Objectives: In the pathogenesis of irritable bowel syndrome (IBS), both increased visceral sensitivity and altered colonic motility seem to play a role. The aim of this study was to quantify the temporal relationship between pain episodes and the occurrence of high amplitude propagated pressure waves (HAPPWs).
Methods: A total of 11 IBS patients with the nonconstipation predominant pattern of IBS and 10 sex- and age-matched healthy volunteers were studied. On day 1, a solid state manometric catheter was positioned in the left colon and connected to a data logger. The subjects then went home. Thereafter they pressed a button on the data logger at the beginning and end of each pain episode. The 24-h manometric signal recorded on day 2 was divided into consecutive 5-min periods. These periods were evaluated for the occurrence of pain and HAPPWs. Fisher's exact test was applied to calculate the probability that HAPPWs and pain episodes were unrelated. The symptom association probability (SAP) was calculated as (1.0 - P) x 100%. A SAP of >95% was considered to indicate that the observed association did not occur by chance.
Results: In four of seven patients with pain on day 2, the SAP was >95%. HAPPWs that were related to pain originated at a more proximal level (p = 0.026) and occurred earlier (p = 0.007) than HAPPWs that were not related to pain. The duration of a pain period was correlated with the number of pain-related HAPPWs in that period (r = 0.906, p = 0.013). Two of the 10 healthy subjects experienced pain, and these pain episodes were not associated with HAPPWs.
Conclusions: Using objective analysis techniques, an association between pain episodes and HAPPWs was found in nonconstipated IBS patients with pain. HAPPWs that are associated with pain are only slightly different from HAPPWs not associated with pain.