European journal of pain : EJP
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Randomized Controlled Trial
Absence of long-term analgesic effect from a short-term S-ketamine infusion on fibromyalgia pain: a randomized, prospective, double blind, active placebo-controlled trial.
To assess the analgesic efficacy of the N-methyl-D-aspartate receptor antagonist S(+)-ketamine on fibromyalgia pain, the authors performed a randomized double blind, active placebo-controlled trial. Twenty-four fibromyalgia patients were randomized to receive a 30-min intravenous infusion with S(+)-ketamine (total dose 0.5mg/kg, n=12) or the active placebo, midazolam (5mg, n=12). Visual Analogue Pain Scores (VAS) and ketamine plasma samples were obtained for 2.5-h following termination of treatment; pain scores derived from the fibromyalgia impact questionnaire (FIQ) were collected weekly during an 8-week follow-up. ⋯ Side effects as measured by the Bowdle questionnaire (which scores for 13 separate psychedelic symptoms) were mild to moderate in both study groups and declined rapidly, indicating adequate blinding of treatments. Efficacy of ketamine was limited and restricted in duration to its pharmacokinetics. The authors argue that a short-term infusion of ketamine is insufficient to induce long-term analgesic effects in fibromyalgia patients.
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Comparative Study
A comparison of the clinical features of fibromyalgia syndrome in different settings.
The "funnel hypothesis" of fibromyalgia syndrome (FMS) assumes that the high levels of somatic and psychological symptoms reported by FMS-patients are due to a selection bias of patients seeking for medical specialist care. We tested the hypothesis by comparing FMS-patients from a general population sample and different clinical settings. ⋯ We found a "funnel" between FMS-persons of the general population and FMS-patients of clinical settings, but not between patients of different levels of care. Patients contacting the health care system did not differ in clinical features.
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We studied the associations of widespread pain with other pain and functional measures among patients with chronic epicondylitis. A total of 190 patients (66% females) participated in the study; with a mean age 43.7, mean duration of symptoms 48weeks, chronic lateral (n=160) and medial (n=30) epicondylitis. We analysed clinical status, grip strength and cubital pain thresholds and interviewed pain and disability, leisure time physical activity, strenuous hobby activities for arms, duration of symptoms, other systemic and upper extremity disorders, arm operations, and work ability. ⋯ It was also related to upper extremity disorders and arm surgery, but not with operated epicondylitis, other systemic diseases, workload or work ability. In addition, 39% of patients without other disease reported widespread pain. Widespread pain is common in chronic epicondylitis with and without other diseases, and is related to high pain scores, decreased function of the arm, long duration of symptoms, sick leave, and with a low level of physical activity.
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Despite the increased recognition of paediatric chronic pain, centres for providing appropriate treatment are scarce, and much remains unknown about optimal treatment approaches. The purpose of this study was to investigate effectiveness of multimodal outpatient treatment (MOT) through the examination of treatment pathways and long-term outcomes. ⋯ MOT appears to be beneficial for children with chronic pain. A short intensive intervention (comprising of a total of 2.5-h) can lead to substantial improvements even for severely affected children.
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Pain is a common and debilitating accompaniment of neuropathy that occurs as a complication of diabetes. In the current study, we examined the effect of continuous release of gamma amino butyric acid (GABA), achieved by gene transfer of glutamic acid decarboxylase (GAD67) to dorsal root ganglia (DRG) in vivo using a non-replicating herpes simplex virus (HSV)-based vector (vG) in a rat model of painful diabetic neuropathy (PDN). Subcutaneous inoculation of vG reduced mechanical hyperalgesia, thermal hyperalgesia and cold allodynia in rats with PDN. ⋯ In vitro, infection of primary DRG neurons with vG prevented the increase in Na(V)1.7 resulting from exposure to hyperglycemia. The effect of vector-mediated GABA on Na(V)1.7 levels in vitro was blocked by phaclofen but not by bicuculline, a GABA(B) receptor effect that was blocked by pertussis toxin-(PTX) interference with Gα((i/o)) function. Taken in conjunction with our previous observation that continuous activation of delta opioid receptors by vector-mediated release of enkephalin also prevents the increase in Na(V)1.7 in DRG exposed to hyperglycemia in vitro or in vivo, the observations in this report suggest a novel common mechanism through which activation of G protein coupled receptors (GPCR) in DRG neurons regulate the phenotype of the primary afferent.