Pain
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Several theories about musculoskeletal pain syndromes such as whiplash-associated disorder (WAD) suggest that pain and muscle activity interact and may contribute to the chronicity of symptoms. Studies using surface electromyography (sEMG) have demonstrated abnormal muscle activation patterns of the upper trapezius muscles in the chronic stage of WAD (grade II). There are, however, no studies that confirm that these muscle reactions are initiated in the acute stage of WAD, nor that these muscle reactions persist in the transition from acute neck pain to chronic neck pain disability. ⋯ Furthermore, follow-up assessments of the EMG level during these two tasks, did not show a time related change. In conclusion, in subjects with future disability, the acute stage is characterized by a reorganization of the muscular activation of neck and shoulder muscles, possibly aimed at minimizing the use of painful muscles. This change of motor control, is in accordance with both the (neurophysiological) 'pain adaptation model' and (cognitive behavioral) 'fear avoidance model'.
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Comparative Study
Peripheral interactions between dextromethorphan, ketamine and amitriptyline on formalin-evoked behaviors and paw edema in rats.
The local, peripheral administration of antidepressants and excitatory amino acid receptor antagonists can cause analgesia in a number of conditions. The present study examined the effects of combinations of dextromethorphan and ketamine, two clinically used N-methyl-D-aspartate (NMDA) receptor antagonists, with amitriptyline on formalin-evoked behaviors and paw edema. Pretreatment with amitriptyline or dextromethorphan (10-300 nmol) resulted in suppression of flinching behaviors induced by 2.5% formalin, but ketamine had no intrinsic effect. ⋯ NMDA receptor blockade, blockage of sodium channels, blockage of biogenic amine receptors), while a lack of intensification (amitriptyline/ketamine) could reflect occluded actions due to expression of similar actions by the other drug. Paw edema induced by dextromethorphan and ketamine involves inhibition of biogenic amine reuptake, and the ability of amitriptyline to block biogenic amine receptors likely accounts for its inhibiton of these actions. Combinations of these particular agents could represent a method for augmented analgesia and minimization of local adverse reactions.
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Randomized Controlled Trial Comparative Study Clinical Trial
The mu-opioid agonist remifentanil attenuates hyperalgesia evoked by blunt and punctuated stimuli with different potency: a pharmacological evaluation of the freeze lesion in humans.
Experimental pain models inducing hyperalgesia, i.e. an increased sensitivity to noxious stimuli often present in clinical pain, are important tools for studying antinociceptive drug profiles. The correct interpretation of results obtained in these models necessitates their mechanistic understanding. This study evaluated the freeze lesion, an experimental model of hyperalgesia, in humans. ⋯ Remifentanil attenuated electrical pain with greater potency for low frequency stimulation. The potency difference of remifentanil suggests that different neuronal mechanisms mediate hyperalgesia to blunt and punctuated stimulation. Absence of brush-evoked and electrical hyperalgesia is compatible with the view that mechanical hyperalgesia to blunt and punctuated stimulation of the freeze lesion is predominantly caused by a peripheral mechanism.
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There has been a surge in interest in medicinal cannabis in Canada. We conducted a questionnaire survey to determine the current prevalence of medicinal cannabis use among patients with chronic non-cancer pain, to estimate the dose size and frequency of cannabis use, and to describe the main symptoms for which relief was being sought. Over a 6-week period in mid-2001, 209 chronic non-cancer pain patients were recruited in an anonymous cross-sectional survey. ⋯ We conclude that cannabis use is prevalent among the chronic non-cancer pain population, for a wide range of symptoms, with considerable variability in the amounts used. Discussions between patients and health care providers concerning cannabis use may facilitate education and follow up, and would allow side effects and potential interactions with other medications to be monitored. Clinical trials of cannabis for chronic non-cancer pain are warranted.
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Case Reports
Musculoskeletal pain in the Netherlands: prevalences, consequences and risk groups, the DMC(3)-study.
The objective of this paper was to present estimates on the prevalence of musculoskeletal pain of five different anatomical areas and ten anatomical sites, and their consequences and risk groups in the general Dutch population. Cross-sectional data from a population-based study of a sex-age stratified sample of Dutch inhabitants of 25 years and older were used. With a postal questionnaire data was assessed on musculoskeletal pain, additional pain characteristics (location, duration, course), its consequences (utilization of health care, sick leave and limitation in daily life) and general socio-demographic characteristics. ⋯ Between 33 and 42% of those with complaints consulted their general practitioner about their pain. With the exception of persons who are work disabled, general sociodemographic characteristics cannot be used to identify high risk groups. Musculoskeletal pain is common in all subgroups of the population and has far-reaching consequences for health, work and the use of health care.