Asymmetric Endoscopic Inflammation of the Ileal Pouch: A Sign of Ischemic Pouchitis?

Background: Pouchitis is associated with dysbiosis and dysregulated mucosal immunity, although secondary pouchitis with special etiologic factors, such as ischemia, can occur. The aim was to describe a disease phenotype of the ileal pouch with an endoscopic appearance suggestive of ischemia. Methods: We identified consecutive patients with endoscopic asymmetric inflammation of the pouch (inflammation of side of the pouch with a completely normal other limb of the pouch one limb and a sharp demarcation along the staple suture line). Patients with Crohn's disease (CD) of the pouch or antibiotic-responsive pouchitis, matched for duration of the pouch, served as controls. Histology slides of mucosal biopsies were re-reviewed independently by 2 blinded gastrointestinal pathologists. Demographic, clinical, endoscopic, histologic, and imaging characteristics were compared between the groups. Results: Ten patients with ischemic pouchitis, 15 with CD of the pouch, and 15 with antibiotic-responsive pouchitis were studied. Pyloric gland metaplasia was observed only in the groups with CD of the pouch (23.1%) or antibiotic-responsive pouchitis (13.3%). Of patients with ischemic pouchitis, 80% had extracellular hemosiderin or hematoidin deposits (versus 30.8% those with CD of the pouch and 13.3% of those with pouchitis, P = 0.003). The majority of patients (80%) with ischemic pouchitis did not respond to conventional antibiotic therapy. It appeared that subsequent abdominal surgeries after pouch construction and a history of postoperative portal vein thrombi were associated with ischemic pouchitis. Conclusions: Endoscopic asymmetric inflammation of the pouch may represent an ischemia-associated pouchitis with characteristic clinical, radiographic, and histologic features. Its hemodynamic, cellular, and molecular basis of mechanism warrants further study.