Tube, Middle Ear, and Mastoid Complex: The Mucoperiosteum Concept�����������������������������������������������������������������  49 Marcos V. Goycoolea, Raimundo José García-Matte, and Catalina Gutiérrez 6 Understanding  the Aeration Avenues of the Middle Ear with the Aid of the Endoscope���������������������������������������������������������������������������������������������������������  59 Alessia Rubini, Margherita Basso, Nicola Bisi, Pierfrancesco Bettini, and Daniele Marchioni 7 Regulated  Balance of Pressure Variations in the Temporal Pneumatic Spaces�������������������������������������������������������������������������������������������������������  69 Bernard Ars and Dominique Estève 8 The  Role of Immunity in the Development of Otitis Media�����������������������������������  75 Sara Concha and Rodrigo Hoyos-Bachiloglu 9 When  to Suspect and How to Evaluate Immune Deficiencies in Otitis Media�������������������������������������������������������������������������������������������������������������  81 Sara Concha and Rodrigo Hoyos-Bachiloglu 10 Genetics  and Otitis Media �����������������������������������������������������������������������������������������  91 Nam K. Lee and Regie Lyn P. Santos-Cortez 11 Predictive  Medicine in Otitis Media������������������������������������������������������������������������� 109 Raimundo José García-Matte, María José Herrera J, and Marcos V. Goycoolea 12 Importance  of Animal Studies in the Understanding of Otitis Media������������������� 119 Marcelo Miguel Hueb, Fernanda Rocha Hueb, Marcela Rocha Hueb, and Michael M. Paparella 13 Critical  Appraisal of Published Research in Otitis Media or How to Sort the Wheat from the Chaff!���������������������������������������������������������������������������� 125 Joel Lavinsky, Vagner Antonio Rodrigues da Silva, and Luiz Lavinsky

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14 Translational  Histopathology in Otitis Media: The Real Evidence-Based Medicine!��������������������������������������������������������������������������������������������������������������������� 133 Suanur M. Kayaalp, Sebahattin Cureoglu, and Michael M. Paparella 15 Patulous  Eustachian Tube and the Differential Diagnosis of Autophony ������������� 143 Bryan K. Ward, Carrie L. Nieman, and Dennis S. Poe 16 Office  Examination in Otitis Media ������������������������������������������������������������������������� 153 Fábio André Selaimen, Alice Lang Silva, Wiquinylson França de Oliveira, and Sady Selaimen da Costa 17 Non-surgical  Strategies to Restore Middle Ear Aeration��������������������������������������� 163 Bernard Ars and Dominique Estève 18 Drug  Delivery Across the Intact Tympanic Membrane: Methods, Mechanisms and Potential Impact ��������������������������������������������������������������������������� 169 Arwa Kurabi, Molly Cooper, Emily Sereno, and Allen F. Ryan 19 Viral  Otitis Media and Acute Otitis Media and Recurrent Acute Otitis Media. An Evidence-Based Approach ����������������������������������������������������������� 177 José Faibes Lubianca Neto, João Pedro Neves Lubianca, and Marcelo Neves Lubianca 20 The  Microbiology of Otitis Media, Biofilms and Its Implication in the Clinical Treatment������������������������������������������������������������������������������������������� 191 Maria Beatriz Rotta Pereira, Manuel Ruttkay Pereira, Denise Rotta Ruttkay Pereira, and Vlademir Cantarelli 21 Otitis  Media with Effusion: Pathophysiology, Clinical Picture and Management��������������������������������������������������������������������������������������������������������� 199 María José Herrera J and José Alzerreca 22 Inflammatory  Mediators in the Pathogenesis of Otitis Media: A Brief Review������������������������������������������������������������������������������������������������������������� 207 Timothy T. K. Jung 23 Retraction  Pockets and Adhesive Otitis Media ������������������������������������������������������� 211 María José Herrera J and Javiera Pardo 24 Ventilation Tubes��������������������������������������������������������������������������������������������������������� 219 Ann Hermansson 25 Post-Tympanostomy  Tube Otorrhea and Other Complications����������������������������� 223 Henrique Furlan Pauna, Rafael C. Monsanto, Letícia A. Oyama, Ana Paula Chornobay, Karina Salvi, Livia Tamie T. Sassaki, and Michael M. Paparella 26 Vaccination  Policies in Otitis Media������������������������������������������������������������������������� 233 Ann Hermansson 27 Managing  Risk Factors in Otitis Media������������������������������������������������������������������� 237 Joshua A. Stramielo and Daniela Carvalho 28 Otitis  Media in Special Populations ������������������������������������������������������������������������� 245 Stephanie J. Wong and Daniela Carvalho 29 Early  in Life Otitis Media and Its Impact in Hearing, Speech Development, and Central Auditory Processing������������������������������������������������������������������������������� 253 Berenice Dias Ramos

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30 Balance  and Otitis Media������������������������������������������������������������������������������������������� 267 Rafael da Costa Monsanto, José Carlos Convento Júnior, José Vicente Boleli Scardini Alves, and Norma de Oliveira Penido 31 The  Use of Topical Treatment and Middle–Inner Ear Interaction ����������������������� 275 Marcos V. Goycoolea, Leandro Rodríguez, and Pilar Epprecht 32 Silent  Otitis Media and Subtle Complications��������������������������������������������������������� 279 Rafael da Costa Monsanto and Michael M. Paparella 33 Complications  of Otitis Media Limited to Within the Temporal Bone ����������������� 287 Diane Biju, Aishan Patil, Shaila Sidam, Aditi Govil, Kanchan Gupta, Vishal Tyagi, Rosemarie de Souza, and Chris de Souza 34 Intracranial  Complications of Otitis Media������������������������������������������������������������� 293 Diane Biju, Aishan Patil, Shaila Sidam, Aditi Govil, Kanchan Gupta, Vishal Tyagi, Rosemarie de Souza, and Chris de Souza 35 Basic  Imaging and Normal Temporal Bone Sections����������������������������������������������� 307 Marcos V. Goycoolea, Catalina Gutiérrez, and Francisco Chiang 36 Evaluation  and Auditory Rehabilitation in Chronic Otitis Media (COM)����������� 327 Byanka Cagnacci Buzo, S. Catherine Catenacci, and G. Raquel Levy 37 Pathogenesis  of Chronic Otitis Media and the Continuum: The Basics, Further and Beyond��������������������������������������������������������������������������������������������������� 337 Sady Selaimen da Costa and Michael M. Paparella 38 Chronic  Otitis Media Without Cholesteatoma��������������������������������������������������������� 363 Fábio André Selaimen, Mauricio Noschang Lopes da Silva, and Sady Selaimen da Costa 39 Tympanic  Membrane Perforations and Tympanoplasty: New Profiles, New Strategies������������������������������������������������������������������������������������������������������������� 373 Fábio André Selaimen, Mauricio Noschang Lopes da Silva, Tiago Isamu Saiguchi Murakami, and Sady Selaimen da Costa 40 Ossicular  Pathology in Chronic Otitis Media���������������������������������������������������������� 389 Cemil Kayaalp, Henrique Furlan Pauna, Rafael C. Monsanto, Hamed Sajjadi, Michael M. Paparella, and Sebahattin Cureoglu 41 Tympanic  Membrane Retractions: Pathophysiology, Classification, and Management��������������������������������������������������������������������������������������������������������� 395 Inesangela Canali, Letícia Petersen Schmidt Rosito, and Caroline Catherine Lacerda Elias 42 Temporal  Bone Cholesteatoma: The Full Picture��������������������������������������������������� 407 Sady Selaimen da Costa, Leticia Petersen Schimdt Rosito, Mauricio Noschang Lopes da Silva, and Fábio André Selaimen 43 Progresses  in Cholesteatoma Research��������������������������������������������������������������������� 447 H. Sudhoff and M. Schürmann 44 Advanced  Hearing and Balance Evaluation in Otitis Media ��������������������������������� 465 Rafael da Costa Monsanto, Leandro Guena de Castro, Matheus Saito, José Carlos Convento Junior, and Norma de Oliveira Penido 45 Radiological  Evaluation of the Temporal Bone in Chronic Otitis Media ������������� 481 Mauricio Noschang Lopes da Silva, Marcela Lehmkuhl Damiani, and Sady Selaimen da Costa

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46 Surgical Anatomy of the Middle Ear Cleft and Mastoid ��������������������������������������� 505 Sady Selaimen da Costa, Douglas K. Reinhardt, and Marcela Lehmkuhl Damiani 47 The  Endoscopic Anatomy of Temporal Bone����������������������������������������������������������� 513 Muaaz Tarabichi, Aneesa Ansar, Mustafa Kapadia, and Daniele Marchioni 48 Surgical  Treatment of Chronic Otitis Media: Menu of Solutions ������������������������� 527 Sady Selaimen da Costa, Fabio Andre Selaimen, Mauricio Noschang Lopes da Silva, and Douglas K. Reinhardt 49 Tympanoplasty:  Underlay Technique Step by Step and the Complex Tympanoplasty ����������������������������������������������������������������������������������������������������������� 541 Fábio André Selaimen, Mauricio Noschang Lopes da Silva, and Sady Selaimen da Costa 50 Tympanoplasty:  The Overlay Technique Step by Step������������������������������������������� 559 Fábio André Selaimen, Mauricio Noschang Lopes da Silva, and Sady Selaimen da Costa 51 Tympanoplasty:  The Inlay Technique Step by Step ����������������������������������������������� 567 José Faibes Lubianca Neto, João Pedro Neves Lubianca, Marcelo Neves Lubianca, and Roland Douglas Eavey 52 Medio-Lateral  Graft Tympanoplasty for Anterior or Subtotal Tympanic Membrane Perforation: An Update ������������������������������������������������������������������������� 585 Timothy T. K. Jung 53 Flexible Approach Tympanoplasty/Mastoidectomy: A Pathology-Guided, Pathogenesis—Oriented Surgery for the Middle Ear��������������������������������������������� 589 Sady Selaimen da Costa, Michael M. Paparella, and Rochane Figini Maciel 54 Principles  of Surgical Management of Cholesteatoma������������������������������������������� 605 Adam C. Kaufman and Peter L. Santa Maria 55 Canal  Wall Down v/s Canal Wall Up������������������������������������������������������������������������� 615 Jorge Caro, Jai-sen F. Leung, and Phoebe H. Ramos 56 Simple  Mastoidectomy: Indications and Techniques����������������������������������������������� 625 Jefferson André Bauer and Felipe da Costa Huve 57 Canal Wall Up Tympanomastoidectomy ����������������������������������������������������������������� 631 Alex Joseph Fejta Tampio and Douglas Backous 58 Canal Wall-Down Tympanomastoidectomy������������������������������������������������������������� 641 Sady Selaimen da Costa, Mauricio Noschang Lopes da Silva, Jefferson André Bauer, Fábio André Selaimen, and Letícia Petersen Schmidt Rosito 59 E  ndoscopic Assisted Canal Wall Up Tmpanomastoidectomy: The Combined Approach Redefined��������������������������������������������������������������������������������������������������� 665 Mauricio Noschang Lopes da Silva, Sady Selaimen da Costa, and Fábio André Selaimen 60 Intact-Bridge Mastoidectomy ����������������������������������������������������������������������������������� 675 Rafael da Costa Monsanto, Henrique Furlan Pauna, and Michael M. Paparella 61 Radical Mastoidectomy ��������������������������������������������������������������������������������������������� 683 Francisco Tocornal J.

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62 Local  Management of the Mastoidectomy Cavity��������������������������������������������������� 691 Leandro Rodríguez, Raimundo José García-Matte, and Marcos V. Goycoolea 63 Reconstruction  and Obliteration of the Mastoid Cavity����������������������������������������� 695 Michael B. Gluth and Ryan T. Judd 64 Subtotal Petrosectomy ����������������������������������������������������������������������������������������������� 707 Gianluca Piras, Wenlong Tang, Antonio Caruso, Lorenzo Lauda, Abdelkader Taibah, and Mario Sanna Index������������������������������������������������������������������������������������������������������������������������������������� 717

Contributors

José  Vicente  Boleli  Scardini  Alves Department of Otolaryngology, Banco de Olhos de Sorocaba Hospital, Sorocaba, Brazil José Alzerreca  Department of Otolaryngology, Clínica Universidad de Los Andes, Santiago, Chile Aneesa Ansar  Department of Otolaryngology, Tarabichi Stammberger Ear and Sinus Institute, Dubai, UAE Bernard Ars  University of Namur, Namur, Belgium Temporal Bone Foundation, Brussels, Belgium Douglas  Backous Department of Neurotology, Proliance Surgeons, Puget Sound ENT, Edmonds, WA, USA Margherita  Basso Department of Otolaryngology-Head and Neck Surgery, University Hospital of Modena, Modena, Italy Jefferson André Bauer  Hospital de Clinicas de Porto Alegre, Porto Alegre, Brazil Hospital Mãe de Deus, Porto Alegre, Brazil Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil Instituto Gaúcho de Otorrinolaringologia, Porto Alegre, Brazil Pierfrancesco Bettini  ENT & Audiology Department, University Hospital of Ferrara, Ferrara, Italy Diane Biju  Holy Spirit Hospital, Mumbai, India Nicola Bisi  Department of Otolaryngology-Head and Neck Surgery, University Hospital of Modena, Modena, Italy Charlotte M. Burford  East Kent Hospitals University NHS Foundation Trust, Ashford, Kent, UK Byanka Cagnacci Buzo  Santa Casa de Sao Paulo School of Medical Science Hearing and Speech Science Program, São Paulo, Brazil Department of Research, Cochlear LATAM, Panamá City, Panamá Inesangela  Canali Department of Otolaryngology, Pontifical Catholic University, Porto Alegre, Rio Grande do Sul, Brazil Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil Vlademir Cantarelli  Department of Basic Health Sciences, Universidade Federal de Ciencias da Saude de Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil Jorge Caro  Pontificia Universidad Católica de Chile, Santiago, Chile Antonio Caruso  Gruppo Otologico and Mario Sanna Foundation, Piacenza-Rome, Italy xiii

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Daniela  Carvalho Division of Otolaryngology Head and Neck Surgery, University of California, San Diego, La Jolla, CA, USA Rady Children’s Hospital, San Diego, San Diego, CA, USA Leandro Guena de Castro  Department of Otolaryngology, Head & Neck Surgery, Banco de Olhos de Sorocaba Hospital, Sorocaba, SP, Brazil Mario Castro  Chilean National Museum of Natural History, Santiago, Chile Department of Morphology, Faculty of Medicine, Clínica Alemana-Universidad del Desarrollo, Santiago, Chile S. Catherine Catenacci  Department of Otolaryngology, Clinica Universidad de Los Andes, Santiago, Chile Francisco Chiang  Department of Radiology, Clínica Universidad de Los Andes, Santiago, Chile Ana Paula Chornobay  Hospital Universitário Cajuru, Curitiba, PR, Brazil Sara  Concha Department of Pediatric Immunology and Infectious Diseases, Pontificia Universidad Católica de Chile, Santiago, Chile Molly  Cooper Department of Surgery/Otolaryngology, UCSD School of Medicine, San Diego, CA, USA Hannah L. Cornwall  Department of Paediatrics, Ysbyty Gwynedd, Bangor, Wales, UK Sady Selaimen da Costa  Department of Otolaryngology, Head and Neck Surgery, School of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil School of Medicine - Federal University of Rio Grande do Sul, Porto Alegre, Brazil Otology and Neurotology Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil International Hearing Foundation, Minneapolis, MN, USA American Academy of Otolaryngology and Head & Neck Surgery, Alexandria, VA, USA Department of Otolaryngology, University of Minnesota, Otopathology Laboratory, Minneapolis, MN, USA Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil Otology and Neurotology Division, Sistema Hospitalar Mãe de Deus, Porto Alegre, Brazil Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil Instituto Gaúcho de Otorrinolaringologia, Porto Alegre, Brazil Felipe da Costa Huve  Hospital de Clinicas de Porto Alegre, Porto Alegre, Brazil Hospital Mãe de Deus, Porto Alegre, Brazil Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil Instituto Gaúcho de Otorrinolaringologia, Porto Alegre, Brazil Rafael da Costa Monsanto  Department of Otolaryngology, Head & Neck Surgery, University of Minnesota, Minneapolis, MN, USA Department of Otolaryngology, Head and Neck Surgery, Universidade Federal de São Paulo/ Escola Paulista de Medicina (UNIFESP/EPM), São Paulo, Brazil Department of Otolaryngology, Head & Neck Surgery, Banco de Olhos de Sorocaba Hospital, Sorocaba, SP, Brazil

