Articles: neuralgia.
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Curr Opin Neurol Neurosurg · Apr 1992
ReviewPain mechanisms and the management of neuropathic pain.
The nociceptive system is not fixed, but changes in response to its input and activity. This 'plasticity' comprises dynamic developments of both pro- and antinociceptive processes. Recent advances in the understanding of these processes have important implications for the treatment of persistent neuropathic pain.
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Ten patients with organic nerve injury causing chronic neuropathic pain were tested for the effects of intravenous lidocaine versus saline upon psychophysical somatosensory variables. The variables assessed were the subjective magnitude of pain, area of mechanical hyperalgesia and presence and magnitude of thermal heat/cold hyperalgesia. The study methods applied to evaluate these conditions were the conventional testing of somatosensory submodalities with area mapping and the subjective magnitude estimation of spontaneous pain. ⋯ This improvement is in keeping with the inhibition of anomalous neural impulses which can be generated anywhere along the sensory channels responsible for generating spontaneous pain and hyperalgesia. Thus, intravenous lidocaine is proposed as a diagnostic aid in the examination of patients complaining of complex sensory disorders associated with nerve injury. The transient pain relief may allow a fuller identification of the area of sensory loss.
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Randomized Controlled Trial Clinical Trial
A new topical treatment for acute herpetic neuralgia and post-herpetic neuralgia: the aspirin/diethyl ether mixture. An open-label study plus a double-blind controlled clinical trial.
Topical aspirin/diethyl ether (ADE) mixture was used to treat 45 consecutive patients with acute herpetic neuralgia (AHN) (n = 28) and with post-herpetic neuralgia (PHN) (n = 17) in an open-label study. Good-to-excellent results were achieved by 93% of AHN patients and by 65% of PHN patients. Earlier treatment yielded better results for the AHN but not the PHN group. ⋯ Treatment tolerance was excellent with no adverse effect observed. In addition to the open trial, a pilot double-blind crossover placebo-controlled study (n = 11) compared the analgesic efficacy of ADE with two other NSAID (indomethacin and diclofenac) drug/ether mixtures. Aspirin (but not indomethacin and diclofenac) was significantly superior to placebo as regards pain relief (P less than 0.05).
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Neuropathic pain, i.e., pain resulting from functional changes in peripheral and central pathways subsequent to injury to the peripheral nervous system, offers a most difficult challenge to therapy. To date, only the antidepressants and the anticonvulsants have shown any effectiveness, albeit incomplete and inconsistent, and many questions remain unanswered: What are the exact indications for the antidepressants? What component of neuropathic pain do they relieve, and through which mechanisms? Which type of antidepressants should be prescribed? A first-generation tricyclic? Or a new compound with a selective action on serotonin reuptake? What are the effective dosage and duration of the treatment? What is it mechanism of action? What other antalgic effects do carbamazepine and baclofen possess apart from their action on trigeminal neuralgia? The opiates are generally considered to be without effect, but recent clinical and experimental findings seem to point otherwise. In the meantime, following a few simple rules will optimize the benefit of drug treatment in neuropathic pain: treatment tailored to individual cases; adequate dosage and duration of treatment. However, it is from the near future that breakthroughs are being expected, dues to the multiplication of animal models and more accurate analysis; new clinical evaluation tools which help in distinguishing the different mechanisms underlying the various aspects of pain; the development of new substances, such as capsaicin, local anesthetics, anti-inflammatory agents (NSAIDs for example); and better defined methodological conditions for therapeutic trials.
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Acta neurochirurgica · Jan 1992
Effects of dorsal root entry zone lesions on CSF and plasma neuropeptides and catecholamines.
Effects of dorsal root entry zone lesions (DREZLs) on cerebrospinal fluid (CSF) and plasma concentrations of neuropeptides, catecholamines, and cyclic nucleotides were studied in 9 patients with intractable chronic pain. Contents of beta-endorphin-like-material in CSF decreased in all patients 12-17 days following DREZLs during which complete to good pain relief was achieved. Contents of beta-endorphin-like-material in CSF increased again about one month after DREZLs in two and remained unchanged in one of three patients tested, who complained of partial reappearance of pain. ⋯ Substance P, noradrenaline, adrenaline, and cyclic nucleotide levels in both CSF and plasma were variable among the subjects and did not change significantly following the operations. Thus, the results suggest that production of beta-endorphin-like-material in the central nervous system is decreased by DREZL, though the increase in its turn-over might not be neglected. The mechanisms of the decrease in contents of beta-endorphin-like-material in CSF after DREZLs were discussed in terms of our current knowledge of pain and pain inhibitory systems.