Mastering Medical
USMLE Step 1 · Gastrointestinal

Primary biliary cholangitis vs Primary sclerosing cholangitis

How to tell Primary biliary cholangitis and Primary sclerosing cholangitis apart when a board question makes them look alike.

Fastest separator

PBC is small intrahepatic ducts plus antimitochondrial antibody; PSC is beaded intra/extrahepatic ducts plus ulcerative colitis association.

Side by side

Primary biliary cholangitisPrimary sclerosing cholangitis
Key clue

Middle-aged woman with pruritus, fatigue, cholestatic labs, antimitochondrial antibodies, and small intrahepatic bile duct destruction.

Cholestatic disease associated with ulcerative colitis, multifocal strictures, and beading of intrahepatic and extrahepatic bile ducts.

Mechanism

Autoimmune lymphocytic destruction targets small intrahepatic bile ducts.

Progressive inflammation and fibrosis scar intrahepatic and extrahepatic bile ducts into alternating strictures and dilation.

Labs and tests

Antimitochondrial antibody and elevated alkaline phosphatase support PBC.

ERCP/MRCP beading, p-ANCA association, ulcerative colitis, and cholangiocarcinoma risk support PSC.

The trap

Both are cholestatic with pruritus, elevated alkaline phosphatase, and progress to cirrhosis. The discriminators are antibody profile, duct anatomy, and demographics plus associated diseases. A middle-aged woman with positive antimitochondrial antibody (AMA) plus elevated IgM plus destruction of SMALL intrahepatic ducts on biopsy equals primary biliary cholangitis (treat with ursodeoxycholic acid first-line, add obeticholic acid for inadequate response). A young or middle-aged man with ulcerative colitis (70 to 80 percent have UC) plus p-ANCA plus beaded large-duct strictures on MRCP/ERCP plus increased risk of cholangiocarcinoma equals primary sclerosing cholangitis (ursodeoxycholic acid has limited benefit; consider transplant; surveillance MRCP and CA 19-9 for cholangiocarcinoma).

Watch it explained

Test it now

The repair move

For cholestatic autoimmune disease, ask antibody and duct map: small intrahepatic autoimmune destruction or beaded large-duct sclerosis.

Try a free question

Core

A middle-aged woman has pruritus, fatigue, cholestatic labs, and antimitochondrial antibodies. Which diagnosis is most likely?

Show answer and explanation

Answer: A. Primary biliary cholangitis. Primary biliary cholangitis is autoimmune destruction of small intrahepatic bile ducts, classically with antimitochondrial antibodies.

Why the other choices are tempting

  • B. Primary sclerosing cholangitis is associated with inflammatory bowel disease and beading of intra/extrahepatic ducts.
  • C. HBV is diagnosed by viral serologies rather than antimitochondrial antibodies.
  • D. Alcohol-associated hepatitis has alcohol exposure and AST-predominant injury.
  • E. Gilbert syndrome causes benign unconjugated hyperbilirubinemia.

Flashcards

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What antibody points to primary biliary cholangitis?

Antimitochondrial antibody is the classic PBC marker.

What imaging pattern points to primary sclerosing cholangitis?

Multifocal strictures with beading of intrahepatic and extrahepatic ducts supports PSC.

Quick answers

What is the fastest way to tell Primary biliary cholangitis from Primary sclerosing cholangitis?

PBC is small intrahepatic ducts plus antimitochondrial antibody; PSC is beaded intra/extrahepatic ducts plus ulcerative colitis association.

What is the key clue for Primary biliary cholangitis?

Middle-aged woman with pruritus, fatigue, cholestatic labs, antimitochondrial antibodies, and small intrahepatic bile duct destruction.

What is the key clue for Primary sclerosing cholangitis?

Cholestatic disease associated with ulcerative colitis, multifocal strictures, and beading of intrahepatic and extrahepatic bile ducts.

What is the common trap with Primary biliary cholangitis vs Primary sclerosing cholangitis?

Both are cholestatic with pruritus, elevated alkaline phosphatase, and progress to cirrhosis. The discriminators are antibody profile, duct anatomy, and demographics plus associated diseases. A middle-aged woman with positive antimitochondrial antibody (AMA) plus elevated IgM plus destruction of SMALL intrahepatic ducts on biopsy equals primary biliary cholangitis (treat with ursodeoxycholic acid first-line, add obeticholic acid for inadequate response). A young or middle-aged man with ulcerative colitis (70 to 80 percent have UC) plus p-ANCA plus beaded large-duct strictures on MRCP/ERCP plus increased risk of cholangiocarcinoma equals primary sclerosing cholangitis (ursodeoxycholic acid has limited benefit; consider transplant; surveillance MRCP and CA 19-9 for cholangiocarcinoma).