European journal of pain : EJP
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The purpose was to investigate the influence of ongoing pain from an inflammatory nociceptive pain with two different disease durations on somatosensory functions and the effect of heterotopic noxious conditioning stimulation (HNCS) on 'diffuse noxious inhibitory controls' (DNIC) related mechanisms. Eleven patients with rheumatoid arthritis of a short duration (<1 year) (RA1), and 10 patients with rheumatoid arthritis of longer duration (>5 years) (RA5) as well as 21 age- and sex-matched healthy controls participated. Pressure pain sensitivity, low threshold mechanoreceptive function and thermal sensitivity, including thermal pain, were assessed over a painful and inflamed joint as well as in a pain-free area, i.e. the right thigh before HNCS (cold-pressor test) and repeated at the thigh only during and following HNCS. ⋯ In conclusion, over an inflamed joint allodynia to pressure was found in both RA groups, with additional sensory abnormalities in RA5. In a non-painful area, allodynia to pressure was found in RA5, suggesting altered central processing of somatosensory functions in RA5 patients. The response to HNCS was similar in both RA groups and controls, indicating preserved function of DNIC-related mechanisms.
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"He slept less and less; they gave him opium and began to inject morphine. But this did not relieve him. The dull pain he experienced in the half asleep condition at first only relieved him as a change, but then it became as bad, or even more agonizing, than the open pain."--Tolstoy, The Death of Ivan Ilyitch. ⋯ Those who work in chronic pain are unfortunately only too aware of the problems that such pains can cause. One of the hallmarks of neuropathic pain is poor or incomplete relief with opioids. As with so many things in medicine, there is nothing novel in this realization, as the Tolstoy quotation shows.
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Neurolytic blockade is one of the therapeutic possibilities to treat spasticity of various muscles. In patients with spasticity of the adductor thigh muscles, a percutaneous approach to the obturator nerve is often difficult. We describe a new approach to the obturator nerve and we examine its feasibility. ⋯ No complications occurred. The combined approach of the obturator nerve represents a new technique which proved to be accurate, fast, simple, highly successful and reproducible. Obturator neurolysis was confirmed as an efficient and cost-effective technique to reduce adductor muscle spasm and related pain and to improve gait and hygienic care in patients with neurological sequelae of stroke, head trauma or any lesion of the motor neurone.
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Systemic morphine selectively depresses a thalamic link of widespread nociceptive inputs in the rat.
The lateral part of the ventromedial thalamus (VM l) relays nociceptive inputs from the whole body surface to the dorsolateral frontal cortex. The aim of the present study was to investigate the effects of systemic morphine on nociceptive activity evoked in VM l neurones either by thermal (48 degrees C) or by supramaximal percutaneous electrical stimuli. The noxious thermal evoked responses were depressed by 10.8 +/- 10.1%, 48.3 +/- 23.0% and 67.3 +/- 10.1%, 5 min after i.v. injections of 1.0, 1.73 and 3.0 mg/kg of morphine, respectively. ⋯ The dose of morphine that reduced VM l neuronal nociceptive responses by 50% (1.73 mg/kg) was around 3.5 times lower than that necessary to inhibit the responses of its spinal or medullary relays under similar experimental conditions. These results, added to the data of the literature, suggest that supraspinal effects of morphine are primarily mediated at the thalamic level. It is tempting to speculate that morphine-induced reductions of attentional or psychomotor responses related to pain may be mediated by its action on VM l.