SUMMARY BackgroundThe agreement between subtyping irritable bowel syndrome (IBS) patients based on Rome II criteria versus Rome III criteria is unknown.

The pathophysiology of IBS is complex and still incompletely known. Both central and peripheral factors, including psychosocial factors, abnormal GI motility and secretion, and visceral hypersensitivity, are thought to contribute to the symptoms of IBS. Several studies have demonstrated altered GI motor function in IBS patients and the pattern differs between IBS subgroups based on the predominant bowel pattern. Few studies have so far addressed GI secretion in IBS, but there are some evidence supporting altered secretion in the small intestine of IBS patients. Visceral hypersensitivity is currently considered to be perhaps the most important pathophysiological factor in IBS. Importantly, several external and internal factors can modulate visceral sensitivity, as well as GI motility, and enhanced responsiveness within the GI tract to for instance stress and nutrients has been demonstrated in IBS patients. Today IBS is viewed upon as a disorder of dysregulation of the so-called brain-gut axis, involving abnormal function in the enteric, autonomic and/or central nervous systems, with peripheral alterations probably dominating in some patients and disturbed central processing of signals from the periphery in others.

Forfa eren har fylt ut ICMJE-skjemaet og oppgir ingen interessekonflikter. Det medisinske fakultet Universitetet i Oslo Mari Zimmermann er medisinstudent. Forfa eren har fylt ut ICMJE-skjemaet og oppgir ingen interessekonflikter. Avdeling for radiologi Oslo universitetssykehus, Rikshospitalet Trygve Syversveen er ph.d. og overlege. Forfa eren har fylt ut ICMJE-skjemaet og oppgir ingen interessekonflikter.