Migraine

Migraine is a neurological syndrome characterized by altered bodily perceptions, severe headaches, and nausea. Physiologically, the migraine headache is a neurological condition more common to women than to men. The word migraine was borrowed from Old French migraigne (originally as "megrim", but respelled in 1777 on a contemporary French model). The French term derived from a vulgar pronunciation of the Late Latin word hemicrania, itself based on Greek hemikrania, from Greek roots for "half" and "skull".
The typical migraine headache is unilateral (affecting one half of the head) and pulsating, lasting from 4 to 72 hours; symptoms include nausea, vomiting, photophobia (increased sensitivity to light), and phonophobia (increased sensitivity to sound). Approximately one-third of people who suffer migraine headache perceive an auraunusual visual, olfactory, or other sensory experiences that are a sign that the migraine will soon occur.
Initial treatment is with analgesics for the headache, an antiemetic for the nausea, and the avoidance of triggering conditions. The cause of migraine headache is unknown; the most common theory is a disorder of the serotonergic control system.
There are migraine headache variants, some originate in the brainstem (featuring intercellular transport dysfunction of calcium and potassium ions) and some are genetically disposed. Studies of twins indicate a 60 to 65 percent genetic influence upon their propensity to develop migraine headache. Moreover, fluctuating hormone levels indicate a migraine relation: 75 percent of adult patients are women, although migraine affects approximately equal numbers of prepubescent boys and girls; propensity to migraine headache is known to disappear during pregnancy, although in some women migraines may become more frequent during pregnancy.

Classification

The International Headache Society (IHS) offers guidelines for the classification and diagnosis of migraine headaches, in a document called "The International Classification of Headache Disorders, 2nd edition" (ICHD-2).
According to ICHD-2, there are seven subclasses of migraines (some of which include further subdivisions):

• Migraine without aura, or common migraine, involves migraine headaches that are not accompanied by an aura (visual disturbance, see below).
• Migraine with aura usually involves migraine headaches accompanied by an aura. Less commonly, an aura can occur without a headache, or with a non-migraine headache. Two other varieties are Familial hemiplegic migraine and Sporadic hemiplegic migraine, in which a patient has migraines with aura and with accompanying motor weakness. If a close relative has had the same condition, it is called "familial", otherwise it is called "sporadic". Another variety is basilar-type migraine, where a headache and aura are accompanied by difficulty speaking, vertigo, ringing in ears, or a number of other brainstem-related symptoms, but not motor weakness.
• Childhood periodic syndromes that are commonly precursors of migraine include cyclical vomiting (occasional intense periods of vomiting), abdominal migraine (abdominal pain, usually accompanied by nausea), and benign paroxysmal vertigo of childhood (occasional attacks of vertigo).
• Retinal migraine involves migraine headaches accompanied by visual disturbances or even blindness in one eye.
• Complications of migraine describe migraine headaches and/or auras that are unusually long or unusually frequent, or associated with a seizure or brain lesion.
• Probable migraine describes conditions that have some characteristics of migraines but where there is not enough evidence to diagnose it as a migraine with certainty.

Diagnosis

Migraines are underdiagnosed and misdiagnosed. The diagnosis of migraine without aura, according to the International Headache Society, can be made according to the following criteria, the "5, 4, 3, 2, 1 criteria":
• 5 or more attacks
• 4 hours to 3 days in duration
• 2 or more of - unilateral location, pulsating quality, moderate to severe pain, aggravation by or avoidance of routine physical activity
• 1 or more accompanying symptoms - nausea and/or vomiting, photophobia, phonophobia

For migraine with aura, only two attacks are required to justify the diagnosis.

The mnemonic POUNDing (Pulsating, duration of 4–72 hOurs, Unilateral, Nausea, Disabling) can help diagnose migraine. If 4 of the 5 criteria are met, then the positive likelihood ratio for diagnosing migraine is 24.

The presence of either disability, nausea or sensitivity, can diagnose migraine with:
• sensitivity of 81%
• specificity of 75%

Migraine should be differentiated from other causes of headaches such as cluster headaches. These are extremely painful, unilateral headaches of a piercing quality. The duration of the common attack is 15 minutes to three hours. Onset of an attack is rapid, and most often without the preliminary signs that are characteristic of a migraine.

Triggers

A migraine trigger is any factor that, on exposure or withdrawal, leads to the development of an acute migraine headache. Triggers may be categorized as behavioral, environmental, infectious, dietary, chemical, or hormonal. In the medical literature, these factors are known as 'precipitants.'

The MedlinePlus Medical Encyclopedia, for example, offers the following list of migraine triggers:
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, hormone fluctuations during the menopause transition
• 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.

Prevention

Preventive (also called prophylactic) treatment of migraines can be an important component of migraine management. Such treatments can take many forms, including everything from taking certain drugs or nutritional supplements, to lifestyle alterations such as increased exercise and avoidance of migraine triggers.

The goals of preventive therapy are to reduce the frequency, painfulness, and/or duration of migraines, and to increase the effectiveness of abortive therapy. Another reason to pursue these goals is to avoid medication overuse headache (MOH), otherwise known as rebound headache, which is a common problem among migraneurs. This is believed to occur in part due to overuse of pain medications, and can result in chronic daily headache.

Many of the preventive treatments are quite effective: Even with a placebo, one-quarter of patients find that their migraine frequency is reduced by half or more, and actual treatments often far exceed this figure. There are many medicines available to prevent or reduce frequency, duration and severity of migraine attacks. They may also prevent complications of migraine. Propranolol, atenolol, metoprolol, flunarizine, sodium valproate, topiramate are some of the commonly used drugs. But they need to be taken for about 3 months or more.

Management

Conventional treatment focuses on three areas: trigger avoidance, symptomatic control, and prophylactic pharmacological drugs. Patients who experience migraines often find that the recommended migraine treatments are not 100% effective at preventing migraines, and sometimes may not be effective at all. Pharmacological treatments are considered effective if they reduce the frequency or severity of migraine attacks by 50%. Children and adolescents are often first given drug treatment, but the value of diet modification should not be overlooked. The simple task of starting a diet journal to help modify the intake of trigger foods like hot dogs, chocolate, cheese and ice cream could help alleviate symptoms.

For patients who have been diagnosed with recurring migraines, migraine abortive medications can be used to treat the attack, and may be more effective if taken early, losing effectiveness once the attack has begun. Treating the attack at the onset can often abort it before it becomes serious, and can reduce the near-term frequency of subsequent attacks.