Pulmonary Embolism USMLE Step 1 Practice Question
A 56-year-old woman with no significant past medical history presents to the emergency department with acute onset dyspnea and chest discomfort that began 2 hours ago while sitting at her desk. She denies recent travel, surgery, or immobilization. On examination: heart rate 102/min, respiratory rate 22/min, blood pressure 128/76 mmHg, oxygen saturation 96% on room air, temperature 37.2°C. Lungs are clear to auscultation bilaterally. Cardiac examination reveals regular rate and rhythm with no murmurs. There is no lower extremity edema or calf tenderness. Chest X-ray shows no acute cardiopulmonary process. Laboratory studies: D-dimer 0.2 mcg/mL (normal <0.5), troponin I 0.01 ng/mL (normal), BNP 95 pg/mL (normal). You estimate her clinical pretest probability for pulmonary embolism as low based on Wells criteria. Which of the following is the most appropriate next step in management?
Answer choices
- ADischarge home with safety-netting instructions; PE is effectively ruled out by normal D-dimer and low clinical probabilityCorrect answer
- BOrder bilateral lower extremity compression ultrasound to evaluate for deep vein thrombosis
- CInitiate therapeutic anticoagulation with unfractionated heparin pending CT pulmonary angiography results
- DObtain CT pulmonary angiography to definitively exclude pulmonary embolism
- EAdmit to hospital for continuous cardiac monitoring and serial troponin measurements
- FPerform ventilation-perfusion scan as first-line imaging given normal chest X-ray
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