Pain
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Randomized Controlled Trial
Growth hormone treatment for sustained pain reduction and improvement in quality of life in severe fibromyalgia.
Functional defects in growth hormone (GH) secretion and its efficacy as a complementary treatment have been suggested for fibromyalgia. This study investigated the efficacy and safety of low-dose GH as an add-on therapy in patients with both severe FM and low insulin-like growth factor 1 levels. A total of 120 patients were enrolled in a multicenter, placebo-controlled study for 18 months. ⋯ Group A patients showed significantly improved FIQ scores (P=.01) compared with group B. Although GH discontinuation worsened all scores in both groups during follow-up, impairment in pain perception was less pronounced in the GH-treated group (P=.05). In this largest and longest placebo-controlled trial performed in FM (NCT00933686), addition of GH to the standard treatment is effective in reducing pain, showing sustained action over time.
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Persistent postsurgical pain in a general population: prevalence and predictors in the Tromsø study.
Population-based data on the prevalence of persistent postsurgical pain are scarce. This study aimed to assess the prevalence of persistent postsurgical pain in a general population and to describe associated physical, social, and psychological factors, including symptoms of nerve injury and sensitization. A cross-sectional survey was performed in northern Norway with questionnaire items covering surgery, pain, and sensory abnormalities in the area of surgery. ⋯ Of the 826 individuals reporting persistent pain in the anatomical area of surgery, 51.0% reported chronic pain when questioned without specific reference to the surgery. The present study supports evidence from clinical studies of persistent postsurgical pain, indicating a high prevalence, but reveals large discrepancies in report of pain, depending on the questions asked and the context in which the questions are presented. Strong associations between sensory abnormalities and pain indicate neuropathic mechanisms in a major proportion of cases.
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Glutamate is an essential transmitter in pain pathways. However, its broad usage in the central and peripheral nervous system prevents us from designing efficient glutamate-based pain therapies without causing harmful side effects. The discovery of vesicular glutamate transporters (VGLUT1-3) has been a crucial step in describing specific glutamatergic neuronal subpopulations and glutamate-dependent pain pathways. ⋯ The animals were less prone to develop an inflammatory-related state of pain and were, in the partial sciatic nerve ligation chronic pain model, much less hypersensitive to mechanical stimuli and did not develop cold allodynia or heat hyperalgesia. To take advantage of this neuropathic pain-resistant model, we analyzed Vglut2-dependent transcriptional changes in the dorsal spinal cord after nerve injury, which revealed several novel candidate target genes potentially relevant for the development of neuropathic pain therapeutics. Taken together, we conclude that VGLUT2 is a major mediator of nociception in primary afferents, implying that glutamate is the key somatosensory neurotransmitter.