Pain
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Randomized Controlled Trial Comparative Study Clinical Trial
Different lipid profiles as constituencies of liquid formula diets do not influence pain perception and the efficacy of opioids in a human model of acute pain and hyperalgesia.
Nutritional support and pain control by medication are often used concomitantly, but interactions are hardly investigated. A randomised, double-blind, cross-over study in ten right-handed volunteers was performed evaluating the influence of cholecystokinin (CCK)-excretion on the perception of pain in a standardised model. CCK-excretion was induced by a liquid formula diet with either long- or medium-chain triglycerides (LCT, MCT). ⋯ In a second series of experiments, alfentanil (4.1+/-0.5 mg) was administered for 90 min using target-controlled infusions and measurements were performed as stated above. Oral administration of LCT as well as MCT may lead to different CCK blood levels, but we found no evidence for CCK-induced effects on pain sensation, touch-evoked allodynia, secondary hyperalgesia or morphine-induced anti-nociception in humans. In our studies, liquid formula diets did not influence acute pain perception or the efficacy of opioids in a human model of pain.
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Age differences in the experience of chronic pain remain unclear. A serious barrier to progress in the field of pain and aging arises from the lack of data regarding the psychometric properties of pain scales for use with the elderly. The present study was designed to assess age differences in pain intensity and quality and to compare the psychometric properties of the McGill Pain Questionnaire (MPQ) in young and elderly chronic pain patients. ⋯ Finally, the latent structure, internal consistency, and pattern of subscale correlations of the MPQ were very similar in the young and elderly groups. Possible explanations for the discrepancy in the pattern of age differences on measures of pain intensity and quality are explored. The implications of this pattern of age differences for basic pain mechanisms and pain management should be given serious empirical attention.
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Comparative Study
Intramuscular injection of tumor necrosis factor-alpha induces muscle hyperalgesia in rats.
The role of proinflammatory cytokines in neuropathic and inflammatory pain is well established. Recent studies suggest that cytokines such as tumor necrosis factor-alpha (TNF) may also be involved in the development of muscle pain. To investigate the pathophysiology of intramuscular TNF, exogenous TNF (0.1-10 microg), formalin (9%) or vehicle was injected into the gastrocnemius or biceps brachii muscles of rats. ⋯ TNF and formalin evoked intramuscular upregulation of CGRP and NGF, whereas PGE2 was increased exclusively after TNF injection. These findings allow us to speculate that endogenous TNF may play a role in the development of muscle hyperalgesia. Targeting proinflammatory cytokines might be beneficial for the treatment of musculoskeletal pain syndromes.
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Case Reports
Pulsed radiofrequency treatment of the Gasserian ganglion in patients with idiopathic trigeminal neuralgia.
Pulsed radiofrequency treatment has been described as a minimal invasive alternative to radiofrequency thermocoagulation for the management of chronic pain syndromes. We present here our first five high-risk patients with idiopathic trigeminal neuralgia who were treated with pulsed radiofrequency after multidisciplinary assessment; with a mean follow-up of 19.2 months (range 10-26). ⋯ An excellent long-term effect was achieved in three of the five patients, a partial effect in one patient and a short-term effect in one patient. No neurological side effects or complications were reported.
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Comparative Study
Facial arthralgia and myalgia: can they be differentiated by trigeminal sensory assessment?
Heat and electrical detection thresholds were assessed in 72 patients suffering from painful temporomandibular disorder. Employing widely accepted criteria, 44 patients were classified as suffering from temporomandibular joint (TMJ) arthralgia (i.e. pain originating from the TMJ) and 28 from myalgia (i.e. pain originating from the muscles of mastication). Electrical stimulation was employed to assess thresholds in large myelinated nerve fibers (Abeta) and heat application to assess thresholds in unmyelinated nerve fibers (C). ⋯ Following arthrocentesis, mean electrical detection threshold ratios in the AUT territory were significantly elevated from 0.64+/-0.06 to 0.99+/-0.04 indicating resolution of the hypersensitivity (paired t-test, P=0.001). In conclusion, large myelinated fiber hypersensitivity is found in the skin overlying TMJs with clinical pain and pathology but is not found in controls. In patients with muscle-related facial pain there was significant elevation of the electrical detection threshold in the AUT region.