<prompt> In Budd chiary syndrome , the site of venous thrombosis isInfra venal IVCInfra hepatic IVCHepatic veinsPortal veins  <response>: i.e. Hepatic veins: 673-CMDT-ll 661, 733, 1945, 1950 H17thBudd chiary syndrome is characterized by post sinusoidal obstruction outside the liver at the level of hepatic veinsFactors that predispose to hepatic vein thrombosis Budd chiary syndrome Polycythemia vera or other myeloproliferative disease Activated protein C resistance factor V Leiden mutation Protein C or S or antithrombin deficiency Hyper prothrombinemia factor 11 G 20210 A mutation Methylenetetra hydrofolate reductase TT 677 mutation, Antiphospholipid antibodies Caval webs, right sided heart failure or constrictive pericarditis, neoplasm. Paroxysmal nocturnal hemoglobinuria, Behcets syndrome, blunt abdominal trauma, use of oral contraceptives and pregnancy Some cytotoxic agents cyclophosphamide, azathioprine, carmustine, busulfan or etoposide and pyrrolizidine alkaloids bush easThe screening test of choice is contrast - enhanced, color or pulsed doppler ultrasonography Classical Triad of Budd Chiary Syndrome - Abdominal pain, ascites and hepatomegaly 