Hepatopancreatobiliary manifestations of inflammatory bowel disease

Inflammatory bowel disease (IBD) is frequently associated with extraintestinal manifestations such as hepatopancreatobiliary manifestations (HPBMs), which include primary sclerosing cholangitis (PSC), pancreatitis, and cholelithiasis. PSC is correlated with IBD, particularly ulcerative colitis (UC); 70-80% of PSC patients in Western countries and 20-30% in Japan have comorbid UC. Therefore, patients diagnosed with PSC should be screened for UC by total colonoscopy. While symptoms of PSC-associated UC are usually milder than PSC-negative UC, these patients have a higher risk of colorectal cancer, particularly in the proximal colon. Therefore, regular colonoscopy surveillance is required regardless of UC symptoms. Administration of 5-aminosalicylic acid or ursodeoxycholic acid may prevent colorectal cancer and cholangiocarcinoma. While PSC is diagnosed by diffuse multifocal strictures on cholangiography, it must be carefully differentiated from immunoglobulin G4 (IgG4)-associated cholangitis, which shows a similar cholangiogram but requires different treatment. When PSC is suspected despite a normal cholangiogram, the patient may have small-duct PSC, which requires a liver biopsy. IBD patients have a high incidence of acute and chronic pancreatitis. Most cases are induced by cholelithiasis or medication, although some patients may have autoimmune pancreatitis (AIP), most commonly type 2 without elevation of serum IgG4. AIP should be accurately identified based on characteristic image findings, because AIP responds well to corticosteroids. Crohn's disease is frequently associated with gallstones, and several risk factors are indicated. HPBMs may influence the management of IBD, therefore, accurate diagnosis and an appropriate therapeutic strategy are important, as treatment depends upon the type of HPBM.