Small Duct Primary Sclerosing Cholangitis

Abstract

Primary sclerosing cholangitis (PSC) is a well documented disease of the biliary tract associated with inflammatory bowel diseases (IBD), especially ulcerative colitis.1 Small-duct PSC, a variant of PSC, also has an association with inflammatory bowel disease.1 The exact pathogenesis of PSC is not well understood, but thought to be due to a combination of a genetic predisposition and gut structure.1 A 34 year-old male with a history significant for rheumatoid arthritis, portal vein thrombosis and ulcerative colitis presented to the hepatology clinic for evaluation of abnormal liver enzymes. He was diagnosed with ulcerative colitis at age 24 and over the years treated with Mesalamine, steroids, Azathioprine, Cyclosporine, and Infliximab. However, he was unresponsive to therapy and underwent total colectomy 2 years after diagnosis. The liver enzymes of concern had a mixed cholestatic and hepatocellular pattern with ALT 203, AST 104, Tbili 1.7, Dbili 0.6, and ALP 339. Hence, the differential was initially broad including possible autoimmune causes, vascular with the portal vein thromboses history, drug induced or primary sclerosing cholangitis (PSC) or primary biliary cirrhosis. A viral hepatitis screen was negative. Autoimmune testing revealed a positive anti-nuclear antibody titer. Magnetic resonance cholangiopancreatography (MRCP) revealed hypoattenuations correlating with his history of portal vein thromboses. Liver biopsy revealed small duct PSC. He is scheuled for imaging every 6 months to observe for cholangitis. A retrospective analysis of patients with PSC from 1980 to 2010 at 37 centers in Europe, North America, and Australia was completed by the International PSC Study Group.2 Of the 7121 patients, 65.5% were men, 89.8% had classical or large-duct disease, and 70.0% developed IBD at some point.2 Small-duct PSC was associated with a lower risk of liver transplant, death or malignancy compared with classic PSC.2 Small-duct PSC characterized a low-risk phenotype in both sexes.2 This suggests that small duct PSC is usually seen in younger individuals, in early stage disease, and suggests better outcomes.