Migraine pain has been called indescribable, yet 35 million Americans know it all too well. Horror author Steven King, himself a migraineur, penned a vivid description of a migraine in his novel Firestarter:
“The headache would get worse until it was a smashing weight, sending red pain through his head and neck with every pulse beat. Bright lights would make his eyes water helplessly and send darts of agony into the flesh just behind his eyes. Small noises magnified, ordinary noises insupportable. The headache would worsen until it felt as if his head were being crushed inside an inquisitor’s lovecap…. He would be next to helpless.”
Migraine is the French derivation of the Greek word hemikrania, meaning “half a head,” referring to the typical pattern of migraine distress — pain only on one side of the head, most often at the temple (see Figure 3). The affected side can vary from one attack to the next or during a single episode.
Migraine pain ranges from moderate to severe. Unlike tension headache, migraine headaches can keep you from functioning or sleeping, and they can even rouse you from sound slumber. Most people describe the pain as pulsating or throbbing. It can also be sharp, almost as if a dagger is piercing your temple or eye.
Nausea and vomiting are common during a migraine headache. Likewise, tense head, neck, and shoulder muscles can accompany a migraine headache. In most cases, this is thought to be an involuntary response to the pain, rather than its cause (although tight muscles can trigger a migraine headache). Bright lights and loud noises worsen the pain and may prompt someone with a migraine headache to seek out quiet, dimly lit places. Similarly, smell may aggravate nausea and cause vomiting. (For information on treating these acute symptoms, see the special section “Mitigating migraine pain.”)
Figure 3: Migraine headache pain
Unlike tension and sinus headaches, which produce a dull, steady pain, the pain of migraine headache is throbbing or sharp. It usually occurs on one side of the head only, confined to the temple, eye, or back of the head.
Anatomy of an attack
To most people, “migraine” means a particular type of head pain. Actually, the term refers to a broader set of changes that may occur throughout the body, although not all of these symptoms are evident in every person who has migraine. Typically, the early sensations include a change in mood, appetite, or activity level. These symptoms, known as prodromal symptoms or the prodrome, warn that a migraine headache is on the way.
Some people also experience visual disturbances shortly before the headache begins. These might include seeing sparkling or flashing zigzag lines (scintillations) or blank spots (scotomas) (see Figure 4). Less often, people will experience tingling on one side of the body, often in the hand, arm, and face. Such visual and sensory disturbances generally last anywhere from 10 to 30 minutes and are known as aura. The presence or absence of aura determines whether an episode is a classic migraine (with aura) or common migraine (without aura). (For information on other types of headaches that have some similarities to migraine, see “Migraine relatives.”)
Figure 4: The visual aura of migraine: Scintillating scotoma
Migraine aura often includes a blind spot or area in one side of the field of vision, known as a scotoma. Although scotomas usually appear black, in migraine they are typically gray, or, in rare cases, colored. The scotoma typically appears as a shimmering zigzag in the shape of a crescent that moves across one side of a person’s field of vision. The above drawing shows what a person experiencing this phenomenon might see while reading a book. Visual auras typically last about 20 minutes and are often but not always followed by headache and the other typical features of migraine (see Figure 7).
What causes a migraine headache and — when it occurs — an aura? Experts aren’t sure. For many years, scientists believed that a tightening of the cerebral arteries interfered with blood flow. The arteries would then dilate to compensate, not only in the brain but also outside the brain, where the dilation causes inflammation. Although scientists still believe that this combination of blood vessel dilation and inflammation causes migraine headache, they no longer think that the tightening of cerebral arteries underlies the aura.
Here’s why: although researchers have confirmed that the aura coincides with a reduction in brain blood flow, this reduction isn’t consistent with blood vessel constriction or spasm because these conditions would have a more substantial effect. Instead, many experts now suspect that the migraine aura is produced by a neurological phenomenon known as spreading depression, which is a wave of decreased electrical activity (indicating lower brain cell functioning) and diminished blood flow that inexplicably washes across the cerebral cortex. As neuronal communication is suppressed, cerebral blood flow diminishes. The areas of lowered activity gradually spread, as if washing across the brain, causing the symptoms of aura (see Figure 5).
Figure 5: Three theories about migraine
The altered cerebral blood flow and electrical activity occur first in the primary visual cortex, which may help explain why visual disturbances often accompany the aura. Symptoms affecting the extremities, such as numbness and tingling, may occur when the spreading depression reaches the primary sensorimotor cortex. The spreading depression usually stops about halfway across the brain. At that point, a parallel process, involving a combination of blood vessel dilation and inflammation, may be causing headache pain. Bolstering this theory is the fact that a resting brain is more susceptible to spreading depression than an active one, which may explain why migraine attacks often strike as people unwind after a stressful period.