Contributors

Contributors

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Sebahattin Cureoglu  Otopathology Laboratory, Department of Otolaryngology, University of Minnesota Physicians (UMP), University of Minnesota, Minneapolis, MN, USA Marcela Lehmkuhl Damiani  Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil Roland Douglas Eavey  Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Nashville, TN, USA Caroline Catherine Lacerda Elias  Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil Department of Otolaryngology, Hospital Nossa Senhora da Conceição, de Porto Alegre (GHC), Porto Alegre, Rio Grande do Sul, Brazil Pilar  Epprecht Department of Otolaryngology, Clínica Universidad de Los Andes and Exequiel González Cortés Hospital, Santiago, Chile Department of Otolaryngology, Exequiel González Cortés Hospital, Santiago, Chile Dominique Estève  Chemin de Sainte-Roustagne, Manosque, France Matthew R. B. Farr  Doncaster Royal Infirmary, Doncaster, UK Francisco  Tocornal J.  Department of Otolaryngology, Clínica Universidad de Los Andes, Santiago, Chile Raimundo José García-Matte  Department of Otolaryngology, Clínica Universidad de Los Andes, and Hospital de la Florida, Santiago, Chile Michael B. Gluth  University of Chicago Section of Otolaryngology-Head and Neck Surgery, Chicago, IL, USA Aditi Govil  Lilavati Hospital and Research Centre, Mumbai, India BJ Medical College, Ahmedabad, India Marcos  V.  Goycoolea  Department of Otolaryngology, Clínica Universidad de Los Andes, Santiago, Chile Kanchan Gupta  Lilavati Hospital and Research Centre, Mumbai, India Catalina Gutiérrez  Hospital Sótero del Río, Santiago, Chile Ann Hermansson  Department of ENT, Lund University Hospital, Lund, Sweden María José Herrera J  Department of Otolaryngology, Clínica Universidad de Los Andes, Santiago, Chile Rodrigo Hoyos-Bachiloglu  Department of Pediatric Immunology and Infectious Diseases, Pontificia Universidad Católica de Chile, Santiago, Chile Fernanda Rocha Hueb  University of Uberaba, Uberaba, Minas Gerais, Brazil Marcela Rocha Hueb  University Unilago, São Paulo, Brazil Marcelo Miguel Hueb  University of São Paulo, São Paulo, Brazil ENT Discipline and ENT Service, Federal University of Triângulo Mineiro, Uberaba, Brazil Hospital Santa Lúcia of Uberaba, Uberaba, Minas Gerais, Brazil Ryan  T.  Judd  University of Chicago Section of Otolaryngology-Head and Neck Surgery, Chicago, IL, USA

xvi

Timothy  T.  K.  Jung Department of Otolaryngology-Head & Neck Surgery, Loma Linda University School of Medicine, Jerry L.  Pettis Veterans Medical Center, Loma Linda, CA, USA Inland Ear Head & Neck Clinic, Riverside, CA, USA José Carlos Convento Júnior  Department of Otolaryngology, Head & Neck Surgery, Banco de Olhos de Sorocaba Hospital, Sorocaba, SP, Brazil Mustafa  Kapadia Department of Otolaryngology, Tarabichi Stammberger Ear and Sinus Institute, Dubai, UAE Adam C. Kaufman  Otorhinolaryngology – Head & Neck Surgery, University of Maryland, Baltimore, Baltimore, MD, USA Cemil  Kayaalp Otopathology Laboratory, Department of Otolaryngology, University of Minnesota, Minneapolis, MN, USA Suanur M. Kayaalp  Otopathology Laboratory, Department of Otolaryngology, University of Minnesota Physicians (UMP), University of Minnesota, Minneapolis, MN, USA Arwa  Kurabi Department of Surgery/Otolaryngology, UCSD School of Medicine, San Diego, CA, USA Lorenzo Lauda  Gruppo Otologico and Mario Sanna Foundation, Piacenza-Rome, Italy Joel Lavinsky  Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil Santa Casa de Porto Alegre, Porto Alegre, Brazil Luiz Lavinsky  Federal University of Rio Grande do Sul, School of Medicine, Porto Alegre, Brazil Sul-Rio-Grandense Academy of Medicine, Porto Alegre, Brazil Nam K. Lee  Department of Otolaryngology-Head and Neck Surgery, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA Jai-sen F. Leung  Pontificia Universidad Católica de Chile, Santiago, Chile João Pedro Neves Lubianca  Federal University of Rio Grande do Sul, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil Marcelo Neves Lubianca  Pontifical Catholic University of Rio Grande do Sul, São Lucas Hospital, Porto Alegre, RS, Brazil Rochane  Figini  Maciel Chronic Otitis Media Study Group, School of Medicine, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil Daniele  Marchioni Department of Otolaryngology-Head and Neck Surgery, University Hospital of Modena, Modena, Italy Matthew J. Mason  Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK Rafael C. Monsanto  Otopathology Laboratory, Department of Otolaryngology, University of Minnesota, Minnesota, MN, USA Department of Otolaryngology, Head & Neck Surgery, University of Minnesota, Minnesota, MN, USA Tiago Isamu Saiguchi Murakami  Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil

Contributors

Contributors

xvii

José Faibes Lubianca Neto  Graduate Program of Pediatrics of Federal University of Health Sciences of Porto Alegre, Porto Alegre, RS, Brazil Otorhinolaryngology Service at Santa Casa de Misericórdia de Porto Alegre Hospital, Porto Alegre, RS, Brazil Pediatric Otorhinolaryngology Service at Santo Antonio Children’s Hospital, Porto Alegre, RS, Brazil Carrie L. Nieman  Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA Wiquinylson França de Oliveira  Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil Norma  de Oliveira  Penido Department of Otolaryngology, Head and Neck Surgery, Universidade Federal de São Paulo/Escola Paulista de Medicina (UNIFESP/EPM), São Paulo, Brazil Letícia A. Oyama  Hospital Universitário Cajuru, Curitiba, PR, Brazil Michael M. Paparella  Department of Otolaryngology, University of Minnesota and Paparella Clinic, Minneapolis, MN, USA Otopathology Laboratory, Department of Otolaryngology, University of Minnesota and Paparella Clinic, Minneapolis, MN, USA American Academy of Otolaryngology and Head & Neck Surgery, Alexandria, VA, USA Department of Otolaryngology, Head & Neck Surgery, University of Minnesota, Minnesota, MN, USA Javiera Pardo  Otolaryngologist Department of Otolaryngology, Clínica Universidad de Los Andes, Santiago, Chile Aishan Patil  Vascular Surgery, Borders General Hospital, Melrose, Scotland, UK Henrique Furlan Pauna  Hospital Universitário Cajuru, Curitiba, PR, Brazil Hospital IPO, Curitiba, Paraná, Brazil Department of Otolaryngology, Hospital Universitario Cajuru, Curitiba, Paraná, Brazil Denise Rotta Ruttkay Pereira  Department of Otolaryngology and Head and Neck Surgery, Hospital de Clinicas de Porto Alegre, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil Manuel  Ruttkay  Pereira Department of Pediatrics, School of Medicine, Pontificia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil Department of Pediatrics, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil Maria Beatriz Rotta Pereira  Department of Otolaryngology and Head and Neck Surgery, Hospital Sao Lucas, Pontificia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, RS, Brazil Gianluca Piras  Gruppo Otologico and Mario Sanna Foundation, Piacenza-Rome, Italy Dennis  S.  Poe  Department of Otolaryngology-Head and Neck Surgery, Boston Children’s Hospital, Boston, MA, USA Berenice Dias Ramos  Phoniatrics, Department of Ophthalmology and Otorhinolaryngology, Faculty of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil Otorhinolaryngology & Head and Neck Surgery Service, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil Phoniatrics, DERDIC—PUCSP, São Paulo, SP, Brazil

xviii

Phoebe H. Ramos  Pontificia Universidad Católica de Chile, Santiago, Chile G. Raquel Levy  Department of Otolaryngology, Clinica Universidad de Los Andes, Santiago, Chile Douglas K. Reinhardt  Hospital São Lucas da PUCRS, Porto Alegre, Brazil Leandro Rodríguez  Department of Otolaryngology, Clínica Universidad de Los Andes, and Hospital del Salvador, Santiago, Chile Letícia Petersen Schmidt Rosito  School of Medicine - Federal Universityof Rio Grande do Sul, Porto Alegre, Brazil Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil International Hearing Foundation, Minneapolis, MN, USA Department of Otolaryngology—Head and Neck Surgery, Porto Alegre Clinica’s Hospital, Porto Alegre, Rio Grande do Sul, Brazil Alessia Rubini  Department of Otolaryngology-Head and Neck Surgery, University Hospital of Modena, Modena, Italy Allen  F.  Ryan Department of Surgery/Otolaryngology, UCSD School of Medicine, San Diego, CA, USA Department of Neurosciences, UCSD School of Medicine, San Diego, CA, USA San Diego VA Healthcare System, La Jolla, CA, USA Matheus Saito  Department of Otolaryngology, Head & Neck Surgery, Banco de Olhos de Sorocaba Hospital, Sorocaba, SP, Brazil Hamed  Sajjadi Stanford University, School of Medicine, San Jose Ear & Sinus Medical Center, Los Gatos, CA, USA Karina  Salvi Department of Otolaryngology, Banco de Olhos de Sorocaba Hospital, Sorocaba, SP, Brazil Mario Sanna  Gruppo Otologico and Mario Sanna Foundation, Piacenza-Rome, Italy Peter L. Santa Maria  Otolaryngology, Head & Neck Surgery, Stanford University, Stanford, CA, USA Claudia M. Santoni  School of Clinical Medicine, University of Cambridge, Cambridge, UK Regie Lyn P. Santos-Cortez  Department of Otolaryngology-Head and Neck Surgery, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA Livia  Tamie  T.  Sassaki Department of Otolaryngology, Banco de Olhos de Sorocaba Hospital, Sorocaba, SP, Brazil M.  Schürmann Department of Otorhinolaryngology, Head and Neck Surgery, Klinikum Bielefeld, Medical Faculty OWL, Bielefeld University, Bielefeld, Germany Fabio Andre Selaimen  Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil Instituto Gaúcho de Otorrinolaringologia, Porto Alegre, Brazil Fábio André Selaimen  Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil Instituto Gaúcho de Otorrinolaringologia, Porto Alegre, Brazil Emily  Sereno Department of Surgery/Otolaryngology, UCSD School of Medicine, San Diego, CA, USA Shaila Sidam  All India Institute of Medical Sciences, Bhopal, Madhya Pradesh, India

Contributors

Contributors

xix

Alice Lang Silva  Instituto Gaúcho de Otorrinolaringologia, Porto Alegre, Brazil Mauricio  Noschang  Lopes  da Silva Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil Instituto Gaúcho de Otorrinolaringologia, Porto Alegre, Brazil Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil Otology and Neurotology Division, Sistema Hospitalar Mãe de Deus, Porto Alegre, Brazil Service of Otolaryngology, Head & Neck Surgery, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil Vagner Antonio Rodrigues da Silva  State University of Campinas (Unicamp), Campinas, Brazil Faculty of Medical Sciences—UNICAMP, Campinas, Brazil Chris de Souza  Lilavati Hospital, Mumbai, India Holy Family Hospital, Mumbai, India Otolaryngology—Head and Neck Surgery, SUNY Brooklyn, New York, NY, USA Otolaryngology—Head and Neck Surgery, LUSHSC, Shreveport, LA, USA Faculty SUNY, Brooklyn, NY, USA LSUHSC, Shreveport, LA, USA Lilavati Hospital, Holy Family Hospital, Holy Spirit Hospital, Mumbai, India Rosemarie  de Souza  Internal Medicine, BYL Nair Hospital and TNM College, Mumbai, India Joshua  A.  Stramielo Division of Otolaryngology Head and Neck Surgery, University of California, San Diego, La Jolla, CA, USA H. Sudhoff  Department of Otorhinolaryngology, Head and Neck Surgery, Klinikum Bielefeld, Medical Faculty OWL, Bielefeld University, Bielefeld, Germany Abdelkader Taibah  Gruppo Otologico and Mario Sanna Foundation, Piacenza-Rome, Italy Alex  Joseph  Fejta  Tampio  Department of Neurotology, Proliance Surgeons, Puget Sound ENT, Edmonds, WA, USA Wenlong Tang  Gruppo Otologico and Mario Sanna Foundation, Piacenza-Rome, Italy Muaaz  Tarabichi Department of Otolaryngology, Tarabichi Stammberger Ear and Sinus Institute, Dubai, UAE Vishal Tyagi  Holy Family Hospital, Holy Spirit Hospital, Mumbai, India Department of ENT, VN Desai Hospital, Mumbai, India Bryan  K.  Ward Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA Stephanie J. Wong  Pediatric Otolaryngology, Mount Sinai, NY, USA

1

Definitions, Terminology, and Classification Marcos V. Goycoolea, Sady Selaimen da Costa, Chris de Souza, and Michael M. Paparella

Otitis media (OM) is a multifactorial, multifaceted disease that manifests as an inflammatory process in the middle ear, mastoid, and Eustachian tube. It is the result of prevailing aggression against the body’s immunological defense system, the degree of which depends on the interactions between the two opposing forces (aggressive and defensive). It is a dynamic disease, often used to describe a continuum of related diseases [1], in which some forms lead to others (Figs. 1.1 and 1.2), resulting at times in complications and

sequelae (Table 1.1). In addition to local factors, this process is directly influenced not only by the neighboring anatomical structures but also by the host’s relationship with the environment. The term “otitis media (OM)” itself describes an inflammation of the middle ear and includes not only the middle ear cavity but also the Eustachian tube and the mastoid. This disease can be classified on a clinical or histopathological basis [3].

M. V. Goycoolea (*) Department of Otolaryngology, Clínica Universidad de Los Andes, Santiago, Chile S. S. da Costa Department of Otolaryngology, Head and Neck Surgery, School of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil Otology and Neurotology Division, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil C. de Souza Lilavati Hospital, Mumbai, India Holy Family Hospital, Mumbai, India Otolaryngology—Head and Neck Surgery, SUNY Brooklyn, New York, NY, USA Otolaryngology—Head and Neck Surgery, LUSHSC, Shreveport, LA, USA M. M. Paparella Department of Otolaryngology, University of Minnesota and Paparella Clinic, Minneapolis, MN, USA e-mail: [email protected] © The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 M. V. Goycoolea et al. (eds.), Textbook of Otitis Media, https://doi.org/10.1007/978-3-031-40949-3_1

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M. V. Goycoolea et al.

2 Fig. 1.1  The continuum of otitis media (Copyright Marcos Y. Goycoolea 2023; all rights reserved)

Table 1.1 (continued) Complications Inner ear Labyrinthitis Sensorineural hearing loss

Bezold’s abscess Zygomatic abscess Postauricular abscess Others Developmental Behavioral

Sequelae Active Recurrent attacks of otitis media Chronic otitis media with effusion Silent otitis media Masked mastoiditis Continuum of POM-SOM-MOM-COMb Inactive Atelectasis Tympanosclerosis Adhesive otitis media

Fig. 1.2  Classification and continuum of otitis media. (Copyright Marcos Y. Goycoolea 2023; all rights reserved). Classification and continuum of otitis media with effusion (OME). POM purulent otitis media, SOM serous otitis media, MOM mucoid otitis media, COM chronic otitis media, OM otitis media

 Tympanic membrane  POM purulent otitis media, SOM serous otitis media, MOM mucoid otitis media, COM chronic otitis media a

b

Table 1.1  Complications and sequelae of otitis media (from Goycoolea and Jung 1991 [2]) Complications Temporal bone Middle ear Facial nerve paralysis Ossicular lesions Perforations of the TMa Mastoid Reduced pneumatization Coalescent mastoiditis

Extratemporal Intracranial Extradural abscess Subdural abscess Brain abscess Meningitis Lateral sinus thrombophlebitis Otitis hydrocephalus Extracranial

Clinical Classification The Task Force of the Fourth International Symposium of Otitis Media, held in June 1987, at Bal Harbor, Florida, classified otitis on clinical grounds [4], as did the Task Force of the Seventh Symposium in 1999 [5]. For purposes of communication and uniform reporting, we have followed this classification, with a clear understanding, however, that it is a working classification that allows a “common language” in the subject. It is important to men-

1  Definitions, Terminology, and Classification

tion that this is more than just a “final classification” written in stone; it has represented, over the years, a “consensus or working agreement” between different clinicians and investigators who have different viewpoints and perspectives. In other words, as Cicero stated centuries ago: “Every rational discussion of anything whatsoever should begin with a definition in order to make clear what is the subject of dispute.” The classification is as follows: 1. Myringitis, which is an inflammation of the tympanic membrane that occurs alone or in association with external otitis or otitis media 2. Acute suppurative otitis media (acute purulent otitis media (POM) or acute otitis media), which refers to a clinically identifiable infection of the middle ear with sudden onset and short duration 3. Otitis media with effusion or secretory otitis media (chronic otitis media with effusion, otitis media with effusion, nonsuppurative otitis media, catarrh, serous otitis media (SOM), serotympanum, mucoid otitis media (MOM), mucositis, or mucotympanum), which refers to the presence of middle ear effusion (MEE) behind an intact tympanic membrane without any acute signs or symptoms. This broad term includes nonsuppurative or clinically noninfectious forms of OM. However, evidence suggests that effusions are, for the most part, infectious. Cultures of serous effusions yield between 22% and 52% positively, percentages that increase to 77.3% if PCR is used [6]. 4. Chronic suppurative otitis media (chronic otitis media), which refers to a chronic discharge from the middle ear through a perforation of the tympanic membrane. Suppurative refers to an active clinical infection. A perforation without discharge can be an inactive stage of the infection (but not of the underlying histopathological process). Over time, a new entity was incorporated: 5. Recurrent otitis media, which refers to repeated episodes of acute otitis media in between periods of “apparent remission” (three episodes in 6  months or four episodes in 1 year) In addition, the definition of “chronic” can also be applied to otitis with an intact tympanic membrane, as in the cases of masked mastoiditis [7] and silent otitis media [8, 9]. Based on its duration, this disease can be divided into acute (up to 3 weeks), subacute (from 3 weeks to 3 months), and chronic (more than 3 months) [10].

Middle Ear Effusions Otitis media is associated with the presence of middle ear fluid (effusion). Basically, three types of effusions are found: (1) serous otitis media (SOM), (2) mucoid otitis media (MOM), and (3) purulent otitis media (POM).

3

Two other types can be added: hemorrhagic and any combination of the previously mentioned effusions. In practice, it is unusual to see a pure effusion because effusions reflect a dynamic process in which some forms evolve into others. This will depend on the interaction between defensive and aggressive forces (e.g., the aggressive forces prevail in the more infectious phases, whereas the defensive forces prevail in the noninfectious phases). Moreover, fluid composition represents what is going on in the underlying mucoperiosteum, as will be described in Chap. 5.

Histopathological Classification Histopathologically an infiltration by polymorphonuclear cells is a sign of acute inflammmation, and an infiltration by round cells is a sign of chronic inflammation. The term “chronic” implies infiltration of the mucoperiosteum by round cells or the cells of chronic inflammation. However, studies of the histopathological process of otitis media provide much more comprehensive knowledge and understanding that goes much further than the practical clinical terms “acute” and “chronic.” These histopathological changes are described in Chap. 5.

Complications and Sequelae In addition to the acute and chronic involvement of the mucoperiosteum by the otitis media process, there are potential complications and sequelae. A complication occurs when the inflammatory process extends beyond the mucoperiosteum. Sequelae refer to histopathological changes that are secondary to the otitis media process that remain within the mucoperiosteum and have the capacity or potential to develop a complication [11]. For example, the granulation tissue is a sequela (active sequela), but erosion of bone and fistula by the granulation tissue is a complication. In addition, the overall consequences of a localized problem (e.g., ossicular disruption causing conductive hearing loss) can have significant effects on a person and their relationship with others (lack of communication, isolation, learning problems, and so forth). Complications and sequelae are described in Table 1.1.

The Concept of Overall Involvement An essential concept in otitis media is that the otitis media process involves not only the middle ear cavity but also the Eustachian tube and the mastoid. This manifests by changes in the whole mucoperiosteum covering these cavities— including osteitis of the underlying bone—(Fig. 1.3) and in the fluids that the cavities contain (middle ear effusions). In addition, effusions are not stagnant spillage but are dynamic

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Fig. 1.3  Middle ear cavity with middle ear effusion (Copyright Marcos Y Goycoolea 2023; all rights reserved). The inflammatory process involves all the walls, cavities, and anatomical structures that these contain as well as the mucoperiosteum that lines these cavities and structures

forms that evolve and change in response to and as part of the overall mucoperiosteal changes [11, 12]. We see the inflammatory changes as a continuum, with some forms evolving or resolving into other forms and, at times, resulting in complications and sequelae, depending on the multiple factors involved. Viewed from this perspective, it becomes obvious that otitis media implies much more than fluid behind the tympanic membrane.

