Pain
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The Current Opioid Misuse Measure (COMM), a self-report assessment of past-month aberrant medication-related behaviors, has been validated in specialty pain management patients. The performance characteristics of the COMM were evaluated in primary care (PC) patients with chronic pain. It was hypothesized that the COMM could identify patients with prescription drug use disorder (PDD). ⋯ For chronic pain patients prescribed opioids, the development of PDD is an undesirable complication. Among PC patients with chronic pain-prescribed prescription opioids, the COMM is a promising tool for identifying those with PDD. Among primary care patients with chronic pain-prescribed opioids, the validated Current Opioid Misuse Measure (COMM) is a promising tool for identifying patients with prescription opioid use disorder.
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Randomized Controlled Trial
Pain tests provoke modality-specific cardiovascular responses in awake, unrestrained rats.
Nociception modulates heart rate (HR) and mean arterial pressure (MAP), suggesting their use of HR and MAP as indicators of pain in animals. We explored this with telemetric recording in unrestrained control and neuropathic (spinal nerve ligation) rats. Plantar stimulation was performed emulating techniques commonly used to measure pain, specifically brush stroke, von Frey fiber application, noxious pin stimulation, acetone for cooling, and radiant heating, while recording MAP, HR, and specific evoked somatomotor behaviors (none; simple withdrawal; or sustained lifting, shaking, and grooming representing hyperalgesia). ⋯ Heating, consistently depressed HR and MAP, independent of behavior. Other than a greater HR response to pin in animals made hyperalgesic by injury, cardiovascular events evoked by stimulation did not differ between control and neuropathic animals. We conclude that (a) thermoregulation rather than pain may dominate responses to heat and cooling stimuli; (b) brush and cooling stimuli may be perceived and produce cardiovascular activation without nocifensive withdrawal; (c) sensations that produce hyperalgesia behavior are accompanied by greater cardiovascular activation than those producing simple withdrawal; and (d) von Frey stimulation lacks cardiovascular evidence of nociception except when hyperalgesia behavior is evoked.
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Forty-five women with fibromyalgia (FM) engaged in a 30-day electronic diary assessment, recording daily ratings of pain and 2 forms of maladaptive coping: pain catastrophizing and pain attention. Participants were genotyped for the val(158)met single nucleotide polymorphism (rs4680) in the catechol-O-methyltransferase (COMT) gene. COMT genotype moderated the daily relations of both maladaptive coping processes and pain. ⋯ Further, the findings advance our understanding of the role of COMT in FM, suggesting that genetic variation in the val(158)met polymorphism may affect FM pain through pathways of pain-related cognition. This study examined 2 forms of maladaptive coping: pain catastrophizing and pain attention. The findings provide multimeasure and multimethod support for genetic moderation of a maladaptive coping and pain process and suggest that genetic variation in the val(158)met polymorphism may affect fibromyalgia pain through pathways of pain-related cognition.
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We determined rates and predictors of future development of fibromyalgia in patients with rheumatoid arthritis (RA). After excluding patients with fibromyalgia and those with high levels of fibromyalgia symptoms (fibromyalgianess score>10) at baseline, we studied fibromyalgia development in 9739 RA patients during 42,591 patient-years of follow-up. We defined fibromyalgia using a modification of the ACR 2010 fibromyalgia criteria. ⋯ Demographic plus RA variables (C=0.720) and demographic plus fibromyalgia variables (C=0.765), and all predictors (C=0.782) increased accuracy. Clinically important hazard ratios were noted for cognition, depression, comorbidity, and high levels of RA and FM continuous variables Overall, study results indicate that multiple, inter-correlated factors that include social disadvantage, psychological distress, comorbidity, RA severity, and fibromyalgia variables predict future development of fibromyalgia, but there is little evidence of the effect of underlying causes. After diagnosis, patients move in both directions across the diagnostic criteria cut points.
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Comparative Study
Intraepidermal nerve fiber loss corresponds to the development of taxol-induced hyperalgesia and can be prevented by treatment with minocycline.
Loss of intraepidermal nerve fibers (IENFs) has been speculated to play a critical role in the development of various neuropathies. In this study, the density of IENFs were studied over time during the induction of Taxol (Bristol-Myers Squibb, NY, USA)-induced chemoneuropathy and compared with the changes in IENFs in animals co-treated with Taxol plus the protective agent minocycline. Rats were injected (intraperitoneally) with 2mg/kg of Taxol every other day for four injections (day 1, 3, 5, and 7). ⋯ Animals receiving minocycline plus Taxol showed no hyperalgesia or loss of IENFs. This study confirms, for the first time, that a loss of IENFs occurs as a neuropathy develops, and further shows a protection against both IENF loss and hyperalgesia with minocycline treatment. The progression of Taxol-induced mechanical hypersensitivity coincides with loss of intraepidermal nerve fibers, and the hyperalgesia and nerve fiber loss were prevented with minocycline treatment.