While primary sclerosing cholangitis (PSC) has been associated with inflammatory bowel disease, and ulcerative colitis (UC) in particular, the pathogenesis of this relationship has not been established.  A fascinating observation on this relationship is that an inflamed colon is important in PSC development (Clin Gastroenterol Hepatol 2012; 10: 439-41).

In this study which reviewed 2754 Irish patients with IBD, 59 (2.2%) had PSC.  PSC incidence correlated with increasing colonic involvement.  Among the 13 patients with Crohn’s disease, none had isolated small bowel disease.  The second part of the study involved a review of 82 separate PSC patients attending the Irish National liver transplant unit.  The majority of ulcerative colitis patients had a pancolitis; all 10 PSC patients with Crohn’s disease had colonic involvement.

Since PSC occurs without IBD, colonic inflammation is not necessary for PSC development.  However, in patients with IBD, colonic inflammation is very important.  In fact, in a previous study of 53 PSC-IBD patients, no UC patient status post a colectomy had recurrent liver disease following liver transplantation whereas seven patients with intact colons had recurrent disease following liver transplantation.

The authors speculate that bacterial translocation along with subsequent portal bacteremia may be an important step in pathogenesis among these patients.

Additional references/previous posts:

• –Challenges with primary sclerosing cholangitis
• -Liver Transplant 2008; 14: 138-43.  Risk factors for recurrent PSC after OLT