References 1. Paparella MM, Goycoolea MV, Jung TK. Otitis media with effusion. In: Paparella MM, Shumrick DA, Gluckman JL, Meyerhoff WL, editors. Otolaryngology, vol. II. Philadelphia: WB Saunders; 1991. p. 1317–42. 2. Goycoolea MV, Jung TK.  Complications of suppurative otitis media. In: Paparella MM, Shumrick DA, Gluckman JL, Meyerhoff WL, editors. Otolaryngology, vol. II. Philadelphia: Saunders; 1991. p. 1381–403. 3. Goycoolea MV, Hueb MM, Ruah CB.  Otitis Media. Definitions and terminology. In: Goycoolea MV, editor. Otitis media. The pathogenesis approach, The otolaryngologic clinics of NA, vol. 24. Philadelphia: WB Saunders; 1991. p. 757–61.

4. Klein JO, Tos M, Hussl B, et al. Definition and classification. Ann Otol Rhinol Laryngol. 1989;98(Suppl 139):10. 5. Bluestone C, Ogra P, Paparella M, et al. Definitions, terminology and classification of otitis media. In: Lim DJ, editor. Recent advances in otitis media. Report of the Seventh Research Conference. Ann Otol Rhinol Laryngol 2002; 111 (suppl.111): 8–18. 6. Liu YS, Lim DJ, Lang R, et  al. Microorganisms in chronic otitis media with effusion. Ann Otol Rhinol Laryngol. 1976;85(Suppl 25):245. 7. Mawson SR. Latent mastoiditis. In: Mawson SR, editor. Diseases of the ear. Baltimore: Williams and Wilkins; 1963. p. 286, 344. 8. Paparella MM, Bluestone CD, Arnold W, et al. Definition and classification. Ann Otol Rhinol Laryngol. 1985;94(Suppl 116):8. 9. Paparella MM, Goycoolea MV, Bassiouni M, et  al. Silent otitis media: clinical applications. Laryngoscope. 1986;96:978. 10. Paparella MM, Senturia BH, Bluestone CD, Lim DJ, et al. Report of the ad hoc committee on definition and classification of otitis media and otitis media with effusion. Ann Otol Rhinol Laryngol. 1980;89(Suppl 68):3–4. 11. Goycoolea MV, Paparella MM, Juhn SK, Carpenter AM.  The cells involved in the middle ear defense system. Ann Otol Rhinol Laryngol. 1980;89(Suppl. 68):121–1980. 12. Goycoolea MV.  Surgical procedures in different forms of otitis media. Summary of concepts. In: Goycoolea MV, et  al., editors. Atlas of otologic surgery, vol. 1. New Delhi: Jaypee Brothers Medical Publishers Ltd; 2012. p. 463–89.

2

Otitis Media: Basic Concepts and Fundamentals Sady Selaimen da Costa and Rafael da Costa Monsanto

“Acute pain of the ear, with continued strong fever, is to be dreaded, for there is danger that man may become delirious and die.” Hippocrates

Introduction The term “otitis media (OM)” describes a multifactorial inflammatory process that involves not only the middle ear but also the Eustachian tube and the mastoid. It is one of the most prevalent infectious diseases, being considered a worldwide public health problem [1–6]. In the United States alone, more than 5 billion dollars are spent annually to treat OM. It is estimated that 30 million dollars are spent toward antibiotic treatment of OM. In 2006, OM-related expenditure with outpatients alone in the United States was around 2.8 billion dollars [7]. The National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey in the USA indicated that—in 2019 only— more than one million emergency department visits were patients with OM. In Germany (2014–2019), the population under 16 years of age only represented more than 900,000 S. S. da Costa (*) Otolaryngology and Head and Neck Surgery, School of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil Service of Otolaryngology and Head and Neck Surgery, Hospital de Clínicas, Porto Alegre, Rio Grande do Sul, Brazil Brazilian Association of Otorhinolaryngology and Cervico-Facial Surgery, São Paulo, SP, Brazil Brazilian Society of Otology, São Paulo, SP, Brazil International Hearing Foundation, Minneapolis, MN, USA International Advisory Board—American Academy of Otolaryngology and Head & Neck Surgery, Alexandria, VA, USA Collegium Oto-Rhino-Laryngologicum Amicitiae Sacrum, Helsinki, Finland R. da Costa Monsanto Department of Otolaryngology, Head & Neck Surgery, University of Minnesota, Minneapolis, MN, USA e-mail: [email protected]

episodes of OM, 15% of which were identified as recurrent [8, 9]. A study in Boston showed that, out of 17,000 pediatric outpatient consultations performed during the first year of life, acute otitis media (AOM) constituted one-third of them [10]. According to Lanphear et al. [11], the number of outpatient consultations due to OM in preschoolers, which has always been traditionally high, increased even more in the past decade. In the United States, half a million patients undergo tympanostomy tube surgery every year, either for OM with effusion (OME) or recurrent acute OM (AOM) that is refractory to conventional clinical treatments [12]. Tympanostomy tube insertion is the most frequent surgical procedure performed under general anesthesia in American children [13]. OM is a dynamic disease in which some forms lead to others, resulting at times in complications and sequelae. The progression of middle ear inflammation and tissue changes is influenced by many factors, including the anatomy and physiology of the middle ear, mastoid, and Eustachian tube, and the host’s immunological response to environmental factors. In addition to local factors, this process is directly influenced not only by the neighboring anatomical structures but also by the host’s relationship with the environment.

Classification and Definitions Otitis media can be classified on a clinical or histopathological basis. Although these elements have been already addressed in Chap. 1, they will be duplicated here in order to stress their importance in the understanding of many concepts that will be discussed in the next paragraphs.

Clinical Classification OM was classified on the clinical basis by both the “Task Force of the Fourth International Symposium of Otitis Media” (June 1987, Bal Harbor, Florida) and the “Task Force of the Seventh Symposium in 1999” [14]. For purposes of

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 M. V. Goycoolea et al. (eds.), Textbook of Otitis Media, https://doi.org/10.1007/978-3-031-40949-3_2

5

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consistency, we have followed this classification throughout this chapter. However, it is important to highlight that this is a working classification that allows a “common language” in the subject. These definitions represent a “consensus or working agreement” between different clinicians and investigators who have different viewpoints and perspectives. In other words, as Cicero stated centuries ago: “Every rational discussion of anything whatsoever should begin with a definition in order to make clear what is the subject of dispute.” The classification is as follows: • Myringitis: Inflammation of the tympanic membrane that occurs alone or in association with external otitis or otitis media • Acute suppurative otitis media (acute purulent otitis media, acute otitis media): A clinically identifiable infection of the middle ear with sudden onset and short duration • Secretory otitis media (chronic otitis media (COM) with effusion, otitis media with effusion, nonsuppurative otitis media, catarrh, serous otitis media, serotympanum, mucoid otitis media, mucositis, mucotympanum): The presence of middle ear effusion (MEE) behind an intact tympanic membrane without any acute signs or symptoms. This broad term includes nonsuppurative or clinically noninfectious forms of OM.  However, evidence suggests that effusions are, for the most part, infectious. Cultures of serous effusions yield between 22% and 52% positively, percentages that increase to 77.3% if PCR is used [15]. • Chronic suppurative otitis media (CSOM) (chronic otitis media): Chronic discharge from the middle ear through a perforation of the tympanic membrane. Suppurative refers to an active clinical infection. A perforation without discharge can be an inactive stage of the infection (but not of the underlying histopathological process). Later, other classification:

terms

were

incorporated

into

this

• Recurrent otitis media: Repeated episodes of acute otitis media in between periods of “apparent remission” (three episodes in 6 months or four episodes in 1 year) • Silent (or “masked”) otitis media: The presence of a chronic inflammatory process affecting the middle ear and the mastoid behind an intact tympanic membrane [16] Additionally, OM can be classified based on its duration into acute (up to 3  weeks), subacute (from 3  weeks to 3 months), and chronic (more than 3 months) [17].

Middle Ear Effusions Otitis media is associated with the presence of middle ear effusion. Three types of effusions can be found in OM cases: (1) serous, which comprises a thin, pale transudate; (2) mucoid, which is a thick exudate that is the result of goblet cells present in the metaplastic epithelium; and (3) purulent, which is characterized by the presence of inflammatory cells. In addition, two other types can be included: hemorrhagic, when red blood cells are present, and middle ear effusions that can appear as a combination of any of these.

Histopathological Classification Histopathologically, the term “acute” refers to infiltration by polymorphonuclear cells, characterized by classic signs of acute inflammation. The term “chronic” implies the presence of clinically intractable tissue changes affecting the middle ear and/or the mastoid. Histopathological changes secondary to OM are described in Chap. 5.

Basic Concepts Otitis media is a multifaceted pathology, and, therefore, its complete understanding can only be achieved through analysis and meticulous study of each of its small facets. These studies will have to be skilled enough to dissect the individual aspects of this disease without, however, denying the fact that they are organically and evolutionarily interconnected. Analogously, it would be as if we tried to understand a chain by examining only one of its links and extrapolating that to include every form of the disease. For this reason, we will dedicate the next paragraphs to dive deeper into the basic concepts that we consider essential for addressing issues relevant to the etiology, classification, pathogenesis, and treatment of this prevalent disease. As mentioned in the “Introduction” section, OM is defined as the presence of an inflammatory process (which may or may not be infectious) affecting the middle ear and the mastoid. However, before navigating through the more specific aspects of this disease, it is important to further discuss definitions. To do so, it is necessary to review foundations related to general pathology and primary anatomy and physiology, which is critical to the global understanding of this entire fascinating process. Inflammation is a nonspecific biological process that is inherent to organisms, which occurs in response to pathogenic stimuli of different nature. These stimuli include chemical, physical, or biological agents. Although inflammation is essentially a defense mechanism, it can sometimes result in damage to the body. In clinical practice, it is more

2  Otitis Media: Basic Concepts and Fundamentals

frequently associated with trauma, infections, deposits of crystals, or antigen–antibody complexes. The first description of inflammation, an important milestone in the history of medicine, is attributed to Celsus in the first century AD, who described four cardinal signs: heat, redness, pain, and tumor. A century later, Galen added another sign: loss of function. The inflammatory process begins with a more or less intense nonspecific tissue injury. As a result, there is local activation of the complement system, which is an enzymatic cascade, constituted by several elements endowed with biological activity [18]. At the histopathological level, two different stages of inflammation occur, namely, acute and chronic. The first is characterized by arteriolar and venular vasodilation, with increased hydrostatic pressure in the microcirculation and fluid leakage into the interstitial tissues (edema); increased permeability in microvascularization, by cell contraction in the venular endothelium (fenestration), with protein escape that decreases vascular oncotic pressure and favors the formation of inflammatory exudates in the tissue; migration of polymorphonuclear cells (chemotaxis), initially; and accumulation of macrophages at the injury site, approximately 24 h later. The chronic phase of inflammation begins 36–48 h after the inflammatory stimulus, where leukocyte migration continues, with a predominance of monocytes, lymphocytes, plasmocytes, and fibroblasts and signs of regeneration and reconstruction of the connective matrix. At the molecular level, there is protein denaturation, from lytic enzymes, released by the rupture of the lysosome membrane, due to the action of phagocytes. Protein alteration is the starting point for the activation of a series of systems that synthesize and release substances such as histamine, serotonin, bradykinin, prostaglandins, leukotrienes, and various chemotactic factors, which are responsible for vasodilation, increased vascular permeability, leukocyte migration, and platelet aggregation, in addition to other manifestations of the acute inflammatory process. One of several characteristics that differentiate inflammation from infection is that the latter only exists in the presence of biological agents and microorganisms, which include bacteria, viruses, and fungi. The infectious process includes an inflammatory response of the body, but as seen, not every inflammatory process is caused by an infectious agent. An infection can be defined through Koch’s principles, which establish criteria for relating a specific microorganism to a given disease: (1) the organism is regularly found in disease lesions, (2) the organism can be isolated in colonies on a solid medium, (3) inoculation of this culture causes lesions in an experimental animal, and (4) the organism can be recovered from lesions in the animals. In the last 10 years, advances in molecular biology have led to a change in Koch’s postulates that link a particular characteristic of an organism to a particular disease: (1) the phenotype or characteristic

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should be associated with virulent strains of the microorganism and not with strains that are not virulent; (2) the specific inactivation of the gene associated with virulence, replacing the wild-type gene with a mutant, can lead to a measurable decrease in the pathogenicity of the microorganism; and (3) replacing the mutant gene with the wild-type gene can restore the pathogenicity of the organism. The infectious process can be didactically divided into the following stages: (a) Interactions between the agent and the host: The infectious agent can be exogenous, such as the flu virus or Pseudomonas bacteria, or endogenous, colonizing agents of the organism, which, for some reason, become pathogenic. (b) Tissue invasion: Penetration of the microorganism can occur through a rupture of the epithelial barrier or, in some situations, through the intact epithelium. The microorganism can also enter through inhalation and ingestion. (c) Dissemination: The microorganism propagates from the original site of entry to the adjacent or distant tissues. In any case, microorganisms only disseminate and proliferate if they overcome the host’s defenses. Dissemination depends on the anatomical factors of the host and also on the characteristics of the invading agent. (d) Tissue damage: The degree of tissue damage mainly depends on the pathogenicity of the invading agent. Damage due to the infectious process may be due to mechanical causes, cell death, pharmacological changes in metabolism, and exaggerated host responses. (e) Outcome: This is the end result of the entire process. It can culminate in elimination of the infectious agent, death, or chronic colonization of the host [19]. In COM, the bacterial flora found in the middle ear is mixed, deriving either from the upper aerodigestive tract and/or through tympanic perforation. The Gram-negative bacteria Pseudomonas aeruginosa and Hemophilus influenzae are the most frequently identified bacteria in patients with COM, whereas the Gram-positive bacteria Streptococcus pneumoniae and Staphylococcus aureus and anaerobic microorganisms are less frequent [20]. There is a correlation between the strain of bacteria present in the middle ear during an episode of infection and those found in the nasopharynx. In children with upper airway infections, the microbiota of the upper aerodigestive tract seems to be less biodiverse as compared with to that in children without infections. The presence of lower airway disease (asthma, for example) is also correlated with lower biodiversity of the middle ear microbiota. After an episode of AOM, the bacteria in the middle ear cleft and nasopharynx can form a biofilm, thus passing to a saprophytic state in the

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local mucosa. A few days after the initial infection, the biofilm matrix is matured by the pathogen. The formation of biofilms protects bacterial colonies and also increases their defense against host immunity and antibiotic treatments. Thus, it seems to play a role in the chronicity of otitis media [6, 21]. This imbalance in the local bacterial flora plays a decisive role in the pathophysiology and perpetuation of COM. More recently, vaccinations against Hemophilus influenzae and Streptococcus pneumoniae seem to have increased the relevance of other bacteria in this process. Alloiococcus otitidis and Turicella otitidis, previously considered normal participants of the middle ear flora, have now been detected as possible pathogens in COM, including helping in the formation of biofilms. Some bacteria seem to have the means of bypassing the host’s immune pathways. The presence of intracellular Gram-positive cocci in the middle ear of children with OME has already been verified, which could imply greater bacterial resistance and perpetuation of inflammatory cascades. Innate immunity is the first line of defense against these microorganisms. It consists of nonspecific barriers (that is, not directed at specific pathogens) that range from mucociliary flow to proinflammatory molecules. Among these, we highlight the role of lysozymes, defensins, complement factors, cytokines, and chemokines in the middle ear. Bacteria and viruses act as triggers for the activation of inflammatory mediators in the nasopharynx, auditory tube, and middle ear cleft. Cellular receptors, such as Toll-like receptors (TLRs), detect the presence of pathogenic antigens, triggering an immunoinflammatory cascade. Adding certain bacterial biofilms (mainly Pseudomonas aeruginosa and Staphylococcus aureus) to the innate immune system receptors that are in a state of upregulation results in the middle ear being in a constant inflammatory state. The clinical effects of this prolonged inflammation translate into what we call chronic otitis media [6, 22, 23]. As for humoral immunity, its role in fighting middle ear infection is mainly through immunoglobulin (Ig)A (present in the mucous membranes) and IgG (found in tissue plasmocytes). These molecules act by adhering to the bacterial wall, in a process called “coating.” One factor that could explain the colonization of P. aeruginosa in the middle ear clefts in COM is that this pathogen easily prevents the “coating” of immunoglobulins. Children with secretory COM seem to have deficiency in the local production of IgA, whose role in the defense of the middle ear mucosa is reduction of adherence and colonization of potentially pathogenic microorganisms. IgG facilitates the phagocytosis of microorganisms and stimulates the complement system. Some children with recurrent respiratory tract infections may also be deficient in specific IgGs, such as IgG2.

