COPD USMLE Step 1 Practice Question
A 38-year-old man with untreated HIV (CD4 count 85/μL) presents with subacute fever, dry cough, and progressive dyspnea over 3 weeks. Vital signs show temperature 38.2°C, heart rate 102/min, respiratory rate 28/min, and oxygen saturation 88% on room air. Chest X-ray reveals diffuse bilateral interstitial infiltrates. Bronchoalveolar lavage with silver stain demonstrates characteristic cup-shaped cysts. He denies chest pain and has no focal consolidations on imaging. Which organism is the most likely diagnosis?
Answer choices
- APneumocystis jirovecii pneumoniaCorrect answer
- BHistoplasmosis
- CLegionella pneumonia
- DMiliary tuberculosis
- EMycoplasma pneumonia
- FCytomegalovirus pneumonitis
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