Increased colon pain in patients with irritable bowel syndrome (IBS) appears to be related more to "a psychological tendency to report pain," rather than to actual increased neurosensory sensitivity, investigators report.
"The implications of this finding are far-reaching," Dr William E. Whitehead of the University of North Carolina and colleagues write in the medical journal Gut.
The findings underscore the importance of considering psychological factors before interpreting sensory function, they say. The results also highlight the importance of centrally mediated processes in visceral sensitivity experienced by IBS patients, and suggest that novel therapies for pain in IBS should target centrally mediated mechanisms.
In the study, 121 IBS patients and 28 healthy controls underwent balloon distensions in the descending colon to assess pain and urge thresholds. Subjects also underwent a battery of tests designed to separate physiological from psychological components of perception.
IBS patients more sensitive to pain
The results indicated that IBS patients, compared with controls, had significantly lower pain thresholds than controls, but similar neurosensory sensitivity patients also had a greater tendency to report pain.
The findings also showed that pain thresholds did not correlate with neurosensory sensitivity, Whitehead and his associates report, but were strongly correlated with the overall tendency to report pain.
Similar results were seen for the non-painful sensation of urgency.
These data, Whitehead and colleagues conclude, indicate that physiological contributions to increased colonic pain sensitivity in IBS patients are relatively small compared to cognitive and psychological influences. - (Reuters Health)
SOURCE: Gut, September 2007.