A migraine attack can also consist of an aura only, with no subsequent headache. This type of migraine is more common in older people and is sometimes confused with a transient ischemic attack (TIA), also called a “mini-stroke,” which often is the first sign of an impending stroke. TIAs occur when a blood clot temporarily interrupts blood flow through one of the smaller arteries in the brain. Symptoms may include weakness on one side of the body or blindness in one eye or one side of the visual field. If you’ve suffered from migraine throughout your life, remember these similarities, because you may be able to avoid expensive and sometimes risky tests for TIAs. But if in doubt, err on the side of caution.
Twenty-eight million Americans — about one in five women and one in 20 men — have migraine.
Timing of attacks
Many migraine attacks occur in the evening or at night and, ironically, may be the result of the body’s attempt to relax after the day’s stresses. Blood vessels tighten in response to stress and widen during relaxation, and dilated blood vessels in the head are a chief trigger for migraine pain. What’s more, relaxation lowers an individual’s pain threshold. Thus, an evening or nighttime migraine usually occurs after a particularly intense day or a period of prolonged stress.
Both the frequency and the duration of migraine headaches vary from person to person. Migraine headaches usually last at least six hours, and usually no longer than 24 hours. On occasion, however, they can persist for days, especially in women who have these headaches before or during menstruation.
Though not classic migraine, these headaches are close cousins.
Weekend headache is often caused by caffeine withdrawal, which leads to the dilation of blood vessels. This type of headache often begins 12 to 24 hours after your last sip of coffee and is apt to develop on weekends, when you delay your first cup of the day or skip coffee entirely. You can easily identify this type of headache by comparing your weekend caffeine intake with your weekday consumption.
Ice-pick headache takes its vivid name from its identifying characteristic: sudden, brief, and severe stabs of pain to the head. Ice-pick headache is so fleeting that it’s over long before any medication could take effect. This type of headache generally afflicts people who suffer from migraine or cluster headache.
Thunderclap headache strikes like a blow to the head, causing sudden, intense pain that peaks within 60 seconds. The pain may begin to subside within an hour, or it can last up to ten days. These uncommon headaches may appear for no obvious physical reason. But others are a warning of a possibly life-threatening condition, such as a subarachnoid hemorrhage (bleeding around the brain). Because of this risk, you should seek emergency treatment if you experience symptoms of a thunderclap headache.
Benign orgasmic headache tends to occur in people with migraine. A severe headache occurs each time a person reaches sexual orgasm. Because the experience may be virtually identical to a thunderclap headache, which is associated with bleeding inside the head, testing may be needed to confirm the diagnosis.
Post-traumatic headache develops after a head or neck injury, generally from relatively minor events that don’t cause a loss of consciousness. Such injuries often cause daily headaches, but they may also share characteristics with migraine. Post-traumatic headaches may persist for a year or more.
Paroxysmal hemicrania is a rare variation of cluster headache. The two disorders are nearly identical, but paroxysmal hemicrania attacks are shorter (lasting 10 to 30 minutes) and more frequent (five to 15 times a day). The condition is much more common in women. Scientists believe that paroxysmal hemicrania and cluster headache are distinct entities, despite their similarity, because they respond differently to medications. Like cluster headache, paroxysmal hemicrania is easy to treat. Indomethacin (Indocin), a prescription NSAID, works swiftly. The required dose varies, but indomethacin doesn’t lose effectiveness over time. On the other hand, it offers little benefit for cluster headache.
Who’s at risk?
During childhood, migraine affects boys and girls equally. But after puberty, the situation shifts, with women more likely to experience migraine headaches. About 9% of men and 16% of women suffer from migraine. The tendency for migraine runs in families, and these headaches seem to be connected with motion sickness, as many adult migraine sufferers recall bouts of carsickness as children.
Estrogens have long been linked to headaches, but the reasons behind this association remain elusive. Both the introduction and withdrawal of these hormones, either naturally (during a woman’s monthly cycle) or artificially (by starting or stopping estrogen-containing medications) can trigger headaches. Women are more likely to experience migraine and other kinds of headaches around the time of menstruation and, to a lesser extent, ovulation (see Figure 6). Migraine headaches that occur in the days before menstruation tend to be particularly severe and incapacitating.
Menstrual migraine headache can be treated like any other migraine headache. For milder cases, try aspirin or another NSAID, such as ibuprofen, daily during the days before and the week of your period. Birth control pills may increase the frequency or intensity of attacks, which usually occur during the placebo week when the pills don’t contain any estrogen. However, low-estrogen birth control pills may prevent menstrual migraine headaches in some women, especially when taken continuously. At menopause, menstrual migraine headaches should improve as long as you don’t take hormone therapy — which may actually increase the frequency and intensity of the attacks.
Figure 6: Menstrual migraine
Most migraine headaches in women occur when estrogen levels are low and falling — usually right before (days 27 to 28 of the cycle) and during menstruation (days 0 to 4 or 5), but sometimes around the time of ovulation (day 14).