Anemias USMLE Step 1 Practice Question
A 39-year-old woman with systemic lupus erythematosus on hydroxychloroquine presents with progressive fatigue and jaundice. Vital signs show BP 118/76, HR 102, RR 18, temperature 37.2°C, SpO2 98%. Examination reveals mild splenomegaly; no lymphadenopathy noted. Laboratory studies show hemoglobin 8.2 g/dL, elevated indirect bilirubin at 2.8 mg/dL, and reticulocytosis of 8.5%. Direct antiglobulin test is positive. Which of the following best explains the mechanism of her anemia?
Answer choices
- AMechanical fragmentation of erythrocytes by fibrin strands
- BReduced synthesis of beta globin chains
- CComplement deficiency causing intravascular hemolysis
- DIgG mediated opsonization of erythrocytes causing splenic destructionCorrect answer
- EIgM mediated agglutination of erythrocytes in the cold
- FOxidative damage to erythrocyte membranes by hydroxychloroquine metabolites
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