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Heart failure follow-up — USMLE Step 3 MCQ

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HardInternal Medicine (chronic management)Heart failure follow-upUSMLE Step 3

A 24-year-old with sickle cell disease develops acute chest syndrome. Despite oxygen, ceftriaxone, azithromycin, incentive spirometry, and analgesia, bilateral infiltrates progress and oxygen saturation falls to 84%. Hemoglobin is 10.6 g/dL from a baseline of 9.2 g/dL. Which transfusion strategy is most appropriate?

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Correct answer: D — Arrange urgent red-cell exchange transfusion with hematology support

The best answer is “Arrange urgent red-cell exchange transfusion with hematology support”. Progressive hypoxemia and multilobar disease indicate severe acute chest syndrome. Exchange transfusion rapidly lowers the hemoglobin S fraction without the dangerous hyperviscosity that a large simple transfusion could cause at an already high hemoglobin. Plasma does not remove sickled erythrocytes, and clinical deterioration cannot await cultures. The alternatives are less suitable because they mistime the intervention, omit a necessary component, or apply treatment for a different physiologic problem; the stem's decisive findings determine the sequence.

Reference: American Society of Hematology, Sickle Cell Disease Transfusion Support: https://www.hematology.org/education/clinicians/guidelines-and-quality-care/clinical-practice-guidelines/sickle-cell-disease-guidelines