The pain just keeps getting worse

New research suggests that migraine sufferers are more likely to develop cerebral infarction and white matter lesions

By Owen Dyer

Migraine sufferers are often not overly fond of the medical community. Many of them have heard unhelpful advice ranging from "stop worrying so much" to "get a boyfriend and the headaches will go away." What's amazing is that such advice has sometimes come from neurologists.

A generation ago, the cause of migraines was largely unknown and many considered it a psychosomatic or hysterical condition — a disease that affected only wealthy women who had nothing better to worry about. Dr Seymour Diamond, who founded one of the first migraine clinics 35 years ago in Chicago, calls migraine sufferers "probably the most misunderstood, misdiagnosed and mistreated group of patients in modern medicine."

The good news is that in recent years research has proven that migraine is a discrete physical condition, and much better symptomatic treatments have come along. The bad news is that evidence has grown that migraine carries additional health risks, which appear to be linked to restricted blood flow in the brain. And most of the extra risk appears to be borne by women.

The January 28 issue of the Journal of the American Medical Association carries the latest bad news on migraine. The research, from the Netherlands, suggests that migraine sufferers are at higher than average risk of developing cerebral infarction and white matter lesions (WMLs). Brain magnetic resonance imaging found that in the cerebellar region of the posterior circulation territory, 295 patients with migraine had a higher prevalence of infarct than 140 controls, by a ratio of seven to one.

In addition, researchers found that women migraine sufferers were twice as likely as migraine-free women to fall in the 20% of the study population with the deepest WMLs. On the other hand, men with migraine showed no extra risk of WMLs.

The number of infarcts was higher in migraine sufferers who typically experienced more than one attack per month. But a more significant indicator of added risk of infarcts is the symptom known as 'aura.' About one in six migraine patients experiences this phenomenon when an attack comes on. The patient sees visual effects like lines and flashing lights or experience double vision. In the Dutch study, subjects who reported migraine with aura showed nearly twice the prevalence of infarcts as other migraine sufferers, which amounts to 14 times the prevalence found among the migraine-free controls.

While these small infarcts are asymptomatic, they point to more serious potential complications, notably stroke. Migraine is a young person's disease and women find that their migraines often resolve upon menopause. Stroke, of course, is very rare in the young, but among young Canadians who do suffer stroke, migraine sufferers are heavily overrepresented.

While a migraine-free woman aged under 35 runs only a 1.3 in 100,000 chance of suffering a stroke in a given year, the presence of migraine raises that chance to 4 in 100,000, and migraine with aura doubles the risk again. The pattern is repeated in the 35-45 age group, though all the risks are correspondingly higher. Indeed, women in their 30s who suffer migraine with aura, and who smoke and take the pill, face a stroke risk that cannot be discounted.

Among Canadians, 17% are "migraineurs," according to the Migraine Association of Canada. Of these, around two-thirds are women. While migraines are much rarer than regular tension headaches, they account for more visits to the doctor. The most recent national survey, way back in 1991, found that about 5.4 million workdays were lost to migraine each year. The survey reported that 77% of migraine sufferers cancel family or social activities when having an episode and 19% reported absence from work.

POTENTIAL TRIGGERS
The pain of migraine begins when a signal that originates in the brain stem activates a branch of the trigeminal nerve leading to the face and forehead. The nerve endings release neuropeptides, which cause local blood vessels to enlarge. The swelling inflames the nerve endings, which release more neuropeptides, causing further vasodilation. This vicious cycle explains why migraines can sometimes last for days.

A long list of potential triggers is associated with the onset of a migraine attack. "The number one trigger has got to be hormonal changes," says Emily Levitt of the Migraine Association. "Two-thirds of women sufferers only get their headaches around the time of their period."

Between 8% and 25 % of people with migraines point to particular foods as a source of their attacks. Other triggers frequently reported include stress, changes in sleeping patterns, and changes in barometric pressure. Neurologists generally recommend keeping a headache diary and bringing it in for each consultation.