Mechanisms of diarrhea in inflammatory bowel diseases.

Diarrhea is a frequent symptom/sign in patients with ulcerative colitis and Crohn's disease (inflammatory bowel diseases), and several different mechanisms likely account for this diarrhea. As treatment of diarrhea is dependent on the pathogenetic process(es) responsible for diarrhea, increased understanding of the pathophysiology of diarrhea will help improve therapy. Inflammation is central to the diarrhea in patients with ulcerative colitis, while in Crohn's disease both inflammatory and noninflammatory mechanisms are responsible. This presentation summarizes the pathophysiology of diarrhea in both ulcerative colitis and Crohn's disease.