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Anaesthesia => Nervous System => Migraine
Migraine
Migraine, severe headache, which frequently occurs over one side of the head only. It is characterized by throbbing and associated with one or more of the following symptoms: sensitivity to light, nausea and vomiting, and dizziness. Flashes or patterns before the eyes may precede the headache. Women are twice as likely as men to experience these headaches, and some evidence suggests that migraine headaches are inherited. They can recur at intervals ranging from one day to several years.
At the onset of a migraine headache, blood vessels within the head constrict. This may cause a decrease in blood flow to the surface of the brain. A dilation of blood vessels of the head and scalp then occurs, setting off a chain of reactions that result in the headache. Evidence indicates that decreased localized brain metabolism initiates the attack and that the initial decrease in blood flow is a response to the lowered metabolic demand, rather than due to constriction of blood vessels. Among the biochemical changes associated with migraine is a reduced level of enkephalins, the brain's pain-relieving chemicals.
Hormone-level changes (such as those experienced by women during menopause or menstruation), endocrine imbalances, and stress are considered precipitating factors of migraine headaches in susceptible individuals. Several treatments have been successful in helping migraine sufferers. These include medications such as ergotamine tartrate, which thwarts the excessive expansion of blood vessels and aborts the acute attack; and propranolol, which stabilizes blood-vessel tone and prevents subsequent attacks. Biofeedback techniques have also proved useful.
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