The Effect of Topical Local Anesthetics on Thermal Pain Sensitivity in Patients with Irritable Bowel Syndrome

Generalized hypersensitivity that extends into somatic areas is common in patients with irritable bowel syndrome (IBS). The sensitized state, particularly assessed by experimental methods, is known to persist even during remissions of clinical pain. It was hypothesized that disease-related nociceptive activity in the gut maintains a systemic-sensitized state. The present study evaluated responses to prolonged thermal stimuli maintained at constant temperature or constant pain intensity during stimulation. The effect of topically applied rectal lidocaine on heat sensitivity was also evaluated. The question is whether silencing potential intestinal neural activity (which may not always lead to a conscious pain experience) with lidocaine attenuates sensitization of somatic areas. Tests were also performed where lidocaine was applied orally to control for systemic or placebo effects of the drug. The IBS subjects exhibited a greater sensitivity to somatic heat stimuli compared to controls; however, lidocaine had no discernible effect on sensitization in this sample of IBS patients, where most of the individuals did not have clinical pain on the day of testing.

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Relationships between Irritable Bowel Syndrome Pain, Skin Temperature Indices of Autonomic Dysregulation, and Sensitivity to Thermal Cutaneous Stimulation

Pain Research and Treatment ◽

10.1155/2010/949027 ◽

2010 ◽

Vol 2010 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Fong Wong ◽

Anthony C. Rodrigues ◽

Christopher D. King ◽

Joseph L. Riley ◽

Siegfried Schmidt ◽

...

Keyword(s):

Irritable Bowel Syndrome ◽

Pain Sensitivity ◽

Thermal Hyperalgesia ◽

Thermal Stimulation ◽

Thermal Pain ◽

Pain Ratings ◽

Irritable Bowel ◽

Thermal Pain Sensitivity ◽

Pain Patients ◽

Skin Temperatures

This study evaluated relationships between irritable bowel syndrome (IBS) pain, sympathetic dysregulation, and thermal pain sensitivity. Eight female patients with diarrhea-predominant IBS and ten healthy female controls were tested for sensitivity to thermal stimulation of the left palm. A new method of response-dependent thermal stimulation was used to maintain pain intensity at a predetermined level (35%) by adjusting thermal stimulus intensity as a function of pain ratings. Clinical pain levels were assessed prior to each testing session. Skin temperatures were recorded before and after pain sensitivity testing. The temperature of palmar skin dropped (1.5) when the corresponding location on the opposite hand of control subjects was subjected to prolonged thermal stimulation, but this response was absent for IBS pain patients. The patients also required significantly lower stimulus temperatures than controls to maintain a 35% pain rating. Baseline skin temperatures of patients were significantly correlated with thermode temperatures required to maintain 35% pain ratings. IBS pain intensity was not significantly correlated with skin temperature or pain sensitivity. The method of response-dependent stimulation revealed thermal hyperalgesia and increased sympathetic tone for chronic pain patients, relative to controls. Similarly, a significant correlation between resting skin temperatures and thermal pain sensitivity for IBS but not control subjects indicates that tonic sympathetic activation and a thermal hyperalgesia were generated by the chronic presence of visceral pain. However, lack of a significant relationship between sympathetic tone and ratings of IBS pain casts doubt on propositions that the magnitude of IBS pain is determined by psychological stress.

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Pain Sensitivity Subgroups in Individuals With Spine Pain: Potential Relevance to Short-Term Clinical Outcome

Physical Therapy ◽

10.2522/ptj.20130372 ◽

2014 ◽

Vol 94 (8) ◽

pp. 1111-1122 ◽

Cited By ~ 21

Author(s):

Rogelio A. Coronado ◽

Joel E. Bialosky ◽

Michael E. Robinson ◽

Steven Z. George

Keyword(s):

Cluster Analysis ◽

High Pressure ◽

Clinical Outcome ◽

Pain Intensity ◽

Pain Sensitivity ◽

Thermal Pain ◽

Dynamic Sensitivity ◽

Spine Pain ◽

Clinical Pain ◽

Thermal Pain Sensitivity

Background Cluster analysis can be used to identify individuals similar in profile based on response to multiple pain sensitivity measures. There are limited investigations into how empirically derived pain sensitivity subgroups influence clinical outcomes for individuals with spine pain. Objective The purposes of this study were: (1) to investigate empirically derived subgroups based on pressure and thermal pain sensitivity in individuals with spine pain and (2) to examine subgroup influence on 2-week clinical pain intensity and disability outcomes. Design A secondary analysis of data from 2 randomized trials was conducted. Methods Baseline and 2-week outcome data from 157 participants with low back pain (n=110) and neck pain (n=47) were examined. Participants completed demographic, psychological, and clinical information and were assessed using pain sensitivity protocols, including pressure (suprathreshold pressure pain) and thermal pain sensitivity (thermal heat threshold and tolerance, suprathreshold heat pain, temporal summation). A hierarchical agglomerative cluster analysis was used to create subgroups based on pain sensitivity responses. Differences in data for baseline variables, clinical pain intensity, and disability were examined. Results Three pain sensitivity cluster groups were derived: low pain sensitivity, high thermal static sensitivity, and high pressure and thermal dynamic sensitivity. There were differences in the proportion of individuals meeting a 30% change in pain intensity, where fewer individuals within the high pressure and thermal dynamic sensitivity group (adjusted odds ratio=0.3; 95% confidence interval=0.1, 0.8) achieved successful outcomes. Limitations Only 2-week outcomes are reported. Conclusions Distinct pain sensitivity cluster groups for individuals with spine pain were identified, with the high pressure and thermal dynamic sensitivity group showing worse clinical outcome for pain intensity. Future studies should aim to confirm these findings.

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