Pain
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Case Reports Randomized Controlled Trial Comparative Study
Drug-induced liver injury following a repeated course of ketamine treatment for chronic pain in CRPS type 1 patients: a report of 3 cases.
Studies on the efficacy of ketamine in the treatment of chronic pain indicate that prolonged or repetitive infusions are required to ensure prolonged pain relief. Few studies address ketamine-induced toxicity. Here we present data on the occurrence of ketamine-induced liver injury during repeated administrations of S(+)-ketamine for treatment of chronic pain in patients with complex regional pain syndrome type 1 as part of a larger study exploring possible time frames for ketamine re-administration. ⋯ In all patients, the ketamine infusion was promptly terminated and the liver enzymes slowly returned to reference values within 2 months. Our data suggest an increased risk for development of ketamine-induced liver injury when the infusion is prolonged and/or repeated within a short time frame. Regular measurements of liver function are therefore required during such treatments.
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Comparative Study
Eugenol reverses mechanical allodynia after peripheral nerve injury by inhibiting hyperpolarization-activated cyclic nucleotide-gated (HCN) channels.
Mechanical allodynia is a common symptom found in neuropathic patients. Hyperpolarization-activated cyclic nucleotide-gated channels and their current, I(h), have been suggested to play an important role in neuropathic pain, especially in mechanical allodynia and spontaneous pain, by involvement in spontaneous ectopic discharges after peripheral nerve injury. Thus, I(h) blockers may hold therapeutic potential for the intervention of mechanical allodynia under diverse neuropathic conditions. ⋯ Eugenol-induced I(h) inhibition was not mediated by G(i/o)-protein activation, but was gradually diminished by an increase in intracellular cAMP concentration. Eugenol also inhibited I(h) from injured TG neurons which were identified by retrograde labeling with DiI and reversed mechanical allodynia in the orofacial area after chronic constriction injury of infraorbital nerve. We propose that eugenol could be potentially useful for reversing mechanical allodynia in neuropathic pain patients.
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Randomized Controlled Trial Comparative Study
Botulinum toxin injection for management of thoracic outlet syndrome: a double-blind, randomized, controlled trial.
We studied the effect of botulinum toxin type A (BTX-A) injections to the scalene muscles on pain in subjects with thoracic outlet syndrome (TOS) in this double-blind, randomized, parallel group trial with follow-up at 6 weeks, 3 months, and 6 months. Thirty-eight patients referred to physiatrists for management of TOS with BTX-A injection were included. One subject was lost to follow-up and all other subjects completed the trial. ⋯ For the primary outcome measure of VAS scores for pain at 6 weeks, the difference in the means adjusted for baseline VAS scores between placebo and BTX-A was 5.03 mm in favor of BTX-A (95% confidence interval -15.7 to 5.7, P=.36). Changes in secondary outcome measures were also not statistically significant. We conclude that BTX-A injections to the scalene muscles did not result in clinically or statistically significant improvements in pain, paresthesias, or function in this population of subjects with TOS.
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Comparative Study
Nerve growth factor selectively decreases activity-dependent conduction slowing in mechano-insensitive C-nociceptors.
Nerve growth factor (NGF) induces acute sensitization of nociceptive sensory endings and long-lasting hyperalgesia. NGF modulation of sodium channel expression might contribute to neurotrophin-induced hyperalgesia. Here, we investigated NGF-evoked changes of the activity-dependent slowing of conduction in porcine C-fibers. ⋯ Accordingly, the number of fibers with pronounced ADS decreased but more units with pronounced ADS were mechano-sensitive. Spontaneously active C-fibers were increased above the control level (1%) by NGF 8 μg (8%). The results demonstrate that NGF changes the functional axonal characteristics of mechano-insensitive C-fibers and enhances spontaneous activity thereby possibly contributing to hyperalgesia.
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Comparative Study
Effects of self-discrepancies on activity-related behaviour: explaining disability and quality of life in patients with chronic low back pain.
In chronic low back pain (CLBP) research, the self-discrepancy model has been applied to explain dysfunctional avoidance and persistence behaviour. The main aim of this study was to evaluate whether specific self-discrepancies in patients with CLBP are associated with the abovementioned types of activity-related behaviour and whether changes in self-discrepancies over time are associated with changes in activity-related behaviour. Furthermore, the aim was to evaluate whether avoidance and persistence behaviour are associated with a higher level of disability and a diminished quality of life and whether changes over time in avoidance and persistence behaviour result in changes in disability and quality of life. ⋯ Results indicate that patients with CLBP who feel closer to their ideal-other show more characteristics of persistence behaviour. Patients who move further away from their ideal-own also show more characteristics of persistence behaviour. Furthermore, in patients characterized as avoider, a decrease in a patient's daily uptime was associated with a decrease of mental health-related quality of life.