Pulmonary Embolism USMLE Step 1 Practice Question
A 52-year-old woman with atrial fibrillation (not anticoagulated) presents to the emergency department with sudden onset dyspnea, right-sided pleuritic chest pain, and blood-tinged sputum. Vital signs: heart rate 118 bpm, respiratory rate 24 breaths/min, oxygen saturation 92% on room air. Chest X-ray shows a wedge-shaped opacity in the right lower lobe. CT pulmonary angiography confirms acute pulmonary embolism in the right lower lobe with corresponding infarction. Which of the following pathophysiologic mechanisms best explains the hemoptysis observed in this patient?
Answer choices
- AAcute increase in pulmonary capillary wedge pressure from right ventricular failure causing pulmonary edema
- BMechanical erosion of the embolus through the pulmonary artery wall into the adjacent bronchus
- CAlveolar hemorrhage secondary to pulmonary infarction and loss of bronchial collateral circulationCorrect answer
- DInflammatory mediator release from activated macrophages causing diffuse alveolar damage
- EDisseminated intravascular coagulation triggered by tissue factor release from damaged lung parenchyma
- FAcute thrombophlebitis of systemic veins with septic emboli seeding the lungs
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