Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) is an uncommon chronic cholastatic liver disease caused by diffuse inflammation and fibrosis of the biliary tree. The aetiology is unknown but presumed to be immune mediated. It is closely associated with inflammatory bowel disease, particularly ulcerative colitis. Small duct PSC is a rare, more benign variant in which only microscopic bile ducts are involved, sparing the large ducts. Secondary sclerosing cholangitis (SSC) is morphologically similar to PSC but differs in that a clear pathological cause can be identified. It may have a more favourable natural history than PSC if the underlying cause can be treated. PSC tends to affect men (male: female, 2: 1), some presenting with fatigue, right upper quadrant abdominal pain, weight loss, pruritus and intermittent jaundice. However, approximately half of the patients are asymptomatic at diagnosis, which is made incidentally when a persistently raised alkaline phosphatase is discovered, usually in the setting of ulcerative colitis. A minority of patients with PSC show features of autoimmune hepatitis (PSC-AIH overlap); this syndrome mainly affects children and adolescents., although it can be found in adults. It may respond to corticosteroid treatment. Serum biochemical tests usually indicate cholestasis (most often in the absence of jaundice), but diagnosis is based on three criteria: (1) generalized beading and stricturing of the biliary system on cholangiography; (2) the exclusion of secondary causes such as choledocholithiasis; and (3) the exclusion of bile duct cancer. There is no curative treatment. PSC is progressive in the majority of symptomatic patients, 50% of whom will die or require liver transplantation after 12 years. The main cause of death is malignancy (hepatobiliary and colonic) and liver failure. Liver transplantation is the only option for patients with advanced liver disease. In contrast, 75% of asymptomatic patients are alive 15 years after the diagnosis of PSC.