Articles: neuralgia.
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Idiopatic trigeminal neuralgia purely paroxysmal (ITNp) distributed in the supraorbital and suprathrochlear dermatomes (SSd), refractory to conventional treatments have been linked to the hyperactivity of the corrugator supercilii muscle (CSM). In these patients, the inactivation of the CSM via botulinum toxin type A (BTA) injections has been proven to be safe and effective in reducing migraine burden. The main limitation of BTA is the need of repetitive injections and relative high costs. Based on the study of the motor innervation of the CSM, we describe here an alternative approach to improve these type of migraines, based on a minimally invasive denervation of the CSM. ⋯ Our findings suggest that the selective CSM denervation represents a safe and minimally invasive approach to improve ITNp distributed in the SSd associated with CSM hyperactivation.
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The transcriptional repressor positive regulatory domain I-binding factor 1 (PRDM1) is expressed in adult mouse dorsal root ganglion and regulates the formation and function of peripheral sensory neurons. The authors hypothesized that PRDM1 in the dorsal root ganglion may contribute to peripheral nerve injury-induced nociception regulation and that its mechanism may involve Kv4.3 channel transcriptional repression. ⋯ PRDM1 contributes to peripheral nerve injury-induced nociception by repressing Kv4.3 channel expression in injured dorsal root ganglion neurons.
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Adequate analgesia can be challenging, as pharmacological options are not necessarily effective for all types of pain and are associated with adverse effects. Methadone is increasingly being considered in the management of both cancer-related and noncancer-related pain. The purpose of this article is to provide a narrative review of all available randomized controlled trials (RCTs) investigating the effectiveness of methadone in the management of pain, in relation to a comparison drug. ⋯ Future research should also aim to standardize reported outcomes for measuring analgesic effectiveness to permit for pooled analysis across studies. PERSPECTIVE: This article presents a systematic review, which includes a summary of published RCTs investigating the effectiveness of methadone in the management of pain. This is important for determining its analgesic utility and for identifying gaps in existing knowledge.
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Diabetic polyneuropathy (DPN) is a common complication of diabetes and is often associated with neuropathic pain. The mechanisms underlying development and maintenance of painful DPN are largely unknown, and quantification of intraepidermal nerve fiber density from skin biopsy, one of the neuropathological gold standard when diagnosing DPN, does not differentiate between patients with and without pain. Identification of possible pain pathophysiological biomarkers in patients with painful DPN may increase our knowledge of mechanisms behind neuropathic pain. ⋯ Peptidergic nerve fiber density correlated with pain ratings in patients with pain (R = 0.33; P = 0.019), but not with quantitative sensory testing results. In this article, we show, for the first time in humans, an increased density of dermal peptidergic fibers in painful DPN. These findings provide new insight in the pathophysiological mechanisms of pain in diabetes and open the research towards new therapeutic targets.
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Observational Study
Neuropathic pain: clinical classification and assessment in patients with pain due to cancer.
Neuropathic cancer pain (NcP) is associated with worse treatment responses and specific therapy indications, but a standardized clinical diagnosis of NcP is still lacking. This is a prospective observational study on outpatients with cancer, comparing different clinical approaches with NcP evaluation. A three-step assessment of NcP was performed using DN4 (cutoff of 4), palliative care physician Clinical Impression, including etiology and pain syndrome identification, and Retrospective Clinical Classification by a board of specialists with the IASP Neuropathic Pain Special Interest Group criteria. ⋯ Higher percentages of discordance were found for specific pain syndromes such as pain due to deep soft tissue infiltration and pain associated with tenesmus. Disagreement among clinicians accounted also for different NcP diagnoses and highlighted lack of homogeneous clinical criteria. Rigorous application of etiological and syndrome diagnosis to explain pain cause, associated with standardized diagnostic criteria and assessment of pain characteristics, that is also specific for the cancer pain condition could improve clinical classification of NcP.