Pain in chronic pancreatitis: The role of reorganization in the central nervous system

Background & Aims: In various chronic pain conditions cortical reorganization seems to play a role in the manifestations. The aim of this study was to investigate cortical reorganization in patients with pain caused by chronic pancreatitis. Methods: Twelve healthy subjects and 10 patients with chronic pancreatitis were included. The esophagus, stomach, and duodenum were stimulated electrically at the pain threshold using a nasal endoscope. The electroencephalogram was recorded from 64 surface electrodes and event-related brain potentials (EPs) were obtained. Results: As compared with healthy subjects, the patient group showed decreased latencies of the early EP components (N1, P < .001; P1, P = .02), which is thought to reflect the exogenous brain pain processing specifically. Source analysis showed that the dipolar activities corresponding to the early EPs were located consistently in the bilateral insula, in the anterior cingulate gyrus, and in the bilateral secondary somatosensory area. The bilateral insular dipoles were localized more medial in the patient group than in the healthy subjects after stimulation of all 3 gut segments (P < .01). There also were changes in the cingulate cortex where the neuronal source was more posterior in patients than in controls to stimulation of the esophagus (P < .05). Conclusions: The findings indicate that pain in chronic pancreatitis leads to changes in cortical projections of the nociceptive system. Such findings also have been described in somatic pain disorders, among them neuropathic pain. Taken together with the clinical data this suggests a neuropathic component in pancreatic pain, which may influence the approach to treatment.