Clinical and histological impact of diffuse inflammation at pouchoscopy

Purpose The anatomical location of inflammation in and around the ileal pouch affects the pouch survival rate, and diffuse inflammation has poor pouch survival rates. We aimed to clarify the symptoms and histological findings of diffuse inflammation of the pouch. Methods We evaluated the symptoms, treatment, and histological findings according to the endoscopic phenotypes of diffuse inflammation, focal inflammation, and normal as the pouch body phenotype and afferent limb involvement, inlet involvement, cuffitis, and fistula as the peripheral findings. Results Of the 318 pouchoscopies, 47 had diffuse inflammation, 201 had focal inflammation, and 70 were normal. Symptomatic patients had diffuse inflammation more frequently (46.8%) than focal inflammation (13.4%) and normal (14.2%), with no difference between focal inflammation and normal. Antibiotics and steroids were higher rate administered in cases of diffuse inflammation, but not in cases of focal inflammation or in normal cases. Histological inflammation, inflammatory bowel disease (IBD)–specific finding, and colonic metaplasia showed severity in the order of diffuse inflammation > focal inflammation > normal. The number of peripheral inflammatory findings overlapped in the following order: diffuse inflammation > focal inflammation > normal. The number of symptomatic patients increased as the number of peripheral inflammatory findings increased. Conclusion Pouches with diffuse inflammation are more symptomatic, have a higher use of therapeutic agents, and have more severe histological inflammation, IBD-specific finding, and colonic metaplasia accompanying peripheral inflammatory findings than the other groups. The higher the overlap of inflammatory findings in the surrounding tissues, the more symptomatic the patients will appear.