S. S. da Costa and R. da Costa Monsanto

However, an individual’s immune response and susceptibility to the chronicity of otitis media does not exclusively depend on the presence of microorganisms. Several other genetic and molecular factors as well as environmental exposure to pollution and cigarette smoke are well-established as an integral part of this process. External factors trigger the onset of an immune-mediated inflammatory cascade in the middle ear cleft. Models in rats also suggest that alterations in the recruitment of neutrophils and macrophages, as well as a deficient phagocytic function, seem to be linked to the prolongation of the inflammatory process in the middle ear. Deficiencies in the tympanic membrane plasminogen, in these specimens, lead to a deficient regeneration after an episode of tympanic perforation. On the other hand, inflammatory pathways that act in  local protection against microorganisms, when overexpressed, lead to a high secretion of cytokines that can also lead to tissue damage and chronicity of the otitis media process. Molecular biology techniques have identified several genes that act in the process of perpetuating the inflammation that occurs in AOM and its subsequent progression to COM. Middle ear inflammation caused by AOM reduces the availability of oxygen to the middle ear mucosa, perpetuating the inflammatory process through production of reactive oxygen species. Hypoxia is a trigger to the nuclear factor kappa B (NF-κB) pathway, releasing further inflammatory mediators such as vascular endothelial growth factor (VEGF), which increases neoangiogenesis, propagates inflammation, and results in production of exudates. This further results in the upregulation of inflammatory gene expression, propagating the inflammatory process and increasing the risks of development of COM. Individual variations in inflammatory response and gene expression also play a role in this process. Polymorphisms of the FBX011 and TGIF1 genes, for example, modulate transforming growth factor beta (TGF-β) expression during inflammatory processes. Interleukin (IL) regulatory genes have also been identified as participants in this process. In COM, polymorphisms of receptor regulatory genes, such as Toll-like and Nod-like, are also found in the middle ear mucosa that is in a state of upregulation. Overexpression of the inflammasome NLRP3 (nucleotide-binding domain, leucine-rich-­containing family, pyrin domain–containing-3), a subtype of the Nodlike receptor, results in alterations in the inflammatory ­pathway of IL-1β and IL-18. The IL-17 inflammatory pathway also appears to be more active in the mucosa of patients with COM and sinusitis. Its deregulation can lead to overexpression of cytokines and chronic inflammation in chronic mucosal diseases. IL-17 also appears to be increased in the effusions and peripheral blood samples from children with OME. The Toll-like receptor (TLR)-2 is capable of recognizing lipoproteins from Gram-positive bacteria and mediating

2  Otitis Media: Basic Concepts and Fundamentals

the inflammatory immune response. TLR-4, on the other hand, recognizes lipopolysaccharides, a cell membrane component of Gram-negative-bacteria present in the middle ear of patients with otitis media. It has been shown that the transtympanic injection of lipopolysaccharides into rat ears generates IL-1β production [24–26]. Conversely, some genes that mediate host innate immunity and signaling pathways, have anti-inflammatory properties and mediate middle ear regeneration after an acute inflammatory episode. The TGF-β pathway, for example, helps minimize a possible exaggerated inflammatory process, modulating the action of these proteins. The balance of molecular forces seems to be at the core of links that are still not well-understood in the pathogenesis of COM [27]. Mucins, which are highly glycosylated glycoproteins that are present in the granules of mucus-producing cells, can also prevent bacterial invasion in mouse ear models. Exposure of the human middle ear to live bacteria or bacterial lysates from S. pneumonia, non-typeable H. influenzae, and Moraxella catarrhalis induces regulation of mucin production via messenger RNA. These pathways are responsible for epithelial metaplasia that transforms the middle ear epithelium into mucus-producing cells. Pollution particles seem to have the same effect on the middle ear epithelium. In acute otitis media, the ossicles undergo an initial reabsorption and posterior remodeling process, which can alter their sound conduction capacity. The activity of osteoclasts responsible for bone remodeling seems to be mediated by lipopolysaccharides. Ossicular destruction in the middle ear of rats is much more strong when the osteoprotegerin cytokine receptor is absent. Some pathogens have the ability to bypass the round window barrier and cause migration of inflammatory cells to the scala tympani. Pneumococcus, for example, when producing the pneumolysin enzyme, caused tissue damage in the inner ear of examined rats [28, 29].

 evelopment, Anatomy, and Physiology D of the Middle Ear Phylogenetic Evolution of the Middle Ear Communication is a key factor in the interrelationship between numerous animal groups. This ability came about as the demands for survival in the environment led to the emergence and improvement of structures adapted for the production and capture of sound energy. Thousands of years of evolution have made this exchange of information indissoluble, at first rudimentary, but largely responsible for the perpetuation of these animals in the biosphere. The structures responsible for sound production and capture show a wide range of variations across species.

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Regarding the capture of sounds from the environment, the crucial moment in the refinement of the auditory system occurs when life-forms born in water start to inhabit the terrestrial environment. Thus, the sound waves previously captured through vibrations in the aquatic environment must overcome the resistance of a different medium, such as air, to be perceived. It was with the intention of improving this process that the evolution occurred from purely sensory structures in aquatic beings to those with much more elaborate auditory functions. Among fish, the sense of hearing is demonstrably more evolved in the teleost group, including carp, catfish, and goldfish, which have auditory structures somewhat similar to those of tetrapods [30]. These fish have developed the so-­ called swim bladder, which works as a hydrophone that captures sound waves transmitted by the water [31]. From the anterior portion of this organ arises pairs of bones derived from the ribs, called the Weberian ossicles, which transmit and amplify vibrations to the perilymphatic space adjacent to the sensory epithelium of the saccule, a rudimentary hearing organ, in addition to its role in maintaining the vestibular balance [30, 32, 33]. This ingenious primitive mechanism of transmission of sound vibrations to a sensorial epithelium through a true bone bridge finds an analogy with the tympanic membrane and middle ear ossicles found in tetrapods. Conversely, other fish have openings called spiracles, which open into the mouth to transport oxygen from the external environment, in addition to the hyomandibular bone, which is adjacent to the inner ear and participates in sound transmission from the aquatic environment [32]. Theoretically, during the evolutionary process, the spiracles gave way to the middle ear and the hyomandibular bone was modified in the columella found in amphibians [34]. Even in the most primitive amphibians, a tympanic membrane is found on the outer surface of the head. In the middle ear, a single bone (“columella”) connects the tympanic membrane to the inner ear. This bone is interposed between the superficial region of the head and the inner ear, and its most proximal portion has already been called stapes by some authors [35]. Similar to the eardrums of amphibians, in fish, communication takes place between the throat and the external environment through the spiracle, an orifice that is located adjacent to the hyomandibular bone and that transmits sound from the cranial vault to the inner ear [34]. This topographic location allows us to deduce the evolution of the spiracle into the auditory tube and middle ear chamber and the hyomandibular bone into the columella, as we find in most modern amphibians. In the most primitive reptiles, for example, lizards, some modifications have been observed. We observed that the columella remains isolated while communicating sounds to the inner ear, with no further involvement of the mandible bones. In addition, the columella can

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become complicated in its most external portion in the extracolumella when it becomes cartilaginous and adapts to the eardrum, thus playing the role of a sound-capturing organ. A small external depression is also observed, which would be an outline of the external acoustic meatus, compared to that found in more evolved vertebrates. In addition to a well-developed cochlea, mammals as a whole also have particularities in the middle ear. In this chamber, there are three typical ossicles, namely, the malleus, the anvil, and the stirrup, whose basic function is to conduct and amplify many times the vibrations captured from the air environment. Much was debated about the phylogenetic origin of such structures, until a joint study between comparative anatomy and paleontology clarified the issue. As already mentioned, primitive reptiles had two bones forming the mandibular joint: the quadrate and the articular. It seems that the first mammals developed other bones of their own for articulation, with which such elements were relegated to exclusive functions in the middle ear. The quadrate, conserving its connection with the eardrum, became the malleus, whereas the articulation placed between it and the stapes was modified into the incus [32]. The biggest stimulus for these changes seems to have been improving hearing in order to capture prey and escape from predators not in the direct line of sight. This was especially striking for the first mammals that survived the tyranny of reptiles in the Mesozoic era, when nocturnal behavior emphasized auditory and olfactory perception [36].

Embryology  he Middle Ear Cleft T Between the third and seventh months of gestation, four endothelial pouches evaginate from the first branchial arch to form the tympanic cavity. At the points where these bags come into contact, mucous folds and suspensory ligaments of the ossicles are formed, thus generating compartmentalization of the middle ear [37]. The middle sac, occasionally with a contribution from the anterior sac, forms the epitympanum, as described by Jackler [38]. It is divided into three saccules: anterior, middle, and posterior. The middle saccule forms Prussak’s space— bounded by Shrapnell’s membrane, the neck, and the lateral process of the malleus and the lateral malleolar fold—and the superior incudal space (laterosuperior to the malleus head and body of the incus) [38]. The posterior saccule pneumatizes the petrous portion of the mastoid cell system. The anterior saccule often gives rise to the anterior compartment of the epitympanum. At these times, the anterior and posterior epitympanic compartments are confluent and separated from the anterior mesotympanum by the tensor tympani fold. The anterior epitympanum

S. S. da Costa and R. da Costa Monsanto

can also derive from the saccus anticus when the anterior saccule delays its expansion in this direction. When this occurs, the saccus anticus—which is already responsible for the formation of the anterior mesotympanum and the anterior space of Von Trölscht—also forms the so-called supratubal recess that freely communicates with the protympanum, since the tympanic tensor fold is incomplete in these cases. The saccus superior forms the inferior incudal space (below the body of the incus) and proceeds to pneumatize the squamous portion of the temporal bone. The limit of mastoid pneumatization proceeding from the superior saccus—squamous—and from the saccus medius—petrous—may become evident as a bone plate known as the petrosquamous plate or Körner’s septum, a reference point in the posterior approach to the antrum. The saccus posticus forms the posterior mesotympanum and hypotympanum.

The Otic Capsule The embryological development of the otic capsule is no less complex, being unique in several aspects. In all bones of the human body, the ossification process takes place concomitantly with the deposition of new cartilage plates. In the otic capsule, however, this pattern is not followed since ossification takes place only after the cartilaginous matrix has reached its definitive stage. By the time the ossification of the otic capsule is complete, all inner ear structures must have reached their adult size since the bony framework thus formed does not allow for further growth. The other peculiarity of this region (and of the ossicles) is that the endochondral bone initially formed will never be removed and replaced by the Haversian periosteal bone, as occurs in other bones. In this way, it will continue throughout life as a relatively avascular bone, of stony consistency, poor in osteogenic responses and exhibiting discreet remodeling activity [39]. The first ossification center appears around the cochlea when it reaches the adult state around the 16th week. The last center appears around the semicircular canals in the 20th week of intrauterine life. Once initiated, ossification progresses at an accelerated pace until the 23rd week when it should be complete, except for a small area over the posterior semicircular canal and a reniform area around the oval window and the ante fenestram fissula [40].

The Ossicles In an 8-week-old embryo, the tympanic cavity corresponds to only the lower half of the future middle ear, and its upper half is completely filled with the mesenchymal tissue. The ossicles originate from small cartilaginous condensations found in the mesenchyme of the first and second branchial arches (hammer and incus predominantly of the first and stapes of the second branchial arch). Initially, the malleus,

2  Otitis Media: Basic Concepts and Fundamentals

incus, and cartilaginous mandible are interconnected as the Meckel’s cartilage of the first branchial arch, whereas the styloid process, hyoid bone, stapes, lenticular process of the incus, and malleus handle make up the so-called cartilage of the incus. Reichert’s cartilage is formed in the second branchial arch. The primitive ossicles quickly separate from the cartilages from which they originated and begin independent development. The ossicles, as well as the otic capsule and the labyrinth, grow only until the first half of intrauterine life when, then, they ossify each one from a single ossification center that appears in the 16th week in the incus, between the 16th and 17th weeks in the malleus, and in the 18th week of intrauterine life in the stapes. Interestingly, the hammer and anvil remain solid and structurally constant after the ossification process. The stapes, on the other hand, develops a curious process of erosion and remodeling right after its ossification. The result of this process is the less robust and a much more delicate appearance of the adult stirrup when compared to the fetal one.

Anatomy At the beginning of this chapter, we defined otitis media as an inflammatory process, infectious or noninfectious, located in the middle ear cleft. It is important to state that the term “middle ear cleft” should be preferred over “middle ear.” As we will discuss below, this deliberate substitution has precise clinicopathological reasons, echoing modern concepts of classification and pathogenesis of otitis, not constituting, therefore, just a semantic caprice. This concern makes sense when we verify that the dimensions of the middle ear have been inadequately compressed to the region subjected to otomicroscopic inspection. In other words, the universe of inflammatory and infectious alterations that are characteristic of this disease would be limited to the mesotympanum, which is clearly exposed through the transparency or even the absence of the tympanic membrane. It is clear that the middle ear is multi-compartmental and that the mesotympanum represents only one of these compartments; however, we note that the conception of this scope is facilitated with the introduction of a new concept, namely, the middle ear cleft, which includes the bony portion of the auditory tube in all its extension as well as its opening next to the protympanum. This association, which may even be debatable from a strictly anatomical point of view, makes sense insofar as this entire complex reacts en bloc when it is subjected to an insult of an inflammatory nature.

 he Middle Ear Cleft T When reviewing and summarizing the anatomy of this region, it is convenient to remember that it is represented by two aerated cavities, an anterior cuboid—the middle ear cleft

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with its three floors, epitympanum or attic, mesotympanum, and hypotympanum, and the tympanic portion of the auditory tube—and a grossly posterior pyramidal—the cell complex of the mastoid with its largest cell: the mastoid antrum. These cavities are continuous and are joined by a small triangular opening called an adyte. The upper boundary of the tympanic cavity is the tegmen tympani, a thin bony roof that separates it from the dura of the middle fossa, communicates inferiorly with another bony lamina in close relationship with the jugular gulf, anteriorly with the tympanic orifice of the Eustachian tube, which connects the middle ear with the nasopharynx, anteromedially with the vertical segment of the petrous portion of the internal carotid artery, posteriorly with the aditus, a passage that connects the upper floor of the tympanic cavity (the epitympanum or attic) with the cells of the mastoid, laterally with the tympanic membrane that separates it from the external auditory canal, and medially with the otic capsule that protects the inner ear and its two windows, oval and round, filled, respectively, by the footplate of the stapes and the membrane of the round window. In addition, the tympanic cavity has a set of small articulated bones, the ossicular chain, constituted by the malleus, incus, and stapes, which, attached to muscles and ligaments, transmits and amplifies the sounds that reach the tympanic membrane and are conducted to the eardrum through the oval window [41]. All the structures described above are covered by the respiratory epithelium, which modifies its ciliary and glandular histological structure according to the region it covers or the pathological alterations to which it adapts [41].

The Eustachian Tube The Eustachian tube consists of a canal comprised part by bone and part by fibrocartilaginous tissue that runs from the nasopharynx to the middle ear. The bony part and the fibrocartilaginous part are connected at the level of the isthmus, which is the narrowest part of the Eustachian tube, with an approximate diameter of 1.5 mm. Thus, the Eustachian tube has an hourglass shape, with its tympanic and nasopharyngeal orifices being much larger than the isthmus. In adults, the Eustachian tube is longer, more inclined, and narrower than in children, which seems to indicate one of the reasons why AOM is more frequent in childhood, when there would be less protection against infected nasopharyngeal secretions. While the bony part of the Eustachian tube is, under normal conditions, permanently open, the fibrocartilaginous portion is closed most of the times. The fibrocartilaginous portion opening mechanism involves a complex muscular contraction in which the tensor and levator palate muscles play a preponderant role [42, 43]. These muscles contract during physiological actions such as swallowing, which happens every minute when the individual is awake and every 5  min when sleeping, by reflex arc, as well as the act of yawning. This dilation causes air to pass from the nasophar-

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ynx to the middle ear cleft, renewing its air content and balancing its pressure with atmospheric pressure, thus keeping the tympanic membrane and ossicular chain in a balanced position, with minimum impedance. The fibrocartilaginous portion of the Eustachian tube can also be passively dilated, as in the act of sneezing or in the Valsalva maneuver when, regardless of muscle action, air is forced into the middle ear cleft. The Eustachian tube has three main functions (ventilation, drainage, and protection) that will be discussed below.

S. S. da Costa and R. da Costa Monsanto

10,000 mm of water (H2O) or 760 mm of mercury (Hg), and its composition at a temperature of 37 °C (when saturated by water vapor) is 150 mmHg of O2, practically zero CO2, and approximately 563  mmHg N2. The amount of water vapor present in one or another environment will dilute or concentrate the other gases in direct dependence on its degree of saturation and also on the function of the temperature where this system is found. The PP of gases present in the alveoli and the TP of inspired air are practically identical and in balance with those found in the arterial blood leaving the alveolar capillaries. As the blood transits the circulation toward Tubal Physiology the tissues, several changes occur in the composition of these gases. Thus, volumetrically speaking, O2 is consumed more Ventilation of the Middle Ear and the Mastoid proportionally at the cellular level than CO2 is produced [44]. As previously mentioned, the middle ear ossicles originated This difference can be expressed through a typical equation in vertebrates when they became terrestrial in order to or as the CO2/O2 respiratory quotient less than one (0.85). recover the loss of energy resulting from the passage of The PP of CO2 is also influenced by the lower solubility of sound from an air medium to a liquid medium or, in other this gas in tissues and blood when compared to O2. This words, to overcome the so-called interface of air–bone asymmetry between the solubility and the shape of the O2 impedances [34]. To fulfill this function properly, the tym- and CO2 saturation curves in the blood results in a sharp drop panic–ossicular system requires minimal friction between its in O2 levels and, on the other hand, in only a slight increase various components and the presence of a physically inert in the CO2 concentration in the transition from the arterial to environment. Such an environment is provided by the middle the venous compartment. For example, partial pressure of ear cleft, which is a structure analogous to a gas bag. oxygen (PO2) decreases from 102  mmHg in the alveoli to Biological gas sacs are not rare in the animal world, as they approximately 93  mmHg in arterial blood, plummeting to are present in a multitude of forms and with the most varied 38 mmHg in venous blood. On the other hand, partial presfunctions: birds have respiratory air sacs that can extend to sure of carbon dioxide (PCO2) has a slight increase from the bones in order to facilitate flight, fish have swim bladders 39  mmHg in the alveoli to only 44  mmHg in the venous with the function of floating, and mammals have intestines, level. Thus, while the metabolic consumption of oxygen paranasal sinuses, and tympanic cavities [34]. In fact, the causes the PO2 to decrease by 55 mmHg, the tissue producmiddle ear cleft and the Eustachian tube can be roughly com- tion of carbon dioxide raises the PCO2 by only 5  mmHg. pared to the lower airways, with the former representing a This difference corresponds to a gaseous pressure deficit sort of a “mini lung.” All these air bags face a common prob- found in the venous blood that circulates in the tympanic lem, which is the possibility of collapsing if they fail to com- cavity and with which this structure has to adapt. These PO2 pensate for pressure variations verified inside them caused and PCO2 variations between arterial and venous blood are by the continuous gaseous exchanges carried out with the not accompanied by corresponding changes in N2 levels adjacent circulation. A second problem characteristic of since this gas hardly participates in metabolic processes. As these structures is the absolute need to maintain their self-­ an example, the partial pressure of nitrogen (PN2) of alveolar cleaning properties. These two attributions, namely, ventila- air is 572 mmHg, whereas in the venous system, this number tion and drainage, and the overlapping function of protection, rises by only 3 mmHg (575 mmHg). Thus, the behavior of are carried out in the middle ear by the Eustachian tube [44]. the gases in the transition from alveolar air to the arterial and There are some general principles that regulate the so-­ then venous system will show a considerable drop in PO2, a called gaseous economy of the middle ear or any other bag slight increase in PCO2, and maintenance of PN2. of biological gas. The presence of a certain gas in a gaseous Consequently, the venous environment surrounding the environment is expressed in terms of its partial pressure (PP). ­middle ear has, at sea level, a TP lower than the atmospheric The sum of all the partial pressures of the gases that make up pressure found in the light of the tympanic cavity [44]. this mixture corresponds to the total pressure (TP) of this The particles of a gas have the tendency to transfer from environment. Under normal conditions of temperature and an environment of high pressure to that of low pressure until pressure, ambient air is composed of a combination of five the balance between these two systems is reached. This transgases: nitrogen (N2), argon (Ar), oxygen (O2), carbon diox- fer occurs in any permeable medium at rates specific to fluids, ide (CO2), and water vapor. The same gases are found in dif- tissues, blood walls, and epithelial surfaces. In this way, the ferent dilutions in blood, tissues and, obviously, in the gases that fill the tympanic cavity “strive” to find a balance tympanic cavity. Thus, the TP of ambient air at sea level is with the corresponding pressures in the adjacent venous cap-

