European journal of pain : EJP
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While morphine is historically the gold standard for the management of severe cancer pain, some patients either do not achieve adequate analgesia, or suffer intolerable side-effects. For these patients an alternative opioid is recommended. ⋯ Similar to morphine, transdermal fentanyl is effective for the management of moderate to severe cancer pain. However, inappropriate prescribing of transdermal fentanyl, particularly in the clinical setting of unstable pain, can cause significant opioid toxicity, as highlighted in the case reports described.
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Awareness that SCI pain is common emerged during the past decade. However, there are a number of unresolved issues. There is a need for variety of experimental models to reflect diversity of SCI pains. ⋯ More attention should be given to a condition of the spinal cord below and above the SCI lesion. A consensus for what is an optimal SCI functional assessment for patients with sensory complaints and pain should be developed. Further extensive SCI pain research is needed prior to spinal cord regeneration trials in order to be able to cope with a potential for newly developed pains that may appear during incomplete spinal cord regenerative attempts.
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Attentional bias in patients with chronic pain was investigated using the emotional Stroop task with personalized pain words. A group of 20 chronic pain patients with 20 matched controls participated in the experiment. Before administration of the emotional Stroop patients were asked to select the five best descriptors of their pain from a list of 19 sensory pain descriptors. ⋯ Results showed a weak Stroop interference effect with slower reaction times to pain words in the patient group, but they did not differ significantly from the controls. Both groups were slower on the threat words and displayed the classical Stroop interference effect for color words. The overall pattern of results are in line with previous Stroop studies on pain patients showing weak support for the attentional bias hypothesis.
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The innervation of the temporomandibular joint (TMJ) has attracted particular interest because of the close association with complex mandibular movement. Although the pathological changes of disk innervation may have a crucial role in the development of TMJ pain, the innervation of the TMJ disk by experimentally induced arthritis has rarely been examined in detail. Arthritic rats were induced by injection with 0.1ml solution of Complete Freund's adjuvant (CFA). ⋯ In addition, the ratio of trkA- and p75-positive small- and medium-sized cells increased in trigeminal ganglia. It is assumed that increasing innervation of the TMJ disk may be important for the pathophysiology of TMJ pain. NGF and its receptors are likely involved in pathological changes of the TMJ disk.
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The increased use of quantitative sensory testing in the study of pain raises the need to characterize various aspects of psychophysical response to noxious stimulation in healthy subjects. The present study aims to address several issues regarding the use of heat pain stimuli: (a) Are pain scores for short-term repeated phasic stimuli consistent? (b) Does an exposure to tonic heat pain stimulus cause sensitization and change the scores for subsequent phasic stimuli? and (c) Are pain scores for phasic and tonic heat pain correlated? To address these questions, a series of four phasic heat pain stimuli of 47 degrees C were given to the forearms of 70 healthy volunteers, over the course of an hour. Pain scores by Visual Analog Scale (VAS) were obtained for each stimulus. In 50 subjects, a tonic heat pain of 70s duration at 47.5 degrees C was given between the first and second phasic stimuli. Pain scores were obtained at four points along this tonic stimulus. Repeated measures ANOVA and a sensitive post hoc analysis indicated that, while the pain perception was reduced on the second, nearly immediate trial, subsequent VAS scores of pain perception were not different from the first (#1: 35.2+/-19.2; #2: 31.4+/-20.2, #3: 33.0+/-21.6; and #4: 33.2+/-20.1, respectively), with strong correlation among the phasic tests. The average tonic pain score was 53.7+/-23.1. Administration of tonic pain stimuli did not result in different VAS scores of subsequent phasic pain stimuli, compared to those subjects who did not receive tonic pain stimuli. Tonic and phasic pain were positively correlated (e.g., r=0.45,p<0.001 for the first phasic stimuli). However, no relation was found between the level of perceived pain, either for phasic or for tonic stimuli, and presence or absence of temporal summation during the tonic pain. ⋯ (i) phasic pain scores assessments at 30' and 60' after baseline is consistent; (ii) tonic heat pain, despite relatively high VAS scores, does not cause a change in the scoring of subsequent phasic stimuli; and (iii) phasic and tonic pain scores correlate with each other. Thus, the normal pattern of pain perception is stable and not altered by single tonic pain stimulation.