Pain
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Randomized Controlled Trial
Reduction of allodynia in patients with complex regional pain syndrome: A double-blind placebo-controlled trial of topical ketamine.
A double-blind placebo-controlled crossover trial was used to determine the effects of topical ketamine, an N-methyl-d-aspartate (NMDA) receptor antagonist, on the sensory disturbances in 20 patients with complex regional pain syndrome (CRPS). On two occasions separated by at least one week, sensory tests to light touch, pressure, punctate stimulation, light brushing and thermal stimuli were performed in the symptomatic and contralateral limb and on each side of the forehead before and 30min after 10% ketamine cream was applied to the symptomatic or healthy limb. Venous blood for the plasma estimations of ketamine and norketamine was obtained 1h after application of the creams. ⋯ Allodynia and hyperalgesia were detected in the ipsilateral forehead to a range of stimuli (brushing, pressure, punctate stimulation, cold, heat, and warmth). In several patients, ketamine treatment of the symptomatic limb inhibited allodynia to brushing the ipsilateral forehead, suggesting that the mechanism that mediates allodynia in the symptomatic limb contributed to allodynia at more remote sites. The present study shows promise for the use of topical ketamine as opposed to parenteral and oral forms which often result in undesirable side effects.
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Randomized Controlled Trial
Randomized controlled trial of an Internet-delivered family cognitive-behavioral therapy intervention for children and adolescents with chronic pain.
Cognitive-behavioral therapy (CBT) interventions show promise for decreasing chronic pain in youth. However, the availability of CBT is limited by many factors including distance to major treatment centers and expense. This study evaluates a more accessible treatment approach for chronic pediatric pain using an Internet-delivered family CBT intervention. ⋯ There were no significant group differences in parental protectiveness or child depressive symptoms post-treatment. Internet treatment was rated as acceptable by all children and parents. Findings support the efficacy and acceptability of Internet delivery of family CBT for reducing pain and improving function among children and adolescents with chronic pain.
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Randomized Controlled Trial
Intrathecal glycine for pain and dystonia in complex regional pain syndrome.
Since glycinergic neurotransmission plays an important inhibitory role in the processing of sensory and motor information, intrathecal glycine (ITG) administration may be a potential therapy for both pain and movement disorders in patients with complex regional pain syndrome (CRPS). Aims of the current study, which is the first report on ITG in humans, were to evaluate its safety and efficacy. ITG treatment during 4 weeks was studied in CRPS patients with dystonia in the period before they received intrathecal baclofen treatment. ⋯ Although there was a trend to worsening on the CGI and PGI during ITG treatment, there were no significant differences between ITG and placebo treatment in any of the outcomes. ITG given over 4 weeks was ineffective for pain or dystonia in CRPS. Although no serious adverse events occurred, further studies are required to rule out potential neurotoxicity of ITG.
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Experimental determination of pain sensitivity has received increasing attention because of emerging clinical applications (including prediction of postoperative pain and treatment response) and scientific implications (e.g. it has been proposed that above-average pain sensitivity is a risk factor for the development of chronic pain disorders). However, the use of experimental pain sensitivity assessment on a broad scale is hampered by its requirements on time, equipment and human resources and the fact that it is painful for the tested subject. Alternatives to experimental pain testing are currently lacking. ⋯ PSQ scores were significantly correlated to experimental pain intensity ratings (r = 0.56, p < 0.001) but not to pain thresholds (r = 0.03). Prediction of experimental pain intensity ratings by the PSQ was better than by pain-associated psychological factors (pain catastrophizing, depression, anxiety). This shows that the PSQ may be a simple alternative to experimental pain intensity rating procedures in healthy subjects and makes the PSQ a highly promising tool for clinical and experimental pain research.
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Patients with neuropathic pain syndromes are heterogeneous. They present with a variety of sensory symptoms and pain qualities. The knowledge of these data and etiology-specific differences is important to optimize clinical trial design and to develop more effective drugs. ⋯ All subgroups occur in relevant numbers in both entities but the frequencies differ between PHN and DPN. Since sensory symptoms likely translate into pain-generating mechanisms enrichment for potential treatment responders might be possible in clinical trials by assessing the sensory profiles. Patient-Reported Outcomes can be used to obtain a precise sensory characterization of each patient.