Primary sclerosing cholangitis is a biliary disease of unknown aetiology characterised by inflammation and fibrosis of intra and extra-hepatic bile ducts.

Associations

• ulcerative colitis: 4% of patients with UC have PSC, 80% of patients with PSC have UC
• Crohn's (much less common association than UC)
• HIV

Features

• cholestasis
  • jaundice, pruritus
  • raised bilirubin + ALP
• right upper quadrant pain
• fatigue

Investigation

• magnetic resonance cholangiopancreatography (MRCP) is the diagnostic investigation of choice, showing multiple biliary strictures giving a 'beaded' appearance
  • endoscopic retrograde cholangiopancreatography (ERCP) was historically the gold-standard investigation but it has now been superceded by MRCP which carries a lower risk of complications such as pancreatitis. ERCP still has an important role for interventional procedures
• p-ANCA may be positive
• there is a limited role for liver biopsy, which may show fibrous, obliterative cholangitis often described as 'onion skin'

Complications

• cholangiocarcinoma (in 10%)
• increased risk of colorectal cancer