Current pain and headache reports
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Neurostimulation methods for control of chronic neuropathic pain have recently gained in popularity. The reasons for this are multifactorial. As opposed to nerve ablation, these methods are minimally invasive and reversible. ⋯ DBS is reserved for carefully selected patients in whom the other treatment modalities have failed. In a minority of patients the "tolerance" to neurostimulation develops after long-term use. Further research is needed to establish better outcome predictors to neurostimulation and possibly improve patient selection criteria.
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Migraine is a highly prevalent headache disorder that has a substantial impact on the individual and society. Over the past decade, substantial advances in research have increased understanding of the pathophysiology, diagnosis, epidemiology, and treatment of the disorder. This article reviews data on the epidemiology and impact of migraine. It also highlights the increased awareness of migraine, citing examples from the popular media and the Internet.
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Of the nearly 20 million American women suffering with migraine, approximately 12 million experience a worsening of their migraines in association with their menstrual cycle. Prior to puberty the prevalence of migraine is slightly higher in boys; however, after puberty there is an emerging female predominance. Estrogen likely plays an important role in explaining this gender difference; however, hormones unlikely explain the entire epidemiologic variation. This article reviews the diagnosis and treatment options for menstrually associated migraine.
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New animal models of peripheral nerve injury have facilitated our understanding of neuropathic pain mechanisms. Nerve injury increases expression and redistribution of newly discovered sodium channels from sensory neuron somata to the injury site; accumulation at both loci contributes to spontaneous ectopic discharge. ⋯ Descending facilitation from the brain stem to the dorsal horn also increases in the setting of nerve injury. These and other mechanisms drive various pathologic states of central sensitization associated with distinct clinical symptoms, such as touch-evoked pain.
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Quantitative sensory testing (QST) refers to a group of protocols that allows for quantitative measures of somesthetic function. Several protocols evaluate perceptual threshold, whereas others evaluate perception of stimuli above threshold. Each protocol has its own advantages and disadvantages, but one must always weigh a trade-off between accuracy (with longer protocols) and expediency (with shorter protocols). ⋯ QST studies, using either neuropathic pain patients or healthy volunteers who have been rendered temporarily hyperalgesic, have demonstrated that pain abnormalities can be modality specific. The fact that various pain abnormalities can exist independently of each other suggests that (at least partially) different neuropathologic processes are responsible for each one. Current research suggests that both peripheral sensitization and central sensitization play a role in these abnormal pain conditions, and identification of precise neuropathologic mechanisms is under active investigation.