Poal hypeension occurs when the pressure in the poal system is increased due to factors that may be divided into three categories Pre-sinusoidal causes of poal hypeension include : sinistral/extrahepatic : I. splenic vein thrombosis II. splenomegaly III. splenic atrioventricular fistula intrahepatic : I. schistosomiasis II. congenital hepatic fibrosis III. idiopathic poal fibrosis IV. myeloproliferative disorder V. sarcoid VI. graft versus- host disease Sinusoidal poal hypeension is a consequence of cirrhosis of any aetiology. Postsinusoidal hypeension can also be divided into : intrahepatic - vascular occlusive disease posthepatic :- I. Budd-Chiari II. congestive hea failure III. IVC webs Post Hepatic Poal Hypeension Right hea failure Tricuspid regurgitation Constrictive pericarditis IVC obstruction Budd - Chiari syndrome Intrahepatic Poal Hypeension Cirrhosis Schistosomiasis Hepatitis Veno - occlusive disease Sclerosing cholangitis Primary biliary cirrhosis Wilson's disease Hemochromatosis Alpha - 1 antitrypsin Granulomatous disease Congenital fibrosis Pre - hepatic Poal Hypeension Poal vein thrombosis Splenic vein thrombosis Splenomegaly Mesenteric aeriovenous fistula DIAGNOSIS : In evaluating patients with suspected poal hypeension, an enlarged poal vein on routine abdominal ultrasonography may suggest poal hypeension but this is not diagnostic. Doppler ultrasound allows identification of vascular occlusion and the direction of poal venous low. CT and MR angiography are useful for evaluating poal venous patency and anatomy. The most accurate method for measuring poal hypeension is hepatic venography. This procedure introduces a balloon catheter directly into the hepatic vein where free hepatic venous pressure (FHVP) is measured. The hepatic vein is then occluded by inflation of the balloon allowing measurement of the wedged hepatic venous pressure (WHVP). The hepatic venous pressure gradient (HVPG) may then be calculated by subtracting the FHVP rom the WHVP (HVPG = WHVP-FHVP). Clinically significant poal hypeension is defined as HVPG greater than 10 mm Hg. Angiographic Findings IVC graphy or percutaneous hepatography or MR Venography 'Spider - Web Collaterals' Long segmental compression of IVC by caudate lobe Dilated hepatic aeries