A migraine is a common type of headache that may occur with symptoms such as nausea, vomiting, or sensitivity to light. In many people, a throbbing pain is felt only on one side of the head.

Some people who get migraines have warning symptoms, called an aura, before the actual headache begins. An aura is a group of symptoms, usually vision disturbances, that serve as a warning sign that a bad headache is coming. Most people, however, do not have such warning signs.

Various types of migraine exist:

* Migraine without aura (no warning symptoms)

* Migraine with aura (visual disturbances before the headache starts)

* Mixed tension migraine (features of both migraines and tension headache)

*Migraine with persistent visual aura

* Cluster Migraine

Until the 1980s, scientists believed that migraines were due to changes in blood vessels within the brain. Today, most believe the attack actually begins in the brain itself, and involves various nerve pathways and chemicals in the brain.

A migraine attack can be triggered by stress, food, environmental changes, or some other factor. However, the exact chain of events remains unclear.

Migraine attacks may be triggered by:

* Allergic reactions
* Bright lights, loud noises, and certain odors or perfumes
* Physical or emotional stress
* Changes in sleep patterns
* Smoking or exposure to smoke
* Skipping meals
* Alcohol
* Menstrual cycle fluctuations, birth control pills
* Tension headaches
* Foods containing tyramine (red wine, aged cheese, smoked fish, chicken livers, figs, and some beans), monosodium glutamate (MSG), or nitrates (like bacon, hot dogs, and salami)
* Other foods such as chocolate, nuts, peanut butter, avocado, banana, citrus, onions, dairy products, and fermented or pickled foods

Causes

Until recently, the general theory on the migraine process rested solely on the idea that abnormalities of blood vessel (vascular) systems in the head were responsible for migraines. Now, however, doctors tend to believe that migraine starts with an underlying central nervous system disorder. When triggered by various stimuli, this disorder sets off a chain of neurologic and biochemical events, some of which subsequently affect the brain's vascular system. No experimental model fully explains the migraine process.

There is certainly a strong genetic component in migraine with or without auras. Researchers have located a single genetic mutation responsible for the very rare familial hemiplegic migraine, but several genes are likely to be involved in the great majority of migraine cases. Numerous chemicals, structures, nerve pathways, and other players involved in the process are under investigation.
General Theories to Explain Migraine

Central Nervous Disorder. One theory that attempts to integrate many of the known events in the migraine process is as follows:

* Stress or some unknown factor triggers the release of certain protein fragments called peptides (Substance P, calcitonin gene-related peptide, and others).
* These peptides dilate blood vessels and produce an inflammatory response that triggers over-excitation of the nerve cells in the trigeminal pathway. [This nerve pathway runs from the brain stem to the head and face. These nerves spread to the meninges (the membrane covering of the brain).]
* While the brain itself is insensitive to pain, the meninges and blood vessels around the brain are sensitive to pain. Some doctors suggest that pain occurs when blood drains from the center of the head to the blood vessels around the brain.
* Auras are believed to be a response to blood flow changes that cause a rapid reduction in brain activity that reaches the cerebral cortex (the outer layer of the brain), referred to as spreading depression. This effect may be visualized as an electrical wave spreading through the brain just as a wave of water is caused by the dropping of a pebble. Some research suggests that in people with auras, the cortical spreading depression itself activates the inflammation in the trigeminal nerves that triggers pain in the meninges.

Treatment Approaches

Many effective headache remedies are available for treating a migraine attack. Still, a study that analyzed over 800,000 cases of migraine reported that most migraines are not treated according to any recommended guidelines. In the study, 30% of patients were treated with potentially addictive opioids -- most often merepidine (Demerol). Furthermore, 70% of these patients were not offered effective and available anti-migraine drugs. Anti-nausea drugs that have no effect on headaches were used six times more often than drugs that reduce headaches.

A 2007 survey of migraine sufferers, commissioned by the U.S. National Headache Foundation, reported that 20% of patients are prescribed non-approved medications containing opioids or barbiturates. The survey also indicated that patients who take non-approved drugs are more likely to experience drug-related side effects. For mild migraines, non-prescription treatments (Excedrin Migraine, Advil Migraine, Motrin Migraine Pain) are the best first choice. For severe migraines, doctors recommend starting with a triptan drug.

Preventive treatment, used to stop migraine attacks before they happen, may help many patients. According to another 2007 survey, more than 1 in 4 patients with migraine are candidates for preventive therapy but most do not receive it.

As many as 30% of patients with migraine also have accompanying headaches resulting from tension, drugs, infections, or other causes. It is important to distinguish between headache types in order to determine appropriate treatment.

