Few afflictions are more common than headaches. Statistics (themselves the cause of many headaches) show that in the U.S., up to 50 million people go to the doctor for headaches annually.
Among headaches, however, migraines hold a special place. The pounding pain can last for hours or even days. Movement makes it worse. Nausea and sensitivity to light and sound heighten the misery.
The word “migraine” comes from the Greek, and means “half a skull”: migraines almost always occur on only one side of the head. About one-third of migraine sufferers report zig-zag flashing lights, blind spots, numbness and distorted visual images before the onset of a migraine. These early warning signs are called an “aura.”
Migraine sufferers have included Thomas Jefferson, Sigmund Freud, Ulysses S. Grant, Karl Marx, Charles Darwin, Lewis Carroll and Virginia Woolf. Overachievers and women (probably because of fluctuating estrogen levels) are particularly at risk. Migraines also seem to run in families.
Until recently, it was generally thought that migraines were caused by dilated blood vessels in the brain. It was thought that cheese, alcohol and chocolate, which are some of the many “triggers” migraine sufferers reported, contained substances that affected the blood vessels. (Stress, fatigue, bright lights and changes in the weather are other common triggers.)
But new research has revealed that migraines apparently aren’t triggered by blood vessels, but by the brain itself. Using medical imaging devices that allow them to watch what happens in a migraine sufferer’s head during an attack, scientists have discovered that migraine sufferers have abnormally excitable brain cells.
When something triggers a migraine, these brain cells (called neurons) fire off electrical pulses at the back of the brain. These pulses ripple across the top of the brain and then back down to the brainstem, where major pain centers are located. Blood flow increases. The pain could be the result of the brainstem excitation or of the increased blood flow–or both.
During one experiment, scientists used a powerful magnet to stimulate neurons in people prone to migraines and people who aren’t. The migraine-prone people reported seeing spots similar to a migraine’s aura, and one even went into a migraine attack. People who weren’t prone to migraines weren’t affected.
Better understanding of the mechanisms behind migraines may lead to better treatments in the future. In the meantime, the researchers say migraines should be treated early and aggressively; it appears that very frequent migraine attacks physically change the brainstem’s pain centers, which can lead to constant headaches.
Some of the drugs that fight epilepsy also prevent migraines–which makes sense, since they’re designed to suppress abnormal neuron firings. As well, drugs called “triptans” help by shrinking inflamed blood vessels. Women are often helped by adjusting birth control or hormone therapy to stabilize estrogen levels.
Of course, migraines aren’t the only headaches that people suffer. Among non-migraine headaches, the most common are tension headaches, usually caused by stress, fatigue or too little (or too much) sleep, but also triggered by bad posture, teeth-grinding and even gum-chewing. Often the muscles in the upper neck feel knotted: it’s not known whether this causes the pain directly or whether the tight muscles bring on the headache by restricting.
Vascular headaches are caused by abnormal blood flow in the brain. One common type is the cluster headache, which most often occurs in men. Cluster headaches are short, severe attacks of pain centered over one eye that may recur several times a day for several months. The pain may go away, but return months or years later. Cluster headaches are sometimes misdiagnosed as a sinus disorder, because they’re usually accompanied by tearing, nasal congestion and a runny nose. Their exact cause isn’t clear.
Then there’s the “ice-cream” headache. Although, again, the exact cause isn’t clear, the best guess is that eating something icy causes blood vessels in the roof of the mouth to contract, which dilates the vessels higher in the head.
For a long time doctors thought that migraine sufferers were most susceptible to ice-cream headaches, and that eating something cold could even trigger an attack. To test that, London Migraine Clinic researchers fed vanilla ice cream to 70 migraine patients and 50 medical students. Only 17 percent of the migraine patients suffered a headache while 46 percent of the medical students did. So, migraine sufferers, enjoy that slurpee without fear!
And the next time a migraine strikes, comfort yourself with the thought that now that scientists better understand what causes migraines, improved treatments could be on the way.