Comparison of rectosigmoid myoelectrical activity in the irritable colon syndrome during relapses and remissions.

Recent studies have suggested that a high incidence of 0.05 Hz (3 c/m) slow wave electrical activity is present within the rectosigmoid of patients with the irritable colon syndrome during symptomatic phases. However, it is known that this is a chronic relapsing disorder and in this study we have compared myoelectrical recordings, using an on-line frequency analyser, during periods of severe symptoms and asymptomatic phases. Treatment with either bran (in the form of bran tablets) or an antispasmodic resulted in 12 of the 20 patients becoming free from symptoms after one to three months. In those patients who were initially constipated a statistically significant increase in mean stool weight and a decrease in mean transit time occurred, but this was not associated with any alteration in either percentage motility or electrical activity. In patients with predominant diarrhoea no statistically significant difference occurred in either transit time or stool weight after treatment nor did the abnormal myoelectrical activity return towards normal with symptomatic improvement. These results suggest that a fixed basic myoelectrical abnormality exists which is unrelated to symptoms. This may help to explain the chronic relapsing nature of the irritable colon syndrome.