Articles: chronic.
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Journal of anesthesia · Sep 1996
Effects of spinal naloxone and naltrindole on the antinociceptive action of intrathecally administered dexmedetomidine.
Intrathecally administered alpha-2 adrenoceptor and opioid agonists are well known to exert antinociceptive effects in humans and various animals. To examine the interaction of these two groups of agents in the spinal cord, we tested the effect of the opioid antagonists naloxone or naltrindole on the antinociceptive action of an intrathecally administered alpha-2 agonist, dexmedetomidine, using a formalin test in rats. 19 groups of Sprague-Dawley rats (250-300 g) were prepared with chronic intrathecal catheters and examined for the effects of agents on the formalin test. Each group contained 6 animals. 50 μl of 5% formalin was injected subcutaneously in the plantar surface of one hind paw. ⋯ Intrathecal dexmedetomidine (1 μg) maximally depressed the behavioral changes in both phase 1 and phase 2 of the formalin test, which was antagonized by the alpha-2 adrenoceptor selective antagonist atipamezole (0.3 μg). Naloxone (0.1-10 μg) or naltrindole (1-10 μg), when coadministered with dexmedetomidine, showed a dose-dependent antagonism to the effect of dexmedetomidine, whereas naloxone, naltrindole, or atipamezole alone showed no effect on the nocieptive behavior due to formalin injection. These results indicate that the antinociceptive effect of intrathecally administered alpha-2 adrenoceptor agonists may involve opioid receptors in the spinal cord.
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A multimodal treatment program is presented in cases of functional restoration for chronic low back pain. The study comprises four parts. Part I gives an overview of the different results of the study. Part II focuses on the medical and functional examination in comparison with persons who do not suffer from back pain. Part III describes psychosocial aspects (depression, complaints, ways of coping, disability) and psychotherapy. In part IV prognostic factors and their reliability for predicting treatment outcome (return to work, pain intensity, self-assessment of success by patients) are examined. In addition the relevant effects of the program on social and health care systems are also addressed. ⋯ The results demonstrate the effectiveness of the multimodal program of functional restoration, not only concerning positive changes in somatic, psychological and physical variables, but also with respect to the number of patients who returned to work. Our methods are also compared with the discrepant results of multimodal treatment in the United States and Scandinavia.
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The contingent negative variation (CNV) is a slow cortical potential recorded from the scalp. This method allows the pathophysiology of chronic headaches to be elucidated. When assessed during the pain-free interval patients suffering from migraine without aura show significantly more negative amplitudes than healthy controls. ⋯ When migraine patients are assessed a few days before a migraine attack occurs, they show pronounced negativity, which normalized during the attack. Despite these interesting findings that are based on group comparisons, evaluating the CNV on an individual basis does not allow specific conclusions. Thus, assessment of the CNV is an important tool to examine pathophysiological aspects of chronic headaches, but is not suitable as a diagnostic procedure.
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The antinociceptive effect of alpha(2)-adrenoceptor agonists is mediated by activation of descending inhibiting noradrenergic systems, which modulates 'wide-dynamic-range' neurones. Furthermore, they inhibit the liberation of substance P and endorphines and activate serotoninergic neurones. Despite this variety of antinociceptive actions, there is still little experience with alpha(2)-adrenoceptor agonists as therapeutic agents for use in chronic pain syndromes. ⋯ In isolated cases clonidine has been administered epidurally at a dose of 1500 microg/day for almost 5 months without evidence for any histotoxic property of clonidine. Side effects often observed during administration of alpha(2)-adrenoceptor agonists are dry mouth, sedation, hypotension and bradycardia. Therapeutic interventions are usually not required.
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Four multidimensional inventories used as instruments for the assessment of pain are examined: "Fragebogen zur Erfassung der Schmerzverarbeitung' [Questionnaire for Assessment of Level of Coping with Pain], "Kieler Schmerzverarbeitungs-Inventar' [Kiel Inventory of Coping with Pain], "Fragebogen zur Schmerzregulation' [Questionnaire on Pain Regulation], and the German version of the "Multidimensional Pain Inventory'. None of these questionnaires assesses all domains that are important in chronic pain. The recommended standardized assessment routine for pain centres includes the use of a diary, the rating of actual, average and maximum pain intensity, the application of the PDI, a measure of disability, and the FESV, which records cognitive processing and coping. As measures of general psychological dysfunction the ADS for the assessment of depression and the B-L, a symptom checklist, are suggested as instruments suitable for routine use in diagnosis and evaluation.