Migraine

View PDF

The headache that’s not really a headache

Laura Jones

I had my first migraine when I was seven years old. Zigzagging patterns of light suddenly cut into my field of vision, then vanished as quickly as they came. I felt as if I had been struck by lightning. After that, extreme head pain would regularly send me crying to my mother, cradling my head between my raised arms. “Stop pretending,” she would respond in her no-nonsense way.“Children don’t get headaches.” That was the thinking of the day.

Possibly she thought I was imitating my father, who often sought out the quiet dark, hiding his head under the covers with the venetian blinds drawn and the bedroom door shut. And migraine does run in families. If both parents have migraines, their child is about 70% more likely to develop them. So far, chromosomes one, 19 and X have been identified as holding migraine genes.

As I entered my teens, the episodes of headache and vomiting worsened, causing me to miss school. I thought it was normal to spend two days of your menstrual period in bed. But it was not until my late 20s that I was diagnosed with migraines. I now have two attacks per month and spend about $3,600 a year on migraine-specific medications.

Dr. Werner Becker, a professor in the division of neurology at the University of Calgary (UC), confirms that, despite its high prevalence in Canada (see “By the Numbers,” right), migraine is still not well understood. “People, including many physicians, do not empathize with the migraine experience,” he says. “Migraine is an under-recognized medical problem requiring treatment.”

Beyond head pain

While migraine causes a severe ache in the head, it is far more complex than an ordinary headache triggered by tension, alcohol, flu or dental problems. Its tentacles reach out to many other systems, causing disturbances in mental function, vision, hearing, smell, motion and the gastrointestinal tract.

“Typically, the general public equates migraine with just a bad headache,” says Dr. Michael Hill, director of the stroke unit and an associate professor of neurology in the department of clinical neurosciences at UC. “This is a vast oversimplification. Migraine is a neurological condition of which just one manifestation is a headache.”

Disorienting and debilitating

When I sense a migraine on the horizon, I’m determined to get everything important done before the full-blown attack crushes me. I know my normal functioning grinds to a halt. My memory deteriorates; I can’t think straight. I can’t find my cellphone, keys or shoes. As I walk to the subway, I may weave and appear drunk. I may forget to get off at my stop and have to go back. Ordinary light seems brighter than sunshine; ordinary sounds seem as loud as a rock concert. If I move too quickly, I vomit. My attacks can last several days. “Migraine affects the normal functioning of the brain. It is a real, not a psychological, disease,” explains Dr. Edith Hamel, a neuroscientist at McGill University’s Neurological Institute. The sensation of pain during migraine comes from the blood vessels in the brain and cranium. But migraine is not really a disease of the blood vessels per se, she adds. “Changes occurring in the brain during the attack affect the milieu surrounding the blood vessels, and these react by transmitting a pain signal to inform the brain that something is wrong.”

Photo: Chad Johnston/ Masterfile

But just what causes these physiological brain changes is not clear. “But it does seem clear that migraine is initiated by the brain itself,” says Becker.
According to a hypothesis mentioned by Hill, a migraineur has a migraine generator in the brain stem, the brain’s central trunk. This generator sends signals
to the brain, causing a spreading depression (see “Stages of Migraine,” p. 38). That results in neurological symptoms and more signals to the brain’s trigeminal nerve, which is involved in pain sensation. The signals trigger biochemical changes at the nerve-artery junctions and lead to intense pain.

Other researchers theorize that an initial elevation in the vasoconstrictive brain chemical serotonin causes certain blood vessels to contract, leading to electrical
disturbances and the warning symptoms of aura (see “Stages of Migraine,” p. 38). Other cranial blood vessels try to compensate for this constriction by expanding.
In addition, nerve endings in certain blood vessels may release inflammatory substances. The result? The throbbing headache and other symptoms of migraine.

Using brain-imaging techniques, Hamel and her colleagues studied the rate of serotonin production in the brains of migraine patients during different phases of their attacks. At the onset of attacks, they noted a strong increase in serotonin-releasing activity in patients’ brains. “Anti-migraine treatment normalized this increase,” she says. “In between attacks, serotonin production in migraineurs compared very well with that of non-migraineurs in various brain regions.”

Whatever her serotonin status, Helen Melbourne, 60, owner of Clean Now Organizing in Toronto, always knows when a migraine is coming. “When I have holes in my vision or can’t see out of my left eye, I know. I smell burning wires, and I look to see if something’s on fire.” That’s her cue to turn off the lights, climb into her recliner and put heating pads on her hands and feet and the back of her neck. She applies an ice pack to her forehead and tries to sleep. Helen, whose worst triggers are weather conditions such as high winds, can’t take most migraine medications, so if these measures don’t work, she must seek treatment in a hospital. She gets some functional relief from triptan medications (see “Migraine Management,” right), but it is sleep that helps the most. “Migraine is almost always relieved by sleep,” says Hill.

