Pain
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Comparative Study
Familial aggregation of depression in fibromyalgia: a community-based test of alternate hypotheses.
Numerous studies report that fibromyalgia (FM), a syndrome characterized by widespread pain and generalized tender points, is comorbid with major depressive disorder (MDD). The current study tests two alternate explanations for their comorbidity using a family study methodology. The first is that FM is a depression spectrum disorder. ⋯ Results indicated that rates of MDD in the relatives of probands with FM but without personal histories of MDD were virtually identical to rates of MDD in relatives of probands with MDD themselves. This outcome is consistent with the hypothesis that FM is a depression spectrum disorder, in which FM and MDD are characterized by shared, familially mediated risk factors. The implications of these findings for a stress-vulnerability model of FM are discussed.
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Comparative Study
The Cheshire Foot Pain and Disability Survey: a population survey assessing prevalence and associations.
Previous foot studies have consistently reported high prevalence estimates in self-reported foot disorders. Few population studies, however, have attempted to assess the impact of foot problems in terms of pain and disability so that the burden associated with foot pain is unknown. A cross-sectional postal survey was conducted on a random community sample of 4780 individuals with 3417 (84%) responding. ⋯ Only 36% of persons with disabling foot pain received professional foot treatment in the 6 months preceding the survey. The results showed that 323/3417 (9.5%) reported symptoms of disabling foot pain and that this condition is likely to be multi-factorial in origin. Further work is necessary to understand more about the extent and type of unmet need and on how patients presenting with symptoms of disabling foot pain should best be managed.
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Comparative Study
Amplitudes of laser evoked potential recorded from primary somatosensory, parasylvian and medial frontal cortex are graded with stimulus intensity.
Intensity encoding of painful stimuli in many brain regions has been suggested by imaging studies which cannot measure electrical activity of the brain directly. We have now examined the effect of laser stimulus intensity (three energy levels) on laser evoked potentials (LEPs) recorded directly from the human primary somatosensory (SI), parasylvian, and medial frontal cortical surfaces through subdural electrodes implanted for surgical treatment of medically intractable epilepsy. LEP N2* (early exogenous/stimulus-related potential) and LEP P2** (later endogenous potential) amplitudes were significantly related to the laser energy levels in all regions, although differences between regions were not significant. ⋯ The lack of correlation of parasylvian cortical N2* with laser energy and pain intensity may be due to the unique anatomy of this region, or the small sample, rather than the lack of activation by the laser. Differences in thresholds of the energy correlation with amplitudes were not significant between regions. These results suggest that both exogenous in endogenous potentials evoked by painful stimuli, and recorded over SI, parasylvian, and medial frontal cortex of awake humans, encode the intensity of painful stimuli and correlate with the pain evoked by painful stimuli.
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Comparative Study
Exaggerated nociceptive responses on morphine withdrawal: roles of protein kinase C epsilon and gamma.
On withdrawal from opioids many patients experience a heightened sensitivity to stimuli and an exaggerated pain response. The phenomenon has been little studied in infants. We present evidence that in postnatal day 7 rats an exaggerated nociceptive ventral root response of spinal cords in vitro and withdrawal-associated thermal hyperalgesia in vivo are dependent on protein kinase C (PKC), and we document the roles of PKC and gamma isozymes. ⋯ In contrast, thermal hyperalgesia during spontaneous withdrawal was inhibited by both PKC and gamma inhibitors. The consistency between the in vivo and in vitro findings with respect to naloxone-precipitated withdrawal provides further evidence that the sVRP reflects nociceptive neurotransmission. In addition the difference between naloxone-precipitated and spontaneous withdrawal in vivo suggests that in postnatal day 7 rats, morphine exposure produces an early phase of primary afferent sensitization dependent upon PKC translocation, followed by a later phase involving spinal sensitization mediated by PKC gamma.
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The main aim of this study was to explore the occurrence and changes of neck pain in pain-free preadolescents. The evaluation was performed at 1- and 4-year follow-ups. Of the pain-free preadolescents, 366 (71.9%) completed structured pain questionnaires at 1 and 4 years. ⋯ This study strengthens the results of the previous cross-sectional studies that occurrence of neck pain increases with age, and that neck pain becomes more common among girls than boys in adolescence. Among preadolescents who were originally pain-free, there was only a small proportion who reported frequent neck pain at both 1 and 4 years. It also showed that the frequency of neck pain reflects the intensity of pain fairly well.