General Guidelines. The general goals of treatment are:

* Choose drugs with as few side effects as possible. Patients should talk to their doctors about various methods for administering the medication (pills, injections, nasal spray, or rectal suppositories) and begin with the one they believe will be the least distressing.
* Treat the attack rapidly, within an hour of symptom onset if possible. Start with low doses, and build up dosage slowly.
* Try to minimize the use of back-up or "rescue medications." (A rescue medication is typically a narcotic opiate drug, which is used for pain relief when other medications fail.)
* Try to guard against rebound effect. Nearly all drugs used for migraine can cause rebound headache, and patients should not take any the drugs for longer than 2 days per week.
* It may take 2 - 4 months for any drug to be effective.

Stepped-Up Treatment Approach. Some doctors recommend a stepped-up treatment course for an acute migraine attack. This involves starting with the least potent treatments and taking increasingly more powerful drugs until the pain stops. In this approach, patients may need up to five different medications to achieve pain relief. A typical stepped-up approach is the following:

* The patient should first use nonprescription pain relievers (NSAIDs, Excedrin Migraine) and stress-reduction techniques.
* If these are not effective within 2 hours, the patient should take migraine-specific drugs. Triptans are the first choice, then ergot derivatives.
* Patients with migraines associated with severe nausea or vomiting may use injected or rectally administered drugs. Nausea itself should be treated with specific anti-nausea drugs, such as metoclopramide (Reglan).
* If migraine medications fail to relieve symptoms within 4 hours, rescue drugs (opioids, corticosteroids) may be used.

Stratified Approach. Many doctors and patients now prefer the stratified approach. The doctor first estimates the severity of the patient's condition based on his or her history. Then, depending on the severity of a typical attack, the doctor decides whether the patient should start with more or less powerful drugs at the first signs of the migraine:

* Patients with less disabling migraines start with general pain relievers.
* Patients with a history of moderate-to-severe migraines start with migraine-specific prescription medicine, such as a triptan, at the onset of mild pain.

Some studies report dramatic relief with the stratified approach. In one study, zolmitriptan, a newer triptan, reduced the intensity of headaches within 2 hours in 70% of patients with moderate pain but only in 44% of those with severe headaches.

Side effects can be severe with many migraine drugs, although newer drugs, such as the recent generation triptans, may provide effective early relief without significant side effects.
Guidelines for Migraines in Children

Studies estimate that between 5 - 10% of children have migraines but that the disorder is underdiagnosed in children. An interesting study reported that when children drew pictures in response to their doctors' questions about their migraines, the doctors were able to tell the difference between migraine and non-migraine headaches in the majority of cases.

Symptoms in Children. The standard diagnostic criteria for migraine in adults may apply to only about two-thirds of migraines in children and adolescents. For example, doctors have seen the following differences:

* Headaches tend to last for a shorter time (as little as an hour) in children.
* Migraine pain tends to occur in the face and on both sides of the head in two-thirds of child patients.
* Children often have a form of migraine known as a migraine equivalent or abdominal migraine, which does not cause a headache at all. Instead, children experience periodic bouts of nausea and vomiting (called cyclic vomiting syndrome) or other secondary symptoms found in adult migraine, such as a reaction against light or sound. Cyclic vomiting may occur in nearly 2% of school-aged children with or without a migraine association.
* Migraine triggers in children are similar to those in adults, but common ones in children are anxiety and fear, and eating ice cream.

Outlook in Children. Migraine in children is disabling, as it is in adults, and they tend to lose more school days than other children. Children with frequent headaches may also be at higher risk for headaches in adulthood and also for other physical and psychiatric problems. However, some children who have migraine eventually stop having attacks when they reach adulthood, or have less severe types of headaches.

Treatments in Children. Most children with migraines may need only mild pain relievers and home remedies (such as ginger tea) to treat their headaches. The American Academy of Neurology’s 2004 practice guidelines for children and adolescents recommend the following drug treatments:

* For children age 6 years and older, ibuprofen (Advil) is recommended. Acetaminophen (Tylenol) may also be effective. Acetaminophen works faster than ibuprofen, but the effects of ibuprofen last longer.
* For adolescents age 12 years and older, sumaptriptan (Imitrex) nasal spray is recommended.

Preventive Measures in Children. Non-medication methods, including biofeedback and muscle relaxation techniques may be helpful. In one study of children with migraines and poor sleep habits, who were taught how to sleep better instructions without using medications had significantly fewer migraine attacks.

If these methods fail, then preventive drugs may be used, although evidence is weak on the effectiveness of standard migraine preventive drugs in children.