Migraine in children

About half of child migraineurs start having attacks around age 11. Even babies can be affected, although rarely. When children have migraines, there is usually a family history of the problem. Between the ages of four and seven, boys are more susceptible than girls.

Youngsters are even more likely than adults to react to food triggers. Repetitive swinging on a swing, gymnastics that involve putting the head downward and emotional excitement are all factors that might set off migraine in a child. Children may also get abdominal migraine, which causes nausea and vomiting, can last as long as 72 hours and may develop into a headache.

Being overweight is associated with more severe headaches in youngsters, and the more overweight a child is, the more intense her attacks. Children who have migraines are 36% more likely to be overweight. By puberty, girls are three times more likely than boys to suffer migraine, probably because of the hormonal fluctuations of the menstrual cycle. In this age group, stress is a common trigger of attacks, too.

Women

Adult females suffer from migraine at three times the rate of males. Women are twice as likely to have a migraine just before and during the first two days of their period (menstrual migraine), when estrogen levels are very low. Low estrogen causes blood vessels to constrict. According to the Heart and Stroke Foundation, women ages 22 to 44 who have migraine have double the risk of stroke. Women of any age who have migraine with aura (see “Stages of Migraine,” p. 38) run 10 times the risk.

Men

Although migraine strikes men less often, it is no less disabling for them. One Australian study found that the fear of having migraines and the unpredictability of living with them caused men to report a lower quality of life and considerable difficulty in planning their lives.

Migraine management

Reducing the number of your migraines is the first step to gaining control. The key to coping is to pay attention to your triggers. Keep a detailed migraine diary that records food intake, weather, daily activities and sleep. Since migraine can occur as a letdown after exciting or stressful events, document your response to them. You’ll acquire greater awareness of what causes your attacks, and you may be able to prevent attacks by avoiding  triggers. During an episode, follow Helen’s example and lie down in a dark, quiet room with a cold compress on your forehead. For Helen, massaging her scalp or putting pressure on her temples gives some relief.

Prescription medications

Prophylactic drugs are taken daily to ward off attacks. They include beta blockers (e.g., atenolol) and calcium channel blockers (e.g., verapamil) — blood pressure drugs that stabilize the contraction and expansion of blood vessels. Tricyclic antidepressants such as amitriptyline and desipramine help normalize levels of serotonin and other brain chemicals. Anti-seizure drugs (e.g., valproic acid and gabapentin) stabilize nerve cells to prevent brain hypersensitivity.

Abortive medications are taken at the onset of or during a migraine to stop or shorten it. These include non-steroidal anti-inflammatory painkillers such as ibuprofen and naproxen. Triptan drugs such as sumatriptan and zolmitriptan act on serotonin receptors in the cranial blood vessels to counteract dilation and inflammatory substances. Ergot preparations are vasoconstrictors that contract swollen blood vessels.

Alternatives

Some people say self-awareness, meditation, stress control, yoga and biofeedback cut attacks. Acupuncture helps others.

Riboflavin

High daily doses of riboflavin (vitamin B2) for three to four months are associated with fewer and shorter attacks and a reduction in migraine medication needed. This vitamin may counteract the cellular dysfunction in the brain that contributes
to migraine.

Magnesium sulphate

This compound is sometimes given in the hospital as an intravenous infusion to abort a migraine, though its mechanism of action is not clear. Regular supplements may reduce attacks for some. 

Feverfew

This anti-constrictive herb may lessen the intensity and duration of migraines.

Botulinum toxin

Injected into the muscles of the brow and side of the head, Botox, the paralyzing nerve toxin that smoothes facial lines, may prevent contraction of the muscles that help trigger migraine. Or it may act on brain chemicals such as substance P, which are associated with pain and migraine mechanisms.

Surgery

Some migraineurs with aura are born with  patent foramen ovale, an abnormal slit-like opening between the right and left upper chambers of the heart. Corrective heart surgery may bring migraine relief. In other migraine surgery, the frown muscles are removed and the nerves associated with chewing are detached.

Migraine zappers

The transcranial magnetic stimulator delivers a painless electrical pulse to the head during the aura phase. The pulse sets up a magnetic field to interrupt the electrical changes that lead to migraine.

Step by step, study by study, the mystery of migraine is being solved. New insights into neurophysiology are promising a brighter future for those who suffer from this debilitating condition. Genetics may be key. “Once the genes involved are better understood, it may be possible to do genetic testing and predict which drugs an individual patient will respond to,” says Becker.