A portacaval shunt (or portal caval shunt) is a treatment for high blood pressure in the liver. A connection is made between the portal vein, which supplies 75% of the liver's blood, and the inferior vena cava, the vein that drains blood from the lower two-thirds of the body. The most common causes of liver disease resulting in portal hypertension are cirrhosis caused by alcohol abuse and viral hepatitis (hepatitis B and C). Less common causes include diseases such as hemochromatosis, primary biliary cirrhosis (PBC), and portal vein thrombosis.
Cirrhotic patients with portacaval shunts who have esophageal varices (or any upper GI bleed) can suffer ammonium intoxication which may lead to coma.
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