[Ileo-anal "pouchitis": a still misunderstood pathology].

Chronic and/or acute inflammation of the ileal reservoir, so-called "pouchitis", is a frequently observed long-term complication of the ileo-anal "pouch" anastomosis. In ulcerative colitis patients, the prevalence of "pouchitis" varies from less than 10% to higher than 40%. These large variations reflect differences in diagnostic criteria and length of follow-up. The definition of "pouchitis" should include clinical symptoms, macroscopic inflammatory lesions at endoscopy and histological evidence of intense acute inflammation of the reservoir mucosa. Local bacterial overgrowth, lack of short chain fatty acids, increased secondary biliary acids, decreased intraepithelial T-lymphocytes and oxygen derived free-radicals could be implicated in the pathogenesis of pouchitis. In the absence of definite aetiology for pouchitis, its treatment is purely empirical: metronidazole, corticosteroids and 5-aminosalicylic acids are the most used drugs. The long-term consequences of the partial colic metaplasia of the pouch mucosa remain to be elucidated by regular clinical, endoscopical and histological longitudinal.