Articles: neuralgia.
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Neuropathic pain encompasses a broad range of conditions associated with a lesion or disease of the peripheral or central somatosensory system and its prevalence in the general population may be as high as 7-8%. The interest in the pathophysiology of neuropathic pain has increased over the last two decades with an exponential increase in the number of experimental studies. However, despite the hopes raised by scientific discoveries, there has been no rational development of a truly new class of drugs. ⋯ Clinical advances have recently been made in this field, following the validation of new specific clinical tools and the standardization of quantitative sensory testing paradigms facilitating improvements in the clinical characterization of these syndromes. It has been clearly demonstrated that neuropathic pain is a consistent clinical entity, but it is multidimensional in terms of its clinical expression, with different sensory profiles, potentially reflecting specific pathophysiological mechanisms. This new conceptualization of neuropathic pain should improve the characterization of the responder profiles in clinical trials and provide valuable information for the development of new and more clinically sound translational approaches in experimental models in animals.
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Palliative care clinicians are increasingly involved in the care of elderly patients suffering from chronic malignant and nonmalignant illnesses, of which neuropathic pain is a prevalent problem. As a person becomes more frail, pain medications such as opioid analgesics and adjuvant pain medications can result in unwanted effects such as sedation, confusion, and increased risk of falls. ⋯ Methadone is an opioid analgesic that is effective in the treatment of neuropathic pain, is excreted by the bowels, is highly lipophilic, and can be administered through the oral, buccal, or sublingual routes. We present three cases highlighting the use of low-dose adjuvant methadone to manage complex neuropathic pain in the frail elderly.
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Persistent pain is a common side effect of breast cancer treatment. The present study aimed to assess the prevalence, associated treatment-related factors, and the type of pain (neuropathic or nociceptive) in patients who had undergone a unilateral mastectomy. ⋯ Persistent pain after breast cancer treatment continues to have a high prevalence. Our results indicate that the largest proportion of patients experiencing persistent pain after breast cancer treatment do not have a clear neuropathic pain component.
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In dorsal root ganglia (DRG), satellite glial cells (SGCs) tightly ensheathe the somata of primary sensory neurons to form functional sensory units. SGCs are identified by their flattened and irregular morphology and expression of a variety of specific marker proteins. In this report, we present evidence that the 3-hydroxy-3-methylglutaryl coenzyme A synthase isoenzymes 1 and 2 (HMGCS1 and HMGCS2) are abundantly expressed in SGCs. ⋯ Western blot showed that HMGCS1 protein level in axotomized L5 DRGs is reduced after SNL to 66±8% at 3 days (p<0.01, n=4 animals in each group) and 58±13% at 28 days (p<0.001, n=9 animals in each group) of its level in control samples, whereas HMGCS2 protein was comparable between injured and control DRGs. These results identify HMGCSs as the alternative markers for SGCs in DRGs. Downregulated HMGCS1 expression in DRGs after spinal nerve injury may reflect a potential role of abnormal sterol metabolism of SGCs in the nerve injured-induced neuropathic pain.
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Chronic postsurgical pain (CPSP) affects 10 to 30% of surgical patients overall and 16 to 20% of patients after knee surgery. Patients report persistent pain in the absence of infection, mechanical disorders, or complex regional pain syndrome type I. In many cases, the mechanism is neuropathic pain related to an intraoperative nerve injury or impaired pain modulation with central sensitization. ⋯ A capsaicin patch is the third-line treatment, and step III opioids are the last option. Rehabilitation therapy and physical exercises are beneficial. Psychological counseling and/or cognitive behavioral therapy should be offered, if indicated, by the results of the evaluation.