Pain
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Comparative Study Controlled Clinical Trial
Effects of subcutaneous administration of glutamate on pain, sensitization and vasomotor responses in healthy men and women.
The present study aimed to investigate if (1) subcutaneous injection of glutamate induces pain, sensitization and vasomotor responses in humans and (2) if sex differences exist in these responses. Thirty healthy volunteers (men-15 and women-15) were included. Each subject received four subcutaneous injections (0.1ml; glutamate 100, 10, 1mM and isotonic saline 0.9%) into the forehead skin in two sessions separated by one week. ⋯ Concentration-dependent local vasomotor responses were found following the subcutaneous injection of glutamate but there was no sex difference in this effect. Glutamate 100mM significantly reduced the PPT values (P<0.001) without sex-related differences. The present study demonstrates for the first time that subcutaneous injection of glutamate evokes pain, vasomotor responses and pinprick hyperalgesia in human volunteers and that there are sex-related differences in some of these responses.
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Randomized Controlled Trial
Parental history of chronic pain may be associated with impairments in endogenous opioid analgesic systems.
A family history of chronic pain has previously been linked to increased incidence of spontaneous acute pain and risk for chronic pain. Mechanisms underlying these associations are unknown, although similar effects on both acute and chronic pain suggest that central endogenous analgesic system differences may be relevant. This study tested whether a positive parental chronic pain history (PH+) was associated with impaired endogenous opioid analgesic responses to acute pain. ⋯ A significant multivariate PHxSubject Type interaction (p<.05) indicated that opioid analgesic impairments were most prominent in PH+ LBP subjects. Similar analyses for finger pressure pain blockade effects were nonsignificant (p>.10). The possible heritability of endogenous opioid analgesic dysfunction observed in individuals with a positive parental chronic pain history remains to be investigated.
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The fear-avoidance beliefs of patients with subacute low back pain (LBP) considered at risk for chronic disabling LBP are not well known. The objectives of this cross-sectional descriptive survey, conducted in secondary care practice, were to assess fear-avoidance beliefs about back pain in patients with subacute LBP and to seek an association between physician or patient characteristics and level of fear-avoidance beliefs. A total of 286 rheumatologists completed a self-administered questionnaire assessing physicians' demographic, professional data, personal history of back pain, and back pain fear-avoidance beliefs (on the Fear-Avoidance Belief Questionnaire [FABQ]) and 443 patients with sLBP completed one on pain, perceived handicap and disability (Quebec Back Pain Disability Scale), anxiety and depression (Hospital Anxiety Depression questionnaire), and back pain beliefs (FABQ). ⋯ A total of 68% of patients and 10% of physicians had a high rating on the FABQ Phys (>14). Patients' fear-avoidance beliefs about physical activity were associated with low level of education (odds ratio [OR] 4.19; 95% confidence interval [CI] 1.83-9.57), patients' perceived disability (OR 1.05; CI 1.03-1.07), and physicians' high FABQ Phys score (OR 5.92; CI 1.31-26.32). Here we show that fear-avoidance beliefs about back pain were high in patients with subacute LBP and their rheumatologists.
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Although the etiology of chronic pain following trauma is not well understood, numerous retrospective studies have shown that a significant proportion of chronic pain patients have a history of traumatic injury. The present analysis examines the prevalence and early predictors of chronic pain in a cohort of prospectively followed severe lower extremity trauma patients. Chronic pain was measured using the Graded Chronic Pain Scale, which measures both pain severity and pain interference with activities. ⋯ In addition, high reported pain intensity, high levels of sleep and rest dysfunction, and elevated levels of depression and anxiety at 3 months post-discharge were also strong predictors of chronic pain at seven years (p<0.001 for all three predictors). After adjusting for early pain intensity, patients treated with narcotic medication during the first 3 months post-discharge had lower levels of chronic pain at 84 months. It is possible that for patients within these high risk categories, early referral to pain management and/or psychologic intervention may reduce the likelihood or severity of chronic pain.
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The objectives of this cross-sectional study conducted in primary care practice in France were to describe general practitioners' (GPs) fear-avoidance beliefs about low back pain (LBP), investigate the impact of these beliefs on their following guidelines for bed rest, physical activities, and sick leave, and uncover factors associated with GPs' fear-avoidance beliefs. A total of 864 GPs completed a 5-part self-administered questionnaire. Parts 1, 2, and 3 concerned demographic, professional data, and personal history of back pain, respectively. ⋯ FABQ Phys score was associated with recommendation of bed rest or rest during sick leave (p<0.0001) for acute LBP and less advice to maintain maximum bearable physical activities (p<0.001) for chronic LBP. FABQ Work score was associated with prescribing sick leave during painful periods (p<0.005) for acute LBP and less advice to maintain maximum bearable physical activities (p<0.001) for chronic LBP. GPs' fear-avoidance beliefs about LBP negatively influence their following guidelines concerning physical and occupational activities for patients with LBP.