Disinfectant colitis. Rinse as well as you wash.

Commercially available endoscope disinfecting solutions readily cause colonic damage if allowed to contact mucosa. The two most common cleaning solutions differ in their initial toxic effect (glutaraldehyde directly injuries crypt epithelium, and hydrogen peroxide compromises mucosal stroma), but both ultimately result in tissue necrosis over time. Within 12-48 h after colonoscopy, patients show signs of bloody diarrhea, cramping, and fever--symptoms that may be confused with an infectious process. Based on a literature review and our own experimental studies, we conclude that hydrogen peroxide alone is responsible for a unique form of colitis commonly referred to as pseudolipomatosis by pathologists. This controversial lesion becomes visible as opaque plaques or pseudomembranes even while colonoscopy is in progress and is almost assuredly due to the effervescent release of molecular oxygen. Diligent rinsing is necessary to minimize patients' exposure to residual disinfecting chemicals in the endoscope. When an automatic disinfecting machine is employed, it may require strict adherence to proper maintenance and volume adjustments in the rinse cycle. Forced air drying and an additional preprocedure rinse of channels and the exterior of the scope should ensure a chemical-free examination.