The journal of pain : official journal of the American Pain Society
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Social communication deficits and repetitive behaviors are established characteristics of autism spectrum disorder (ASD) and the focus of considerable study. Alterations in pain sensitivity have been widely noted clinically but remain understudied and poorly understood. The ASD population may be at greater risk for having their pain undermanaged, especially in children with impaired cognitive ability and limited language skills, which may affect their ability to express pain. Given that sensitivity to noxious stimuli in adolescents with ASD has not been systematically assessed, here we measured warm and cool detection thresholds and heat and cold pain thresholds in 20 high-functioning adolescents with ASD and 55 typically developing adolescents using a method-of-limits quantitative sensory testing protocol. Adolescents with ASD had a loss of sensory function for thermal detection (P < .001, both warm and cool detection thresholds) but not pain threshold (P > .05, both heat and cold pain thresholds) in comparison to controls, with no evidence for significant age or sex effects (P > .05). Intelligence quotients and symptomatology were significantly correlated with a loss of some types of thermal perception in the ASD population (ie, warm detection threshold, cool detection threshold, and heat pain threshold; P < .05). Decreased thermal sensitivity in adolescents with ASD may be associated with cognitive impairments relating to attentional deficits. Our findings are consistent with previous literature indicating an association between thermal perception and cortical thickness in brain regions involved in somatosensation, cognition, and salience detection. Further brain-imaging research is needed to determine the neural mechanisms underlying thermal perceptual deficits in adolescents with ASD. ⋯ We report quantitative evidence for altered thermal thresholds in adolescents with ASD. Reduced sensitivity to warmth, coolness, and heat pain was related to impaired cognitive ability. Caregivers and clinicians should consider cognitive ability when assessing and managing pain in adolescents with ASD.
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Acute postoperative pain remains a significant health care issue. Development of anatomically relevant animal models of postoperative pain, with improved predictive validity, would advance understanding of postoperative pain mechanisms and improve treatment outcomes. This study aimed to develop, characterize, and validate a rat model of acute postoperative pain associated with inguinal hernia repair based on the Lichtenstein inguinal hernia repair procedure (without hernia induction). We hypothesized that the surgery would result in reduced spontaneous locomotor activity, which would represent a pain-related phenotype. Postsurgical characterization involved extensive monitoring of home cage and open field locomotor activity, as well as mechanical hypersensitivity and assessment of c-Fos expression in the dorsal horn of the spinal cord. In pharmacologic validation studies, rats received morphine, carprofen, or paracetamol 1 hour before, and/or immediately after, surgery. Rats that underwent hernia repair surgery exhibited significantly lower horizontal and vertical activities in the home cage and open field in the early postsurgical period, compared with sham rats or rats that underwent skin incision only. Morphine, carprofen, and paracetamol attenuated the surgery-induced reductions in locomotor activity, to varying degrees. Surgery was associated with significantly increased c-Fos expression in the ipsilateral dorsal horn of the spinal cord, an effect attenuated by carprofen treatment. These results support the development and characterization of a novel, anatomically relevant animal model of acute postoperative pain that may facilitate development of improved treatment regimens. ⋯ Acute pain following inguinal hernia repair can be difficult to treat. Here we report, for the first time, the development of a novel, anatomically relevant rat model to facilitate improved understanding and treatment of acute postoperative pain following inguinal hernia repair.
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Review
Quality of pain intensity assessment reporting: ACTTION systematic review and recommendations.
