Hematology Case Review [1st ed.] 145119143X, 9781451191431, 9781469852706

Citation preview

Donald

�·, '

....'!��' ¥

�

''":"�--., . ;:

:\ � �-.

•

�..

A 7 LJ -year-old female presen ts for eval ua tion of c h ronic a n d p rogressive fatigue and weakness. She l ives with two ca ts and a German Shepherd dog. Patien t has a h istory of hypertension and hyperlipidemia with occasional gastroesophageal reflux sym p­ tom s . Pa t ie n t reports n o prior s u rgical p roced u res . U r i n e a n a lys is reveals no evi ­ dence of hematu ria or hemoglob i n uria. Stool is negative for occ u l t blood . Labora tory eva l ua tion reveals hemoglobin o f LJ . 2 g/d l, mean corpuscular vol u m e (MCV) of 1 2 0 fl. l e u kocyte cou n t o f 2 , 1 00/JLL, platelet cou n t o f LJ S, OOO/JLL, and an LDH level of LJ , 700 U/L. Peri p heral blood smear is shown .

CASE F I G U R E LJ - 1

CASE FIGURE LJ-2

QU ESTION 1 7\r Which of the following is not among the possible explanations of the patient's presentation? A.

Folic acid deficiency

B. Hereditary elliptocytosis C.

Hemolytic anemia

D.

Liver disease

E.

Medication use

12

I:

Case .��·.... ' :\

' '

'

', '

'

' '

�

'

'

A 5 3 -year-old female pa tien t is seen for eval uation prior to a plan ned den tal extrac­ tion . She has sys tem ic l u pus erythema tosus and has been noted to be thrombocyto­ penic on recen t labora tory eva l ua tion by h e r rheumatologist. The peri pheral smear is shown below.

CASE F I G U RE 88- 1

QU ESTION 1 * What is the mechanism of this patient's thrombocytopenia? A. B. C. D.

Autoantibodies related to EDTA anticoagulant Antiphospholipid antibodies Antinuclear antibodies Warm autoantibodies

Answer: A. The blood smear shows numerous platelets surrounding granulocytes, that is, platelet satellitism, a cause of pseudothrombocytopenia. This scenario is an in vitro phenomenon probably related to interactions between platelet glycoprotein lib/lila complex and the neutrophil Fe receptor, caused by the anticoagulant EDTA contained in some blood collection containers. Platelet satellitism is less common than platelet clumping, also related to pseudothrombocytopenia (N Engl J Med. 1 998;338:5 9 1 ) .

1 93

A S LJ -year-old male patien t is being evaluated for a l u ng mass seen on a CT scan for chest pai n . He is otherwise h ea l thy and his physical exam is norma l . Com pl e te b lood cou n t shows leukocyte coun t 5 . 700/jl.l. hemoglobin 1 LJ . 2 g/d l. and platelet cou n t 2 89 . 000/jl.L. The peripheral blood smear is shown below.

CASE FIGU RE 89- 1

QUESTION 1 * Based on the patient's history and peripheral blood smear, which of the following statements is most likely?

A. Hereditary elliptocytosis, which is most commonly inherited as an autosomal dominant condition B. Hereditary spherocytosis, which is most commonly inherited as an autosomal recessive condition C. Hereditary elliptocytosis, which is most commonly inherited as an autosomal recessive condition D . Hereditary pyropoikilocytosis, which is most commonly inherited as an autosomal recessive condition

Answer: A. The blood smear shows that the majority of RBCs are biconcave elliptocytes consistent with a diagnosis of hereditary elliptocytosis (HE). HE is usually an autosomal dominant disorder and is most commonly asymptomatic. Elliptocytes may be found in iron deficiency, megaloblastic anemia, thalassemia, myelodysplasia, and myelofibrosis. However, in contrast to HE, the percentage of ellipto­ cytes in these disorders does not usually exceed 40% to 50%.

1 94

Case 89

1 95

Q U ESTION 2 1tf What is the pathophysiologic difference between hereditary spherocytosis (HS) and HE? A. HE involves vertical protein interactions, most commonly affecting ankyrin B. HE involves horizontal protein interactions, most commonly affecting spectrin C . HS involves horizontal protein interactions, most commonly affecting spectrin D . HS involves vertical protein interactions, most commonly affecting band 3

Answer: B. The principal defect in HE is a mechanical weakness or fragility of the erythrocyte mem­ brane, primarily involving horizontal protein interactions, especially spectrin-spectrin and spectrin­ protein 4. 1 and the lipid bilayer. On the other hand, HS involves abnormalities of vertical protein interactions, especially ankyrin and ankyrin-spectrin.

.

• _-

0

• ' '"!

•. -

�; .

'P� ..oi:,-\�"(S/� " J� �J� �_;! .J'b ��L4T �'.,.o ��·�

.�Jb \) u a..:...:, IJ� � ��� )�

www.pooyan-ebooks.ir

[email protected]