Migraine headache is a complex, recurrent headache disorder that is one of the most common complaints in medicine. In the United States, more than 30 million people have 1 or more migraine headaches per year. Approximately 75% of all persons who experience migraines are women (see Epidemiology).
The term migraine is derived from the Greek word hemikrania. This term was corrupted into low Latin as hemigranea, which eventually was accepted by the French translation as migraine.
Migraine was previously considered a vascular phenomenon that resulted from intracranial vasoconstriction followed by rebound vasodilation. Currently, however, the neurovascular theory describes migraine as primarily a neurogenic process with secondary changes in cerebral perfusion (see Pathophysiology).
Approximately 70% of patients have a first-degree relative with a history of migraine. In addition, a variety of environmental and behavioral factors may precipitate migraine attacks in persons with a predisposition to migraine (see Etiology).
The classic migraine episode is characterized by unilateral head pain preceded by various visual, sensory, motor symptoms, collectively known as an aura. Most commonly, the aura consists of visual manifestations such as scotomas, photophobia, or visual scintillations (eg, bright zigzag lines) (see Clinical Presentation).
In practice, however, migraine headaches may be unilateral or bilateral and may occur with or without an aura. In the current International Headache Society (IHS) categorization, the headache previously described as classic migraine is now known as migraine with aura, and that described as common migraine is now termed migraine without aura. Migraines without aura are the most common, accounting for more than 80% of all migraines.
The diagnosis of migraine is clinical in nature, based on criteria established by the International Headache Society. A full neurologic examination should be performed during the first visit; the findings are usually normal. Neuroimaging is not necessary in a typical case (see Workup).
Migraine treatment involves acute (abortive) and preventive (prophylactic) therapy. Patients with frequent attacks usually require both. Measures directed toward reducing migraine triggers are also generally advisable.
Acute treatment aims to stop or prevent the progression of a headache or reverse a headache that has started. Preventive treatment, which is given even in the absence of a headache, aims to reduce the frequency and severity of the migraine attack, make acute attacks more responsive to abortive therapy, and perhaps also improve the patient's quality of life (see Treatment and Management).
See Migraine in Children for a pediatric perspective on migraine. Also see Migraine Variants.
Migraine classification
The second edition of the International Classification of Headache Disorders[1] lists the following types of migraine:
Migraine without aura (formerly common migraine)
Probable migraine without aura
Migraine with aura (formerly classic migraine)
Probable migraine with aura
Chronic migraine
Chronic migraine associated with analgesic overuse
Childhood periodic syndromes that may not be precursors to or associated with migraine
Complications of migraine
Migrainous disorder not fulfilling above criteria
Hemicrania continua
Migraine guidelines
In April 2000, the US Headache Consortium, a multispecialty group that includes the American College of Emergency Physicians, released evidence-based guidelines for the diagnosis, treatment, and prevention of migraine headaches. Guidelines are also available from the American Academy of Neurology, the National Headache Foundation, and the Canadian Association of Emergency Physicians.[2, 3, 4]
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