European journal of pain : EJP
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In patients with localized musculoskeletal pain, spread of pain and tenderness outside the primarily painful area and sometimes even generalization of pain have been reported, the latter possibly indicating a dysfunction of endogenous pain modulatory systems. The purpose of the study was to use patients with long-term trapezius myalgia as a model to investigate the possible influence of a localized muscle pain on somatosensory processing in a remote pain-free area and the effect of heterotopic noxious conditioning stimulation (HNCS) on 'diffuse noxious inhibitory controls' (DNIC) related mechanisms. Altered somatosensory processing may indicate subclinical derangement of endogenous modulatory systems. ⋯ During HNCS, the sensitivity to pressure pain and suprathreshold heat pain decreased in patients and controls alike (p<0.02 and p<0.04 respectively) and returned to baseline following HNCS. In conclusion, in a remote non-painful area allodynia to pressure and hypoaesthesia to cold were found in conjunction with preserved function of DNIC-related mechanisms. Whether altered central somatosensory processing at rest may indicate a predisposition for further spread of pain is at present unclear.
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The study assessed the influence of stimulus modality on adaptation or facilitation of pain during tonic cold and tourniquet pressure stimulation. Experimental set-up for the cold stimulation consisted of a thermo-tank with water, cooled to 3 degrees C, circulation pump, electronic thermometer and an electronic 10 cm visual analogue scale (VAS). Experimental set-up for the tonic pressure stimulation consisted of a pneumatic tourniquet cuff, a computer-controlled air compressor, and an electronic VAS. ⋯ The overshoot magnitude was lowest during "VAS 6" session. Adapting and non-adapting/facilitating responses to cold and to pressure during "VAS 6" session were not correlated, suggesting that pain course and therefore stimulus tolerance during tonic stimulation are modality-specific. The results of the study suggest that tolerance of tonic painful pressure and cold stimulations is specific to stimulus modality and may represent separate nociceptive mechanisms.
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The continuous intrathecal infusion of drugs with implantable and programmable pumps is commonly used for the treatment of otherwise intractable pain and spasticity. There is now a consensus that it is possible to use mixtures of two or even three drugs in selected cases. ⋯ These values are determined from the desired quantity of each drug to be infused in 24h, the concentration of each drug solution and the volume of the reservoir. It is essential that the drugs do not react with one another, that they will remain stable in the reservoir at body temperature and that they are safe for a long-term infusion.
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Clinical Trial
Morphine responsiveness in a group of well-defined multiple sclerosis patients: a study with i.v. morphine.
Pain in multiple sclerosis (MS) is more common than has previously been believed. About 28% of all MS patients suffer from central pain (CP), a pain that is difficult to treat. In the present study we have investigated the responsiveness of this pain to morphine. ⋯ Thus, compared with nociceptive pain, only a minority of the patients with CP due to MS responded to morphine and only at high doses. The present results are in accord with experimental studies indicating that neuropathic pain is poorly responsive but not totally unresponsive to opioids. The results do not support the routine use of strong opioids in MS patients with CP.
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Past research examined measures of pain among seniors who were experiencing movement-related exacerbations of musculoskeletal pain and obtained clear support for the utility of the behavioural coding of pain-related body movements (e.g., bracing, guarding). Support for the utility of the Facial Action Coding System (FACS), which involves the objective coding of facial reactions, was not as strong. The findings concerning FACS could have been an artifact of the methodology that was used. ⋯ Facial reactions were coded using FACS. Facial reactions varied as a function of the degree to which the various activities were strenuous. The results support the utility of FACS in the assessment of musculoskeletal pain among seniors undergoing rehabilitation following knee surgery.