[Inflammatory bowel diseases (IBD) -- critical discussion of etiology, pathogenesis, diagnostics, and therapy]

Crohn's disease and ulcerative colitis are the most frequent inflammatory bowel diseases (IBD) with a prevalence of approximately one out of 500. Cytokine research opened new and potent treatment options and thus stimulated clinical and basic research.However, the IBD still remain a challenge for patients and physicians,demanding close cooperation between gastroenterologists,radiologists and surgeons. The basic understanding of IBD,which is necessary for efficient diagnostic and therapeutic concepts is reviewed.

Based upon recent publications and our clinical experience we discuss aspects of etiology,pathogenesis,diagnostics,and therapy of Crohn's disease and ulcerative colitis.

A genetically influenced, exaggerated and sustained immune response against the own gut flora seems to be one of the most important factors in the pathogenesis of IBD. Not less important are environmental influences. For instance, cigarette smoking had been judged to have some negative influence on the natural course of Crohn's disease.Now,however, recent studies show that smoking is even a significant independent risk factor in the pathogenesis of IBD. Since IBD and especially Crohn's disease can effect the whole body, detailed analysis of inflammatory organ involvement is necessary before therapy. For instance, the MRI enteroclysis technique adds a necessary diagnostic tool for the exploration of those parts of the small bowel that cannot been reached by routine endoscopy like the upper ileum and the lower jejunum. In terms of therapy, a change of paradigms can be observed: patients will no longer be treated only when symptoms arise, but will early be integrated into a therapeutic concept, which is determined by site and extent of the disease and adapted to the abilities and needs of the patient.Furthermore,immunosuppressive agents like azathioprine and 6-mercaptopurine will establish as central concept in the medical treatment of IBD.

IBD-therapy should rather be adapted to the patient's individual inflammatory pattern than be oriented to schematic treatment rules. New endoscopic and radiologic techniques provide the necessary diagnostic tools.