Pouchitis is inflammation of the ileal pouch (an artificial rectum surgically created out of ileal gut tissue in patients who have undergone a colectomy), which is created in the management of patients with ulcerative colitis, indeterminate colitis, FAP, or, rarely, other colitides.
Patients with pouchitis typically present with bloody diarrhea, urgency in passing stools, or discomfort while passing stools. The loss of blood and/or dehydration resulting from the frequent stools will frequently result in nausea. Extreme cramping and pain can occur with pouchitis.
Endoscopy in patients with pouchitis usually reveals erythematous pouch mucosa, loss of pseudocolonic vasculature or other architecture, and friability of the mucosa. Biopsies show evidence of inflammatory cells or red blood cells in the lamina propria.
Symptom severity does not always correlate with severity of endoscopically- or histologically-evaluated pouch inflammation. Additionally, these symptoms are not necessarily specific for pouchitis, as they may arise from other inflammatory or functional pouch disorders such as Crohn's disease of the pouch, cuffitis, pouch sinus, or irritable pouch syndrome. The most reliable tool for diagnosis is endoscopy combined with histologic features (derived from tissue biopsies obtained during endoscopy).
The duration of pouchitis is defined as acute (less than or equal to four weeks) or chronic (four weeks or more) and the pattern classified as infrequent (1-2 acute episodes), relapsing (three or fewer episodes) or continuous. Finally, the response to medical treatment as labelled as treatment responsive or treatment refractory, with the medication for either case being specified.
There is no clinically approved treatment for pouchitis. First line treatment is usually with antibiotics, specifically with ciprofloxacin and metronidazole.Ampicillin or piperacillin can also be considered as alternatives to empiric ciprofloxacin and metronidazole. Administration of metronidazole at a high daily dose of 20 mg/kg can cause symptomatic peripheral neuropathology in up to 85% of patients. This can be a limiting factor in the use of maintenance metronidazole to suppress chronic pouchitis.
Other therapies which have been shown to be effective include probiotics, the application of which usually begins as soon as any antibiotic course is completed so as to re-populate the pouch with beneficial bacteria. Biologics, such as anti-TNF antibodies, may also be useful but the evidence for their use is largely anecdotal. In addition, discussion by patients using related internet forums appears to give evidence of benefits (again, after cessation of antibiotics) from certain diets, such as the specific carbohydrate diet, Paleolithic diet, and low-FODMAP diet. In particular, attention has been drawn to the exclusion of complex carbohydrates, as well as other foods with high starch content (such as grains, rice, and potatoes) and certain dairy products including milk and soft cheese.
Alicaforsen (an antisense inhibitor which targets the messenger RNA for the production of human ICAM-1 protein) was evaluated in a Phase 3 clinical trial, which did not meet the co-primary endpoints in the primary analysis (an adaptation of the Mayo Score of improvement in endoscopic remission and bowel frequency).