The typical migraine headache is throbbing or pulsating, and often is associated with nausea and changes in vision. While many migraines are severe, not all severe headaches are migraines, and some migraines can be quite mild. Two-thirds of people who get migraines are women, probably because of the influence of hormones. Migraines also tend to run in families.
Despite years of research, scientists do not know exactly why migraines occur. The pain of migraines almost certainly results from swelling in blood vessels and nerves that surround the brain. This swelling probably is triggered by changes in brain chemicals and electrical activity in a primitive part of the brain known as the brain stem. The brain chemical serotonin appears to play an important role in this process as it does in other conditions, including depression and eating disorders.
One unique feature of migraines is an unusual sensation that a migraine is about to occur, called a prodrome. Prodrome symptoms can include fatigue, hunger and nervousness. Another unique feature of migraines is an aura. In a typical aura, a person suddenly will develop blurry or distorted vision or will see pulsating lights. These changes in vision will come and go over 15 to 30 minutes and alert someone that a headache is about to begin. Sometimes, auras affect the sense of hearing, smell or taste. A health care provider usually will diagnose migraine based on your history and symptoms. In most cases, a physical and neurological examination will be entirely normal. There are no special tests to diagnose migraines. For example, a computed tomography (CT) or magnetic resonance imaging (MRI) scan of the brain usually will be normal.
Not all migraine headaches can be prevented. However, identifying your headache triggers can help to reduce the frequency and severity of migraine attacks. Common migraine triggers include:
- Caffeine (either using too much or suddenly cutting back on regular use)
- Certain foods and beverages, including those that contain tyramine (aged cheeses and meats, fermented beverages), sulfites (preserved foods, wines) and monosodium glutamate (MSG), a common flavor enhancer
- Stress, or relief from stress
- Hormone levels (menstrual cycles, hormone-containing medication such as birth control pills or estrogen)
- Lack of sleep or disrupted sleep patterns
- Travel or changes in weather or altitude
- Overuse of pain-relieving medications