PBC (Primary Biliary Cholangitis) vs PSC (Primary Sclerosing Cholangitis)

Primary Biliary Cholangitis (PBC)

Pathology

• Autoimmune disease targeting intrahepatic bile ducts

• Mostly older women (~90%), typically >45 years old, often smokers

• Strong associations with other autoimmune conditions (e.g. SLE, CREST, RA)

History

• Fatigue, pruritus, RUQ abdominal pain

• Extrahepatic features like arthralgias and dry eyes (Sjögren’s syndrome)

Diagnosis

• AMA (Antimitochondrial Antibody) positive ~95% (high specificity)

• Cholestatic LFT pattern: ↑ ALP, GGT > ALT/AST

• Imaging (e.g. ultrasound) to exclude obstructive causes

• Liver biopsy if diagnosis unclear

Treatment

• Ursodeoxycholic acid: Improves LFTs, slows progression

• Obeticholic acid if inadequate response to ursodeoxycholic acid

• Address osteoporosis risk: Calcium, vitamin D, bisphosphonates

Complications

• Cirrhosis, portal hypertension

• HCC (small but increased risk with advanced disease)

Mnemonic – “Old b**s treating themselves to a ciggie”

• Old b****s = older women

• Treating = treatable condition

• Themselves = intrahepatic only

• A = Autoimmune, AMA-positive, ↑ ALP

• Ciggie = association with smoking

Primary Sclerosing Cholangitis (PSC)

Pathology

• Unknown aetiology: Likely autoimmune + genetic predisposition

• Affects intra- and extrahepatic bile ducts

• Predominantly in younger men (~60%), often <40 years

History

• Often asymptomatic at diagnosis

• IBD association (70–80% have ulcerative colitis)

• Fatigue, jaundice, pruritus

Diagnosis

• MRCP/ERCP: “Beaded appearance” of bile ducts (multifocal strictures)

• Liver biopsy: “Onion-skin” fibrosis in advanced cases

• Exclude secondary causes (biliary obstruction, infection, ischaemia)

Treatment

• No curative treatment → mainly symptom management

• Ursodeoxycholic acid use is controversial, sometimes used for itch/liver enzyme improvement

• Liver transplant if advanced disease or recurrent cholangitis

Complications

• Cirrhosis, portal hypertension

• Cholangiocarcinoma (~10–15% lifetime risk)

Mnemonic – “Sht – literally and figuratively”*

• Literal: IBD-associated diarrhoea

• Figurative: No cure available, high risk of cholangiocarcinoma

Key Points

• PBC → Intrahepatic ducts, older women, AMA-positive, responds to ursodeoxycholic acid

• PSC → Intra- and extrahepatic ducts, younger men, strong UC association, risk of cholangiocarcinoma

• Both can lead to cholestasis, cirrhosis, and require monitoring for complications