In primary sclerosing cholangitis (PSC) associated with IBD, the bowel disease has a characteristic distribution pattern. Which feature is typical of PSC-associated UC?

• A Severe pancolitis with prominent rectal involvement
• B Mild pancolitis with rectal sparing and backwash ileitis ✓
• C Left-sided colitis with prominent proctitis
• D Skip lesions resembling Crohn's colitis

Explanation

PSC-associated IBD characteristically presents as mild, extensive (pan-)colitis with relative rectal sparing (unlike typical UC) and backwash ileitis — a pattern termed 'PSC-IBD' which is clinically and genetically distinct from UC alone. Despite mild bowel symptoms, this IBD subtype carries significantly elevated risk of colorectal cancer (annual surveillance colonoscopy from diagnosis of PSC). The PSC itself is treated with ursodeoxycholic acid (symptomatic but no mortality benefit at high doses) and liver transplantation for decompensated disease.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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