The Clinical Course of Postinfectious Irritable Bowel Syndrome

OBJECTIVES: Irritable bowel syndrome (IBS) is a common disorder seen in general practice. Bacterial gastroenteritis has been known to be a risk factor for IBS. We investigated the clinical course, risk factors, and prognosis of postinfectious IBS (PI-IBS) 5 years after Shigella infection. METHODS: We recruited 153 individuals and used a questionnaire to investigate their current bowel habits. We also looked for the presence of other functional bowel disorders (FBDs). The Shigella-exposed group consisted of hospital employees and medical students who experienced abdominal pain, diarrhea, or fever during the shigellosis outbreak and whose stool culture revealed Shigella sonnei. The control group consisted of age-matched and sex-matched subjects who corresponded fairly well with patients, considering that they were enrolled from the same hospital and were not infected. RESULTS: Complete data were obtained from 119 individuals who were divided into the Shigella-exposed group (59) and the control group (60). In the Shigella-exposed group, 3 patients had IBS before infection (previous IBS) and 6 out of 13 cases of PI-IBS after 3 years showed persistent IBS after 5 years. Five out of 11 PI-IBS patients (45.5%, 2 excluded), 3 out of 6 previous IBS patients (50%) in the Shigella-exposed group, and 7 out of 11 previous IBS patients (63.6%) in the control group recovered after 5 years (P>0.05). Five cases in the Shigella-exposed group and 3 in the control group developed new cases of IBS after 5 years. The prevalence of PI-IBS after 5 years in the previous FBD groups was 63.6%, whereas the prevalence of PI-IBS without a history of FBDs was 36.4% (P<0.05). There were no significant differences among the other risk factors in each group. CONCLUSIONS: About half of PI-IBS and previous IBS patients with or without infection recover over 5 years. Previous IBS and FBDs are risk factors of PI-IBS after 5 years. We suggest that our results support the understanding of the clinical course and prognosis of PI-IBS.