Irritable bowel syndrome: current concepts and future trends

About five per cent of the adult population each year will see their doctor with complaints that are finally characterised as irritable bowel syndrome (IBS). The complaints are constipation (perhaps alternating with diarrhoea), abdominal pain (dull or colicky), abdominal distension, abdominal rumbling and flatulence. The diagnosis of IBS implies that a relevant examination has precluded any organic disease. The etiology is unknown and the syndrome probably does not represent a disease entity. It is therefore difficult, if not impossible, to produce a definite rationale of treatment. However, several aspects of the pathogenesis of the individual symptoms of IBS are well known: 1) chronic constipation is most likely due to fibre-depleted diet, psychological factors, local organic disorders (e.g., anal fissures, hemorrhoids, diverticulosis) and disturbance of the body fluid balance (e.g., high consumption of diuretic compounds such as coffee and tea); 2) pain is related to spasms and motility disturbances causing increased intraluminal pressure; 3) meteorism is not due to an increased amount of intestinal gas, but "air traps" and segmental accumulation of gas seem to occur. Furthermore, psychopathological factors and perhaps also food intolerance may play an etiological role. At present the rationale of treatment in IBS is: 1) management of constipation, 2) ease of spasms, 3) reduction of surface tension of intestinal contents, 4) ease of mental stress.