The journal of pain : official journal of the American Pain Society
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The pathogenesis of complex regional pain syndrome (CRPS) is unresolved, but tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) are elevated in experimental skin blister fluid from CRPS-affected limbs, as is tryptase, a marker for mast cells. In the rat fracture model of CRPS, exaggerated sensory and sympathetic neural signaling stimulate keratinocyte and mast cell proliferation, causing the local production of high levels of inflammatory cytokines leading to pain behavior. The current investigation used CRPS patient skin biopsies to determine whether keratinocyte and mast cell proliferation occur in CRPS skin and to identify the cellular source of the up-regulated TNF-α, IL-6, and tryptase observed in CRPS experimental skin blister fluid. Skin biopsies were collected from the affected skin and the contralateral mirror site in 55 CRPS patients and the biopsy sections were immunostained for keratinocyte, cell proliferation, mast cell markers, TNF-α, and IL-6. In early CRPS, keratinocytes were activated in the affected skin, resulting in proliferation, epidermal thickening, and up-regulated TNF-α and IL-6 expression. In chronic CRPS, there was reduced keratinocyte proliferation, leading to epidermal thinning in the affected skin. Acute CRPS patients also had increased mast cell accumulation in the affected skin, but there was no increase in mast cell numbers in chronic CRPS. ⋯ The results of this study support the hypotheses that CRPS involves activation of the innate immune system, with keratinocyte and mast cell activation and proliferation, inflammatory mediator release, and pain.
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Pain-related self-efficacy and pain-related fear have been proposed as opposing predictors of pain-related functional outcomes in youth with chronic pain. Self-efficacy is a potential resiliency factor that can mitigate the influence that pain-related fear has on outcomes in youth with chronic pain. Drawing from theoretical assertions tested among adults with chronic pain, this study aimed to determine whether pain-related self-efficacy mediates the adverse influence of pain-related fear on functional outcomes in a sample of youth with chronic headache. In a cross-sectional design of 199 youth with headache, self-efficacy was strongly associated with fear, disability, school impairment, and depressive symptoms. Pain intensity and self-efficacy were only modestly related, indicating that level of pain has less influence on one's confidence functioning with pain. Self-efficacy partially mediated relationships between pain-related fear and both functional disability and school functioning but did not mediate the relationship between pain-related fear and depressive symptoms. These results suggest that confidence in the ability to function despite pain and fear avoidance each uniquely contributes to pain-related outcomes in youth with chronic headache. These results further suggest that treatment for chronic headache in youth must focus not only on decreasing pain-related fear but also on enhancing a patient's pain-related self-efficacy. ⋯ Pain-related self-efficacy is an important resiliency factor impacting the influence of pain-related fear on functional disability and school functioning in youth with headache. Enhancing self-efficacy may be a key mechanism for improving behavioral outcomes. Clinicians can reduce pain-related fear and enhance pain-related self-efficacy through interventions that encourage accomplishment and self-confidence.
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Racial disparities in pain treatment pose a significant public health and scientific problem. Prior studies have demonstrated that clinicians and nonclinicians are less perceptive of, and suggest less treatment for, the pain of African Americans relative to European Americans. Here we investigate the effects of explicit/implicit patient race presentation, patient race, and perceiver race on pain perception and response. African American and European American participants rated pain perception, empathy, helping motivation, and treatment suggestion in response to vignettes about patients' pain. Vignettes were accompanied by a rapid (implicit) or static (explicit) presentation of an African or European American patient's face. Participants perceived and responded more to European American patients in the implicit prime condition, when the effect of patient race was below the level of conscious regulation. This effect was reversed when patient race was presented explicitly. Additionally, female participants perceived and responded more to the pain of all patients, relative to male participants, and in the implicit prime condition, African American participants were more perceptive and responsive than European Americans to the pain of all patients. Taken together, these results suggest that known disparities in pain treatment may be largely due to automatic (below the level of conscious regulation) rather than deliberate (subject to conscious regulation) biases. These biases were not associated with traditional implicit measures of racial attitudes, suggesting that biases in pain perception and response may be independent of general prejudice. ⋯ Results suggest that racial biases in pain perception and treatment are at least partially due to automatic processes. When the relevance of patient race is made explicit, however, biases are attenuated and even reversed. We also find preliminary evidence that African Americans may be more sensitive to the pain of others than are European Americans.
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Although persistent pain occurs in a sociocultural context, the influence of personal devaluation and invalidation is often neglected. As such, the present study sought to consider whether individuals' experience, perception, or anticipation of negative social reactions to their pain may become internalized and affect the self. To examine this issue, 92 adults with chronic pain responded to a questionnaire exploring the presence of internalized stigma and its association with a range of psychological consequences. As predicted, a large percentage of people with chronic pain (38%) endorsed the experience of internalized stigma. The results showed that internalized stigma has a negative relationship with self-esteem and pain self-efficacy, after controlling for depression. Internalized stigma was also associated with cognitive functioning in relation to pain, in terms of a greater tendency to catastrophize about pain and a reduced sense of personal control over pain. Overall, this study presents a new finding regarding the application of internalized stigma to a chronic pain population. It offers a means of extending our understanding of chronic pain's psychosocial domain. Implications are discussed in terms of the potential to inform clinical treatment and resiliency into the future. ⋯ This article presents a novel finding regarding the presence of internalized stigma among people living with chronic pain. Internalized stigma is strongly associated with indicators of patient outcome. It presents an area for future work with the aim to improve our understanding and treatment of people living with pain.
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Chronic widespread pain (CWP) is a common and potentially debilitating disorder. Patterns of physical activity (PA) in adults with CWP have primarily been investigated using subjective, self-report measures. The current study sought to characterize PA among community-dwelling individuals with CWP, chronic regional pain, or no chronic pain using objective measurements obtained via accelerometry in the 2003 to 2004 National Health and Nutrition Examination Survey. Data from 3,952 participants ages 20 and older were analyzed to assess relationships between pain status and objective measurements of PA. Prevalence of CWP was 3.3% and 5.4% in men and women, respectively. In men and women, the average activity counts per minute and time spent in moderate-to-vigorous PA were significantly lower for the CWP group than for the no chronic pain group. Interestingly, time spent in sedentary, light, and lifestyle activities was not associated with pain status. Statistical interaction tests indicated that the effects of chronic pain on counts per minute were stronger in men than in women. Despite recommendations for increased moderate-to-vigorous PA as a pain management strategy for CWP, results from this nationally representative study indicate that adults with CWP participate in less moderate-to-vigorous PA than individuals without chronic pain. ⋯ Using objective measurement of PA in a nationally representative sample, this study demonstrates that adults with CWP participate in reduced daily and moderate-to-vigorous PA in comparison to people with no chronic pain. Findings indicate that clinicians should emphasize the importance of increasing PA in patients with CWP.