Pain
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Case Reports
Topical application of clonidine relieves hyperalgesia in patients with sympathetically maintained pain.
Patients with reflex sympathetic dystrophy or causalgia characteristically have ongoing pain and pain to light touch (hyperalgesia). Some of these patients obtain relief of their pain following interruption of sympathetic function to the affected area and, therefore, have sympathetically maintained pain (SMP). Evidence suggests that the pain and hyperalgesia in SMP are related to activation of peripheral adrenergic receptors. ⋯ In two SMP patients, intradermal injection of norepinephrine or phenylephrine (a specific alpha 1-adrenergic agonist) at a site treated with clonidine evoked intense pain and rekindled the pre-clonidine hyperalgesia at that site. It is likely that clonidine locally blocks the release of norepinephrine via activation of alpha 2 receptors on the sympathetic terminals. This study suggests, therefore, that SMP is mediated via alpha 1-adrenergic receptors located in the affected tissue.
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Chronic pain is a problem among patients with spinal cord injuries, but the psychosocial factors associated with spinal cord injury (SCI) pain are not well understood. To understand SCI pain further, 54 patients (19 with quadriplegia and 35 with paraplegia) completed the Beck Depression Inventory, State-Trait Anxiety Inventory, Profile of Mood States, Acceptance of Disability Scale and SCI Interference Scale. Forty-two patients stated they had SCI pain and completed the Multidimensional Pain Inventory and the Pain Experience Scale. ⋯ Finally, pain was associated with emotional distress over and above the distress associated with the SCI itself. Overall, psychosocial factors, not physiological factors, were most closely associated with the experience of pain. Multidimensional aspects of pain are used to explain these findings and suggest that treatment should be directed at the emotional and cognitive sequelae of chronic SCI pain.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of intermittent bolus with continuous infusion of epidural morphine in the treatment of severe cancer pain.
Twenty-eight patients with severe pain due to cancer, who could no longer obtain acceptable pain relief from optimised doses of oral opioids, were entered into a study which compared pain relief, satisfaction with pain therapy and estimates of neuropsychological functioning during treatment with spinally administered (i.e., epidural and intrathecal) morphine as either repeated bolus doses or as a continuous infusion. These measures of efficacy and side effects were repeated every 2 weeks until either the patient died (82% of patients), withdrew from the study or were no longer able to complete the tests due to deterioration of their condition. The mean (range) duration of treatment was 169 (6-537) days for those patients receiving continuous infusion and 140 (28-378) days for those patients receiving repeated bolus doses. ⋯ There was a significantly greater degree of dose escalation in patients receiving continuous infusion compared to patients receiving repeated bolus doses. For 6 patients in the infusion group the catheter was sited in the intrathecal space, as the dose requirements by the epidural route exceeded the delivery capacity of the pump. For 4 patients in the bolus group the catheter was similarly sited, due to pain on injection and leakage/blockage.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Clinical Trial
Comparative effectiveness of different stimulation modes in relieving pain. Part II. A double-blind controlled long-term clinical trial.
Part I of our earlier pilot study demonstrated that patients preferred modulated stimulation forms - frequency modulation and burst - rather than conventional continuous mode. To assess whether long-term therapeutic effects validate the immediate test results, this trial was performed in 14 patients with 21 pain conditions. Considering the results of the pilot study, the test stimulator was modified and 4 different forms of transcutaneous electrical nerve stimulation were randomly delivered to each patient who was blind to the modes of stimulation for 20 min. ⋯ The stimulation modes employed were: (1) conventional continuous stimulation (continuous pulses with a constant frequency of 70 Hz), (2) burst stimulation (80 msec long trains of pulses, each train consisting of 8 pulses, with an internal frequency of 90 Hz repeated 1.3 times a second), (3) high-rate frequency modulation, HRFM (continuous pulses changed from 90 Hz to 55 Hz over 90 msec, 1.3 times a second), (4) low-rate frequency modulation, LRFM (continuous pulses changed from 60 Hz to 20 Hz over 90 msec, 1.3 times a second). After the test treatment of 4 sessions in the clinic, depending on the pain scores and duration of pain relief recorded, the most effective stimulation mode was determined for each patient and a portable stimulator preset appropriately for that mode was given to be used at home, under our supervision, for 3 months. Fourteen pain conditions out of 21 (66%) responded well to the therapy; the majority preferred was the HRFM and burst-type stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)
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Clinical Trial Controlled Clinical Trial
Morphine differentially affects the sensory and affective pain ratings in neurogenic and idiopathic forms of pain.
In a double-blind, placebo controlled crossover study, the effect of morphine on the affective and sensory pain ratings in different forms of chronic pain was investigated. Six patients suffering from central neurogenic pain, 8 from peripheral neurogenic pain and 6 from idiopathic pain participated in the study. Morphine (0.3 mg/kg bodyweight) and placebo (saline) were administered intravenously. ⋯ From our results it appeared that morphine reduced the affective but not the sensory dimension of pain sensation in both groups of neurogenic pain patients. In the idiopathic pain group, neither the affective nor the sensory dimension of pain sensation were affected. The observed differences in opioid responsiveness were neither the result of differences in opioid consumption nor of differences in baseline pain levels.