Hepatic venous outflow obstruction.

Hepatic venous outflow obstruction also called the Budd-Chiari syndrome is increasingly being recognized as a cause of portal hypertension. In western countries the obstruction is usually in the hepatic veins while in reports from South Africa, Japan and India the predominant cause is a block in the IVC at the level of the diaphragm above the entry of the hepatic veins. A hypercoagulable state caused by myeloproliferative haematological disorders, clonal defects in haemopoietic stem cells, lupus anticoagulant, contraceptive pills and postpartum state are some of the aetiological conditions described. However in 25% to 75% cases no cause can be identified. The predominant presenting features in patients with hepatic vein obstruction are hepatomegaly and ascites while those with IVC obstruction show prominent veins on the trunk and back. Ultrasound examination should be the first investigative step. However a liver biopsy is the gold standard of diagnosis. To confirm the site of obstruction inferior vena cavography or functional hepatography may be required. In the acute phase thrombolytic therapy may be useful but for established cases either surgical intervention in the form of shunts or recently balloon angioplasty may be helpful. For patients with established cirrhosis and end-stage liver failure the only alternative is liver transplantation. All these patients however should be put on long term anticoagulants to prevent rethrombosis. Some series have reported that upto 45% of patients may develop hepatocellular carcinoma on long term followup. With proper management a larger proportion of patients can be returned to a useful productive life.