Pain
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Clinical Trial
Gender differences in associations between trauma history and adjustment among chronic pain patients.
This study examines the relationship between a trauma history and emotional functioning in response to a chronic pain condition. We broadened the traditional study of trauma in chronic pain from sexual and physical abuse to include a variety of traumatic events and experiences that occurred not only during childhood, but during adulthood as well. Seventy-three (51% female, 60% lower back) chronic pain patients were administered the Trauma History Questionnaire (Green, B. ⋯ Univariate tests showed that the interaction was significant only for emotional distress variables and not for pain severity and disability. Further, the multivariate effect of Trauma Group and the univariate effects for emotional distress variables were significant only among men. Results indicate that a substantial history of trauma may detrimentally impact a chronic pain patient's ability to manage their pain effectively, particularly among men.
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Patients who develop malignant infiltration of the psoas muscle and the lumbar plexus often experience a severe complex pain syndrome characterised by deep somatic pain, neuropathic pain and psoas spasm. Conventional analgesic regimes may not relieve these symptoms adequately. We describe the use of patient-controlled boluses of local anaesthetic via a psoas sheath catheter in this scenario. The recent availability of portable infusion pumps with the capability to deliver large volume boluses with long lockout times made this intervention possible and allowed the patient to be discharged home with effective relief of pain.
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The aim of this study was to investigate the analgesic effects of epidural opioids upon persistent pain sensitivity in neonatal rat pups. Two models of persistent pain were used, subcutaneous injection of carrageenan, and topical application of capsaicin cream, both to the hind paw. The contribution of individual opioid receptor subtypes in the spinal cord to analgesia were tested at different developmental stages using epidural mu (morphine sulphate), delta (DPDPE) and kappa (U69593) opioid receptor agonists in neonatal rats aged P (postnatal day) 3, 10 and 21. ⋯ The results show that newborn rat pups are capable of displaying both allodynia and hyperalgesia following experimental inflammation that is blocked by epidural mu, delta and kappa opioids. The opioid potency is enhanced compared with antinociception in acute tests. This is not observed following capsaicin hyperalgesia and is therefore not a general consequence of C fibre induced increases in central excitability but relies upon mechanisms special to inflammatory pain.
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Withdrawal reflex responses to graded von Frey filaments applied to the plantar surface of the paw were measured before and after bone hole damage in rats with either a dorsal column (DC) lesion or a sham DC lesion. Two methods were employed to produce models of osteotomy; a small hole was drilled through either the (1) tibia or (2) calcaneus (Houghton, A. K., Hewitt, E. and Westlund, K. ⋯ Nocifensive behavior, characterized by a lifting and guarding of the damaged limb, was also observed in animals with a hole through the calcaneus. In contrast, we found that interrupting the dorsal column pathway with a small mid-line lesion (1 week prior to the osteotomy) prevented the development of both the primary and secondary mechanical hyperalgesia and allodynia but not the guarding of the damaged limb. This study provides evidence that axons in the medial part of the dorsal column are involved in the development of mechanical hyperalgesia and allodynia after bone hole injury.
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Clinical Trial
Experimental human muscle pain and muscular hyperalgesia induced by combinations of serotonin and bradykinin.
In the present study, we assessed the muscle pain and possible development of muscular hyperalgesia to mechanical stimuli after two subsequent intramuscular infusions of serotonin (5-HT) and bradykinin (BKN). The pain intensity after the infusions was continuously scored on a visual analogue scale (VAS). The subjects drew the distribution of the pain areas on a map. ⋯ Cutaneous sensibility to mechanical stimuli and SPPTs were not affected by any of the combinations. The combinations of serotonin and bradykinin produce experimental muscle pain and muscular hyperalgesia to mechanical stimuli. Pre-treatment with serotonin may enhance the effect of bradykinin in the generation of muscle pain and muscular hyperalgesia in humans.