By EDUARDO GONZALES
Q—I get an attack of severe migraine that is preceded by about half an hour with blurring of vision every few months. What causes this migraine? —firstname.lastname@example.org
A—Migraine is a primary headache disorder, which means, in migraine, the headache is not the symptom of an underlying disease but is the disease itself. Migraine headache varies in location, character, intensity, and duration from person to person and from one migraine attack to another in the same person, but typically, it is characterized by a moderate to severe throbbing or pulsating pain on one side of the head that is aggravated by physical activity, coughing, straining, sounds, odors, and light.
A migraine attack is often very disabling and is usually accompanied by an assortment of other signs and symptoms including loss of appetite, nausea, vomiting, numbness, tingling, weakness, dislike for sound, light and certain smells, temporary paralysis of a limb, ringing of the ear, speech difficulty, temporary blindness, confusion, and disorientation.
Migraine where the headache is heralded by an aura, as in your case, is referred to as classical migraine. The aura often consists of a visual disturbance like blurring of vision, as in your case, or perception of flashes of lights, halos, stars, and blind spots. Most migraines, however, have no aura. Ironically, there is also such a thing as headache-free migraine, where there is an aura but no headache.
What causes migraines?
Migraine is still a poorly understood disorder, but genetics and environmental factors appear to play a role. The current thinking is that they occur because of inherited idiosyncrasies in nerve cells. Migraine, which is three times more common in women than in men, runs in families.
A migraine attack is generally triggered by any of a variety of conditions including emotional or physical stress; lack or excess sleep; hunger; intake of certain foods (e.g., MSG, chocolate, cheese), alcoholic beverages, and coffee; certain smells such as perfume, smoke, and paint thinner; intake of certain medications such as oral contraceptives and vasodilators; exposure to intense light or glare as well as loud sounds; changes in weather, altitude or time zone; and, in women, the drop in the blood level of the female hormone estrogen that occurs before menstruation. Most migraine sufferers know their triggers.
A migraine attack starts when in reaction to a trigger, certain nerve cells send out signals that activate the trigeminal nerve, the nerve that supplies sensation to your head and face. Activation of the nerve causes the release of certain chemicals like serotonin and calcitonin gene-related peptide (CGRP). CGRP causes blood vessels in the lining of the brain to swell. This releases neurotransmitters that create inflammation and pain.
Clinical course of migraine
The onset of a migraine can be at any age, but the attacks usually start during adolescence or early adulthood. The attacks peak when the person is in his or her 30s, and gradually become less severe and less frequent in the following decades.
During an attack of migraine, the headache and other symptoms typically increase in intensity over a period of one to two hours before gradually and spontaneously subsiding within a few hours. Occasionally, however, the headache persists up to 24 hours or even days.
The frequency of migraine attacks varies from once every several months or years to several times a month. Rarely, migraine becomes chronic, i.e., the attacks last for 15 or more days a month for more than three months.
Treatment for migraine
There is no cure for migraine but attacks can be relieved and prevented. A mild migraine headache can usually be relieved by over the counter pain relievers such as acetaminophen and ibuprofen. Severe attacks, however, may require prescription medications such as triptans and antidepressants known as selective serotonin reuptake inhibitors (SSRIs) or serotonin and norepinephrine reuptake inhibitors (SNRIs).
Other measures that help ease the symptoms of migraine include resting in bed in a dark and quiet room and applying cold compress over the affected area. Incidentally, a modality that many find effective in relieving migraine is acupuncture.
The best way to prevent migraines is by avoiding its triggers. Adopting certain lifestyle changes may also help prevent the disorder—regular sleep patterns, regular meals, regular exercise, and maintenance of healthy body weight.
A variety of drugs to prevent migraines are also available, but these drugs are recommended only for people with frequent attacks (three or more a month) and should only be taken with doctor’s supervision.
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