Pain intensity assessments are used widely in human pain research, and their transparent reporting is crucial to interpreting study results. In this systematic review, we examined reporting of human pain intensity assessments and related elements (eg, administration frequency, time period assessed, type of pain) in all empirical pain studies with adult participants in 3 major pain journals (ie, European Journal of Pain, Journal of Pain, and Pain) between January 2011 and July 2012. Of the 262 articles identified, close to one-quarter (24%) ambiguously reported the pain intensity assessment. Elements related to the pain intensity assessment were frequently not reported: 31% did not identify the time period participants were asked to rate, 43% failed to report the type of pain intensity rated, and 58% did not report the specific location or pain condition rated. No differences were observed between randomized clinical trials and experimental (eg, studies involving experimental manipulation without random group assignment and blinding) and observational studies in reporting quality. The ability to understand study results, and to compare results between studies, is compromised when pain intensity assessments are not fully reported. Recommendations are presented regarding key details for investigators to consider when conducting and reporting pain intensity assessments in human adults. ⋯ This systematic review demonstrates that publications of pain research often incompletely report pain intensity assessments and their details (eg, administration frequency, type of pain). Failure to fully report details of pain intensity assessments creates ambiguity in interpreting research results. Recommendations are proposed to increase transparent reporting.
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Identification of patients at increased risk for problem opioid use is recommended by chronic opioid therapy (COT) guidelines, but clinical assessment of risks often does not occur on a timely basis. This research assessed whether structured electronic health record (EHR) data could accurately predict subsequent problem opioid use. This research was conducted among 2,752 chronic noncancer pain patients initiating COT (≥70 days' supply of an opioid in a calendar quarter) during 2008 to 2010. Patients were followed through the end of 2012 or until disenrollment from the health plan, whichever was earlier. Baseline risk indicators were derived from structured EHR data for a 2-year period prior to COT initiation. Problem opioid use after COT initiation was assessed by reviewing clinician-documented problem opioid use in EHR clinical notes identified using natural language processing techniques followed by computer-assisted manual review of natural language processing-positive clinical notes. Multivariate analyses in learning and validation samples assessed prediction of subsequent problem opioid use. The area under the receiver operating characteristic curve (c-statistic) for problem opioid use was .739 (95% confidence interval = .688, .790) in the validation sample. A measure of problem opioid use derived from a simple weighted count of risk indicators was found to be comparably predictive of the natural language processing measure of problem opioid use, with 60% sensitivity and 72% specificity for a weighted count of ≥4 risk indicators. ⋯ An automated surveillance method utilizing baseline risk indicators from structured EHR data was moderately accurate in identifying COT patients who had subsequent problem opioid use.
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Chronic pruritic conditions are often associated with dry skin and loss of epidermal barrier integrity. In this study, repeated application of acetone and ether followed by water (AEW) to the cheek skin of mice produced persistent scratching behavior with no increase in pain-related forelimb wiping, indicating the generation of itch without pain. Cheek skin immunohistochemistry showed a 64.5% increase in total epidermal innervation in AEW-treated mice compared to water-treated controls. This increase was independent of scratching, because mice prevented from scratching by Elizabethan collars showed similar hyperinnervation. To determine the effects of dry skin treatment on specific subsets of peripheral fibers, we examined Ret-positive, calcitonin gene-related peptide (CGRP)-positive, and glial cell line-derived neurotrophic factor family receptor α3 (GFRα3)-positive intraepidermal fiber density. AEW treatment increased Ret-positive fibers but not CGRP-positive or GFRα3-positive fibers, suggesting that a specific subset of nonpeptidergic fibers could contribute to dry skin itch. To test whether trigeminal ganglion neurons innervating the cheek exhibited altered excitability after AEW treatment, primary cultures of retrogradely labeled neurons were examined using whole-cell patch clamp electrophysiology. AEW treatment produced no differences in measures of excitability compared to water-treated controls. In contrast, a significantly higher proportion of trigeminal ganglion neurons was responsive to the nonhistaminergic pruritogen chloroquine after AEW treatment. We conclude that nonpeptidergic, Ret-positive fibers and chloroquine-sensitive neurons may contribute to dry skin pruritus. ⋯ This study examines the underlying neurobiological mechanisms of persistent dry skin itch. Our results indicate that nonpeptidergic epidermal hyperinnervation and nonhistaminergic pruritic receptors are potential targets for chronic pruritus.