Visceral algesia in irritable bowel syndrome, fibromyalgia, and sphincter of oddi dysfunction, type III.

Visceral hyperalgesia has been demonstrated in patients with irritable bowel syndrome who are seen in tertiary care centers. It has been hypothesized that visceral hyperalgesia may be related to psychological distress associated with health care seeking behavior in these patients. Patients with fibromyalgia and sphincter of Oddi dysfunction, type III, share many demographic and psychosocial characteristics with patients with irritable bowel syndrome and provide an opportunity to test the hypothesis that rectal hyperalgesia is unique to IBS. Fifteen patients with IBS, 10 patients with fibromyalgia, 10 with sphincter of Oddi dysfunction, type III, and 12 controls underwent evaluation of rectal pain perception in response to phasic distensions and psychological testing with a self-report instrument. Patients with irritable bowel syndrome demonstrated significantly lower rectal pain thresholds and increased levels of psychologic distress compared to controls. Although sphincter of Oddi dysfunction patients also exhibited increased psychologic distress, rectal pain perception was similar to controls. Patients with fibromyalgia exhibited rectal algesia that was not significantly different from either controls or IBS. In conclusion, rectal hyperalgesia is not a function of chronic functional pain, health care seeking behavior, or psychological distress. However, it may not be specific for IBS.