Vol. 7, Issue 2, Part A (2025)

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disorder with diverse clinical manifestations. Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is a recognized complication of SLE but rarely serves as the initial presenting feature, particularly in males. We report a case of a 21-year-old previously healthy male who presented with intermittent fever, right lower limb swelling, and pain. Clinical evaluation revealed tachycardia and high-grade fever. Laboratory investigations showed proteinuria, hematuria, elevated D-dimer, and active urine sediments. Doppler ultrasonography identified extensive thrombosis in the right iliac and femoral veins, and computed tomography pulmonary angiography revealed acute PE with infarcts. Autoimmune screening was notable for strong ANA positivity and positive antiphospholipid antibodies. Renal biopsy demonstrated focal endocapillary proliferative glomerulonephritis with a ‘full house’ immunofluorescence pattern, consistent with ISN/RPS Class III lupus nephritis. The patient was treated with catheter-directed thrombolysis, anticoagulation, and immunosuppressive therapy using the Euro-Lupus protocol. This case represents an unusual presentation of SLE in a male patient, where thromboembolism was the first clinical manifestation without classic lupus features. Such presentations may lead to delayed diagnosis if autoimmune causes are not considered in the differential for unprovoked VTE. Clinicians should maintain a high index of suspicion for SLE in young patients with unexplained VTE. Early diagnosis and multidisciplinary management are crucial for improving outcomes and preventing disease progression.