Migraine

Migraine is a specific type of headache. The pain is often an intense pulsing or throbbing in one area of the head. It is often accompanied by extreme sensitivity to light and sound, nausea and vomiting.

Migraine can occur in both children and adults. It is three times more common in women than in men.

Migraine with aura
Also known as classic migraine, these headaches are preceded by an aura, a visual disturbance that appears as flashing lights, zigzag lines (called fortification spectra, because they resemble the angular tops of forts) or a temporary loss of vision (scotoma). The phenomenon is striking, and many artists have depicted what it looks like (see video below). An aura may also include tingling in one arm or leg, and, rarely, weakness or trouble with speech.

Migraine without aura
Also known as common migraine, these headaches are not preceded by an aura. Warning signs often appear a few hours before the onset of the headache. These signs include feelings of elation or intense energy, depression, drowsiness, and irritability. Sometimes these signs include a craving for sweets or extreme thirst. These migraines are more frequent than classic migraine, see figure below.

The International Headache Society has an exacting classification system to help neurologists diagnose the different types of migraine. The scheme classifies headaches into primary, secondary, cranial neuralgias, facial pain, and other headaches.



Symptoms
Migraine pain is not the same in every sufferer, but it can usually be distinguished from other types of headache. Usually the symptoms in adults and children are different.

Adults
Common symptoms in adults include the following:


 * Intense pain on one or both sides of the head
 * Throbbing pain
 * Pain in the eye or temple, jaw, face or neck
 * Intense sensitivity to light (photophobia) and noise (phonophobia)--migraineurs seek out dark, quiet rooms during their headaches
 * Nausea and vomiting

Symptoms worsen with even minor exertion. Migraines typically last 4 to 72 hours.

Tension headaches, cluster headaches, and the headache of subarachnoid hemorrhage (bleeding in the brain) are sometimes mistaken for migraine. In first-time migraine sufferers, subarachnoid hemorrhage can be ruled out by a computerized tomography (CT) scan and spinal tap. Usually migraines in a single patient resemble each other, and the patient recognizes that this is his or her typical headache.

Children
Migraines in children tend to occur all over the head, not on just one side, and tend to be shorter-lasting than migraines in adults. Sometimes children have the symptoms that accompany a migraine--light sensitivity, nausea, and vomiting--without any headache. This is called an abdominal migraine, and it can be difficult to diagnose.

Triggers
Recurrent attacks of migraine are triggered by a lack of food or sleep, exposure to light, or menstruation. Anxiety, stress, foods or drinks, or relaxation after stress can also be triggers.

Causes
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 genes that control the activities of certain cell populations in the brain. According to this theory, the brain is said to be hyperexcitable, This excitability may irritate the trigeminal nerve of the face, which causes pain signals to be felt by the migraineur.

Stress-induced migraines may result from the release of serotonin, which is a neurotransmitter. Neurotransmitters mediate signaling between nerves. Serotonin release can trigger pain in a variety of ways, including the constriction and dilation (widening) of blood vessels. Constriction and dilation of blood vessels cause them to leak, which triggers inflammation and pain.

Another cause of migraines is cortical spreading depression. In this process, inflammation and irritation to nerves is caused by reduced electrical activity in the cortex.

Treatment
Stress management strategies, such as exercise, relaxation, biofeedback, and other therapies designed to help limit discomfort, may also reduce the occurrence and severity of migraine attacks.

Medications
There are two ways to approach the treatment of migraine headache with medication.


 * Prevent the attacks. Some migraineurs have more than one headache a week, and these people benefit most from a daily preventive medication.  The Food and Drug Administration (FDA) has approved the following drugs for the prevention of migraines:
 * 1) Propranolol (Inderal): This beta-blocker medication also treats high blood pressure.
 * 2) Timolol (Blocadren): Another beta-blocker medication.
 * 3) Topiramate (Topamax): Originally an antiseizure medication, it is also useful in migraine.
 * 4) Divalproex sodium (Depakote): Another antiseizure medication helpful in migraine.