2  Otitis Media: Basic Concepts and Fundamentals

illaries, which effectively happens in relation to water vapor, O2, and CO2 in the middle ear cleft. Under these conditions, when we provoke a perforation in the tympanic membrane, the gaseous content of the middle ear quickly becomes similar to atmospheric air. Just a few moments after the closure of this perforation, the middle ear’s gaseous concentration returns to find its balance point with the venous capillary system that surrounds it [44]. Assuming that the venous blood draining the middle ear has a gaseous PP and TP composition similar to that of the venous system, a steady state of equilibrium will finally be reached at slightly subatmospheric levels or around 56 mmHg (760 − 704 = 56). This theoretical composition would result in a pressure difference acting on the tympanic membrane (with an excess of 56 Hg external to it), which would be absolutely undesirable for the perfect functioning of the tympanic-ossicular mechanism. Thus, for the middle ear to obtain a TP equal to the atmospheric pressure, some physiological mechanism must be put into action, which effectively happens in the form of periodic openings of the Eustachian tube, causing the entry of an air bolus into the middle ear from the nasopharynx. As we discussed earlier, water and CO2 moving from the mucosa into the tympanic cavity lumen and diffusing in the opposite direction of O2 quickly equilibrate, leaving it to N2 (which diffuses poorly and remains longer in the CT light) to partially offset this pressure deficit of 56 mmHg. Due to its diffusion and solubility characteristics, N2 tends to present a higher PP in the middle ear than in blood, thus compensating for the discrepancy produced by the negative O2/CO2 equation. This extra dose of air that fills the middle ear and balances the extra- and intratympanic pressures is a direct consequence of the ventilatory function of the Eustachian tube. The amount of gas admitted (which occurs mainly during swallowing) is so proportionally small, when compared with the total amount of gas present in the light of the middle ear cleft, that the alterations in the PP of H2O, O2, and CO2 resulting from it are practically imperceptible. In other words, the act of swallowing does not significantly modify the PP of these gases in the middle ear cleft [44]. On the other hand, the gas that penetrates the middle ear in this way is not exactly the same as the atmospheric one (since it is slightly modified by expiration) presenting in its composition: 99 mmHg of O2, 36 mmHg of CO2, 47 mm of H2O, and 578 mmHg of N2. Thus, the main gas inhaled by the middle ear at each swallow is N2, which slowly diffuses into the adjacent circulation. As a result, a difference in the PP of N2 is consistently maintained between the middle ear cleft and the circulation with an excess of around 56 mmHg for the former. This PP difference (light × circulation) systematically transfers N2 molecules from the middle ear lumen to the circulation, consequently reducing the middle ear PN2 until a new gush of air penetrates via the Eustachian tube, fulfilling what we call the ventilatory cycle of the middle ear cleft [44].

13

Normally, this process repeats itself periodically at a rate directly proportional to the diffusion of N2. Even today, much is discussed in relation to the factors that positively or negatively modulate this rhythm. It has been suggested that the ventilatory function of the Eustachian tube is controlled by neuronal feedback circuits with sensory components capable of detecting both TP and PP alterations of the gases present in the middle ear and effector components that modulate the activities responsible for the opening of the Eustachian tube or the variation of peritubal pressures. Consubstantiating this hypothesis, a series of possible chemoreceptors and baroreceptors have been identified to be dispersed in the middle ear cleft. Likewise, afferent and efferent nerve pathways between the tympanic plexus and the respiratory subnucleus of the solitary tract, trigeminal motor nucleus, nucleus ambiguus, and peritubal musculature have been described in rabbits, cats, and chimpanzees [15, 45, 46]. Cantekin et al. [47] demonstrated that stimulation of the tympanic nerve in the middle ear of monkeys increased the electrical activity verified in the muscle fibers of the palate tensor in these animals. Shupak et al. [48], using animal models, confirmed these findings and showed that this electrical activity could be modified according to the concentration of different gases present in a gaseous mixture offered experimentally to these animals. Without the possibility of periodically renewing the air dispersed inside, all biological air pockets would definitely be doomed to collapse. In the middle ear cleft, a situation of negative pressure would imply, at first, a more dramatic repercussion on its only non-­ osseous wall: the tympanic membrane. In the tympanic membrane, these pressure deficiencies affect its dimer composition portion or the tympanic pars flaccida (Shrapnell’s membrane) more strongly. Thus, this small triangular fraction of the tympanic membrane in opposition to the rest of the eardrum, which is highly inelastic under normal conditions, would function as a legitimate mirror of intratympanic pressure variations. Even today, we have little information regarding the laws that govern the quantitative and qualitative physiological parameters of gas transfer from the nasopharynx to the middle ear. This lack of knowledge becomes critical as we wish to identify and compare operational ventilatory parameters in healthy and diseased ears. The volume of gas admitted in the middle ear cleft (which could be defined as the v­ entilatory coefficient) is equivalent to the product of the inhaled volume by the number of gaseous admissions per unit of time [44]. In humans, the Eustachian tube has a total length of around 4  cm and roughly resembles two conical portions joined by a narrow ring called the isthmus. The anterior and medial cone is formed by an elastic cartilage, which is collapsed most of the time. The posterior portion is bony and, therefore, rigid, when considered from a physiological point of view as an extension of the middle ear. These two portions

14

meet at the isthmus, which is an annular structure 1–2 mm long and 0.6–1.2 mm in diameter. The cartilaginous portion is actively opened through contraction of the tensor palatini muscle during swallowing, yawning, or lateral movements of the mandible. This opening is in the order of 0.2 ms every 1 or 2 min (for a total of 3–4 min over 24 h). In general, a gas moves from one environment to another according to the difference in pressure between these two environments. During its course through the Eustachian tube, the air column coming from the nasopharynx finds its point of maximum obstruction next to the tubal isthmus. For practical purposes, once the air passes the isthmic region, it is already inside the middle ear. As we will see later, the geometry of the Eustachian tube is peculiar in the sense that its ventilatory and drainage functions do not interfere with each other. Drainage is carried out through the ciliary beat that generates a current of mucus that follows from the tympanic cavity to the nasopharynx through the floor of the Eustachian tube, whereas ventilation is processed in the opposite direction and in the middle and upper floors of the Eustachian tube (unless they meet—if blocked by mucus due to acute or subacute inflammatory events). The amount of gas that passes through the isthmus is a direct function of the pressure difference existing between the nasopharyngeal and tympanic ends of the Eustachian tube, the time this channel opens, and its dimensions (length  ×  diameter). Elner [49] calculated that, under physiological and stable conditions, around 1–2 mL of gas penetrates the middle ear cleft every 24 h, a volume that would correspond to the daily gaseous loss from the middle ear lumen to the circulation. Even though there are small pressure fluctuations in the nasopharynx when we breathe, these variations are practically insignificant during swallowing and the consequent tube opening (1 mm H2O). Thus, the main, if not the only, difference in pressure between the Eustachian tube and the nasopharynx is due to the continuous loss of gas from the middle ear to the adjacent circulation. As seen, if the middle ear transfers between 1 and 2 mL of gas into the circulation daily, and around 1000 swallows are performed every 24 h, it is calculated that 1–2 μL of gas diffuses into the circulation at intervals of 1–2 min and that the same volume is retrieved from the nasopharynx with each swallow. It is worth mentioning that not all swallows open the Eustachian tube, and, likewise, even if this occurs, there are occasions when this opening does not transfer air to the CT. The magnitude of the difference in pressure between the middle ear and the nasopharynx (due to the loss of gas by diffusion, as already mentioned) is also directly proportional to the total dimension of the middle ear cleft (Eustachian tube orifice, meso-, hypo-, and epitympanum, aditus, antrum, and, mainly, the mastoid cell complex). In a system with the mastoid normally pneumatized (12  cm3), the difference in negative pressure resulting from the subtraction of 1–2 μL of gas due to diffusion is in the order of only 1–2 mm H2O. This

S. S. da Costa and R. da Costa Monsanto

difference is so small that it provides the ability to passively move an air current across the tubal isthmus (1 mm in diameter × 2 mm in length for a total volume of 1–3 μL) in a time interval of only 0.2 ms [44]. From these considerations, it is suggested that this transfer of air from the nasopharynx to the middle ear should not be an exclusive consequence of passive events but that active mechanisms may also play a role (supporting or even the main) in this scenario. Sadé [44] even proposed a theoretical model in this sense: when the palate tensor muscle contracts during swallowing or yawning, the cartilaginous portion of the Eustachian tube opens, thus creating a new volume with a pressure lower than that found in the nasopharynx or middle ear, and the air coming from the nasopharynx quickly occupies this new volume. In the second phase, the tubal walls, after muscle contraction, tend to return to their resting state and do so by practically pushing this new air pocket toward the isthmus. Another force that could help in this regard would be the contraction that happens just milliseconds after the palate elevator muscle. In this sense, this muscle (whose function is not yet fully elucidated) is larger than the tensor palate. Furthermore, it is located on the Eustachian tube floor and contracts for a much longer period of time (0.45 s). The existence of more than one operational mechanism in the equalization and maintenance of intra- and extratympanic pressures increases the degree of complexity of these functions. A logical and expected side effect of this refinement is the possibility of pathological phenomena interfering in several phases of these operations [2]. In other words, there is a need to identify and test a series of etiological variants (anatomical and/or functional) that are still little explored in the pathophysiology of the Eustachian tube and its most relevant consequences: otitis media.

Drainage The drainage function allows the flow of middle ear secretions toward the nasopharynx through the Eustachian tube. It is basically exercised by three factors, namely, the mucociliary flow from the middle ear to the nasopharynx, the air renewal mechanism of the ventilatory function that can mobilize secretions in the same direction, and the surface tension of the secretions themselves [41]. All living surfaces of an organism are covered by an epithelium whose purpose is to offer protection to the deeper tissues. The epithelium that is in contact with the outside world is our skin; those that cover the internal organs are the mucous membranes or their analogues. The inner surface of organs such as the intestines and lungs are lined by a modified mucosa with flat cells. The life span of the cells that form part of this protective lining is limited, and, when dead, they are automatically removed from the organ in question. In order to keep this epithelial mantle intact, the cells of the deeper layers begin to divide, replacing the first ones, until

2  Otitis Media: Basic Concepts and Fundamentals

they themselves mature and descend in a monotonously repetitive cycle. The anterior portion of the middle ear is covered by the respiratory epithelium whose cells live for a short time. Under inflammatory conditions, the epithelium differentiates with increased numbers of mucus-producing cells and hair cells. This occurs throughout the respiratory tract: nose, trachea, bronchi, etc. The excess of dead and desquamated cells must be constantly eliminated, otherwise it will accumulate and fill the cavity from where it originated. Nature has conveniently provided the middle ear cleft with a cleansing organ: the Eustachian tube. Both the middle ear cleft and the Eustachian tube are lined by a mucociliary system similar to that found in the trachea and bronchi. A thin layer of mucus produced by the secretory cells remains as a film on the surface of the cilia. These move synchronously, removing any middle ear debris similarly to a conveyor belt that travels through the Eustachian tube from the middle ear to the nasopharynx. The composition and consistency of this mucus layer is critical to the functioning of this entire self-­ cleaning mechanism. As an example, if a small particle of charcoal is placed in the anteroinferior part of the headland, through a perforation in the tympanic membrane, one can observe this particle being propelled toward the opening of the Eustachian tube. Although this mucociliary “belt” system transports mucus unidirectionally from the middle ear via the Eustachian tube to the nasopharynx, some microorganisms can travel in the opposite direction and reach the middle ear cleft from the nasopharynx. The mechanism used by these microorganisms to reach the middle ear is one of the many issues that needs to be completely elucidated in the pathogenesis of otitis media. The resulting inflammatory reaction, otitis media, leads to the formation of an inflammatory exudate and usually causes cells to synthesize more mucus than usual. Again, this phenomenon is analogous to tracheobronchitis, or nasal secretions, produced during a common cold. Long-lasting inflammation induces the middle ear mucosa to differentiate, through metaplastic processes, into a typically secretory epithelium (cylindrical, ciliated, pseudo-­ stratified, rich in goblet cells and submucosal glands), which, in turn, synthesizes greater amounts of mucus than under normal physiological conditions. In fact, some of these histopathological findings are found even in healthy ears since, at some point in life, they have been subjected to inflammatory insults. Only animals reared in germ-free conditions are completely devoid of such glands, cysts, or previous evidence of inflammation. This metaplastic alteration, with the consequent increase in mucus production, may cause it to completely fill the middle ear. The excessive presence of mucus in the respiratory tree can be easily eliminated by coughing or, in the case of the nasal cavity, by sneezing. However, through the narrow Eustachian tube, it is not possible to cough or sneeze, and, so, these secretions can accu-

15

mulate inside the AF for several months. Why large amounts of mucus are not rapidly cleared from the middle ear by ciliary beating is still an intriguing question today, especially since cilia, although microscopic in size, are biologically quite robust organelles. Mechanical (adenoid) and functional tubal obstructions, changes in the rheological characteristics of secretions, primary or secondary ciliary dysfunction, mucus plugging, negative pressure, and vacuum are some of the hypotheses already tested in this regard. It is our conviction that the course developed by middle ear inflammatory processes from their most incipient phases to chronification can be compared to a theatrical play with a few main actors, several supporting characters, and countless extras. The latter, when analyzed separately, lack greater importance, but as a whole they acquire significance and are absolutely essential in triggering the entire process.

Protection The protective function comprises defending the middle ear from sounds, especially from contaminated secretions from the nasopharynx. This objective is achieved by the fact that the Eustachian tube remains closed, opening only quickly during swallowing. On the other hand, it has an ascending path, making contamination in this direction difficult due to gravity, and a narrow isthmus that by capillarity protects the passage of secretions in the ascending direction. In addition, the air column inside it also makes it difficult for secretions to pass through. As its direction is from the middle ear to the nasopharynx, the mucociliary flow contributes to the protective function. This protective mechanism, however, can be overcome in some circumstances, such as positive pressure in the nasopharynx, which occurs when blowing your nose, sneezing, and crying. It should be remembered that swallowing, in the presence of severe nasal obstruction, also creates positive pressure in the nasopharynx when the palate contracts. Minor Eustachian tube obstructions that create moderately and slowly progressive negative pressure in the middle ear can lead to aspiration of nasopharyngeal secretions into this cavity. This does not happen when the obstruction is complete and of sudden installation because then the negative pressure contributes even more to aggravate the obstruction that caused it. In children, because they have a wider, more horizontal, and shorter Eustachian tube, the protective function is less effective. The fact that children spend more time lying down and younger ones eat in this posture ­facilitates the reflux of secretions and food into the middle ear. The vulnerability of the Eustachian tube in children has been identified as one of the factors responsible for the high incidence of AOM in this age group [41].  eration of the Middle Ear Cleft A Proctor [50] demonstrated that despite the fact that the middle ear cleft has its aeration ensured by the Eustachian tube,

16

the paths taken by the air currents inside the tympanic cavity are narrow and sinuous. A series of mucous folds, ligaments, and parts of the ossicles make up the so-called tympanic diaphragm, practically separating the mesotympanum from the epitympanum and mastoid. This diaphragm comprises the head of the malleus, the body of the incus, the lateral and medial incudal folds, the anterior and lateral malleolar folds, and the tensor tympani fold. Only two narrow passages—the anterior and posterior tympanic isthmuses—pass through this diaphragm. The anterior isthmus is larger and more consistent, lying medially to the body of the incus, passing between the states and the tendon of the tensor tympani. When the medial incudal fold is present, a small posterior isthmus appears between this fold and the posterior tympanic wall. As previously mentioned, in less than 10% of individuals, the anterior epitympanum can be formed from the saccus anticus, opening a second air channel between the two compartments. From the point of view of embryological anatomy, the tympanic isthmus corresponds to an area where the structures of the first and second branchial arches come together, through which the first pharyngeal pouch extends to the extrabranchial region.

Epidemiology AOM has an annual incidence rate of 10.8 episodes per 100 people per year. There are a number of factors that influence the incidence patterns among different locations, with the most critical one being socioeconomic conditions: developed regions (such as central Europe) have an average AOM incidence of 3.6 episodes per 100 people/year, whereas in less developed areas (such as sub-Saharan West Africa and Central Africa), the incidence rises up to 43.4/100 people/year [4]. Although AOM can affect people of all age groups, the peak of maximum prevalence occurs at the age of 4 years. Children are the most at risk in the first year of life, with an incidence of 45.3 episodes of AOM per 100 children per year [4]. The incidence and prevalence of otitis media with effusion (OME) might be even higher than those of AOM. Studies have shown that by the age of 3 years, virtually all children will have had experienced at least one episode of OME [6, 51, 52]. The peak of incidence/prevalence of chronic suppurative otitis media (CSOM), differently from than AOM and OME, has a less clear pattern: children 10  mbar), the neurosensory reflex loop implements gas exchanges essentially at the level of the mastoid and of the opening of the fibrocartilaginous Eustachian tube, depending on the intensity of the initial stimulus. There is a true specialization of the sensors as well as of the effectors. In this isobaric system, the fibrocartilaginous Eustachian tube and the mastoid are capable of active counter-regulation of the middle ear cleft pressure variations and function in a complementary way where the tube is related to the intermittent regulation of higher pressures (it is a security valve) and where the mastoid is related to the continuous regulation of smaller pressures, especially of climatic origin. In the isobaric system of the middle ear cleft, the key point is the “neuronal reflex arc,” based on a mechanism that is highly sensitive to a pressure gradient between the middle ear cleft and the ambient environment, on the one hand, and on an

Fig. 7.1  Schematic representation of the middle ear cleft isobaric system

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effector process of pressure balancing, on the other hand—a neural feedback control similar to the respiratory control and related to similar central centers in the nucleus of the solitary tract of the brainstem [22–24]. The afferent plexus of the “neuronal reflex arc” are the mechanoreceptors, barosensors, located in the epitympanum and antrum, the pars flaccida, and those located in the pharyngeal recess and the posterior rhino pharyngeal wall. The efferent plexus of the “neuronal reflex arc” are the tubal muscles, resulting in tube opening, and the blood vessels of the mastoid mucosa, regulating middle ear cleft gas exchanges. In normal conditions, i.e., in a healthy mucosa, when a pressure gradient between the middle ear cleft and the ambient environment is detected, two distinct and combined patterns contribute to maintain near-ambient pressures in the middle ear cleft, namely, the tubal opening with steep intermittent changes in pressure against 0 Pa and mastoid-related changes in pressure, which are gradual and appear in both negative and positive directions and which could transverse 0 Pa into opposite pressures. These gradual pressure changes by gas exchanges are related to the perfusion of the mastoid mucosa (Table 7.1). The “neuronal reflex arc” of the isobaric system of the middle ear cleft can be reeducated, an extremely important property in the clinical management of gas and pressure disorders in the middle ear cleft [25, 26].

