A 30-year-old woman of West African descent develops acute hemolytic anemia after starting dapsone for dermatitis herpetiformis. Heinz body preparation is positive. Which RBC enzyme deficiency is responsible?

• A Pyruvate kinase
• B Hexokinase
• C Glucose-6-phosphate dehydrogenase (G6PD) ✓
• D Phosphofructokinase

Explanation

G6PD deficiency impairs NADPH generation via the hexose monophosphate shunt, leaving hemoglobin susceptible to oxidative denaturation by drugs like dapsone, primaquine, and sulfonamides. Denatured hemoglobin precipitates as Heinz bodies, which are removed by splenic macrophages producing bite cells, and the RBCs undergo extravascular or intravascular hemolysis. Pyruvate kinase deficiency causes chronic non-spherocytic hemolytic anemia without Heinz bodies. Hexokinase and PFK deficiencies are extremely rare.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.