Other medications that can be helpful in preventing migraine include the antidepressant amitriptyline (Elavil, Endep).
 * Relieve, or "abort," the symptoms during the attacks. A variety of drugs may be helpful in aborting a migraine once it has started:
 * 1) Triptans (such as sumatriptan (Imitrex)): These drugs target serotonin levels in the brain. They can be given by mouth, by injection or by spray into the nose. Typically they need to be given at the onset of an aura migraine to be effective.
 * 2) Ergot derivatives (such as dihydroergotamine or DHE): These drugs cause blood vessels to constrict. DHE is available for self-injection or as a nasal spray.
 * 3) Antinausea drugs (such as prochlorperazine(Compazine) and promethazine (Phenergan)): Though usually used for nausea, these drugs can often completely abort a migraine headache. Some patients may be so severely affected by their migraines that they are unable to take food or drink, in which case antinausea drugs can be very useful. In rare occasions, nausea is so bad that patients must get intravenous antinausea drugs and fluids to prevent dehydration.
 * 4) Narcotics (codeine component of Tylenol 3; butalbital in Fioricet): These are typically used as backup drugs. Narcotic withdrawal can make migraines worse. Rarely, when migraine is unbearably severe, intravenous narcotics are given.

Typically both approaches are used. Medications originally developed for epilepsy and depression are used to prevent future attacks, and triptans are used to treat attacks. Hormone therapy may help some women whose migraines seem to be linked to the menstrual cycle.

Biofeedback
Biofeedback teaches recognition of one’s stress reactions and learning how to control them. It can be particularly helpful in children.

Epidemiology and Statistics
The World Health Organization ranks migraines as the 19th leading cause of disability worldwide. In the United States, the prevalence of migraine is about 18.2% among females and 6.5% among males, is most common in Caucasians, and is slightly more common in people of lower socioeconomic class.

Related Problems
As with many diseases and conditions, the treatment itself can cause some problems. And in some cases, the migraine symptoms are accompanied by associated complications.

Overmedication
Overmedication increases the risk of developing side effects. For example, taking too much ibuprofen (Advil) can cause bleeding in the stomach or kidney problems, and taking too much acetaminophen (Tylenol) can lead to life-threatening liver damage, particularly when taken with alcohol. Rebound headache can occur when medication is overused. Overuse of acetaminophen and anti-inflammatory drugs, such as ibuprofen, can also themselves cause headache.

Medication interactions

 * Serotonin syndrome is a rare but dangerous problem in which serotonin levels in the brain reach extremely high levels. This can occur when drugs that elevate serotonin are used in combination. Some of these combinations include triptans (e.g., sumatriptan with either serotonin reuptake inhibitors (e.g., fluoxetine (Prozac) or paroxetine (Paxil)), or serotonin-norepinephrine reuptake inhibitors (e.g., venlafaxine (Effexor)).

Complications

 * Status migrainosus: A migraine that lasts 24 hours or longer. These cases may be treated with corticosteroids.
 * Stroke: Very rarely, a migraine can lead to stroke, with permanent weakness or loss of sensation. This is more common in young women.

Prognosis
Taking a combination of drugs to prevent and treat migraine attacks when they happen can limit the disabling effects. Migraine attacks associated with menstruation occur less frequently and are milder after menopause.

Research
Researchers believe that migraine is the result of fundamental neurological abnormalities that have a genetic basis. The role of specific genes in the genesis of migraine is continually being investigated. Understanding the cascade of biological events underlying migraine and their mechanisms will give researchers opportunities to develop and test drugs that could prevent or interrupt attacks.

A study published in 2008 was the first to convincingly show a link between a specific gene and migraines. The study found that a gene located on chromosome 10 was associated with the development of migraine. The association was especially strong in women. Findings similar to this one will help direct treatment strategies.

History
The word migraine comes from the French migraigne, from vulgar pronunciation of the Latin hemicrania, "pain in one side of the head, headache," from Greek hemikrania, from hemi-, "half," + kranion-, "skull."

Famous people
Migraine has afflicted humankind since prehistory, and many famous people are reported to have had migraines, including the authors Lewis Carroll and Virginia Wolff, the Roman leader Julius Caesar, the father of psychoanalysis Sigmund Freud, and the philosopher Friedrich Nietzsche.

Oliver Sacks, the neurologist-writer who wrote Awakenings, has written about migraines, including the book Migraine: Understanding a Common Disorder.

Related Videos
In this video from NHS Choices, Dr. Anne McGregor describes common causes of headaches, the differences between a normal headache and more severe forms such as a migraine, and treatment options.