Postinfectious Irritable Bowel Syndrome: Clinical Aspects, Pathophysiology, and Treatment

INTRODUCTION Bacterial diarrhea is considered a self-limiting illness lasting 3–5 days, but its complications can persist for weeks, months, and even years in some patients (1–3). One such complication is postinfectious irritable bowel syndrome (PI-IBS), defined as the development of new enteric symptoms meeting objective criteria of irritable bowel syndrome (IBS) in patients who had normal bowel function prior to an enteric infection (1,4). Factors such as duration of initial episode of diarrheal illness may increase a patient’s risk of developing PI-IBS (5,6). Most current treatments target the symptoms of PI-IBS, but therapies aimed at preventing or reducing the duration of acute infection Herbert L. DuPont, M.D., St. Luke’s Episcopal Hospital, University of Texas, Houston School of Public Health, and Baylor College, Houston, TX. Although acute diarrhea is usually a self-limiting illness, postinfection complications may persist long after the initial infection resolves. Postinfectious irritable bowel syndrome (PI-IBS), which is defined as new onset of irritable bowel syndrome after an acute episode of infectious diarrhea, has been reported in 4%–31% of patients within 6 months to 3 years after an initial enteric infection. Chronic mucosal inflammation, immunologic changes, and biochemical alterations triggered by microbial infection may be involved in mechanisms leading to persistent intestinal symptoms. Patients with PI-IBS may have heightened mucosal inflammatory response during an acute infection that leads to a persistent pathophysiologic response and serotonin release long after the acute infection has resolved. Treatment for PI-IBS often focuses on symptom relief, but prevention and early treatment of acute bacterial illness with antimicrobial drugs may be important potential strategies for reducing the risk of PI-IBS development.