Postpartum “Hypercoagulable Storm” With Extensive Iliocaval Thrombosis and Pulmonary Embolism in a Patient With Heterozygous Factor V Leiden

A 26-year-old woman presented to the emergency department four weeks after a lower segment cesarean section with a four-day history of progressive dyspnea, bilateral lower limb swelling, and leg pain.At presentation to the emergency department, she was tachycardic (150 beats/min), hypotensive (88/60 mmHg), and tachypneic (38/min), with an oxygen saturation of 93% on room air.Venous Doppler ultrasonography demonstrated extensive bilateral deep vein thrombosis (DVT) involving the iliac veins, right external iliac vein, infrarenal inferior vena cava (IVC), and right popliteal vein, with left popliteal involvement.Computed tomography (CT) pulmonary angiography demonstrated acute pulmonary embolism (PE) involving the right pulmonary artery and multiple segmental branches, with right lower lobe pulmonary infarction.Thrombophilia evaluation identified heterozygous Factor V Leiden, with negative antiphospholipid antibodies and lupus anticoagulant and normal protein C, protein S, and antithrombin III levels.The initial presentation raised concern for high-risk acute pulmonary embolism physiology, with hypotension (88/60 mmHg), marked tachycardia, and respiratory compromise requiring high-flow oxygen.Category D1+R was considered provisionally; however, definitive classification was limited by the absence of documented hypotension duration and fluid responsiveness, lactate, echocardiographic right ventricular assessment, and computed tomography (CT) right ventricular (RV)/left ventricular (LV) ratio.A Pulmonary Embolism Response Team (PERT) was activated, and intravenous unfractionated heparin (UFH) was initiated.A retrievable suprarenal IVC filter was placed, followed by mechanical thrombectomy extending from the right popliteal vein to the IVC.At three months, the patient remained ambulatory without exertional dyspnea, and bilateral lower limb swelling had completely resolved.Repeat venous Doppler demonstrated recanalization of the previously thrombosed segments without significant residual occlusive thrombus.This case is presented because of the uncommon combination of extensive bilateral lower limb and iliocaval thrombosis with acute PE and pulmonary infarction in the early postpartum period in a patient with heterozygous Factor V Leiden.It highlights how postpartum hypercoagulability may interact with inherited thrombophilia to produce extensive multisite thrombosis and emphasizes the importance of early recognition, severity-based risk stratification, and coordinated multidisciplinary management.