Articles: neuralgia.
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Numerous studies have shown associations between genetic variants and neuropathic pain disorders. Rare monogenic disorders are caused by mutations of substantial effect size in a single gene, whereas common disorders are likely to have a contribution from multiple genetic variants of mild effect size, representing different biological pathways. ⋯ Biobank cohort. Successfully replicated association with a neuropathic pain construct for 2 variants in IL10 underscores the importance of neuroimmune interactions, whereas genome-wide significant association with low back pain (P = 1.3e-8) and false discovery rate 5% significant associations with hip, knee, and neck pain for variant rs7734804 upstream of the MAT2B gene provide evidence of shared contributing mechanisms to overlapping pain conditions at the molecular genetic level.
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To assess cognitive performance of chronic pain (CP) patients diagnosed with three types of pain-neuropathic pain (NP), musculoskeletal (MSK), and fibromyalgia (FM)-and to analyze the factors influencing cognitive difficulties in each group. ⋯ These results highlight the importance of taking into account the type of pain when assessing cognitive performance in CP patients and demonstrate the influence of the emotional state of the patient, especially if depression is present.
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Review
Emerging therapies for neuropathic pain: new molecules or new indications for old treatments?
Neuropathic pain represents a highly unmet medical need because most of the available treatments have a modest efficacy or dose-limiting side effects. Hence, novel therapeutic perspectives are warranted. Many compounds acting on new pain targets are in preclinical or early clinical development. ⋯ Another type of emerging drug therapy in neuropathic pain is represented by drugs largely used for other indications, such as botulinum toxin A and the antiepileptic oxcarbazepine, which have recently found to be effective in peripheral neuropathic pain. Emerging nondrug medical therapy with promising results in neuropathic pain also encompasses noninvasive brain neurostimulation techniques, such as repetitive transcranial magnetic stimulation and transcranial direct electrical stimulation. In this article, we review emerging medical treatments for neuropathic pain that are clinically available or with promising results from clinical trials.
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Peripheral nerve injuries and diseases often lead to pain persisting beyond the resolution of damage, indicating an active disease-promoting process, which may result in chronic pain. This is regarded as a maladaptive mechanism resulting from neuroinflammation that originally serves to promote regeneration and healing. Knowledge on these physiological and pathophysiological processes has accumulated over the last few decades and has started to yield potential therapeutic targets. ⋯ Research from several groups has shown an important role of both proinflammatory and anti-inflammatory cytokines in neuropathic and other chronic pain states in humans. There is ample evidence of an analgesic action of anti-inflammatory cytokines in animal models. The interplay of anti-inflammatory cytokines and the nociceptive system provides possibilities and challenges concerning treatment strategies based on this concept.
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Primary burning mouth syndrome (BMS) is defined as an "intraoral burning or dysaesthetic sensation, recurring daily… more than 3 months, without clinically evident causative lesions" (IHS 2013). In addition to pain, taste alterations are frequent (dysgeusia, xerostomia). Although lacking clinical signs of neuropathy, more accurate diagnostic methods have shown neuropathic involvement at various levels of the neuraxis in BMS: peripheral small fiber damage (thermal quantitative sensory testing, electrogustatometry, epithelial nerve fiber density), trigeminal system lesions in the periphery or the brainstem (brainstem reflex recordings, trigeminal neurography, evoked potentials), or signs of decreased inhibition within the central nervous system (deficient brainstem reflex habituation, positive signs in quantitative sensory testing, neurotransmitter-positron emission tomography findings indicative of deficient striatal dopamine function). ⋯ According to these findings, the clinical entity of BMS can be divided into 2 main subtypes compatible with either peripheral or central neuropathic pain, which may overlap in individual patients. The central type does not respond to local treatments and associates often with psychiatric comorbidity (depression or anxiety), whereas the peripheral type responds to peripheral lidocaine blocks and topical clonazepam. Burning mouth syndrome is most prevalent in postmenopausal women, having led to a hypothesis that BMS is triggered as a consequence of nervous system damage caused by neurotoxic factors affecting especially vulnerable small fibers and basal ganglia in a setting of decrease in neuroprotective gonadal hormones and increase in stress hormone levels, typical for menopause.