Post-infectious Irritable Bowel Syndrome

inflammatory component of IBS. A proportion of patients with diarrhea-predominant IBS recall acute infectious enteritis as a boot for the onset of their symptoms, and 7%-33% of patients with acute bacterial enteritis will experience IBS symptoms for over 6 months. A chronic latent inflammation has been documented in mucosal biopsies of these patients. Post-infectious IBS (PI-IBS) has been linked to bacterial (campylobacter, shigella, salmonella) or parasitic (trichinella spiralis) infections. The prevalence of PI-IBS is 6% to 17% among IBS patients in different series and lower in older people (over 60 years old), probably due to their weaker immune system. The risk for PI-IBS correlates to the duration and severity of the initial illness. Infection in early childhood has a milder course and induces partial immunity, therefore PI-IBS is rarer in tropical areas where the prevalence of pediatric gastrointestinal infections is high. Vomiting seems to exert a protective role possibly because it reduces the ingested bacterial load. Other risk factors include female gender, hypochondriasis and adverse life events. PI-IBS is twice as frequent in monozygotic twins compared with dizygotic twins, so a genetic parameter may also interfere.