Page 1 of 1: Deficiency of which substances likely responsible?

mdali007 · Credits: 5763 My Scrapbook

A 17-year-old man notices that his urine becomes red after he is given sulfonamides for treatment of a sinus infection. Both urine and serum test positive for free hemoglobin, and the urine red cell count is 1.2 million/mm3. A peripheral blood smear shows normocytic and normochromic red cells, and a few red cells with an indentation in their peripheral membrane, as if a bite had been taken from their cytoplasm. Deficiency of which of the following substances is most likely responsible for these symptoms?

Options:beo

A. Alpha-chain of hemoglobin.

B. Beta-chain of hemoglobin.

C. Glucose-6-phosphate dehydrogenase.

D. Glycoprotein IIb/IIIa.

E. Spectrin.

dosha · Credits: 365 My Scrapbook

the ans is G6PD defficiency ans c

mdali007 · Credits: 5763 My Scrapbook

correct dosha

The right answer is C.

The presence of free hemoglobin in the serum and urine, and "bite cells" due to splenic removal of Heinz bodies (oxidized hemoglobin) all point to hemolysis. Hemolysis following oxidant injury by drugs (sulfonamides, for example) or infection suggests glucose-6-phosphate dehydrogenase deficiency or the related deficiencies of glutathione synthetase, pyruvate kinase, and hexokinase. These conditions are typically asymptomatic between episodes of hemolysis.

Deficiencies of the alpha (choice A) and beta (choice B) chains of hemoglobin produce alpha and beta thalassemia, respectively.

Deficiencies of glycoprotein IIb/IIIa (choice D) produce thrombasthenia, a platelet aggregation defect.

Deficiencies of spectrin (choice E) produce hereditary spherocytosis, characterized by hemolytic anemia and splenomegaly.

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