Definition of Migraine - Migraine

A migraine is a specific and common form of headache that has been known since antiquity. It has traditionally been classified as a vascular headache due to the belief that it is due to abnormal changes in blood vessel tone, although the mechanism now appears to be more complicated than that.

Description of Migraine
Migraines affect approximately 28 million people in the United States, roughly 75 percent of them women. The headaches typically begin in adolescence or early adulthood, but onset may be earlier or later in some cases. There is clustering in families, suggesting a genetic component.

The older model of migraine development suggested that it begins with the release of serotonin, an important neurotransmitter. When serotonin is released, the blood vessels constrict (narrow). This is followed by a reactive dilation (expansion) of blood vessels that is the direct cause of pain. A more current model suggests that when the visual aura is present, it is caused by changes in blood flow patterns in the brain and cortical spreading depression (CSD), which refers to decreased activity on the surface of the brain. The headache portion of the migraine is caused by a complex process involving, blood vessel dilation, decreased cerebral blood flow, and abnormal activity of the trigeminal nerve causing local inflammation. Evidence also suggests that pain control centers in the brainstem may be dysfunctional in migraine patients.