Blood Disorders Case
You are seeing a 1-year-old boy for a well-child visit.
In reviewing his history, you note that he has had 4 episodes of otitis media and 1 hospitalization for pneumonia, and has had eczema since 4 months of age. You obtain a screening CBC and note that he has Hgb of 11 g/dL, WBC of 6 × 109/L, and a platelet count of 47 × 109/L. The pathologist notes that the platelets appear small.
You suspect that this patient has:
A. Thrombocytopenia absent radius
B. Wiskott-Aldrich syndrome (WAS)
C. Fanconi anemia
D. Congenital amegakaryocytic thrombocytopenia
E. Hyper-IgE syndrome
The correct answer is B.
WAS, and the related entity X-linked thrombocytopenia (XLT), should be suspected in any male patient with thrombocytopenia and small platelets. WAS differs from XLT in that patients with WAS have impaired immunity and are at risk for infections and lymphoreticular malignancies. Patients typically present to medical attention due to bleeding during infancy.
While thrombocytopenia absent radius, Fanconi anemia, and congenital amegakaryocytic thrombocytopenia are all associated with thrombocytopenia, the presence of small platelets and frequent infections in this patient is more suggestive of WAS. Patients with hyper-IgE syndrome are also likely to have infections and eczema, but do not have small and decreased numbers of platelets. (Page 1585, Section 23: Disorders of the Blood, Part 3: Disorder of Coagulation and Platelet, Chapter 439; Page 1594, Part 4: Disorders of the Spleen and Lymph Nodes, Chapter 441; Page 1550, Part 2: Disorders of Red Blood Cell and Anemia, Chapter 432)