Pain
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Chronic pain is often associated with reduced tactile acuity. A relationship exists between pain intensity, tactile acuity and cortical reorganisation. When pain resolves, tactile function improves and cortical organisation normalises. ⋯ Pain and TPD were lower after the discrimination phase [mean (95% CI) effect size for pain VAS = 27 mm (14-40 mm) and for TPD = 5.7 mm (2.9-8. ), p < 0.015 for both]. These gains were maintained at three-month follow-up. We conclude that tactile stimulation can decrease pain and increase tactile acuity when patients are required to discriminate between the type and location of tactile stimuli.
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Peripheral nerve injury causes neuropathic pain including mechanical allodynia and thermal hyperalgesia due to central and peripheral sensitization. Spontaneous ectopic discharges derived from dorsal root ganglion (DRG) neurons and from the sites of injury are a key factor in the initiation of this sensitization. Numerous studies have focused primarily on DRG neurons; however, the injured axons themselves likely play an equally important role. ⋯ The function of these accumulated channels was verified by local application of ZD7288, a specific HCN blocker, which significantly suppressed the ectopic discharges from injured nerve fibers with no effect on impulse conduction. Moreover, mechanical allodynia, but not thermal hyperalgesia, was relieved significantly by ZD7288. These results suggest that axonal HCN channel accumulation plays an important role in ectopic discharges from injured spinal nerves and contributes to the development of mechanical allodynia in neuropathic pain rats.
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Painful hypersensitivity to norepinephrine (NE) has been reported in various chronic pain conditions that exhibit sympathetically-maintained pain (SMP), particularly CRPS-I and II. We investigated the parallels between the nociceptive and vascular sensitivity to NE in rats with chronic post-ischemia pain (CPIP), an animal model of CRPS-I induced by hind paw ischemia-reperfusion injury. Intradermal injections of NE to the affected hind paw induced dose-dependent nociceptive behaviours in CPIP rats, but not sham animals. ⋯ These results suggest CPIP rats display abnormal nociceptive responses to adrenergic and non-adrenergic vasoconstrictive agents. Furthermore, the nociceptive responses to NE in CPIP rats are paralleled by enhanced vasoconstrictive responses to NE, and are relieved by alpha-adrenergic antagonists or a vasodilator. We conclude that persistent tissue ischemia and hypersensitivity to sympathetic vasoconstriction are important mechanisms for pain in CPIP rats, and that either reducing vasoconstriction or enhancing vasodilatation may be effective methods of relieving the pain of CRPS-I.
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When an adolescent has chronic pain many aspects of a parent's life can be affected, including their emotional and social functioning. The assessment of this multidimensional parental impact is an essential, yet often neglected, clinical task. This study reports on the development and psychometric evaluation of the Bath Adolescent Pain--Parental Impact Questionnaire (BAP-PIQ), an assessment tool comprising multiple scales thought to be relevant for better understanding changes in functioning and behavior associated with parenting an adolescent with chronic pain. ⋯ The BAP-PIQ may offer a comprehensive assessment of these impacts in both a research and a clinical setting. Further study of the validity of BAP-PIQ scales and their ability to detect clinically meaningful change would be of use. Additional data from samples comprising fathers of adolescents with chronic pain and parents of adolescents with non-musculoskeletal pain would be of benefit.
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Given the high prevalence of depression in individuals with chronic pain and the negative outcomes associated with such comorbidity, the importance of assessing depressive symptoms is widely acknowledged by chronic pain specialists. The BDI-II is a commonly employed measure of depressive symptomatology at pain centres; however, little is known about its psychometric properties in this population. This study evaluated factorial validity, internal consistency, and gender invariance of the BDI-II in 481 patients with chronic pain. ⋯ Overall, results support the construct validity and internal consistency of the BDI-II for assessing depressive symptoms in both women and men with chronic pain. Results support the appropriateness of computing a total score and/or subscale scores. These results impact chronic pain researchers and clinicians, particularly given current trends toward empirically supported assessment.