Pneumonia USMLE Step 1 Practice Question
A 70-year-old woman with atrial fibrillation not on anticoagulation presents with acute-onset fever (39.2°C), pleuritic chest pain, and a new diastolic murmur. Vital signs show HR 112 bpm, BP 128/76 mmHg, RR 22/min, SpO2 94% on room air. Chest X-ray demonstrates a wedge-shaped infiltrate in the right lower lobe. Blood cultures grow Streptococcus viridans. No petechiae noted on skin examination. Which diagnosis best explains these findings?
Answer choices
- ASeptic pulmonary embolism secondary to infective endocarditisCorrect answer
- BAcute bacterial pneumonia from community-acquired pathogen
- CAcute myocardial infarction with cardiogenic shock
- DPulmonary infarction from thromboembolism
- EPneumothorax with secondary infection
- FAcute pericarditis with fibrinous exudate secondary to rheumatic heart disease
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.