Patients with Irritable Bowel Syndrome More Sensitive to Pain

New research from Ohio State University (OSU) has found that patients with irritable bowel syndrome (IBS) are more sensitive to pain than controls without IBS.

G. Nicholas Verne, of the department of medicine at OSU and lead author of the study, and his team of researchers found that patients with diarrhea-predominant IBS (D-IBS) and constipation-predominant IBS (C-IBS) had a “significantly lower pain threshold and pain tolerance” than controls, and that “thermal hyperalgesia was present in both groups of IBS patients.” The researchers did not see a significant difference in pain threshold and pain tolerance among D-IBS and C-IBS patients.

Thermal pain hypersensitivity was examined among the participants, which included 42 patients with D-IBS, 24 with C-IBS, and 52 control subjects, with a Medoc Thermal Sensory Analyzer. According to the researchers, “heat pain threshold (HPTh) and heat pain tolerance (HPTo) were assessed on the left ventral forearm and left calf using an ascending method of limits,” and “the Functional Bowel Disease Severity Index (FBDSI) was also obtained for all subjects.”

According to an abstract of the article on the study that was published in the online edition of the World Journal of Gastroenterology, a “cluster analysis revealed the presence of subgroups of IBS patients based on thermal hyperalgesia. One cluster (17% of the sample) showed a profile of heat pain sensitivity very similar to that of healthy controls; a second cluster (47% of the sample) showed moderate heat pain sensitivity; and a third cluster (36% of the sample) showed a very high degree of thermal hyperalgesia.”

In what the authors of the study call a “unique finding,” they also discovered that a “strong relationship” exists “between heat pain measures and FBDSI scores. IBS patients with high FBDSI scores had the highest thermal pain sensitivity compared to those IBS patients with low to moderate FBDSI scores.”