A 40-year-old man with known ulcerative colitis presents with pruritus and fatigue. ALP is 480 U/L (elevated 3× ULN), GGT 320 U/L, total bilirubin 2.1 mg/dL, ALT 65 U/L. p-ANCA is positive. MRCP shows multifocal strictures and beading of intrahepatic and extrahepatic bile ducts. Which is the most likely diagnosis?
- A Primary biliary cholangitis
- B Primary sclerosing cholangitis ✓
- C IgG4-related sclerosing cholangitis
- D Drug-induced cholestatic liver injury
Correct answer: B. Primary sclerosing cholangitis
Explanation
Primary sclerosing cholangitis classically presents with cholestatic enzyme elevation (raised ALP, GGT) with the characteristic multifocal strictures and beading of bile ducts on cholangiography (MRCP or ERCP). About 70% of PSC patients have associated inflammatory bowel disease (usually UC). p-ANCA positivity supports the diagnosis. PBC shows antimitochondrial antibodies and affects small intrahepatic ducts without the large-duct beading. IgG4-related disease shows elevated serum IgG4 and responds to steroids.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.