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Community-acquired pneumonia in immunosuppressed outpatient — USMLE Step 3 MCQ

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HardInternal Medicine (chronic management)Community-acquired pneumonia in immunosuppressed outpatientUSMLE Step 3

A 39-year-old woman with ulcerative colitis treated with infliximab develops 5 days of fever and productive cough. Temperature is 38.4°C, pulse is 104/min, and oxygen saturation is 93% on room air. Chest radiograph shows a left lower-lobe infiltrate. WBC count is 15,000/mm3. She is stable for outpatient treatment. Which of the following is the most appropriate next step in management?

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Correct answer: E — Levofloxacin

Outpatient CAP with comorbidities or immunosuppression requires broader empiric therapy such as a respiratory fluoroquinolone or beta-lactam plus macrolide/doxycycline. Amoxicillin alone is for selected low-risk adults without comorbidities.

Reference: ATS/IDSA Community-Acquired Pneumonia Guideline 2019