Hypersensitivity to visceral and cutaneous pain in the irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the moat common gastrointestinal i llnesses and is characterized by altered visceral perception. Previous stud ies in IBS have failed to demonstrate altered somatic or cutaneous percepti on. The aims of the study were to determine whether IBS patients have visce ral hypersensitivity and cutaneous heat-induced hyperalgesia restricted to lumbosacral dermatomes. consistent with a localized segmental mechanism. Tw elve patients (ten women, two men) with IBS and 17 control subjects (13 wom en. four men) rated pain intensity and unpleasantness to distension of the rectum (35, 55 mmHg) and thermal stimulation (45, 47 degreesC) of the hand and foot. Patients: with IBS demonstrated cutaneous allodynia/hyperalgesia to thermal pain applied to the hand and foot. The cutaneous hyperalgesia wa s pronounced in the lower extremity yet present in the upper extremity to a lesser extent. Psychological tasting revealed the IBS patients report more state anxiety and a greater number of somatic symptoms that significantly correlated with most of the pain measures. However. they did not differ fro m controls on several personality trait measures. These results suggest tha t patients with IBS have visceral hyperalgesia and cutaneous hyperalgesia t hat is distributed over a considerable rostral-caudal distance yet optimall y expressed in lumbosacral dermatomes. This distribution is consistent with patterns of spinal hyperexcitability observed in experimentally induced pe rsistent pain conditions. (C) 2001 International Association for the Study of Pain. Published by Elsevier Science B.V. All rights reserved.