Pneumonia USMLE Step 1 Practice Question
A 37-year-old man with untreated HIV presents with progressive dyspnea, dry cough, and fever for 2 weeks. Vital signs: BP 118/76, HR 102, RR 28, Temp 38.5°C, SpO2 88% on room air. CD4 count is 80 cells/mm³. Chest radiograph shows diffuse bilateral interstitial infiltrates. Lactate dehydrogenase is elevated at 520 U/L. Sputum cultures are negative. Which of the following is the most likely diagnosis?
Answer choices
- AHistoplasma capsulatum
- BCommunity acquired pneumonia
- CLegionella pneumophila
- DPneumocystis jirovecii pneumoniaCorrect answer
- EPulmonary embolism
- FMycobacterium avium complex
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.