Anemias USMLE Step 1 Practice Question
A 34-year-old woman presents to the emergency department with a 3-day history of fatigue, dyspnea on exertion, and dark urine. She reports a sore throat and low-grade fever 2 weeks prior that resolved spontaneously. Vital signs: temperature 37.2°C, heart rate 108 bpm, blood pressure 122/78 mmHg, respiratory rate 22/min, SpO2 98% on room air. Physical examination reveals mild jaundice and splenomegaly. Laboratory studies: hemoglobin 6.8 g/dL, reticulocyte count 14%, total bilirubin 3.1 mg/dL (indirect 2.8 mg/dL), LDH 580 U/L, haptoglobin 8 mg/dL. Direct antiglobulin test (Coombs) is positive. Peripheral blood smear shows spherocytes and polychromasia. Which of the following is the most likely diagnosis?
Answer choices
- AHereditary spherocytosis with acute hemolytic crisis
- BCold agglutinin disease secondary to recent infection
- CAutoimmune hemolytic anemia (warm-antibody type)Correct answer
- DMicroangiopathic hemolytic anemia
- EG6PD deficiency with oxidative stress
- FThrombotic thrombocytopenic purpura (TTP)
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