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B. Ars and D. Estève

Table 7.1  Schematic characterization of the middle ear cleft isobaric system effectors System type

Starting point Baroreceptor sensitivity (innate character)

Center Level of intervention

Type of response after implementation Effects on middle Ear/blood gas concentration Circumstances of implementation

Gas exchanges Isobaric function Sensory reflex loop then neuro-muscular and neuro-vascular with common barostatic integrating center Pars flaccida of the Tubal ridge area tympanic membrane Ruffini corpuscles (TM) ∆P ≥ 10 mbar and Stretch receptors high pressure rise ∆P > 0.1 mbar and low slope pressure rise slope Inferior salivary nucleus Immediate Tubal opening: early, late, or absent (areflexia) Slow Fast Maintained balance

Imbalance

Works permanently

Only if there is middle ear cleft barotrauma risk

Acknowledgment We thank Professor Jean Lebacq for thoroughly reviewing this chapter.

References 1. Ars B, Ars-Piret N. Morpho-functional partition of the middle ear cleft. Acta Otorhinolaryngol Belg. 1997;51:181–4. 2. Ars B, Ars-Piret N. Morpho-functional partition of the middle ear cleft. Mediterranean J Otol. 2007;3:31–9. 3. Ars B, Ars-Piret N.  Middle ear pressure balance under normal conditions. Specific role of the middle ear structures. Acta Otorhinolaryngol Belg. 1994;48(4):339–42. 4. Ars B. Physiology of Eustachian tube dysfunction. In: Suddhoff H, editor. Eustachian tube dysfunction. 2nd ed. Bremen: UNI-MED Verlag; 2017. p. 23–33. 5. Tideholm B.  Middle ear cleft pressure. In: Ars B, editor. Fibrocartilaginous Eustachian tube—middle ear cleft. The Hague, The Netherlands: Kugler Publications; 2003. p. 99–112. 6. Kania R.  Modélisation expérimentale et mathématique des échanges gazeux transmuqueux de l’oreille moyenne en conditions normales et inflammatoires. Thèse de doctorat de l’Université de Paris VI; 2006. p. 155. 7. Poe D. Pathophysiology and surgical treatment of Eustachian tube dysfunction. Academic dissertation, University of Helsinki; 2011. p. 74.

8. Ars B, Decraemer W, Ars-Piret N. The lamina propria and cholesteatoma. Clin Otolaryngol. 1989;14:471–5. 9. Estève D.  Tubomanometry and pathology. In: Ars B, editor. Fibrocartilaginous Eustachian tube-middle ear cleft. The Hague, The Netherlands: Kugler Publications; 2003. p. 159–17. 10. Ars B, Wuyts F, Van de Heyning P. Histomorphometric study of the normal middle ear mucosa. Preliminary results supporting the gas exchange function in the postero-superior part of the middle ear cleft. Acta Otolaryngol (Stockh). 1997;117:704–7. 11. Matanda R, Van de Henning P, Bogers J, Ars B.  Behaviour of middle ear cleft mucosa during inflammation: histomorphometric study. Acta Otolaryngol (Stockh). 2006;126:905–9. 12. Ars B, Dirckx J, Ars-Piret N, Buytaert J.  Insights in the physiology of the human mastoid: message to the surgeon. Int Adv Otol. 2012;8(2):296–310. 13. Padurariu S, Röösli C, Røge R, Stenshalle A, Vyberg M, Huber A, Gaihede M. On the functional compartmentalization of the normal middle ear. Morpho-histological modeling parameters of its mucosa. Hear Res. 2019;378:176–84. 14. Gussen R. Pacinian corpuscules in the middle ear. J Laryngol Otol. 1970;84:71–6. 15. Lim DJ. Human tympanic membrane. An ultrastructural observation. Acta Otolaryngol. 1970;70:176–86. 16. Nagai T, Tono T. Encapsuled nerve corpuscules in the human tympanic membrane. Arch Otolrhinolaryngol. 1989;246:169–72. 17. Salburgo F, Garcia S, Lagier A, Estève D, Lavieille JP, Montava M.  Histological identification of nasopharyngeal mechanoreceptors. Eur Arch Otorhinolaryngol. 2016;273:4127–33. 18. Nagai T, Nagai M, Nagata Y, Morimitsu T. The effects of anesthesia of the tympanic membrane on Eustachian tube function. Arch Otorhinolaryngol. 1989;246:210–2. 19. Estève D, Dubreuil C, Vella Vedova C, Normand B, Laveille JP, Martin C.  Physiology and physiopathologie of the Eustachian tube opening function: interest of tubomanometry. J F ORL. 2001;50:233–41. 20. Kanagasuntheram R, Wong WC, Chan HL.  Some observations on the innervation of the human nasopharynx. J Anat. 1969;104:361–76. 21. Guindi GM.  Nasopharyngeal mechanoreceptors and their role in auto regulation of endotympanic pressure. ORL J Otorhinolaryngol Relat Spec. 1981;43:56–60. 22. Eden AR. Neural connections between the middle ear, Eustachian tube and brain. Implications for the reflex control of middle ear aeration. Ann Otol Rhino Laryngol. 1981;90:566–9. 23. Eden AR, Gannon PJ. Neural control of middle ear aeration. Arch Otolaryngol Head Neck Surg. 1987;113:133–7. 24. Eden AR, Laitman JT, Gannon PJ. Mechanisms of middle ear aeration: anatomic and physiologic evidence in primates. Laryngoscope. 1990;100:67–75. 25. Ars B.  Chronic otitis media. In: Ars B, editor. Pathogenesis oriented therapeutic management. The Hague, Amsterdam: Kugler Publications; 2008. p. 355. ISBN13: 978 6299 216 4. 26. Kania R, Ars B.  In: Kania R, Ars B, editors. Biofilms in otitis. The Hague, Amsterdam: Kugler Publications; 2015. p. 363. ISBN 978-90-6299-243-0.

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The Role of Immunity in the Development of Otitis Media Sara Concha and Rodrigo Hoyos-Bachiloglu

 art I: The Role of Innate and Adaptive P Immunity in Otitis Media The term “immunity” comes from the Latin word immunitas, which refers to the protection from legal prosecution offered to Roman senators during their tenures in office. The immune system is responsible for protecting an organism against foreign substances, especially infectious microbes, and also products of damaged cells [1]. A normal immune response against microbes involves sequential and coordinated responses by different branches of the immune system (Table 8.1). Innate immunity is essential for the defense against microbes during the first few hours or days after infection, is mediated by mechanisms that are in place even before an infection occurs, facilitates rapid responses to the invading microbes, and stimulates adaptive immunity. Innate immunity detects microbial infections using pattern recognition receptors (PRRs) that are specific to molecules shared by groups of related microbes (pathogen-associated molecular patterns (PAMPs)). Adaptative immunity is stimulated by exposure to infectious agents and generates pathogen-specific immune responses, and it also has significant receptor diversity and memory. Immunological memory allows the adaptive system to increase in magnitude and defensive capabilities with each successive exposure to a particular agent.

Innate Immunity The innate system is composed of cellular and chemical barriers such as the skin, mucosal epithelia, antimicrobial peptides, blood proteins, including the complement system, and cells like macrophages and neutrophils.

S. Concha (*) · R. Hoyos-Bachiloglu Department of Pediatric Immunology and Infectious Diseases, Pontificia Universidad Católica de Chile, Santiago, Chile e-mail: [email protected]; [email protected]

Table 8.1  Components of innate and adaptive immunity Epithelial and chemical barriers

Blood proteins Cells

Innate •  Mucociliary apparatus •  Mucous glycoproteins • Surfactants • Defensins, interferons, lactoferrin, and nitric oxide • Middle ear epithelial cells Complement • Neutrophils • Macrophages •  Mast cells •  Dendritic cells

Adaptive Epithelial lymphocytes and antibodies

Antibodies •  Lymphocytes T  –  CD4     Th1     Th2     Th17  –  CD8 •  Lymphocytes B

 pithelial and Chemical Barriers E Mucosal immunity constitutes the first line of defense against respiratory pathogens in the respiratory tract. Epithelial cells of the middle ear contain several key defense mechanisms such as the mucociliary apparatus, the trapping function of mucous glycoproteins and surfactants, and the ability to secrete innate defense molecules such as defensins, interferons, lactoferrin, and nitric oxide [2]. Mucins are high-molecular-weight glycoproteins responsible for the viscous properties of middle ear effusion [3]. Although mucins are important components of innate immunity in the respiratory tract, they can also play a pathological role. Abnormally high levels of mucins have been demonstrated in middle ear effusions of chronic suppurative otitis media (OM) patients, preventing the transmission of sound waves and leading to conductive hearing loss. The upregulation of some mucin genes such as MUC2, MUC5AC, and MUC5B plays an important role in the pathogenesis of otitis media [2]. Surfactant proteins (SPs) such as SP-A are expressed in the middle ear and Eustachian tube and play an important role in innate responses through opsonization and comple-

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 M. V. Goycoolea et al. (eds.), Textbook of Otitis Media, https://doi.org/10.1007/978-3-031-40949-3_8

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ment activation. SP-A opsonizes Gram-negative bacteria and modulates the expression of pro-inflammatory cytokines like interleukin (IL)-1β, IL-6, and tumor necrosis alpha (TNF-α). The immune function of SP-A in vivo has been studied using mouse models of otitis media, which demonstrated its role in enhancing bacterial phagocytosis and modulating middle ear inflammation [4]. Defensins are cationic proteins, whose main antimicrobial mechanisms are forming a pore in the microbial membrane and stimulating the production of pro-inflammatory cytokines and chemokines. Human B-defensin 2 and 3 are upregulated in the middle ear in response to bacteria and play a critical role in eliminating Haemophilus influenzae (Hi) [5, 6]. Middle ear epithelial cells express PRRs such as Toll-like receptors (TLRs) that detect infections by recognizing PAMPs and activate the innate immune response. Peptidoglycans such as those on the surface of Haemophilus influenzae (Hi) are recognized by TLR2; upon biding to its ligand, TLR2 initiates nuclear factor kappa B (NF-κB)dependent cascades that activate the immune response and upregulate TLR2 expression in a positive feedback loop [7, 8]. Polymorphisms of the TLR4 gene are associated with recurrent acute OM. When infected with Hi, TLR4 knockout mice had a worse mucosal immune response, with impairment of phagocytosis and phagosome maturation of polymorphonuclear cells as compared to wild-type mice [9]. Additional genes involved in the innate immunity have been found to be differentially regulated in acute otitis media (AOM)-prone children compared to healthy-age appropriate controls. Downregulation of TLR adaptor molecule 2 was found in middle ear fluid of 24 children with acute otitis media [10]. TLRs are not the only PRRs involved in the pathogenesis and recovery of otitis media; Nod-like receptors (NLRs) have also been shown to initiate and support robust immune responses through the production of inflammatory cytokines and recruitment of leukocytes to the middle ear [11]. Finally, impairment of epithelial and chemical barriers in otitis-prone children has been observed. They have lower capacity for epithelial repair, lower pro-inflammatory neutrophil chemoattractants such as macrophage inflammatory protein-1β (MIP-1β), IL-8, and CXCL5 [12], and pro-­ inflammatory cytokines of higher levels such as IL-2 and lower levels such as IL-7, IL-6, and IL-10 in nasal washes, thus showing that middle ear cytokine responses mirror those of the nasal mucosa versus the peripheral blood and suggesting that proximal mucosal sites may better predict the quality of middle ear responses compared to peripheral blood [13].

 he Complement System T The complement system consists of several plasma proteins that work together to opsonize microbes, promote recruit-

S. Concha and R. Hoyos-Bachiloglu

ment of phagocytes to the sites of infection, and, in some cases, directly kill the microbes [1]. There are three pathways of complement activation, among which the most important for responding to capsulated bacteria is the classical pathway, which is one of the major effector mechanisms of the humoral arm of adaptive immune responses.

Cells Neutrophils are the most abundant leukocytes and the first line of defense against invading pathogens in the middle ear, experiencing roughly a 600-fold increase during acute otitis media [14]. They express multiple TLRs and play a crucial role in eradicating middle ear infections [2]. Upon activation, they form neutrophil extracellular traps (NETs) that are positively correlated with higher bacterial loads within middle ear fluids and surface-attached bacteria and contribute to effusion viscosity, thus leading to chronic suppurative otitis media [15]. Macrophages are also present in middle ear effusions, and their role in infection depends on the causative agent. Streptococcus pneumoniae serotypes 14 and 19F were found to be resistant to phagocytosis that can lead to bacterial antigens being trapped in the middle ear, thus promoting effusion [2]. Haemophilus influenzae utilizes a system of phase-variable epigenetic regulation, to facilitate adaptation and survival by evading opsonization, the process by which it is marked for destruction by macrophages [16]. Mast cells are distributed throughout the tubotympanum, predominantly in the pars flaccida, and can trigger allergic rhinitis, thus causing persistent inflammation that can lead to tube dysfunction and also impediment of mucociliary function that can lead to recurrent otitis media with effusion [17]. A possible role of mast cells and their cytokines in the pathogenesis of chronic serous otitis media has been suggested as these cells are increased in the patient’s adenoid tissue and in thymic stromal lymphopoietin [18]. A normal tympanic membrane also contains abundant dendritic cells that have the potential to migrate and activate T cells. A significant increase in the number of these cells has been found in tubotympanic disease and in atticoantral disease, with the difference being more pronounced in the latter form of otitis media [19].

Adaptive Immune Responses The adaptive immune system is composed of T and B lymphocytes and their products. There are two branches of adaptive immunity, namely, humoral immunity, which is mediated by antibodies and B cells, and cell-mediated or cellular immunity mediated by T cells.

8  The Role of Immunity in the Development of Otitis Media

Humoral Immunity A humoral immune response combats microbes in many ways. Antibodies bind to microbes and prevent them from infecting cells, thus neutralizing the microbes. In fact, antibody-­mediated neutralization is the only mechanism of adaptive immunity that stops an infection before it is established; this is why eliciting the production of potent antibodies is the key goal of vaccination. Immunoglobulin (Ig)G antibodies coat microbes and target them for phagocytosis because phagocytes (neutrophils and macrophages) express receptors for parts of IgG molecules. Both IgG and IgM activate the complement system, and complement products promote phagocytosis and destruction of microbes. IgA is secreted from mucosal epithelia and neutralizes microbes in the lumens of mucosal tissues, such as the respiratory and gastrointestinal tracts, thus preventing inhaled and ingested microbes from infecting the host [1]. There are differences between children and adult’s humoral immunity, and the susceptibility of infants to AOM wanes with age due to immunological maturation. During pregnancy, IgG antibodies are passively transferred to the infant and progressively decrease during extrauterine life, reaching their lowest point at 6 months of life. The production of IgM and IgA begins progressively from birth. The capacity to respond to protein antigens is approximately 80% at birth and achieves levels like those of adults around 3 months of life. The ability to respond to polysaccharide antigens is not optimal until 2 years of life due to the absence of B cells in the marginal zone of the spleen [1]. For the normal development of humoral immunity, a correct development of B cells and a normal interaction of these with circulating T lymphocytes is necessary. Developing antibody-mediated immunity to Streptococcus pneumoniae and non-typeable Hi (NTHi), the two most common pathogens causing AOM, is a cardinal step in preventing recurrent infections in young children. Upon receiving T cell help, B lymphocytes that recognized an antigen proliferate and differentiate into plasma cells that secrete different classes of antibodies with distinct functions. Polysaccharides and lipids stimulate secretion mainly of the antibody class called immunoglobulin M (IgM). Protein antigens induce the production of antibodies of different classes (IgG, IgA, IgE) from a single clone of B cells. Otitis prone children have lower serum bactericidal antibody titers against pneumococcal proteins: histidine triad protein D (PhtD), pneumococcal choline binding protein A (PcpA) and pneumolysin (PlyD1) compared with nonotitis prone children after nasopharyngeal colonization and acute otitis media [20]. This may be due to poor memory B-cell and T-helper cell generation associated with reduced levels

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of pneumococcal-specific IgG in the serum after the infection [21]. Comparing acute to convalescent antibody titers after AOM, otitis-prone children had no significant change in total IgG responses to three Hi proteins (protein D, P6, and OMP26), whereas non-otitis-prone children had significant increases in protein D. Anti-protein D, P6, and OMP26 antibody levels measured longitudinally during Hi colonization between the ages of 6 and 24  months demonstrated subtle anti-protein D IgG increases over time in otitis-prone children compared to more than fourfold increases in non-otitis-­ prone children [22]. The raise in the antibody’s levels in non-otitis-prone children probably prevents them from having recurrent otitis.

