Inferior vena cava thrombus due to hyperhomocysteinemia.

We report a case of a 39-year-old man with inferior vena cava (IVC) thrombus after withdrawal of IVC filter. He complained of 1-week history of swelling in his right leg, and computed tomography (CT) demonstrated occlusive thrombus in right femoral and popliteal veins. Venous thrombectomy was attempted after IVC filter placement. The filter was withdrawn without IVC filter-associated thrombus and the patient was discharged on warfarin. On day 21 after discharge, he complained of progressive swelling and CT revealed a significant amount of thrombus in IVC where the filter had been placed. Despite adequate anticoagulant therapy, CT showed increased thrombus extending from infra-renal IVC to common iliac vein. Systemic work-up for the risk factors of venous thromboembolism revealed the presence of hyperhomocysteinemia (total homocysteine 83.1 μmol/L; normal range 5-15 μmol/L) due to unbalanced diet with deficiency of folic acid and vitamin B12. Four weeks after administration of folic acid, vitamin B6/B12 as the treatment of hyperhomocysteinemia in addition to warfarin, swelling of his leg improved with significant resolution of thrombus by CT. CT also demonstrated a severe stenosis of the IVC just below the renal veins. At 6 months, he complained of mild post-thrombotic sequelae with no evidence of recurrent IVC thrombus. <Learning objective: Hyperhomocysteinemia is associated with higher risk for venous thromboembolism as well as atherosclerotic diseases. Serum homocysteine level is partly explained by genetic background as well as dietary deficiency of folic acid or vitamin B6/B12. Hyperhomocysteinemia is related with low intake of vegetables and seafood. We should be aware of hyperhomocysteinemia when the thrombus increased despite optimal anticoagulant therapy. B vitamins and folic acid therapy might be effective in patients with severe hyperhomocysteinemia.>.