Inferior Vena Cava Agenesis Presenting with Recurrent Deep Vein Thrombosis in a 54-Year-Old Woman: A Rare Case Report

Abstract

Congenital anomalies of the inferior vena cava (IVC) are uncommon vascular abnormalities that are frequently asymptomatic. When clinically significant, they may predispose to venous stasis and recurrent deep vein thrombosis (DVT). Case presentation: A 54-year-old woman with a history of recurrent right lower-limb DVT (a first episode five years earlier in the posterior tibial vein and a second episode three years earlier in the femoral vein) presented with chronic recurrent lower abdominal pain, loss of appetite, and bilateral lower-limb pain. Physical examination was unremarkable. A thrombophilia work-up, including inherited and acquired thrombophilia investigations, was reported as negative. She also had a history of three recurrent abortions. Contrast-enhanced computed tomography of the abdomen and pelvis demonstrated a major congenital venous anomaly characterised by agenesis/hypoplasia of the infrahepatic segment of the inferior vena cava with extensive, dilated collateral venous channels. The hepatic veins and left renal vein were visualised and remained intact. The patient was admitted to the hospital and initially treated with subcutaneous enoxaparin (8,000 IU twice daily) for one week and was started on oral warfarin (5 mg once daily) four days after initiation of enoxaparin, once the diagnosis was confirmed. Her INR increased from 1.2 before anticoagulation to 2.5 after one month of treatment. Complete resolution of the abdominal and bilateral lower-limb pain was reported after approximately two weeks of anticoagulant therapy. Congenital IVC agenesis should be considered in patients with recurrent or otherwise unexplained DVT, particularly when routine thrombophilia investigations are negative. Contrast-enhanced CT can demonstrate the venous anomaly and the associated collateral circulation. Recognition of this anatomical abnormality is important for long-term thromboembolic risk assessment and management.