Primary Sclerosing Cholangitis

Primary sclerosing cholangitis (PSC) is a chronic fibro-inflammatory cholangiopathy. Its cause is not fully established; current models involve immune, genetic, gut-barrier, microbiome, and bile-duct epithelial factors. Inflammation and fibrosis narrow intrahepatic and/or extrahepatic bile ducts. Alternating strictures and normal or mildly dilated segments create the characteristic beaded appearance on cholangiography. Narrowed ducts impede bile flow and produce cholestasis. Alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT) are commonly elevated, while symptoms may include pruritus, fatigue, abdominal pain, jaundice, and fever. Disease course is variable and often slowly progressive. Persistent cholestatic injury can lead to biliary fibrosis, cirrhosis, portal hypertension, hepatic decompensation, and liver failure. A relevant stricture is one associated with obstructive cholestasis or bacterial cholangitis; it may need endoscopic treatment rather than observation alone. PSC is closely associated with inflammatory bowel disease (IBD), especially ulcerative colitis. Colitis may be clinically quiet, so absence of bowel symptoms does not remove the need for colorectal surveillance. PSC also increases the risks of cholangiocarcinoma and gallbladder cancer. These malignancies and progressive stricturing may emerge before severe symptoms, which is why structured follow-up continues...