Pain
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Despite similar behavioral hypersensitivity, acute and chronic pain have distinct neural bases. We used intraplantar injection of complete Freund's adjuvant to directly compare activity of pain-modulating neurons in the rostral ventromedial medulla (RVM) in acute vs chronic inflammation. Heat-evoked and von Frey-evoked withdrawal reflexes and corresponding RVM neuronal activity were recorded in lightly anesthetized animals either during the first hour after complete Freund's adjuvant injection (acute) or 3 to 10 days later (chronic). ⋯ During early immune-mediated inflammation, ON-cell spontaneous activity promotes hyperalgesia. After inflammation is established, the antinociceptive influence of OFF-cells is dominant, yet the lowered threshold for the OFF-cell pause allows behavioral responses to stimuli that would normally be considered innocuous. The efficacy of OFF-cells in counteracting sensitization of ascending transmission pathways could therefore be an important determining factor in development of chronic inflammatory pain.
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Randomized Controlled Trial
The Pain Course: a randomised controlled trial of a clinician-guided Internet-delivered cognitive behaviour therapy program for managing chronic pain and emotional well-being.
The present study evaluated the efficacy of a clinician-guided Internet-delivered cognitive behaviour therapy (iCBT) program, the Pain Course, to reduce disability, anxiety, and depression associated with chronic pain. Sixty-three adults with chronic pain were randomised to either a Treatment Group or waitlist Control Group. Treatment consisted of 5 iCBT-based lessons, homework tasks, additional resources, weekly e-mail or telephone contact from a Clinical Psychologist, and automated e-mails. ⋯ These outcomes were sustained at follow-up and participants rated the program as highly acceptable. Overall, the clinician spent a total mean time of 81.54 minutes (SD 30.91 minutes) contacting participants during the program. The results appear better than those reported in iCBT studies to date and provide support for the potential of clinician-guided iCBT in the treatment of disability, anxiety, and depression for people with chronic pain.
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Musculoskeletal disorders constitute major public health problems. Few studies have, however, examined risk of disability pension among persons sickness absent due to musculoskeletal diagnoses. Thus, we constructed a prospective nationwide population-based cohort study based on Swedish registers, consisting of all 4,687,756 individuals living in Sweden December 31, 2004/2005, aged 20-64 years, who were not on disability or old-age pension. ⋯ Similar associations were observed among both women and men sickness absent due to all 3 musculoskeletal diagnostic categories. Moreover, increased risks of disability pension because of cancer, mental, circulatory and musculoskeletal diagnoses were observed among individuals sickness absent because of any musculoskeletal diagnostic category (disability pension due to musculoskeletal diagnoses, adjusted model, category 2 diagnoses, IRR = 50.66, 95% CI = 49.06-52.32). In conclusion, this nationwide cohort study reveals strongly increased risks of all-cause and diagnosis-specific disability pension among those sickness absent due to musculoskeletal diagnoses.
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The purpose of this systematic review was to summarize and critically appraise research developing or validating instruments to assess patient-reported safety, efficacy, and/or misuse in ongoing opioid therapy for chronic pain. Our search included the following datasets: OvidSP MEDLINE (1946-August 2012), OvidSP PsycINFO (1967-August 2012), Elsevier Scopus (1947-August 2012), OvidSP HaPI (1985-August 2012), and EBSCO CINAHL (1981-August 2012). Eligible studies were published in English and pertained to adult, nonsurgical/interventional populations. ⋯ The studies employed a wide variety of psychometric tests, with most demonstrating statistical significance, but several potential sources of bias and generalizability limitations were identified. Lack of testing in clinical practice limited assessment of feasibility. The dearth of safety and efficacy items and lack of testing in clinical practice demonstrates areas for further research.
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When a newly developed experimental method to vibrate vellus hairs on human skin was applied to the face and arm in healthy subjects, intense itch was reproducibly induced on the face, but not on the arm, without any flare reactions. In contrast to histamine-induced itch, mechanically evoked itch was not characterized as burning or stinging by any subjects, and was resistant to histamine H1-receptor antagonists. When the stimulation was continued for 10 min, mechanically evoked itch reached the maximum intensity within 10 s, but gradually attenuated after 60 to 90 s and was rarely perceivable at the end of stimulation. ⋯ Touch-alloknesis was present in the adjacent skin area until mechanically evoked itch completely diminished, supporting the hypothesis that itch sensitization can be caused by a continuous activation of peripheral itch neurons whether or not they are histamine-sensitive C nerves. In conclusion, this study provides direct evidence of mechanosensitive nerves involved in itch in human skin. The purity of mechanically evoked itch without any pain-related sensory components is a major advantage for investigating the differentiation of itch from pain.