HOME
Return to Table of Contents
129 THE YIELD OF COLONOSCOPY VERSUS SIGMOIDOSCOPY IN CHRONIC DIARRHEA A Rostom1, K Muir, C Dubé2, N Saloojee2 BACKGROUND AND AIMS: Chronic diarrhea is frequent reason for GI referral. Colonic abnormalities account for an important proportion of the causes of chronic diarrhea, but it is unclear if a full colonoscopy is required in all cases to make the diagnosis. The aim of this study was to determine the incremental diagnostic yield of colonoscopy and biopsy over standard flexible sigmoidoscopy in the work of non-bloody chronic diarrhea.
1University of Calgary, Calgary, Alberta; 2University of Ottawa, Ottawa, Ontario
METHODS: All patients, 18 years or older, referred to a primary care GI clinic for chronic non-bloody diarrhea were included. Chronic diarrhea was defined as a decrease in stool consistency with an increase in stool frequency occurring for 4 weeks or longer. Patients were excluded if they had a clear diagnosis of irritable bowel syndrome based on the modified ROME criteria and without any alarm features, had a clear cut diagnosis of a condition that would not normally require endoscopy (such as chronic pancreatitis), had undergone prior investigation for diarrhea, had a known HIV infection, had co-morbidities preventing colonoscopy, refused to undergo colonoscopy or follow-up, or had symptoms that were resolved at presentation. Included patients underwent colonoscopy. Biopsies were to be taken from the terminal ileum, right colon, transverse colon, and left colon (within the reach of a standard 60 cm flexible sigmoidoscope). Patients were excluded at this stage if the ascending colon was not reached and the descending colon was normal, since the absence of right-sided biopsies in this case would make it impossible to tell whether sigmoidoscopy alone would have been sufficient.
RESULTS: 741 patients were evaluated - 183 were excluded, and 252 did not require colonoscopy for diagnosis of their diarrhea, leaving 306 patients that underwent colonoscopy and biopsy. The colonoscopy was normal in 260 (85%), but 34% of these had an abnormal biopsy. Colonoscopy was reported as abnormal in 46 (15%) but 35% of these had a normal or nonspecific biopsy. A total of 125 patients had a diagnosis at colonoscopy and biopsy. Sigmoidoscopy and biopsy would have made the diagnosis in 88.9%, while colonoscopy added only an additional 4.6%.
CONCLUSION: In a cohort of previously uninvestigated non-bloody chronic diarrhea patients who require lower endoscopy, biopsy is important even if the mucosa looks normal. The incremental yield of colonoscopy is only 4.6%. Sigmoidoscopy and biopsy appears to be an appropriate first step.