Colonic sensitive-motor alterations in the irritable bowel syndrome.

The pathogenetic factors involved in the genesis of the irritable bowel syndrome (IBS) has not been fully explained yet. The abnormalities observed in these patients are a hypersensitivity to distension and an amplification of painful sensations. The motor activity of sigmoid colon shows an increased motility index in IBS patients with constipation and a low motility index in those with diarrhea. An hypercaloric meal induces a hypermotility in these patients. In our experience rectal distension evokes abdominal pain in 78% of cases at volumes of 100ml (less than than controls and constipated patients). The perfusion of rectum induces continuous abdominal pain in 89% of IBS patients. We can say that the motility of the whole colon over prolonged periods of time may represent an important progress in understanding the motor function in these patients.