Pneumonia USMLE Step 1 Practice Question
A 35-year-old immunocompromised man with CD4 count of 45 cells/μL presents with progressive dyspnea, fever (38.8°C), and dry cough for 2 weeks. Vital signs show BP 118/76 mmHg, HR 102/min, RR 28/min, SpO2 92% on room air. Chest X-ray demonstrates bilateral interstitial infiltrates with ground-glass opacification. Lactate dehydrogenase is markedly elevated at 520 U/L. He denies chest pain. Which of the following is the most likely diagnosis?
Answer choices
- APneumocystis jirovecii pneumoniaCorrect answer
- BAspergillus pneumonia
- CBacterial pneumonia
- DTuberculosis
- ECytomegalovirus pneumonia
- FLegionella pneumophila pneumonia
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.