Pulmonary Embolism USMLE Step 1 Practice Question
A 65-year-old man with a 40 pack-year smoking history and GOLD stage 4 COPD presents to the emergency department with acute dyspnea. His wife reports he has had progressive exercise intolerance over the past 6 months. Vital signs: HR 104/min, RR 26/min, BP 128/82 mmHg, SpO2 84% on room air. Physical examination reveals barrel chest, pursed-lip breathing, and prominent jugular venous distension. Chest X-ray shows hyperinflation and flattened diaphragms without focal infiltrates. Computed tomography pulmonary angiography (CTPA) is negative for pulmonary embolism. Transthoracic echocardiography demonstrates an estimated pulmonary artery systolic pressure of 62 mmHg with right ventricular dilation. Which of the following mechanisms most likely accounts for the pulmonary hypertension in this patient?
Answer choices
- AChronic hypoxic vasoconstriction and medial hypertrophy of pulmonary arterioles secondary to obstructive lung diseaseCorrect answer
- BAcute thromboembolism with incomplete thrombolytic response despite negative CTPA
- CMitral stenosis causing postcapillary pulmonary hypertension
- DLeft ventricular systolic dysfunction from myocardial infarction
- EAcute respiratory distress syndrome with increased alveolar-capillary permeability
- FInterstitial lung disease with pulmonary fibrosis
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations ā plus adaptive practice that targets your weak areas ā with a free MedBoardPRO account.