These are rare diseases of the liver in which one or more major blood vessels of the liver get blocked by a clot affecting the blood circulation to the liver. The liver is supplied by a large blood vessel called the portal vein and a hepatic artery, while it is drained by three vessels called the hepatic veins. Blockage of the hepatic veins is known as Budd Chiari Syndrome, while blockage of the portal vein is called portal vein thrombosis. These conditions can present suddenly and usually occur in patients who have a blood clotting defect.

The blockage can occur insidiously without any symptoms and patients later with portal hypertension, usually in the form of internal bleeding or collection on fluid in the belly. These disorders can be treated by blood thinners or by placing stents to open up the veins. Rarely vascular surgery or liver transplant may be needed.