Arterial and Venous Thrombotic Storm in Primary Membranous Nephropathy: A Case Report

Introduction: Membranous nephropathy (MN) is one of the most common causes of adult-onset nephrotic syndrome and is associated with an increased risk of thromboembolic events. While venous thromboembolism (VTE) is well recognized, arterial thrombosis is less common. Thrombotic storm,a rare phenomenon involving simultaneous arterial and venous thromboses is an extreme manifestation of the hypercoagulable state in MN. Case Description: We present a rare case of thrombotic storm in a 42-year-old male with newly diagnosed primary membranous nephropathy (MN). The patient presented with generalized edema, fatigue, and exertional dyspnea over one month. Clinical examination revealed bilateral pitting edema, moderate ascites, and raised jugular venous pressure. Laboratory findings were consistent with nephrotic syndrome. Autoimmune workup revealed a positive ANA (1:640) and low C3, but negative PLA2R antibodies, ANCA, anti-GBM, and antiphospholipid antibodies. On day three of hospitalization, the patient developed acute right lower limb ischemia. Arterial Doppler and CT angiography confirmed thrombus in the superficial femoral and popliteal arteries. Concurrently, chest imaging showed subsegmental pulmonary embolism with peripheral pulmonary infarction. A diagnosis of thrombotic storm—simultaneous arterial and venous thromboses was established. The patient was treated with therapeutic anticoagulation (LMWH transitioned to warfarin), surgical thrombectomy, and intra-arterial thrombolysis. Immunosuppressive therapy was initiated with high-dose corticosteroids and a single dose of rituximab. Due to high bleeding risk, kidney biopsy was deferred. He later developed complications including an infected groin hematoma with MSSA bacteremia, requiring surgical debridement and prolonged antibiotics. Delayed kidney biopsy confirmed primary MN with IgG4 deposits, consistent with a PLA2R-negative form. Discussion: MN is a known cause of nephrotic syndrome in adults and confers a high risk of thrombotic events. While venous thromboses are more common, arterial events are less frequently reported . Thrombotic storm involving multiple vascular beds is exceptionally rare. This case highlights the importance of early recognition, aggressive anticoagulation, and tailored immunosuppression in managing complex thrombotic presentations in MN.T