The journal of pain : official journal of the American Pain Society
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Emerging evidence suggests that some individuals with regional pain disorders go on to develop chronic widespread pain (CWP). However, the mechanism behind this transition and the nature of risk factors that predispose a person to develop CWP remain to be elucidated. The purpose of this study was to describe the frequency with which participants with chronic back or neck pain develop CWP and to determine the risk factors associated with this development. In a sample of 512 individuals, we found that nearly a quarter (22.6%) of subjects who presented with regional back or neck pain in 2001/2002 had developed CWP by 2007. Logistic regression indicated that 7 factors were associated with the transition to CWP: moderate or severe pain intensity, female gender, history of abuse, family history of CWP, severe interference with general activity, having 1 or more central sensitivity syndromes, and using more pain management strategies. History of abuse was not significant in multivariate analysis. Notably, number of depressive symptoms endorsed, pain duration, age, body mass index, number of medication classes used, and receipt of disability benefits were not significantly associated with this transition. ⋯ This study offers insight into risk factors associated with the development of CWP. This information not only offers clues as to the mechanism behind the expansion of pain sensitivity from a regional pain locus to a widespread pain disorder but also provides insight as to how clinicians might mitigate this transition.
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Research has largely ignored the systematic examination of physicians' attitudes towards providing care for patients with chronic noncancer pain. The objective of this study was to identify barriers and facilitators to opioid treatment of chronic noncancer pain patients by office-based medical providers. We used a qualitative study design using individual and group interviews. Participants were 23 office-based physicians in New England. Interviews were audiotaped, transcribed, and systematically coded by a multidisciplinary team using the constant comparative method. Physician barriers included absence of objective or physiological measures of pain; lack of expertise in the treatment of chronic pain and coexisting disorders, including addiction; lack of interest in pain management; patients' aberrant behaviors; and physicians' attitudes toward prescribing opioid analgesics. Physician facilitators included promoting continuity of patient care and the use of opioid agreements. Physicians' perceptions of patient-related barriers included lack of physician responsiveness to patients' pain reports, negative attitudes toward opioid analgesics, concerns about cost, and patients' low motivation for pain treatment. Perceived logistical barriers included lack of appropriate pain management and addiction referral options, limited information regarding diagnostic workup, limited insurance coverage for pain management services, limited ancillary support for physicians, and insufficient time. Addressing these barriers to pain treatment will be crucial to improving pain management service delivery. ⋯ This article demonstrates that perceived barriers to treating patients with chronic noncancer pain are common among office-based physicians. Addressing these barriers in physician training and in existing office-based programs might benefit both noncancer chronic pain patients and their medical providers.
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Multicenter Study Clinical Trial
Initial Psychometric Properties of the Pain Care Quality Survey (PainCQ).
This study examined the psychometric properties of the Pain Care Quality (PainCQ) survey, a new instrument to measure the quality of nursing and interdisciplinary care related to pain management. Hospitalized medical/surgical oncology patients with pain from 3 states completed the 44-item version of the PainCQ survey following completion of a nursing shift. Interdisciplinary items were evaluated over the entire hospital stay; nursing care was evaluated during the previous shift. The sample included 109 patients ranging in age from 20 to 84 (mean = 53.09). The sample was 58.7% female, 88% non-Hispanic white. Principal Axis Factoring with an oblimin rotation was used as factors were correlated. Two scales resulted. The PainCQ-Interdisciplinary scale included 11 items representing 2 constructs and explaining 47.1% of shared item variance: partnership with the health care team (k = 6 items; α = .85) and comprehensive interdisciplinary pain care (k = 5 items; α = .76). The PainCQ-Nursing scale measured three constructs and explained 60.8 % of shared item variance: being treated right (k = 15 items; α = .95), comprehensive nursing pain care (k = 3 items; α = .77), and efficacy of pain management (k =4 items; α = .87). Results supported the internal consistency reliability and structural validity of the PainCQ survey with 33 items. ⋯ This article presents the psychometric properties of a new tool to measure interdisciplinary and nursing care quality related to pain management from the patient's perspective. This tool can be used for research and as a clinical performance measure to monitor and improve quality of care and patient outcomes.
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The endocannabinoids anandamide and 2-arachidonoylglycerol are predominantly regulated by the respective catabolic enzymes fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL). Inhibition of these enzymes elevates endocannabinoid levels and attenuates neuropathic pain. In the present study, CB₁ and CB₂ receptor-deficient mice were subjected to chronic constriction injury (CCI) of the sciatic nerve to examine the relative contribution of each receptor for the anti-allodynic effects of the FAAH inhibitor, PF-3845, and the MAGL inhibitor, JZL184. CCI caused marked hypersensitivity to mechanical and cold stimuli, which was not altered by deletion of either the CB₁ or CB₂ receptor, but was attenuated by gabapentin, as well as by each enzyme inhibitor. Whereas PF-3845 lacked anti-allodynic efficacy in both knockout lines, JZL184 did not produce anti-allodynic effects in CB₁ (-/-) mice, but retained its anti-allodynic effects in CB₂ (-/-) mice. These data indicate that FAAH and MAGL inhibitors reduce nerve injury-related hyperalgesic states through distinct cannabinoid receptor mechanisms of action. In conclusion, although endogenous cannabinoids do not appear to play a tonic role in long-term expression of neuropathic pain states, both FAAH and MAGL represent potential therapeutic targets for the development of pharmacological agents to treat chronic pain resulting from nerve injury. ⋯ This article presents data addressing the cannabinoid receptor mechanisms underlying the anti-allodynic actions of endocannabinoid catabolic enzyme inhibitors in the mouse sciatic nerve ligation model. Fatty acid amide hydrolase and monoacylglycerol lipase inhibitors reduced allodynia through distinct cannabinoid receptor mechanisms. These enzymes offer potential targets to treat neuropathic pain.
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The protein kinase mammalian target of rapamycin (mTOR) regulates mRNA translation and is inhibited by rapamycin. Signaling pathways involving mTOR are implicated in physiological and pathophysiological processes. We determined the spinal effects of the rapamycin analogue cell cycle inhibitor (CCI)-779 on neuronal responses and behavioral hypersensitivity in a model of persistent neuropathic pain. We also assessed the anatomical distribution of spinal mTOR signaling pathways. Specifically, we ligated rat spinal nerves L5 and L6 to produce a model of neuropathic pain. After confirming neuropathy with behavioral testing, we obtained in vivo single-unit extracellular stimulus-evoked recordings from deep dorsal horn spinal neurons. We applied CCI-779 spinally in electrophysiological and behavioral studies and assessed its effects accordingly. We also used immunohistochemistry to probe for mTOR signaling pathways in dorsal root ganglia (DRG) and the spinal cord. We found that spinally administered CCI-779 rapidly attenuated calibrated mechanically but not thermally evoked neuronal responses and mechanically evoked behavioral responses. Immunohistochemistry showed presence of mTOR signaling pathways in nociceptive-specific C-fiber DRG and in neurons of inner lamina II of the spinal cord. We conclude that alterations in the activity of spinal mTOR signaling pathways are crucial to the full establishment of spinal neuronal plasticity and behavioral hypersensitivity associated with nerve injury. ⋯ This study is consistent with growing evidence implicating mTOR signaling pathways as important modulators of persistent pain, providing novel insights into the molecular mechanisms of pain maintenance and potential for novel approaches into treating chronic pain.