A prospective, observational study of colonic mucosal abnormalities associated with orally administered sodium phosphate for colon cleansing before colonoscopy.

Background: Colonic mucosal abnormalities associated with sodium phosphate colonic preparations have been described. The aim of this prospective study was to determine the frequency at which these occur and to define the endoscopic and histopathologic patterns of these changes.

Methods: Within a 16-month period, 730 of patients referred for elective colonoscopy entered the study. Patients with known inflammatory bowel disease and those taking non-steroidal anti-inflammatory drugs were excluded. A sodium phosphate solution was ingested orally 14 and 8 hours before endoscopy. After standard colonoscopy, a 3-year clinical follow-up program was conducted.

Results: Endoscopically, mucosal lesions, possibly associated with sodium phosphate ingestion, were visible in 24 patients (3.3%). Erosions were found in 3 patients, aphthoid lesions in 21 patients, and an ulcer in one patient. Lesions often were multiple. Histopathologically, findings included focal active inflammation in 14 of 24 patients, mucosal disruption and erosion (7/24), edema of the lamina propria (5/24), mucosal hyperemia or focal hemorrhage (5/24), lymphoid nodules (5/24), and ulceration (1/24).

Conclusions: Orally administered sodium phosphate-associated colonic mucosal abnormalities are infrequent but can mimic an non-steroidal anti-inflammatory drug-induced injury or inflammatory bowel disease, and in particular must be differentiated from Crohn's disease.