Brain functional magnetic resonance imaging of rectal pain and activation of endogenous inhibitory mechanisms in irritable bowel syndrome patient subgroups and healthy controls. Issue 11 (11th October 2004)

• Record Type: Journal Article
• Authors: Wilder-Smith, C H; Schindler, D; Lovblad, K; Redmond, S M; Nirkko, A
• Is Part Of: Gut. Volume 53:Issue 11(2004)
• Page Start: 1595
• Page End: 1601
• Publication Date: 2004-10-11
• Subjects: ACC, anterior cingulate cortex -- BOLD, blood oxygen level dependent -- DNIC, diffuse noxious inhibitory controls -- fMRI, functional magnetic resonance imaging -- IBS, irritable bowel syndrome -- IBS-C, IBS with constipation -- IBS-D, IBS with diarrhoea -- PAG, periaqueductal gray -- PET, positron emission tomography -- RVM, rostroventromedial medulla -- VOI, volumes of interest -- VAS, visual analogue scale; irritable bowel syndrome -- brain imaging -- functional magnetic resonance imaging -- pain inhibitory pathways -- visceral pain; Gastroenterology -- Periodicals; 616.33
• DOI: 10.1136/gut.2003.028514
• Languages: English
• ISSNs: 0017-5749

Abstract

Abstract : Background and aims: Many patients with irritable bowel syndrome (IBS) show intestinal hypersensitivity to distension and sensitisation after repeated intestinal distensions. Abnormalities in endogenous pain inhibitory mechanisms, such as diffuse noxious inhibitory controls (DNIC), may be implicated and were investigated during brain functional magnetic resonance imaging (fMRI). Patients and methods: fMRI was performed in 10 female patients with IBS (five constipated (IBS-C) and five with diarrhoea (IBS-D)) and 10 female healthy controls during rectal balloon distension alone or during activation of DNIC by painful heterotopic stimulation of the foot with ice water. Rectal pain was scored with and without heterotopic stimulation (0 = none, 10 = maximal). Results: Heterotopic stimulation decreased median rectal pain scores significantly in healthy controls (−1.5 (interquartile range −2 to −1); p = 0.001) but not in IBS-C (−0.7 (−1 to 0.5)), IBS-D (−0.5 (−1.5 to 0.5)), or in all IBS patients (0 (−1.5 to 1.3)). Brain activation changes during heterotopic stimulation differed highly significantly between IBS-C, IBS-D, and controls. The main centres affected were the amygdala, anterior cingulate cortex, hippocampus, insula, periaqueductal gray, and prefrontal cortex, which form part of the matrix controlling emotional, autonomic, and descending modulatory responses to pain. Conclusions: IBS-C and IBS-D appear to have differing abnormal endogenous pain inhibitory mechanisms, involving DNIC and other supraspinal modulatory pathways.