A 25-Year-Old Woman with a High-Risk Large and Occlusive Pulmonary Embolism, Later Diagnosed with Primary Antiphospholipid Syndrome and Hyperhomocysteinemia: A Case Report.

BACKGROUND High-risk pulmonary embolism (PE) occurs when the pulmonary circulation is suddenly occluded by a thrombus and is a life-threatening medical emergency. In young and otherwise healthy individuals, there may be undiagnosed underlying risk factors for PE that require investigation. This report presents the case of a 25-year-old woman admitted as an emergency with a high-risk large and occlusive PE, later diagnosed with primary antiphospholipid syndrome (APS) and hyperhomocysteinemia. CASE REPORT A 25-year-old woman presented with sudden-onset dyspnea after elective cholecystectomy. One year earlier, the patient had lower limb deep vein thrombosis without an identified predisposing cause, and she received anticoagulation for 6 months. On physical examination, she had right leg edema. Laboratory tests revealed elevated levels of troponin, pro-B-type natriuretic peptide, and D-dimer. Computed tomography pulmonary angiography (CTPA) demonstrated a large and occlusive PE, and an echocardiogram showed right ventricular dysfunction. Successful thrombolysis was performed with alteplase. On repeat CTPA, a significant reduction in filling defects in the pulmonary vasculature was observed. The patient evolved uneventfully and was discharged home on a vitamin K antagonist. Due to unprovoked recurrent thrombotic events, suspicion of underlying thrombophilia was raised, and hypercoagulability studies confirmed primary APS and hyperhomocysteinemia. CONCLUSIONS This report presents the case of a life-threatening high-risk PE in a previously healthy young woman and highlights the importance of emergency management followed by investigation and treatment of underlying risk factors for venous thromboembolism, including APS and hyperhomocysteinemia.