Articles: neuralgia.
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Anesthesia and analgesia · Jul 2019
Ryanodine Receptor to Mitochondrial Reactive Oxygen Species Pathway Plays an Important Role in Chronic Human Immunodeficiency Virus gp120MN-Induced Neuropathic Pain in Rats.
Chronic pain is one of the most common complaints in patients with human immunodeficiency virus (HIV)-associated sensory neuropathy. Ryanodine receptor (RyR) and mitochondrial oxidative stress are involved in neuropathic pain induced by nerve injury. Here, we investigated the role of RyR and mitochondrial superoxide in neuropathic pain induced by repeated intrathecal HIV glycoprotein 120 (gp120) injection. ⋯ These data suggest that repeated intrathecal HIV gp120 injection induced an acute to chronic pain translation in rats, and that neuronal RyR and mitochondrial superoxide in the spinal cord dorsal horn played an important role in the HIV neuropathic pain model. The current results provide evidence for a novel approach to understanding the molecular mechanisms of HIV chronic pain and treating chronic pain in patients with HIV.
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The conceptualization of placebo has changed from inactive pills to a detailed understanding of how patients' perception of receiving a treatment influences pain processing and overall treatment outcome. Large placebo effects were recently demonstrated in chronic neuropathic pain, thereby opening the question of whether placebo effects also apply to orofacial neuropathic pain. ⋯ Orofacial neuropathic pain is a new research area, and we review the status on definition, diagnosis, mechanisms, and pharmacologic treatment of neuropathic pain after trigeminal nerve injury, as this condition may be especially influenced by placebo factors. Finally, we have a detailed discussion of how knowledge of placebo mechanisms may help improve the understanding, diagnosis, and treatment of orofacial neuropathic pain, and we illustrate pitfalls and opportunities of applying this knowledge to the test of dental treatments.
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Patient-Reported Outcome (PRO) instruments have been developed to evaluate pain management in daily practice; the Patients' Global Impression of Change (PGIC) is particularly recommended by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials. The prospective non-interventional multicenter PRO-QURE study aimed at assessing correlations between PGIC and pain measurements and treatment effects in patients followed in French pain centres. ⋯ Clinically important improvement in peripheral neuropathic pain, as assessed by PGIC scores, significantly correlated with well-established measures of pain intensity, pain interference in daily life and treatment efficacy. This result, associated with the ease of administration and scoring, encourages the widespread use of the PGIC in daily practice.
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Diffuse noxious inhibitory controls (DNICs) is a pain-inhibits-pain phenomenon demonstrated in humans and animals. Diffuse noxious inhibitory control is diminished in many chronic pain states, including neuropathic pain. The efficiency of DNIC has been suggested to prospectively predict both the likelihood of pain chronification and treatment response. ⋯ Systemic application of nor-binaltorphimine, a kappa opioid antagonist, did not ameliorate SNL-induced hyperalgesia but reversed loss of the behavioral DNIC response. Microinjection of nor-binaltorphimine into the right central amygdala (RCeA) of SNL rats did not affect baseline thresholds but restored DNIC both behaviorally and electrophysiologically. Cumulatively, these data suggest that net enhanced descending facilitations may be mediated by kappa opioid receptor signaling from the right central amygdala to promote diminished DNIC after neuropathy.
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The rate of chronic migraine (CM) has been shown to be 20% or greater in the post 9/11 combat veteran population with a history of traumatic brain injury, while the rate is much lower at 3-5% in the general population. Studies have shown that medications such as oral topiramate or intramuscular injections of onabotulinum toxin A (Botox) have been used for CM prevention, and occipital blocks have been shown to be helpful in treating occipital neuralgia and short-term relief of CM. However, there are no known studies that have specifically evaluated the use of Botox and occipital blocks for reducing headache frequency in the US veteran population. The purpose of this study was to evaluate the effectiveness of using occipital blocks and Botox as dual therapy for reducing headache frequency in post 9/11 combat veterans with CM, occipital neuralgia, and a history of TBI or neck trauma. ⋯ This study evaluated the effectiveness of using occipital blocks and Botox as dual therapy for reducing headache frequency for post 9/11 combat veterans with CM, occipital neuralgia, and a history of TBI or neck trauma. Results revealed a statistically significant reduction in the number of headache days per month after the dual therapy. There were multiple limitations to the study to include a small sample size, lack of a control group, self-reported headaches for only 1 month pre-and post-treatment, and no control for other interventions or events which may have influenced the outcome. There is a strong need for randomized, double blinded, placebo- controlled studies involving dual therapy in this population. This study, though small, may be helpful in stimulating additional studies and treatments in this veteran population.