Chronic Diarrhea Evaluation in the Elderly: IBS or Something Else?

Chronic diarrhea is a common problem in all age groups but is a particularly challenging diagnostic problem in the elderly, since many different conditions need to be considered. The purpose of this review is to discuss the evaluation of chronic diarrhea in older individuals. It highlights those conditions that seem to occur with increased frequency in the elderly, discusses the diagnostic tests that are of greatest value in sorting out these problems, and presents an approach to evaluation that is both practical and affordable. There appears to be little value in distinguishing irritable bowel syndrome with diarrhea (IBS-D) from functional diarrhea in most patients, including older individuals. Both conditions need a thoughtful analysis of potential causes that may lead to more focused treatment. Older individuals may be more at risk of having certain structural disorders, and these need to be considered when constructing a differential diagnosis. In addition, elderly patients may have atypical presentations of specific disorders that require an increased index of suspicion. Diagnostic tests generally seem to perform well in older patients but have not been validated in this cohort of patients. Although the pretest probabilities of certain diseases are different in the elderly, the conventional algorithm for assessment of chronic diarrhea should lead to a diagnosis in most cases. Better studies are needed to adequately quantitate the likelihood of different diagnoses and the operating characteristics of diagnostic tests in older patients with chronic diarrhea. Lacking that information, physicians can still do a good job of making a diagnosis in these patients by adopting a stepwise approach.