A practical approach to treating patients with chronic diarrhea.

Although diarrhea is a common complaint, its evaluation and treatment can be challenging. Appropriately defining and classifying diarrhea provide the framework for approaching diagnostic and therapeutic options. Diarrhea can be defined based on frequency, consistency, and/or weight, and classified as acute or chronic with specific clinical characteristics and stool appearance. Colonoscopy is the most common diagnostic tool used in the evaluation of patients with chronic diarrhea. Other evaluation strategies include timed stool collections, evaluation of inflammatory markers, and hydrogen breath tests. A focused workup of chronic diarrhea may yield a specific diagnosis, including diarrhea-predominant IBS (dIBS), functional diarrhea, diabetic diarrhea, bile acid-induced diarrhea, and microscopic colitis. Ideally, therapeutic decisions are specifically tailored to target the underlying pathophysiology, including, for example, gluten restriction for celiac disease, rotating antibiotics for small bowel bacterial overgrowth, budesonide therapy for collagenous colitis, and loperamide for treatment of functional diarrhea. It is also important to assess the role of diet and medications in chronic diarrhea. However, if no specific causes are identified following workup, empiric therapy with simple opiate antidiarrheals such as loperamide may be effective. If this proves unsuccessful, the use of more potent agents, including codeine and opium, may be considered.