Visceral hypersensitivity is not a feature of fibromyalgia syndrome

Objective: Visceral hyperalgesia is commonly observed in irritable bowel syndrome [IBS], a common cause of comorbidity with fibromyalgia syndrome [FMS]. The aim of this study was to evaluate in patients affected by FMS the presence of IBS-like symptoms and of visceral hyperalgesia. Methods: Twenty-seven FMS patients were studied and compared with 32 IBS patients for visceral hyperalgesia by the anorectal balloon distension test. Results: Eighteen [66%] of FMS patients fitted the Rome criteria for IBS. Patients with IBS presented lower than normal thresholds for the sensation of urgency and pain [P < 0.05], whereas the sensation of gas present in the rectum and of desire of defecation were not statistically different from normals. On the contrary, patients with FMS, either with or without IBS-like symptoms, presented values similar to normals for all the examined thresholds [P > 0.05]. Conclusions: Our study confirms that IBS symptoms are present in a relevant proportion of FMS patients, and that the majority of IBS patients present a condition of visceral hypersensitivity, as induced by a rectal balloon distension test. Patients with FMS, however, do not present this feature. The reason why FMS patients frequently have IBS-like symptoms with a normal visceral hypersensitivity remains elusive.