Cellular Immunity T lymphocytes consist of two functionally distinct populations: helper T cells or CD4+ cells and cytotoxic T lymphocytes (CTLs) or CD8+ cells. The functions of helper T cells are mainly mediated by secreted cytokines, whereas CTLs produce molecules that directly kill other cells. CD4+ T cells comprise functionally distinct populations characterized by specific transcription factors and cytokine profiles; T helper 1 (Th1), Th2, and Th17 [1]. Antigen-specific CD4+ T cells have been shown to reduce Streptococcus pneumoniae nasopharyngeal colonization. An effective pathogen-specific T-cell response in adults has been associated with protection from invasive Streptococcus pneumoniae disease (invasive pneumococcal disease, IPD) and chronic obstructive pulmonary disease (COPD) caused by Streptococcus pneumoniae and NTHi, respectively. More recently, Th17 cells have been described to mediate antibody-­ independent protection in a mouse model of pneumococcal infection. Moreover, CD4+ T cells in samples collected from the adenoids and tonsils of traditionally defined otitis-prone children showed no proliferation in response to NTHi protein P6, which led the authors to conclude that otitis-prone children lack pathogen-specific T cells. [23] Other authors have shown that adenoids have a reduced capacity to produce interferon-gamma (IFN-γ) and speculate that this alteration could cause susceptibility to recurrent acute otitis media [24]. For several decades, Pichichero et al. studied the underlying pathogenesis of AOM in children and also why the risk of AOM decreases over time. They observed that this susceptibility is not only due to a Eustachian tube dysfunction but also due to immune factors [13]. Peripheral blood mononuclear cells (PBMCs) from otitis-prone children between the ages of 6 and 12  months display a general skewing away from Th1 and Th17 immunity and toward Th2 and regulatory T cell (Treg) dominance [25]. This abnormality was largely outgrown by 3 years of age, coinciding with the epidemio-

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logical observation of diminishing AOM at that age [13]. They also showed that otitis-prone children are more frequently diagnosed with viral upper respiratory infections possibly due to deficient antiviral responses at the nasopharynx with decreased production of pro-inflammatory cytokines and chemokines like IL-6, IL-10, and TNF-α [26].

Part II: The Ear Microbiota The microbiota plays critical roles in the regulation and development of the major components of the host’s immune system, whereas the immune system orchestrates the maintenance of the key features of the host–microbe symbiosis [27]. The human microbiota consists of ecological communities of commensal, symbiotic, and pathogenic microorganisms that colonize several body sites and play a critical role in the regulation of many homeostatic processes, including inflammation and defense against pathogens, to inhibit the colonization and growth of otopathogens [28]. Immediately after birth, the respiratory tract becomes colonized, and, in the first week of life, there is a predominance of Staphylococcus spp., Corynebacterium, Dolosigranulum, and Moraxella. This early bacterial colonization plays a pivotal role in the stability of microbial communities: profiles dominated by Moraxella and Dolosigranulum/Corynebacterium are associated with a stable microbiota and with lower rates of respiratory infections in later stages of life, whereas the less stable profiles are associated with a high abundance of Hi and Streptococcus [29]. Several environmental factors can influence the shaping of the microbiota’s composition in the first years of life. Children born by vaginal delivery have predominance of bacteria previously associated with microbiome stability and respiratory health, but some authors suggest that this impact disappears at 6 weeks of age. Breastfed infants develop a bacterial profile enriched by Dolosigranulum and Corynebacterium at 6 weeks of age in comparison with formula-­ fed infants; however, this effect also disappears around 6 months of age. In children with AOM, recent antibiotic therapy induces a reduction of beneficial bacteria such as Streptococcaceae and Corynebacteriaceae and an increased abundance of Enterobacteriaceae and Pasteurellaceae in the upper respiratory tract. The effect of the conjugated pneumococcal vaccines in the microbiome is controversial and it seems to vary by ethnicity; Swiss vaccinated children have an increase in beneficial bacteria and in bacterial diversity, whereas in children from Gambia, vaccination reduced the nasopharyngeal carriage of vaccine serotypes, but pneumococcal carriage remained high among

S. Concha and R. Hoyos-Bachiloglu

vaccinated infants, probably because of an immediate expansion of non-vaccine serotypes [30]. According to the pathogen reservoir hypothesis (PRH), the adenoid pad serves as a source of pathogens that can grow in this region and further spread to the respiratory system and middle ear, leading to infections and diseases [31]. Owing to the introduction of culture-independent techniques such as gene analysis with a polymerase chain reaction (PCR) using primers that target a segment of the 16SrRNA gene, microbiological investigations now allow the knowledge of entire bacterial communities. There are keystone species that maintain the balance and function of the bacterial community such as Dolosigranulum spp. and Corynebacterium spp. In children, a diverse microbiota and a higher relative abundance of Corynebacterium, Dolosigranulum, Propionibacterium, Lactococcus, and Staphylococcus were associated with a lower incidence of S. pneumoniae, H. influenzae, and Moraxella catarrhalis colonization, lower AOM, a shorter course of AOM, and a better clinical outcome [30]. An unstable microbiota during an acute respiratory tract infection episode with the predominance of otopathogens is associated with the occurrence of a symptomatic viral infection and with a higher risk of transition to otitis, whereas children with asymptomatic viral infections had no predominance of otopathogens [32]. There are several trials of probiotic administration for prevention of middle ear diseases in children, but there is lack of evidence for their use [33].

References 1. Abbas A, Lichtman A, Pillai S. Cellular and molecular immunology, vol. 1. Elsevier; 2019. p. 1–2. 2. Mittai R, Kodiyan J, Gerring R, Mathee K, Li J-D, Grati M, et al. Role of innate immunity in the pathogenesis of otitis media. Int J Infect Dis. 2014;0:29–267. 3. Mittal R, Grati M, Gerring R, Blackwelder P, Yan D, Li JD, et al. In vitro interaction of Pseudomonas aeruginosa with human middle ear epithelial cells. PLoS One. 2014;9(3):1–11. 4. Abdel-Razek O, Ni L, Yang F, Wang G.  Innate immunity of surfactant protein A in experimental otitis media. Innate Immun. 2019;25(7):391–400. 5. Jones EA, McGillivary G, Bakaletz LO. Extracellular DNA within a nontypeable Haemophilus influenzae-induced biofilm binds human beta defensin-3 and reduces its antimicrobial activity. J Innate Immun. 2013;5(1):24–38. 6. Lee HY, Takeshita T, Shimada J, Akopyan A, Woo JI, Pan H, et al. Induction of beta defensin 2 by NTHi requires TLR2 mediated MyD88 and IRAK-TRAF6-p38MAPK signaling pathway in human middle ear epithelial cells. BMC Infect Dis. 2008;8:87. 7. Chen R, Lim JH, Jono H, Gu XX, Kim YS, Basbaum CB, et  al. Nontypeable Haemophilus influenzae lipoprotein P6 induces MUC5AC mucin transcription via TLR2-TAK1-dependent p38 MAPK-AP1 and IKKβ-IκBα-NF-κB signaling pathways. Biochem Biophys Res Commun. 2004;324(3):1087–94. 8. Shuto T, Imasato A, Jono H, Sakai A, Xu H, Watanabe T, et  al. Glucocorticoids synergistically enhance nontypeable Haemophilus

8  The Role of Immunity in the Development of Otitis Media influenzae-induced toll-like receptor 2 expression via a negative cross-talk with p38 MAP kinase. J Biol Chem. 2002;277(19):17263– 70. https://doi.org/10.1074/jbc.M112190200. 9. Hirano T, Kodama S, Fujita K, Maeda K, Suzuki M. Role of Toll-like receptor 4 in innate immune responses in a mouse model of acute otitis media. FEMS Immunol Med Microbiol. 2007;49(1):75–83. 10. Kaur R, Casey J, Pichichero M.  Differences in innate immune response gene regulation in the middle ear of children who are otitis prone and in those not otitis prone. Am J Rhinol Allergy. 2016;30(6):e218–23. 11. Lee J, Leichtle A, Zuckerman E, Pak K, Spriggs M, Wasserman SI, et  al. NOD1/NOD2-mediated recognition of non-typeable Haemophilus influenzae activates innate immunity during otitis media. Innate Immun. 2019;25(8):503–12. 12. Verhoeven D, Nesselbuch M, Pichichero M. Lower nasopharyngeal epithelial cell repair and diminished innate inflammation responses contribute to the onset of acute otitis media in otitis-prone children. Med Microbiol Immunol. 2013;202(4):295–302. 13. Pichichero M.  Immunologic dysfunction contributes to the otitis prone condition. J Infect. 2020;80(6):614–22. 14. Morris MC, Pichichero ME.  Streptococcus pneumoniae burden and nasopharyngeal inflammation during acute otitis media. Innate Immun. 2017;23(8):667–77. 15. Simon D, Simon HU, Yousefi S. Extracellular DNA traps in allergic, infectious, and autoimmune diseases. Allergy Eur J Allergy Clin Immunol. 2013;68(4):409–16. 16. Robledo-Avila FH, Ruiz-Rosado JD, Partida-Sanchez S, Brockman KL.  A bacterial epigenetic switch in non-typeable Haemophilus influenzae modifies host immune response during otitis media. Front Cell Infect Microbiol. 2020;10(October):1–15. 17. Quaranta N, Iannuzzi L, Gelardi M. Does the type of rhinitis influence development of otitis media with effusion in children? Curr Allergy Asthma Rep. 2014;14(11):1–5. 18. Kumral TL, Dikker O, Yıldırım G, Karaketir S, Altındağ C, Çakın MC, et  al. The role of thymic stromal lymphopoietin in the development of chronic otitis media with effusion. Eur Arch Otorhinolaryngol. 2021;279:1937. https://doi.org/10.1007/ s00405-­021-­06995-­z. 19. Jacob TM, Indrasingh I, Yadav BK, Rupa V. Langerhans cells in the human tympanic membrane in health and disease: a morphometric analysis. Otol Neurotol. 2013;34(2):325–30. 20. Xu Q, Casey JR, Newman E, Pichichero ME. Otitis-prone children have immunologic deficiencies in naturally acquired nasopharyngeal mucosal antibody response after streptococcus pneumoniae colonization. Pediatr Infect Dis J. 2016;35(1):54–60. 21. Sharma SK, Casey JR, Pichichero ME.  Reduced serum IgG responses to pneumococcal antigens in otitis-prone children

79 may be due to poor memory B-cell generation. J Infect Dis. 2012;205(8):1225–9. 22. Kaur R, Casey J, Pichichero M. Serum antibody response to three non-typeable Haemophilus influenzae outer membrane proteins during acute otitis media and nasopharyngeal colonization in otitis prone and non-otitis prone children. Vaccine. 2011;29(5):1023–8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3624763/pdf/ nihms412728.pdf. 23. Sharma S, Pichichero M. Cellular immune response in young children accounts for recurrent acute otitis media. Curr Allergy Asthma Rep. 2013;13(5):495. 24. Avanzini AM, Castellazzi AM, Marconi M, Valsecchi C, Marseglia A, Ciprandi G, et  al. Children with recurrent otitis show defective IFNγ-producing cells in adenoids. Pediatr Allergy Immunol. 2008;19(6):523–6. 25. Surendran N, Nicolosi T, Kaur R, Pichichero ME. Peripheral blood antigen presenting cell responses in otitis-prone and non-otitis-­ prone infants. Innate Immun. 2016;22(1):63–71. 26. Ren D, Xu Q, Almudevar AL, Pichichero ME.  Impaired proinflammatory response in stringently defined otitis-prone children during viral upper respiratory infections. Clin Infect Dis. 2019;68(9):1566–74. 27. Zheng D, Liwinski T, Elinav E. Interaction between microbiota and immunity in health and disease. Cell Res. 2020;30(6):492–506. https://doi.org/10.1038/s41422-­020-­0332-­7. 28. Peterson J, Garges S, Giovanni M, McInnes P, Wang L, Schloss JA, et  al. The NIH Human Microbiome Project. Genome Res. 2009;19(12):2317–23. 29. Paradise JL, Rockette HE, Colborn DK, Bernard BS, Smith CG, Kurs-Lasky M, et al. Otitis media in 2253 Pittsburgh-area infants: prevalence and risk factors during the first two years of life. Pediatrics. 1997;14(1):121–8. 30. Folino F, Ruggiero L, Capaccio P, Coro I, Aliberti S, Drago L, et al. Upper respiratory tract microbiome and otitis media intertalk: lessons from the literature. J Clin Med. 2020;9(9):1–27. 31. Nistico L, Kreft R, Gieseke A, Coticchia JM, Burrows A, Khampang P, et al. Adenoid reservoir for pathogenic biofilm bacteria. J Clin Microbiol. 2011;49(4):1411–20. 32. Lappan R, Imbrogno K, Sikazwe C, Anderson D, Mok D, Coates H, et  al. A microbiome case-control study of recurrent acute otitis media identified potentially protective bacterial genera. BMC Microbiol. 2018;18(1):1–20. 33. Scott AM, Clark J, Julien B, Islam F, Roos K, Grimwood K, et al. Probiotics for preventing acute otitis media in children. Cochrane Database Syst Rev. 2019;2019(6):CD012941.

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When to Suspect and How to Evaluate Immune Deficiencies in Otitis Media Sara Concha and Rodrigo Hoyos-Bachiloglu

 art I: General Features of Inborn Errors P of Immunity (IEI) Immunodeficiencies are clinical situations where there is a quantitative or functional deficiency of the immune system. They can be divided into two main groups based on their ontogeny. Secondary immunodeficiencies include conditions such as surgical asplenia, prematurity, human immunodeficiency virus (HIV) infection, malnutrition, hematological diseases, autoimmune diseases, and metabolic diseases such as diabetes and can result from various immunosuppressive drugs. Inborn errors of immunity (IEI), also referred to as primary immunodeficiencies (PIDs), are caused by mutations affecting genes involved in the normal functioning of the immune system. Although recurrent infections are the main symptoms of such conditions, PIDs have a broad spectrum of clinical presentations even for the same genetic defect (Table 9.1). An underlying immunodeficiency should be considered not only in patients presenting with frequent infections but also in those with infections lasting for a longer duration than usual, severe infections, infections with a poor response to antibiotic treatment, complicated infections, and infections due to unusual, multiple, or opportunistic microorganisms (Table 9.2). Noninfectious manifestations of an underlying PID can be extremely broad and include severe allergic diseases like eczema and food allergies, recurrent skin inflammation, oral ulcers, autoimmunity (most frequently autoimmune cytopenias), and lymphoproliferative diseases amongst others [1]. IEI are caused by monogenic germline mutations that result in loss of expression and/or loss of function or gain of function of the encoded protein. This results in aberrant immunity due to the critical roles that these proteins play in the development, maintenance, and function of cells of the immune system or cells other than

S. Concha (*) · R. Hoyos-Bachiloglu Department of Pediatric Immunology and Infectious Diseases, Pontificia Universidad Católica de Chile, Santiago, Chile e-mail: [email protected]; [email protected]

leukocytes that contribute to immunity, during homeostasis and in response to external (e.g., infectious agents or environmental antigens) and internal (e.g., cytokines, self-­ antigens, and cancer cells) stimuli [2]. For a long time, IEI were consider rare diseases, but with the technological advances in genetics leading to improved diagnostic capabilities, the number of IEI has increased in more than 200 new conditions over the past 10 years and their incidence is now estimated to be around 1:1000 to 1:5000 in newborns [3]. In the last International Union of Immunological Societies (IUIS) classification of 2019, 404 phenotypes with 430 known genetic defects were included and they were separated into 10 groups (Table 9.1) [2]. In the last few years, there has been great advances in the development of new methods to expedite the identification of defects of the immune system and the cellular, molecular, and genetic aberrations underlying these conditions. Sequencing in general and next-generation sequencing (NGS) techniques are becoming technically more accurate, fast, and affordable and are therefore widely available to researchers and physicians [1]. A new insight into the pathogenesis of IEI has introduced targeted treatments next to substitution and symptomatic therapy (immunoglobulin replacement, antimicrobial and anti-inflammatory or immunosuppressive treatments), on one side, and replacement of the flawed immune system by hematopoietic stem cell transTable 9.1 Inborn errors of immunity: International Union of Immunological Societies (IUIS) classification of 2019   1. Immunodeficiencies affecting cellular and humoral immunity   2. Combined immunodeficiencies with associated or syndromic features   3. Predominantly antibody deficiencies   4. Diseases of immune dysregulation   5. Congenital defects of phagocyte number or function   6. Defects in intrinsic and innate immunity   7. Autoinflammatory disorders   8. Complement deficiencies   9. Bone marrow failure 10. Phenocopies of inborn errors of immunity

© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 M. V. Goycoolea et al. (eds.), Textbook of Otitis Media, https://doi.org/10.1007/978-3-031-40949-3_9

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plantation (HSCT) or gene therapy, on the other [4]. This has improved not only the survival rate but also the quality of life of these patients.

 art II: When to Suspect IEI in Patients P with Recurrent Otitis Media Otitis media is one of the most common diseases in young children. The decrease in the occurrence of otitis with age is explained by the transitioning of the Eustachian tube’s anatomy by 3–5 years of age to a more “adult-like” structure and also by the maturation of the immune system [5]. In most children, otitis will not reveal a deficient immune system beyond physiological immaturity; however, it can be the first sign of a congenital disorder and unrecognized immunodeficiencies can lead to severe and potentially fatal infections. Recurrent otitis, with more than 4 episodes in a year, has been established as the first of the 10 warning signs of EIE in children by the Jeffrey Modell Foundation and the American Red Cross (Table 9.2). In adults, the European Society for Immunodeficiencies (ESID) advise suspecting IEI in case of four or more infections treated with antibiotics in 1 year (otitis, bronchitis, sinusitis, pneumonia) and ­recurrent infections needing prolonged therapy with antibiotics [6]. Although the number of infections is an important warning sign, the most important red flag is a family history of IEI. This feature has proven to be the key warning sign suggesting the presence of IEI and, as such, should be actively investigated when evaluating a patient with recurrent infections, including patients with recurrent otitis media [7]. Bardou et al. have proposed four warning signs for underlying IEI in otitis media: progressing infections leading to mastoiditis, associated abscesses or systemic infections, lack of responsiveness to adequate antibiotic treatment, and occurrence of unusual, severe, or frequently relapsing infections in other sites [6] (Table 9.3). Table 9.2  Warning signs of primary immunodeficiency   1. Four or more new ear infections within 1 year   2. Two or more serious sinus infections within 1 year   3. Two or more months on antibiotics with little effect   4. Two or more pneumonias within 1 year   5. Failure of an infant to gain weight or grow normally   6. Recurrent, deep skin or organ abscesses   7. Persistent thrush in the mouth or fungal infection on the skin   8. Need for intravenous antibiotics to clear infections   9. Two or more deep-seated infections, including septicemia 10. A family history of primary immunodeficiency

Table 9.3  Warning signs to investigate inborn errors of immunity in otitis 1. Otitis media evolving with mastoiditis, abscesses or systemic infections 2. No response to appropriate antibiotic therapy 3. Otitis media associated with other infections 4. Recurrent otitis, leading to failure to thrive and general developmental delay 5. Family history of primary immunodeficiency and/or consanguinity

Part III: IEI Presenting with Otitis Media Otitis media and pneumonia are the main infectious manifestations of IEI, with up to 57% of patients reporting having otitis media [8]. We will detail those IEI most frequently associated with otitis media.

