Journal: The Clinical Journal of Pain. 2007 May;23(4):323-330.
Authors and affiliations: Moshiree B, Price DD, Robinson ME, Gaible R, Nicholas Verne G. University of Florida Colleges of Medicine, Dentistry, Public Health and Health Professions, Gainesville, FL; and North Florida/South Georgia Veteran Health System.
Background: Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder characterized by both visceral and somatic hyperalgesia [extreme sensitivity to pain], producing a similar effect seen with the central hypersensitivity mechanism in Fibromyalgia (FM).
Objectives: The aim of the current study was to compare magnitudes of visceral [internal organs] and thermal [heat] hypersensitivity in IBS patients and FM patients with IBS (FM+IBS) compared with healthy controls.
Methods: Female patients with IBS (n=12), FM+IBS (n=12), and control participants (n=13) rated pain intensity to hot water immersion (45 and 47 degrees C) of the hand/foot and to phasic distension of the rectum (35, 55 mm Hg) on a Mechanical Visual Analog Scale. The data were analyzed with 3 separate 1-way analyses of variance with post hoc Tukey tests.
- For both thermal and visceral stimuli, the control group had lower pain ratings than either the IBS or FM+IBS groups (P<0.001).
- IBS patients rated rectal distension as more painful than the FM+IBS group (P=0.005).
- During hot water immersion of the foot, the FM+IBS group had higher pain ratings than the IBS group (P<0.001).
During hand immersion, FM+IBS and IBS patients did not significantly differ in their pain intensity ratings (P=0.4).
Conclusions: FM+IBS patients show greater thermal hypersensitivity compared with IBS patients. However, IBS patients exhibit higher pain ratings to rectal distension compared with FM+IBS patients. This data suggests that regions of primary and secondary hyperalgesia are dependent on the primary pain complaint.