The main cause of portal hypertension is cirrhosis. This is a scarring of the liver. It can result from several conditions such as hepatitis (an inflammatory disease) or alcohol abuse. Autoimmune diseases of the liver such as autoimmune hepatitis, primary sclerosing cholangitis, and primary biliary cholangitis also are causes of cirrhosis and portal hypertension. Whenever your liver is harmed, it attempts to heal itself. This causes scar tissue to form. Too much scarring makes it harder for your liver to do its job.