Bowel Preparation for Colonoscopy in Patients with a Colostomy

General Principles

The need for bowel preparation depends on which portion of the colon will be examined and whether the colostomy diverts stool away from the segment being visualized, as noted by the American Gastroenterological Association 1, 2

No oral bowel preparation is needed if only examining the proximal colon through the colostomy stoma, according to the American Gastroenterological Association 1
The US Multi-Society Task Force on Colorectal Cancer notes that patients with prior gastrointestinal surgical resection, including those with ostomies, are at significantly higher risk for inadequate bowel preparation (OR 7.5; 95% CI 3.4-17.6) 1
Full oral bowel preparation IS required if examining the distal colon (the bypassed segment), as recommended by the American Gastroenterological Association and the European Society for Clinical Nutrition and Metabolism 1, 4

The American Gastroenterological Association recommends using mechanical bowel preparation (MBP) when examining the defunctionalized distal segment, with a standard split-dose PEG preparation (2-4L) 2, 3, 4
Split-dosing improves preparation quality even in high-risk patients (strong recommendation, high-quality evidence), as noted by the American Gastroenterological Association 2, 3
Complete the second dose 2 hours before the procedure, as recommended by the American Gastroenterological Association 2, 3

Provide intensified patient education and navigation (weak recommendation, moderate-quality evidence), as suggested by the American Gastroenterological Association 2, 5
Consider restricting vegetables and legumes for 2-3 days before colonoscopy rather than just the day before, as recommended by the American Gastroenterological Association 2
Allow only clear liquids the day before the procedure in this high-risk population, as recommended by the American Gastroenterological Association 2
Consider adding a promotility agent to the standard preparation, as suggested by the American Gastroenterological Association 2

The ERAS Society guidelines note that when a diverting ileostomy is present during low anterior resection, MBP may be necessary, though this requires further study 4
If the distal colon will be examined, full oral preparation should be administered, as recommended by the American Gastroenterological Association and the European Society for Clinical Nutrition and Metabolism 1, 4