Pain
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Non-invasive, movement-based models were used to investigate muscle pain. In rats, the masseter muscle was rapidly stretched or electrically stimulated during forced lengthening to produce eccentric muscle contractions (EC). Both EC and stretching disrupted scattered myofibers and produced intramuscular plasma extravasation. ⋯ In contrast, stretching significantly increased the number of P2X(3) muscle afferent neurons for 12d. The sustained, elevated P2X(3) expression evoked by EC and stretching may enhance nociceptor responsiveness to ATP released during subsequent myofiber damage. Movement-based actions such as EC and muscle stretching produce unique tissue responses and modulate neuropeptide and nociceptive receptor expression in a manner particularly relevant to repeated muscle damage.
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Review Meta Analysis
The burden of neuropathic pain: a systematic review and meta-analysis of health utilities.
Patients with neuropathic pain (NeuP) experience substantially lower health-related quality of life (HRQoL) than the general population. The aim of this systematic review and meta-analysis is to test the hypothesis that NeuP is associated with low levels of health utility. A structured search of electronic databases (MEDLINE, EMBASE, Cochrane Library and CINAHL) was undertaken. ⋯ This study confirms the hypothesis that patients with NeuP experience low utilities and therefore low HRQoL. However, the contribution of non-NeuP co-morbidity remains unclear. Neuropathic pain severity emerged as a primary predictor of the negative health impact of NeuP.
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Randomized Controlled Trial Multicenter Study
Contributions of change in clinical status parameters to Patient Global Impression of Change (PGIC) scores among persons with fibromyalgia treated with milnacipran.
Clinical trials on the treatment of pain syndromes have adopted Patient Global Impression of Change (PGIC) as a primary outcome. However, little is known about how change in clinical status influences these ratings. The present study examined relationships between changes in pain, depressed mood, physical functioning, vitality, sleep disturbance, cognitive complaints, and PGIC ratings among 1260 participants with fibromyalgia (FM) who completed one of two trials examining the safety and efficacy of milnacipran. ⋯ Among responders, improvements in pain were significantly associated with better PGIC ratings, along with improvements in vitality, sleep, physical function, and cognitive complaints. These findings underscore the complexity of global ratings in FM patients, and suggest the association between clinical status and PGIC ratings varies as a function of perceived treatment response. Several domains were associated with PGIC ratings, highlighting the need to assess multiple outcomes in clinical trials of treatments for FM.
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Randomized Controlled Trial
Fibromyalgia: Moderate and substantial pain intensity reduction predicts improvement in other outcomes and substantial quality of life gain.
Chronic pain is associated with a range of other problems, including disturbed sleep, depression, anxiety, fatigue, reduced quality of life, and an inability to work or socialise. We investigated whether good symptom control of pain (using definitions of moderate and substantial benefit) is associated with improvement in other symptoms. Individual patient data from four randomised trials in fibromyalgia (2575 patients) lasting 8-14weeks were used to calculate percentage pain reduction for each completing patient (1858), divided into one of five groups according to pain reduction, irrespective of treatment: substantial benefit - 50% pain reduction; moderate - 30% to <50%; minimal - 15% to <30%; marginal - 0% to <15%; worse - <0% (increased pain intensity). ⋯ Substantial pain intensity reduction resulted in 0.11 QALYs gained, and moderate pain intensity reduction in 0.07 QALYs gained over a 12-month period. Substantial and moderate pain intensity reduction predicts broad beneficial outcomes and improved quality of life that do not occur without pain relief. Pain intensity reduction is a simple and effective predictor of which patients should continue treatment, and which should discontinue and try an alternative therapy.
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Although the verbal numeric scale (VNS) is used frequently at patients' bedsides, it has never been formally validated in children with acute pain. In order to validate this scale, a prospective cohort study was performed in children between 8 and 17years presenting to a pediatric emergency department (ED) with acute pain. Pain was graded using the VNS, the visual analogue scale (VAS), and the verbal rating scale (VRS). ⋯ The VNS minimal clinically significant difference was 1. The VNS had good test-retest reliability with 95% limits of agreement of -0.9 and 1.2. In conclusion, the VNS provides a valid and reliable scale to evaluate acute pain in children aged 8-17years but is not interchangeable with the VAS.