Usefulness of Colonoscopy with Biopsy in the Evaluation of Patients with Chronic Diarrhea

Abstract & commentary

Synopsis: Using colonoscopy with biopsy, the diagnoses were Crohn’s disease, ulcerative colitis, lymphocytic colitis, ischemic colitis, infectious colitis including CMV, and assorted miscellaneous diseases including such entities as radiation colitis, eosinophilic colitis, and melanosis coli.

Source: Shah RJ, et al. Am J Gastroenterol. 2001;96:
1091-1095.

Chronic diarrhea is a common problem leading to referral to gastroenterologists, and work-up often includes colonoscopy. Referring physicians need to have some explicit information regarding the use of this approach to their patients, but there is little information available outside the setting of HIV patients. It has been reported that lymphocytic and collagenous colitis may occur in as many as 5-9% of patients evaluated for chronic diarrhea, and these diseases do require colonoscopy and biopsies for diagnosis although biopsy of normal-appearing mucosa otherwise has been discouraged as unhelpful.1,2

This study from the University of Cincinnati reviewed 168 patients having colonoscopy with biopsies to evaluate "unexplained" or "chronic" diarrhea of at least 4 weeks duration, with 85% also having ileoscopy performed. Exclusions included prior intestinal surgery, known inflammatory bowel disease, HIV infection, incomplete colonoscopy, and any prior history of colonoscopy for diarrhea. Sixty-eight percent of the patients were women. Diagnoses were Crohn’s disease, ulcerative colitis, lymphocytic colitis, ischemic colitis, infectious colitis including CMV, and assorted miscellaneous diseases including such entities as radiation colitis, eosinophilic colitis, and melanosis coli (the last finding assumed to indicate surreptitious laxative use). Shah and colleagues recommended biopsies sampling various areas of the colon and ileum. A total of 31% of patients with normal findings ultimately were diagnosed as having irritable bowel syndrome.

Comment by Malcolm Robinson, MD, FACP, FACG

This paper addresses an important question, and primary care physicians should be aware of the potential advantages of colonoscopic and biopsy evaluations of their patients with unexplained chronic diarrhea. There remains some uncertainty as to the increased yield from complete colonoscopy vs. flexible sigmoidoscopy, but 2 patients would not have been correctly diagnosed had ileoscopy not been done. Many experts would argue with the need to perform colonoscopy in all patients with symptoms that strongly suggest irritable bowel syndrome, but this approach is widely used by gastroenterologists. It is difficult not to believe that the 31% of patients in this series receiving specific diagnoses from endoscopic interventions benefited from these procedures.

References

1. MacIntosh DG, et al. Am J Gastroenterol. 1992;87: 1407-1409.

2. Prior A, Lessells AM, Whorwell WJ. Dig Dis Sci. 1987; 32:673-676.