Pain
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Randomized Controlled Trial Clinical Trial
Quantitative sensory examination of epidural anaesthesia and analgesia in man: effects of pre- and post-traumatic morphine on hyperalgesia.
The objectives of the study were: (1) comparison of hypoalgesic effects of pre- and post-traumatic epidural morphine (EM) on primary and secondary hyperalgesia, and (2) comparison of EM hypoalgesia in normal and injured skin. Burn injuries (25 x 50 mm rectangular thermode, 47 degrees C, 7 min) were produced on the calves of healthy volunteers, at 2 different days at least 1 week apart. In randomized order, the subjects received 4 mg of EM administered via the L2-L3 intervertebral space on one day and no treatment on the other day. ⋯ Following NAL, the areas of secondary hyperalgesia expanded beyond control size. It is suggested that the major effect of EM on secondary hyperalgesia is inhibition of C fibre-mediated activity which maintains the altered response properties of central neurons responsible for secondary hyperalgesia. Possible mechanisms of action of NAL in enhancement of hyperalgesia are discussed.
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Case Reports Comparative Study Clinical Trial
Altered pain and temperature perception following cingulotomy and capsulotomy in a patient with schizoaffective disorder.
Recent studies have renewed interest in the role of limbic structures, such as the cingulate cortex, in nociception. To investigate the involvement of the limbic system in pain and temperature perception further, we have quantified ratings of innocuous and noxious thermal stimuli in a patient with schizoaffective disorder before and after 2 surgical procedures. Psychophysical tests were conducted at a control session prior to surgery. ⋯ These altered ratings of noxious heat and cold stimuli were reflected on both a pain intensity and pain affect (unpleasantness) scale. In summary, these data suggest that cingulotomy and capsulotomy disinhibited the patient's noxious heat and cold appreciation. These findings provide support for a role of the cingulate cortex and frontal cortical regions in the perception of innocuous and noxious thermal stimuli and suggest that under normal conditions, these areas may act to suppress the subjective intensity of noxious heat and cold.
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Case Reports
Difficult management of pain following sacrococcygeal chordoma: 13 months of subarachnoid infusion.
We report on a patient suffering severe pain following a long-standing sacral chordoma in whom management of therapy and pain was extremely difficult. Because orally administered morphine was observed to be ineffective in the early stages of treatment, we tried to achieve pain relief by using epidural morphine. This was also unsatisfactory. ⋯ Periods of analgesia were followed by occasional crises of intense sharp pain suggesting incomplete relief. No serious complications or meningitis occurred. This case emphasizes the difficulty in managing pain in this type of cancer.
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Hyperalgesia and allodynia in 4 cancer patients treated with morphine disappeared after discontinuing or substituting morphine with other opioid agonists. The first case describes a young female who developed hyperalgesia and myoclonus during intravenous morphine infusion. The hyperalgesia and myoclonus disappeared when the morphine administration was discontinued and she felt comfortable on small and sporadic oral doses of methadone. ⋯ The fourth case describes a boy developing hyperalgesia after high doses of oral and intramuscular morphine. The hyperalgesia disappeared after discontinuing morphine administration but withdrawal symptoms developed due to too small doses of methadone. Possible mechanisms of morphine-induced hyperalgesia are discussed.
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Seventeen drawings of localised low-back pain were analysed by two assessors using 4 systems. Three were grid-based systems and one was by computer. The mean area or 'extent' was calculated to be 7.7%, 4.7%, 3.6% and 2.3% of the body outline using 45, 200, 560 and 61,102 section analyses, respectively. ⋯ Correlation coefficients of extent between the systems varied from 0.46 to 0.94. Correlation was highest between systems of adjacent magnitude of sections. It is concluded that grid-based assessment of small areas overestimates the actual area of pain and this may account for the lack of sensitivity to change in clinical status.