Inflammatory bowel disease in patients with primary sclerosing cholangitis - a unique phenotype of IBD
Lukáš Bajer Orcid.org 1, David Kamenář Orcid.org 1, Eva Sticová Orcid.org 2, Pavel Wohl Orcid.org 1, Julius Špičák Orcid.org 1, Pavel Drastich Orcid.org 1
1 Klinika hepatogastroenterologie, Transplantcentrum, IKEM, Praha
2 Pracoviště klinické a experimentální patologie, Transplantcentrum, IKEM, Praha
Inflammatory bowel disease associated with primary sclerosing cholangitis (PSC-IBD) can be understood as a unique phenotype of IBD due to its specific characteristics. The highest prevalence can be found in north European and American countries which also have the highest prevalence of PSC. Both IBD and PSC are multifactorial diseases, in the development of which genetic predispositions play a decisive role. A pathogenetic association between these two diseases is almost undeniable but their precise causal relationship remains unclear. An important role is probably played by secondary bile acids, intestinal microflora, intestinal barrier malfunction, and regulatory T-lymphocytes. In spite of all the relations mentioned, the origin of these two diseases is usually metachronous - PSC can manifest many years after a total proctocolectomy and, on the contrary, colitis appears de novo in liver transplant patients in as many as 30% of cases. In most patients, however, the onset of IBD precedes the development of PSC. PSC-IBD typically manifest as a relatively mild pancolitis with the predominant involvement of the right-side colon. Typical manifestations include simultaneous affection of the terminal ileum ("backwash" ileitis) and "rectal sparing". From the histological point of view, in the vast majority of cases it is referred to as ulcerative colitis (79-91.2%), and only rarely as Crohn's disease (6.3-7 %). Dueto its mild progression, colitis is most often treated with aminosalicylate monotherapy. As regards thiopurines, it is necessary to consider the increased occurrence of adverse effects, especially hepatotoxic ones. There are no sufficient data on the use of biological treatment in this group of patients. The first-choice method in surgical treatment is proctocolectomy with ileal pouch-anal anastomosis (IPAA). PSC patients displayed a higher rate of pouchitis (63-75%), both acute and chronic. Considering the increased risk of colorectal carcinoma in this group of patients, it is recommended to perform a total colonoscopy once a year. A single focus of non-lipoid lesions with low-grade dysplasia verified by two pathologists should lead to considering prophylactic colectomy, with a view to a high risk of progression to colorectal carcinoma (up to 50% within five years). As regards chemoprevention of colorectal carcinoma in PSC-IBD patients, good results are achieved by administering ursodeoxycholic acid in low doses (8-15 mg/kg/day).
Keywordsinflammatory bowel disease, colorectal cancer, primary sclerosing cholangitis, ulcerative colitis
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