HEIGHTENED VISCERAL SENSATION IN FUNCTIONAL GASTROINTESTINAL-DISEASE IS NOT SITE-SPECIFIC - EVIDENCE FOR A GENERALIZED DISORDER OF GUT SENSITIVITY

Alteration in visceral sensation locally at the site of presumed sympt om origin in the gastrointestinal tract has been proposed as an import ant etiopathological mechanism in the so-called functional bowel disor ders. Patients presenting with one functional gastrointestinal syndrom e, however, frequently have additional symptoms referable to other par ts of the gut, suggesting that enhanced visceral nociception may be a panintestinal phenomenon. We measured the sensory thresholds for initi al perception (IP), desire to defecate (DD), and urgency (U) in respon se to rectal balloon distension, and the thresholds for initial percep tion and for discomfort in response to esophageal balloon distension i n 12 patients with irritable bowel syndrome (IBS) and 10 patients with functional dyspepsia (FD), in comparison with healthy controls. As ex pected, IBS patients exhibited lower rectal sensory thresholds than co ntrols (P < 0.0001), but in addition had significantly lower sensory t hresholds for both perception and discomfort evoked by balloon distens ion of the esophagus (mean +/- SEM: 8.8 +/- 1.3 ml vs 12.1 +/- 1.5 ml (P < 0.05) and 12.2 +/- 1.4 ml vs 16.4 +/- 1.4 ml (P < 0.02) respectiv ely. Patients with FD showed similarily enhanced esophageal sensitivit y, with thresholds for perception and discomfort of 8.1 +/- 0.9 ml (P < 0.02), and 10.1 +/- 1.0 ml (P < 0.001), respectively, but were also found to have sensory thresholds for rectal distension similar to thos e observed in the IBS group, significantly lower than in controls: IP 45.0 +/- 17.6 vs 59.3 +/- 1.5 ml (P < 0.001), DD 98.0 +/- 17.9 vs 298. 7 +/- 9.0 ml (P < 0.0001), U 177.2 +/- 25.4 vs 415.1 +/- 12.6 ml (P < 0.0001). Somatic nerve sensory thresholds showed no significant differ ences between the patient and control groups. Our findings indicate th at alterations in visceral sensitivity in functional gastrointestinal disease affect sites in the gut other than the putative organ of sympt om origin, supporting the concept of generally enhanced visceral aware ness in patients with functional bowel disorders.