Intestinal Infection, Psychological Factor, Stress And Irritable Bowel Syndrome

Irritable bowel syndrome(IBS) is a common alimentary disorder. Little is known about its etiology and pathogenesis. Current studies suggest that IBS is related to intestinal infection, psychological factors and stress. Our research aimed at exploring role of intestinal infection, psychological factors and stress on IBS, and the pathophysiological mechanism of IBS was also studied.1. IBS was related to intestinal infection, psychological factors and stress.329 patients who had had dysentery were followed up. After 1-2 years, 66(20.06%) patients were reported to have persistence of altered bowel habit, and 24(7.29%) patients developed irritable bowel syndrome. Whereas the occurence rates of intestinal dysfunction and IBS in those patients' spouse or sibblings who had not been infected with dysentery were lesser(P＜0.01). The risk is higher if the patients suffered from a longer duration of dysentery. In animal model, we found that intestinal infection could sensitisize the intestinal response to stress.In this study, life stressful events, psychological abnormality and personality abnormality were common in IBS patients with or without dysentery. Stress could also increase myoelectric activity of terminal ileum and distal colon of rabbits. This showed psychological factors played an important role in the development of IBS.In animal studies, the intestinal motor index of rabbits induced by stress and intestinal infection was higher than those rabbits induced by stress or intestinal infection alone. And after infection, motor response of terminal ileum and distal colon of rabbits to stress was much higher. This showed that stress and intestinal infection were coactive factors in the induction of intestinal motor disorder.Our study suggested that intestinal infection and/or stress could alter intestinal motility and sensitize the mucosal perception in patients with IBS, whereas abnormal psychological factors could induce perceive changes and symptoms in IBS patients.2. Pathophysiological mechanism of IBS.