The IBD and PSC Phenotypes of PSC-IBD

To review the characteristics of IBD and PSC that occur in association, as well as their reciprocal influences on disease evolution, in adult and pediatric populations.

IBD co-existing with PSC is genetically and clinically distinct from IBD alone. It is frequently characterized by pancolitis, rectal sparing, and possibly backwash ileitis, as well as a threefold increased risk of colorectal dysplasia. Adults and children with colitis and PSC appear to be at increased risk of active endoscopic and histologic disease in the absence of symptoms compared to individuals without PSC. PSC occurring with Crohn's disease has been observed to be less severe than PSC co-existing with ulcerative colitis, independent of its association with small duct disease. Recent studies suggest that colectomy is associated with a decreased risk of recurrent PSC after liver transplantation, challenging the traditional teaching that PSC and IBD evolve independently. While much about the gut-liver axis in PSC-IBD remains poorly understood, the IBD associated with PSC has a unique phenotype, of which subclinical inflammation is an important component. Additional research is needed to characterize further the potentially protective role of colectomy against recurrent PSC post-liver transplantation and to investigate the influence of IBD control and/or colectomy on PSC progression.