Section: USMLE

29) A 24-year-old woman with a history of allergic rhinitis is involved in an automobile accident and sustains a splenic laceration. She undergoes abdominal surgery and is then transfused with four units of blood of the appropriate ABO and Rh type. As the transfusion progresses, she becomes rapidly hypotensive and develops airway edema, consistent with anaphylaxis. Which of the following pre-existing conditions best accounts for these symptoms?

1. AIDS
2. C1 esterase inhibitor deficiency
3. DiGeorge syndrome
4. Selective IgA deficiency
5. Wiskott-Aldrich syndrome

Patients with selective IgA deficiency may have circulating antibodies to IgA. Fatal anaphylaxis may ensue if they are transfused with blood products with serum containing IgA, although many patients with selective IgA deficiency are asymptomatic and never diagnosed. Symptomatic patients may have recurrent sinopulmonary infections and diarrhea, as well as an increased incidence of autoimmune and allergic diseases.

AIDS predisposes for infections and neoplasms, but not anaphylaxis.

C1 esterase inhibitor deficiency is an autosomal dominant disease characterized by recurrent attacks of colic and episodes of laryngeal edema, without pruritus or urticarial lesions. This disorder is also known as hereditary angioedema.

DiGeorge syndrome is characterized by thymic aplasia and, sometimes, hypoparathyroidism. The disorder is due to abnormal development of the third and fourth pharyngeal arches.

Wiskott-Aldrich syndrome is a form of immunodeficiency associated with thrombocytopenia and eczema.