Causes of Migraine


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Triggers list for Migraine: The list of triggers mentioned in source as possible causal factors for Migraine includes:

  • Lack of sleep
  • Lack of food
  • Pregnancy
  • Fatigue
  • Menstruation
  • Glaring lights
  • Flickering lights
  • Strobe lights
  • Relaxation after a period of stress - can trigger a "weekend migraine"
  • Television
  • Video screens
  • Weather changes
  • Certain foods
  • Yogurt
  • Nuts
  • Lima beans
  • Cheese
  • Chocolate
  • Alcoholic drinks
  • Low blood sugar
  • Female hormonal irregularities
  • Anxiety
  • Fatigue
  • Stress

Cause details for Migraine: Research scientists are unclear about the precise cause of migraine headaches. There seems to be general agreement, however, that a key element is blood flow changes in the brain. People who get migraine headaches appear to have blood vessels that overreact to various triggers.

Scientists have devised one theory of migraine which explains these blood flow changes and also certain biochemical changes that may be involved in the headache process. According to this theory, the nervous system responds to a trigger such as stress by causing a spasm of the nerve-rich arteries at the base of the brain. The spasm closes down or constricts several arteries supplying blood to the brain, including the scalp artery and the carotid or neck arteries.

As these arteries constrict, the flow of blood to the brain is reduced. At the same time, blood-clotting particles called platelets clump together-a process which is believed to release a chemical called serotonin. Serotonin acts as a powerful constrictor of arteries, further reducing the blood supply to the brain.

Reduced blood flow decreases the brain's supply of oxygen. Symptoms signaling a headache, such as distorted vision or speech, may then result, similar to symptoms of stroke.

Reacting to the reduced oxygen supply, certain arteries within the brain open wider to meet the brain's energy needs. This widening or dilation spreads, finally affecting the neck and scalp arteries. The dilation of these arteries triggers the release of pain-producing substances called prostaglandins from various tissues and blood cells. Chemicals which cause inflammation and swelling, and substances which increase sensitivity to pain, are also released. The circulation of these chemicals and the dilation of the scalp arteries stimulate the pain-sensitive nociceptors. The result, according to this theory: a throbbing pain in the head.1

The relationship between female hormones and migraine is still unclear. Women may have "menstrual migraine"—headaches around the time of their menstrual period—which may disappear during pregnancy. Other women develop migraine for the first time when they are pregnant. Some are first affected after menopause.

The effect of oral contraceptives on headaches is perplexing. Scientists report that some women with migraine who take birth control pills experience more frequent and severe attacks. However, a small percentage of women have fewer and less severe migraine headaches when they take birth control pills. And normal women who do not suffer from headaches may develop migraines as a side effect when they use oral contraceptives. Investigators around the world are studying hormonal changes in women with migraine in the hope of identifying the specific ways these naturally occurring chemicals cause headaches.1

For many years, scientists believed that migraines were linked to the dilation and constriction of blood vessels in the head. Investigators now believe that migraine is caused by inherited abnormalities in certain cell populations in the brain. Using new imaging technologies, scientists can see changes in the brain during migraine attacks. Scientists believe that there is a migraine pain center located in the brainstem, a region at the base of the brain. As neurons fire, surrounding blood vessels dilate and become inflamed, causing the characteristic pain of a migraine. In order to keep this process in check, prompt treatment is of the essence.2

Though the causes are not precisely known, it is clear that migraine is a genetic disorder. For some forms of migraine, specific abnormal genes have been identified. People with migraine have an enduring predisposition to attacks triggered by a range of factors.2

Triggers discussion for Migraine: triggers include stress and other normal emotions, as well as biological and environmental conditions. Fatigue, glaring or flickering lights, changes in the weather, and certain foods can set off migraine. It may seem hard to believe that eating such seemingly harmless foods as yogurt, nuts, and lima beans can result in a painful migraine headache. However, some scientists believe that these foods and several others contain chemical substances, such as tyramine, which constrict arteries—the first step of the migraine process. Other scientists believe that foods cause headaches by setting off an allergic reaction in susceptible people.

While a food-triggered migraine usually occurs soon after eating, other triggers may not cause immediate pain. Scientists report that people can develop migraine not only during a period of stress but also afterwards when their vascular systems are still reacting. For example, migraines that wake people up in the middle of the night are believed to result from a delayed reaction to stress.1

Lack of food or sleep, exposure to light, or hormonal irregularities in women, can set off a migraine attack in individuals with the disorder. Anxiety, stress or relaxation after stress, and fatigue are also triggers. 2

There is a long recognized association between ovarian hormones and migraine. Over half of women with migraine report an association between their headaches and their menstrual cycle. The frequency and severity of migraine is increased commonly with the use of oral contraceptive pills and during the menopause. In addition, changes in the levels of ovarian hormones and prolactin during pregnancy and breast-feeding may modify the course of a migraine. A better understanding of these changes is leading to better treatment of migraine.3

Migraine as a complication: Other conditions that might have Migraine as a complication might be potential underlying causes of Migraine. The list of conditions listing Migraine as a complication in our database includes:

Causes of Migraine: medical news summaries: The following medical news items are relevant to causes of Migraine:

Related information for causes of Migraine: Further relevant information on causes of Migraine may be found in the risk factors for Migraine and underlying causes of Migraine.

Footnotes:
1. excerpt from Headache - Hope Through Research: NINDS
2. excerpt from Migraine Update: NINDS
3. excerpt from MIGRAINE HEADACHES: NWHIC

Last revision: June 2, 2003

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