Anemias USMLE Step 1 Practice Question
A 34-year-old woman with systemic lupus erythematosus comes to the clinic because of fatigue and jaundice. Examination shows mild splenomegaly. Laboratory studies reveal anemia, elevated reticulocyte count, elevated indirect bilirubin, and elevated lactate dehydrogenase. Peripheral smear shows spherocytes, and the direct Coombs test is positive. Which of the following is the most likely mechanism of her anemia?
Answer choices
- AComplement-mediated intravascular hemolysis due to absent GPI-anchored proteins
- BMechanical destruction of red blood cells in narrowed vessels
- CDefective ankyrin synthesis causing loss of membrane surface area
- DIgG-mediated opsonization of red blood cells with splenic extravascular hemolysisCorrect answer
- EIgM binding to red blood cells only in cool peripheral tissues
- FIgA-mediated agglutination of red blood cells in bone marrow with central nervous system hemolysis
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