[Functional and inflammatory bowel disorders]

Current investigations suggest that postinflammatory mechanisms might induce subtle changes in the mucosa and enteric nervous system which cannot be readily detected by routine diagnostic measures in subgroups of functional bowel disorders, especially in postinfectious irritable bowel syndrome (PI-IBS). DEFINITION OF PI-IBS: Characteristic of IBS is a symptom cluster with abdominal pain/discomfort and altered bowel movement without pathologic findings during routine work-up. PI-IBS is characterized by acute onset of symptoms, fever, vomiting, diarrhea and/or positive stool culture.

The incidence of PI-IBS is 10-17% in unselected IBS patients of whom 70% develop diarrhea, 26% alternating bowel movement and 8% constipation.

Initial gastrointestinal infections might induce subtle ongoing inflammation with consecutive altered mucosal function. Pathomechanisms include mutations within the interleukin-(IL-) 10 promoter polymorphism, hyperplasia of specialized cells including Paneth and enteroendocrine cells (EC) through cytokines as well as inflammatory-mediated modulation of neurones and neurotransmitters within the enteric nervous system. DIAGNOSIS, DIFFERENTIAL DIAGNOSIS, AND THERAPY: It is essential to exclude alarm symptoms. IBS can be positively diagnosed with a sensitivity and specificity of > 90% by standardized questionnaires. Indications of PI-IBS are the acute onset of symptoms, fever, vomiting, diarrhea and/or positive stool culture. Differential diagnoses include lactose intolerance, small bowel bacterial overgrowth, bile acid malabsorption, celiac disease, giardiasis, chronic inflammatory bowel disease, collagenous colitis, and diverticulitis. Therapeutic options in PI-IBS remain symptomatic. So far, no specific anti-inflammatory treatment modalities are available.