What is primary sclerosing cholangitis (PSC)?
PSC is an uncommon chronic liver disease in which the bile ducts inside and outside the liver progressively decrease in size due to inflammation and scarring (fibrosis). The disease may occur alone, but frequently is associated with inflammatory diseases of the colon, especially chronic ulcerative colitis.
Bile ducts are tubes which carry bile (a greenish yellow liquid made by the liver) into the upper part of the bowel. Bile acts as a detergent breaking up fat from the food we eat into small droplets that can then be absorbed into the body. It also enables the body to absorb vitamins A, D, E and K from our diet.
As a consequence, bile that is normally carried by these ducts accumulates within the liver. This blockage to bile flow also causes damage to liver cells causing inflammation and scarring. Over many years the scarring can affect the whole liver and the system of bile ducts. A damaged liver can re-grow without scarring but in PSC, the re-growth goes wrong and the healing process is incomplete. The combination of scar tissue and irregular growth is known as cirrhosis.