Antibody Deficiencies Antibodies are antigen-specific proteins produced by B cells and are synthesized and secreted by plasma cells, which arise from terminally differentiated B cells. They neutralize toxins and viruses, prevent colonization by pathogenic organisms, opsonize bacteria and fungi, activate the complement cascade, which enhances opsonization, and may directly lyse Gram-negative bacteria. Most patients with primary antibody deficiencies present with recurrent, severe, or persistent bacterial infections of the sinopulmonary tract, including recurrent otitis media, sinusitis, and pneumonia most commonly secondary to Streptococcus pneumoniae, Hemophilus influenzae, Staphylococcus, and Pseudomonas. Diarrhea affects up to 25% of these patients, often caused by Giardia lamblia infection [9]. Of the nine IEI categories, predominantly, antibody deficiency has the highest prevalence (1:25,000), but, despite advances in genomics, utilizing the current gold standard of whole exome sequencing for diagnosis, pathogenic gene variants are only identified in less than 20% of patients, especially in nonconsanguineous populations [10]. They are classified into four groups: 1. Severe reduction in all serum immunoglobulin isotypes with profoundly decreased or absent B cells, agammaglobulinemia Agammaglobulinemia is defined by the complete or near absence of B cells (less than 1%) and severe reduction of all major serum immunoglobulin isotypes (immunoglobulin (Ig)G, IgM, IgA). Clinical onset is typically

9  When to Suspect and How to Evaluate Immune Deficiencies in Otitis Media

within the first year(s) of life and is characterized by recurrent infections, mainly by encapsulated bacteria, which may affect the respiratory and gastrointestinal tracts, the skin, the joints, and the central nervous system [11]. The most common IEI in this group is X-linked agammaglobulinemia (XLA) due to Bruton’s tyrosine kinase (BTK) deficiency, which plays a critical role in precursor B-cell development in the bone marrow [12]. The incidence of XLA is around 1:100,000 to 1:200,000 depending on ethnicity [11]. Clinical symptoms in affected patients initiate between the age of 6 and 12 months, when the maternal IgGs are catabolized; however, some patients may remain asymptomatic in the first years of life. Recurrent bacterial respiratory and/or gastrointestinal infections are the hallmarks of this disorder. The most frequent type of upper respiratory tract infection in large cohorts of XLA patients is otitis media (70%), followed by sinusitis (almost 60%). Recurrent otitis media may be the only infectious manifestation prior to diagnosis in XLA patients and should therefore always be considered as an alarm sign for immune deficiency during routine clinical practice [13]. Other frequent infections are pneumonia and gastrointestinal infections due to Giardia lamblia, the mycoplasma species, and enteroviruses. They also present with autoimmunity and up to 20% may develop arthritis. In a limited number of cases, gross deletions encompassing BTK and TIMM8A (translocase of inner mitochondrial membrane 8A) have been associated with sensorineural hearing loss in the first year of life, even though the underlying pathogenic mechanisms are not known [14]. Immunoglobulin replacement therapy is fundamental in XLA as in all humoral immunodeficiencies. Maintaining pre-infusion IgG levels >500 mg/dL assures a notable reduction in the number of infections. Using a dose of 400  mg/kg/dose every 3–4 weeks (in the case of intravenous immunoglobulin (IVIG)) or 100 mg/kg/dose every week (in the case of subcutaneous immunoglobulin) is usually sufficient to maintain such levels [15]. Frequently, antibiotic prophylaxis is necessary in order to control the number of infections even when IVIG therapy is adequate [11]. 2. Severe reduction in at least two serum immunoglobulin isotypes with a normal or low number of B cells, common variable immunodeficiency (CVID) phenotype CVID is a heterogeneous condition in which there is reduction of serum IgG by two or more standard deviations (SDs) below the mean age, along with a reduction of at least one of the other two isotypes (IgA or IgM) and with poor-to-absent specific antibody responses to an infection or vaccination [11]. Bonilla and coworkers, in an international consensus document in 2016, proposed that the main diagnostic criteria should also include the onset of immune deficiency after 2 years of age and that

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Table 9.4  Diagnostic criteria for probable common variable immunodeficiency (CVID) International consensus document CVID Male or female patient who has a marked decrease of IgG (at least 2 SD below the mean age), a marked decrease in either IgM or IgA, and fulfills all of the following criteria: 1. Onset of immune deficiency at greater than 2 years of age 2. Absent isohemagglutinins and/or poor response to vaccines 3. Defined causes of hypogammaglobulinemia have been excluded

European Society for Immunodeficiencies (ESID) criteria for CVID Male or female patient older than 4 years with at least one of the following: increased susceptibility to infection, autoimmunity, granulomatous disease, unexplained polyclonal lymphoproliferation, and/or affected family member with antibody deficiency AND marked decrease of IgG and marked decrease of IgA with or without low IgM levels (measured at least twice;  2 (p = 2.6 × 10−3) LOD > 2 (p = 3.0 × 10−3) p = 9.1 × 10−7

5p15.33

Allen et al. [59]

p = 0.045

2q31.1

Allen et al. [59]

p = 1.3 × 10−5

the pathogenic variants responsible for OM susceptibility remain unknown. This is partly due to the lack of genetic studies performed in families with OM and potentially due to genetic heterogeneity for OM where families carry variants within multiple genes that are mostly rare or private variants, such that current family cohorts lack the power to detect ­significant OM loci. Below is a review of loci that have been mapped using families with OM.

19q13.42–q13.43 Daly et al. (2004) first identified the 19q13.42–q13.43 region as a suggestive susceptibility locus (LOD 2.61, p = 5.3 × 10−4) using genotype data from Minnesotan families with OM [32]. Approximately 100 annotated genes are present in this region, but many of their functions remain unknown. The leukocyte receptor cluster (LRC) genes were suggested as potential candidate genes within the 10q locus. Within this region are genes encoding the leukocyte Ig-like receptor (LIR; also known as Ig-like transcripts) and the killer cell immunoglobulin-like receptor (KIR), which are transmembrane proteins expressed on cells of immune function for various protein activation or inhibition [33]. Such proteins include tyrosine phosphatases Src homology region 2 domain-containing phosphatase (SHP)-1 and/or SHP-2 [34]. This region was replicated by Chen et al. (2011), who fine-­ mapped the locus to chromosome 19q13.43 using additional single nucleotide variant genotypes (LOD 3.75,

Significance and candidate genes within the loci Presumed to be involved in the gene–gene interaction between 19q13.42 and 10q26.3 HRH1—an inflammatory mediator [195] IRAK2—mediates inflammatory gene expression via NF-κB [196] Adaptor-related protein complex2, beta 1 subunit (AP2B1)—CD8+ downregulation [198]Chemokine C–C motif ligand (CCL)—recruitment of eosinophils [199] SFTPA2—part of surfactant protein A, which regulates the phagocytosis of pathogens; expressed in the Eustachian tube [45] – – – – KIF7—the region is related to the splice site; regulates sonic hedgehog [200] and Indian hedgehog [64] via protein trafficking TICRR—initiation of DNA replication [65] Tubulin polymerization-­promoting protein (TPPP)—located at the intron; affects microtubule function [63] Non-coding region: possible role in the regulation of LDLR (ch19), which is expressed in ciliated airway epithelial cells [201]

p = 1.6 × 10−5) [35]. The additional candidate genes identified within the 19q locus include genes related to zinc fingers, the tumor necrosis factor-alpha (TNFα), bone morphogenetic protein (BMP), and fibroblast growth factor-­ beta (FGFβ) pathways, lymphocyte activation, and the inflammasome protein complex, all of which regulate innate immunity in response to harmful stimuli [35–37].

10q26.3 In an initial linkage study for OM using the Minnesota family cohort, the 10q26.3 locus was identified with a LOD score of 3.78 (p = 3.0 × 10−5) and was replicated in another cohort of Western Australia-based trios by Rye et al. in 2014 (Zlr 2.69, p = 3.6 × 10−3) [32, 33]. Herein, trios are composed of the OM-affected individual (proband) and both parents, without affected or unaffected siblings. Within the 10q26.3 locus, the Minnesotan and Australian studies identified candidate genes encoding a disintegrin and metalloproteinase (ADAM) domain. ADAM8 is found in leukocytes in response to allergen exposure in asthma and is also upregulated in epithelial cells of the airway during allergic inflammation [38, 39]. The function of ADAM12 is most strongly associated with cell adhesion and fusion, extracellular matrix restructuring, and cell signaling [40]. It has been found to be upregulated in the middle ear in response to tobacco smoke [41]. Other genes implicated in this region include DOCK1 (MIM 601403), which is involved in phagocytosis; TCERG1L

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encoding transcription elongation regulator-like protein, and PPP2R2D (MIM 613992), which modulates the modulator of the transforming growth factor (TGF)/Activin/Nodal pathway [33, 42, 43].

10q22.3 Chromosomal region 10q22.3 has also been identified (LOD >2, p  =  1.81  ×  10−3) and replicated with suggestive evidence (Zlr 1.64, p = 0.05), though not reaching statistical significance [2, 33]. SFTPA1 (MIM 178630) and SFTPA2 (MIM 178642) are genes within this region that together encode the human surfactant protein (SP-A) and have previously been implicated in OM [44]. SP-A haplotype and genotype variations have been observed in children with the first episode of OM before 6 months, and common variants in these genes were associated with protection against OM in infants at risk of asthma [45, 46]. SP-A is expressed in the middle ear mucosa and in the Eustachian tube and is known to ­contribute to innate immune responses by increasing the phagocytosis of otopathogens [45–48].

Candidate Gene Association Studies Using a gene of interest, candidate gene association studies estimate the frequency with which the minor allele, or the less prevalent allele in the background population, is found in OM-affected patients in comparison to a control group. Healthy or unaffected individuals that are related to the OM-affected

patients within the same families, or unrelated healthy individuals with no previous history of OM, may be used as controls (case–control study). Numerous studies have been conducted, particularly using candidate genes, relating to inflammation and innate immune responses, but many candidate gene studies will not lead to a significant association when a more stringent threshold for genome-wide significance is applied. Nonetheless, some genes that were initially identified in smaller case–­control association studies, such as the HLA and ABO (MIM 110300) genes, were also deemed significant loci in genome-wide association studies (GWASs) for OM [49–56].

Genome-Wide Association Studies (GWASs) A GWAS is currently the starting point in identifying the loci of interest. It assesses the association of variants spread throughout the genome with the trait or disease under investigation and, in contrast to candidate gene association studies, does not assume an association between a locus of interest and the trait. Instead, a GWAS employs an agnostic approach to identifying the loci of interest, which may be a regulatory variant often found in the non-coding region, a haplotype encompassing variants that are inherited together, or a gene harboring multiple rare variants associated with the trait. For OM, a series of GWASs have been conducted using common variant genotypes from microarrays, with each describing independent findings (Table 10.2). With advances

Table 10.2  Otitis media susceptibility genes identified from genome-wide association studies Study Rye et al. 2012 [33]

SNP 2,524,817

Cases 416

Significant associationsa rs6755194 (p  =  8.3 × 10−7) rs1862981 (p  =  2.2 × 10−5)

829

Controls Cohort 1075 Western Australian Pregnancy Cohort (Raine) Study 229 University of Minnesota [20] University of Pittsburgh [24] 2118 Finnish

Allen et al. 2013 [59]

324,748

373

Einarsdottir et al. 2016 [66]

964,193

van Ingen et al. 2016 [70]

460,000

825

7936

rs2932989 (p = 4.4 × 10−8) rs3767498 (p = 1.25 × 10−6) rs12725646 (p = 4.3 × 10−5) rs255142 (p = 1.9 × 10−6) rs9514552 (p = 2.1 × 10−5) rs12888576 (p = 7.8 × 10−6) rs2809139 (p = 3.2 × 10−6) rs8036951 (p = 3.8 × 10−5) rs10409140 (p = 4.4 × 10−5)

European-descent Americans

rs1110060 (p = 9.1 × 10−7) rs10497394 (p = 1.5 × 10−8) rs10775247 (p = 6.3 × 10−5) rs16974263 (p = 1.8 × 10−7) rs268662 (p = 1.6 × 10−6) rs4150992 (p = 3.4 × 10−6)

Candidate genes CAPN14 GALNT14 BPIFA gene cluster KIF7 TICRR TPPP PLD3 SERTAD1 SERTAD3 HIPK4 PRX BLVRB FNDC1 KIF21B CACNA1S ASCL5 Intergenic region near MIR205HG CRHR2 INMT ARGLU1 BDKRB2 Intergenic region near C14orf177 FAM189A1 TPM4

10  Genetics and Otitis Media

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Table 10.2 (continued) Study Pickrell et al. 2016 [49]; Tian et al. 2017 [53]

SNP 560,000– 950,000

Cases Controls Cohort 46,936 74,874 European-descent Americans

Significant associationsa rs681343 (p = 3.5 × 10−30) rs1978060 (p = 1.2 × 10−19) rs2808290 (p = 5.1 × 10−16) rs7174062 (p = 3.5 × 10−14) rs4329147 (p = 9.6 × 10−12) rs8176643 (p = 3.7 × 10−11) rs1802575 (p = 1.5 × 10−10) rs5829676 (p = 1.8 × 10−10) rs72931768 (p = 2.6 × 10−9) rs35213789 (p = 3.8 × 10−9) rs114947103 (p = 5.4 × 10−9) rs13281988 (p = 9.8 × 10−9) rs67035515 (p = 1.6 × 10−8) rs73015965 (p = 3.8 × 10–8)

Candidate genes HLA genes Several intergenic regions FUT2 ABO TBX1 MKX AUTS2 CDHR3 PLG

 p-values in bold font indicate those that passed the genome-wide significant thresholds of the study

a

in computational efficiency, continuous decline in the cost of sequencing, and increasing availability of large-scale biobank data with genotypes and OM phenotypes, the discovery of additional novel findings from GWASs, which include both common and rare variants, is possible in the near future. In the first GWAS on OM, Rye et  al. (2012) used data from Australian trios and identified three novel candidate genes/gene clusters, namely, (1) rs6755194 within chromosome 2p23.1, which is either upstream of or intronic to two isoforms of CAPN14 (MIM 610229); (2) rs1862981, also located on 2p23.1, intronic to GALNT14 (MIM 60822) and proximal to CAPN14; and (3) BPIFA clusters, including BPIFA1 (MIM 607412), BPIFA2, and BPIFA3 on the genomic region 20q11.21 [57]. However, these findings could not be replicated in an independent cohort [58]. Other genes identified in this study with trends toward association were linked to the TGF-β pathway [57]. In the Minnesota-based cohort, Allen et al. (2013) identified an intergenic locus rs10497394 between the genes CDCA7 (MIM 609937) and SP3 (MIM 601804) on 2q31.1, which was subsequently replicated in an independent Pittsburgh-based US cohort as being associated with both chronic OM with effusion and recurrent acute OM [59]. This locus was found to regulate the expression of LDLR (MIM 606945) on chromosome 19, a gene that is expressed in ciliated epithelial cells of the airway with its transcribed protein predicted to be a binding site for human rhinovirus C, a known pathogen for upper respiratory tract infections and OM [60]. Newer data from the Genotype-Tissue Expression (GTEx) database showed that the rs10497394 variant significantly regulates RNA levels of CDCA7 in thyroid and arterial tissues; however, GTEx does not include data from middle ear tissues [61]. CDCA7 mutations cause immunodeficiency, centromeric instability, and facial anomalies syndrome (MIM 616910), wherein hypoor agammaglobulinemia leads to recurrent life-threatening

infections [62]. Additional loci on chromosomes 5 and 15 (rs386057, rs1110060, and rs10775247) were also identified but did not reach genome-­wide significance in the replication study [59]. The genes affected by these three variants are involved in microtubule function, regulation of mammalian sonic hedgehog and Indian hedgehog pathways, and DNA replication [63–65]. Einarsdottir et al. (2016) found three variants, all on chromosome 19, to be associated with childhood OM in the Finnish population [66]. None of the identified regions overlapped with those previously found in association with OM on chromosome 19. Genome-wide significance was established for rs16974263, a variant intronic to the PRX (MIM 605725) gene, which was found in association with chronic OM with effusion in a UK cohort, albeit with opposite directions of effect [66]. Out of the several genes identified within this region are three candidate genes, PLD3 (MIM 615698), SERTAD1 (MIM 617850), and BLVRB (MIM 600941), which are previously known to be associated with immune function with expression found in macrophages [67, 68]. In the GTEx database, the rs16974263 variant regulates either the RNA levels or splicing of isoforms for SERTAD3, HIPK4 (MIM 611712), PLD3, and PRX in various tissues [61]. In particular, SERTAD3 is expressed in the mucosal tissue and its protein inhibits the replication of influenza A virus upon induction by type I interferon responses during an infection [61, 69]. Additional studies in Americans of European-descent identified genome-wide significance for a variant on chromosome 6 (rs2932989) that alters the methylation status of the gene encoding fibronectin type III domain containing 1 (FNDC1, MIM 609991) [70]. Although its function is not clearly elucidated, the study found an upregulation of this gene in the middle ear tissue under pro-inflammatory conditions [70]. Other candidate genes from suggestive loci largely contained those related to immune responses.

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Finally, 14 genome-wide significant loci were identified by Pickrell et al. (2016) and Tian et al. (2017) using GWAS data from 23&Me [49, 53]. Among these loci, the OM-associated genes included FUT2 (MIM 182100) and ABO, both involved in glycosphingolipid biosynthesis, as well as TBX1 (MIM 602054) and MKX (MIM 601332), which encode transcription factors. Genes important for embryogenesis and neurodevelopment (FGF3 (MIM 164950) and AUTS2 (MIM 607270)), as well as those implicated in asthma (CDHR3 (MIM 615610)), and spontaneous chronic OM in mice (PLG (MIM 173350)) were also found in association with OM [71–73]. To date, only 4 of these 14 loci, FUT2, TBX1, ABO, and CDHR3, have been replicated in independent human cohorts with additional evidence from functional or multi-­omics studies performed for FUT2 and CDHR3 [49–52, 74–78]. To identify pathways that are potentially important for OM susceptibility, 21 genes with p