Background: Oral sodium phosphate (NaP) is increasingly used as a colonic cleansing agent for colonoscopy. It has been shown to be efficacious, well-tolerated, and safe. Mucosal abnormalities associated with NaP have recently been described. We carried out this controlled study to assess whether bowel cleansing preparations commonly used in colonoscopy are associated with colonic mucosal changes that may mimic inflammatory bowel disease (IBD).

Method: All patients undergoing colonoscopy from January 1994 to June 1994 were considered for the study. Patients with history or symptoms suggestive of IBD were excluded. Patients were randomized to receive polyethylene glycol–based lavage (PEG-ELS) or NaP solution as their bowel cleansing preparation. Two gastroenterologists performing the colonoscopies were blinded to the type of preparation. Any mucosal abnormalities were noted and photographic documentation and biopsy specimens were taken.

Results: Ninety-seven patients were studied, 44 receiving PEG-ELS and 53 receiving NaP. Both groups were similar with regard to sex, age, and indication for colonoscopy. Fourteen patients were found to have nonspecific aphthoid-like erosions similar in appearance to Crohn's disease. These lesions, however, were not friable and biopsy results were not compatible with IBD. This mucosal abnormality was found in 13 patients who received NaP (24.5%) and only 1 patient who received PEG-ELS (2.3%).

Conclusion: Nonspecific aphthoid-like mucosal lesions occur frequently in patients who received NaP for colonoscopy preparation. These lesions are endoscopically similar to those seen in Crohn's disease. Because of the potential for misinterpretation of these lesions, we do not recommend the use of NaP as a colonic cleansing preparation for patients with chronic diarrhea or in whom the diagnosis of IBD is suspected (Gastrointest Endosc 1996;43:463-6.)