Headache
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Cortical spreading depression (CSD) is an electrophysiological phenomenon characterized by a wave of excitation followed by inhibition. The aura phase that precedes migraine headache in about 20-30% of migraineurs shares overlapping characteristics with CSD. Studies of rare autosomal-dominant forms of migraine with aura provide strong evidence that the threshold for evoking CSD and aura are related to neuronal excitability. Although the relationship between CSD and migraine without aura is not completely understood, the molecular abnormalities that predispose to migraine with aura illustrate the importance of physiologic events associated with neuronal hyperexcitability, and provide a basis for understanding a more generalized view of migraine.
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The Convergence Hypothesis postulates a single pathophysiological mechanism to explain the clinical spectrum of primary headaches seen in patients with migraine. The history and the scientific underpinnings of the Convergence Hypothesis are presented. Extrapolations from the Convergence Hypothesis are used to explore the evolution of episodic to chronic migraine and the development of common migraine co-morbidities as a consequence of frequent migraine. A patient staging system is presented to illustrate this transformation process in migraine patients.
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This article reviews hormonal strategies used to treat headaches attributed to the menstrual cycle or to peri- or postmenopausal estrogen fluctuations. These may occur as a result of natural ovarian cycles, or in response to the withdrawal of exogenously administered estrogen. ⋯ Hormonal treatment of migraine is not a first-line treatment strategy for most women with migraine. Evidence is lacking regarding its long term harms and migraine is a contraindication to the use of exogenous estrogen in all women with aura and those aged 35 or older. The harm to benefit balances of several traditional nonhormonal therapies are better established.
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Chronic daily headache (CDH), a heterogeneous group of headache disorders occurring on at least 15 days per month, affects up to 4% to 5% of the general population. CDH disorders include transformed (or chronic) migraine, chronic tension-type headache, new daily persistent headache, and hemicrania continua. Patients with CDH have greater disability and lower quality of life than episodic migraine patients and often overuse headache pain medications. ⋯ Side effects are generally transient, mild to moderate, and nonsystemic. The results of clinical trials using traditional oral pharmacotherapy, while supportive of their use as prophylactic treatment of CDH, are limited by several factors, including small numbers of patients, the choice of efficacy measures, and short treatment periods. The use of oral agents was associated with systemic side effects, which may limit their effectiveness as prophylactic treatment of CDH.
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This article discusses the problem of medication-overuse headache from a variety of perspectives, based on the best available evidence. This presentation clarifies the definition of the disorder, distinguishing it from alternative terminology, and describes its epidemiology, natural history, and clinical course. Antimigraine medications are believed to differ in their relative liability to contribute to the development of medication-overuse headache. Patients most at risk of developing medication-overuse headache need to be identified so that appropriate preventive measures can be initiated.