Organ System Pathology USMLE Step 1 Practice Question
A 19-year-old college student presents with a 5-day history of low-grade fever, headache, dry cough, and malaise. Vital signs: temperature 38.2°C, heart rate 92/min, respiratory rate 18/min, blood pressure 118/76 mmHg, SpO2 98% on room air. Chest radiograph reveals patchy interstitial infiltrates disproportionate to modest auscultatory findings. Otoscopy demonstrates bullous myringitis. Complete blood count shows normal WBC count. He denies recent antibiotic use. Which organism most likely explains this clinical presentation?
Answer choices
- APseudomonas aeruginosa
- BLegionella pneumophila
- CChlamydophila psittaci
- DMycoplasma pneumoniaeCorrect answer
- EStreptococcus pneumoniae
- FRespiratory syncytial virus
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