Migraine is a type of headache marked by severe head pain lasting several hours or more.
Description
Migraine is an intense and often debilitating type of headache. The term migraine is derived from the Greek word hemikrania, meaning "half the head," because the classic migraine headache affects only one side of the person's head. Migraines affect as many as 24 million people in the United States, and are responsible for billions of dollars in lost work, poor job performance, and direct medical costs. Approximately 18% of women and 6% of men experience at least one migraine attack per year. Currently, one American in 11 now suffers from migraines, more than three times as many are women, with most of them being between the ages of 30 and 49. Migraines often begin in adolescence, and are rare after age 60.
Two types of migraine are recognized. Eighty percent of migraine sufferers experience "migraine without aura" (common migraine). In "migraine with aura," or classic migraine, the pain is preceded or accompanied by visual or other sensory disturbances, including hallucinations, partial obstruction of the visual field, numbness or tingling, or a feeling of heaviness. Symptoms are often most prominent on one side of the head or body, and may begin as early as 72 hours before the onset of pain.
Causes
The physiological basis of migraine has proved difficult to uncover. There are a multitude of potential triggers for a migraine attack, and recognizing one's own set of triggers is the key to prevention.
PHYSIOLOGY. The most widely accepted hypothesis of migraine suggests that a migraine attack is precipitated when pain-sensing nerve cells in the brain (called nociceptors) release chemicals called neuropeptides. At least one of the neurotransmitters, substance P, increases the pain sensitivity of nearby nociceptors. This process is called sensitization.
Other neuropeptides act on the smooth muscle surrounding cranial blood vessels. This smooth muscle regulates blood flow in the brain by relaxing or contracting, thus dilating (enlarging) or constricting the enclosed blood vessels. At the onset of a migraine headache, neuropeptides are thought to cause muscle relaxation, allowing vessel dilation and increased blood flow. Other neuropeptides increase the leakiness of cranial vessels, allowing fluid leak, and promote inflammation and tissue swelling. The pain of migraine is thought to result from this combination of increased pain sensitivity, tissue and vessel swelling, and inflammation. The aura seen during a migraine may be related to constriction in the blood vessels that dilate in the headache phase.
GENETICS. Susceptibility to some types of migraine is inherited. A child of a migraine sufferer has as much as a 50% chance of developing migraines. If both parents are affected, the chance rises to 70%. In 2002, a team of Australian researchers identified a region on human chromosome 1 that influences susceptibility to migraine. It is likely that more than one gene is involved in the inherited forms of the disorder. Many cases of migraine, however, have no obvious familial basis. It is likely that the genes that are involved set the stage for migraine, and that full development requires environmental influences, as well.
Two groups of Italian researchers have recently identified two loci on human chromosomes 1 and 14 respectively that are linked to migraine headaches. The locus on chromosome 1q23 has been linked to familial hemiplegic migraine type 2, while the locus on chromosome 14q21 is associated with migraine without aura.
TRIGGERS. A wide variety of foods, drugs, environmental cues, and personal events are known to trigger migraines. It is not known how most triggers set off the events of migraine, nor why individual migraine sufferers are affected by particular triggers but not others.
Migraine without aura may be preceded by elevations in mood or energy level for up to 24 hours before the attack. Other pre-migraine symptoms may include fatigue, depression, and excessive yawning.
Aura most often begins with shimmering, jagged arcs of white or colored light progressing over the visual field in the course of 10–20 minutes. This may be preceded or replaced by dark areas or other visual disturbances. Numbness and tingling are common, especially of the face and hands. These sensations may spread, and may be accompanied by a sensation of weakness or heaviness in the affected limb.
Migraine pain is often present only on one side of the head, although it may involve both, or switch sides during attacks. The pain is usually throbbing, and may range from mild to incapacitating. It is often accompanied by nausea or vomiting, painful sensitivity to light and sound, and intolerance of food or odors. Blurred vision is also common.
The pain tends to intensify over the first 30 minutes to several hours, and may last from several hours to a day, or longer. Afterward, the affected person is usually weary, and sensitive to sudden head movements.
Diagnosis
Ideally, migraine is diagnosed by a careful medical history. Unfortunately, migraine is underdiagnosed because many doctors tend to minimize its symptoms as "just a headache." According to a 2003 study, 64% of migraine patients in the United Kingdom and 77% of those in the United States never receive a correct medical diagnosis for their headaches.
So far, laboratory tests and such imaging studies as computed tomography (CT scan) or magnetic resonance imaging (MRI) scans have not been useful for identifying migraine. However, these tests may be necessary to rule out a brain tumor or other structural causes of migraine headache in some patients.
Treatment
At the onset of symptoms, the migraine sufferer should seek out a quiet, dark room and attempt to sleep. Placing a cold, damp cloth or a cold pack on the fore-head may help. Additionally, tying a headband tightly around the head can relieve migraines.
Migraine headaches are often linked with food allergies or intolerances. Identification and elimination of the offending food or foods can decrease the frequency of migraines and/or alleviate these headaches altogether.
Alternative treatments for migraine include:
Acupressure. Pressing on the Gates of Consciousness (GB 20) points can relieve migraine.
Acupuncture. A National Institutes of Health (NIH) panel concluded that acupuncture may be a useful treatment for headache.
Autogenic training. Autogenic training is a form of self-hypnosis developed in Germany in the 1930s that has been shown in several studies to relieve the pain of migraine.
Hydrotherapy. Contrast showers, in which a short hot shower is followed by a longer cold shower, may halt an oncoming migraine. A hot enema can temporarily relieve migraine pain.
Naturopathy. Migraine headaches are one of the most common reasons for consulting naturopathic practitioners. Naturopaths typically treat migraine with a combination of nutritional therapy and mind/body techniques.
Sumatriptan and other triptan drugs (zolmitriptan, rizatriptan, naratriptan, almotriptan, and frovatriptan) should not be taken by people with any kind of vascular disease because they cause coronary artery narrowing. Otherwise these drugs have been shown to be very safe.
Continued use of some antimigraine drugs can lead to "rebound headache," marked by frequent or chronic headaches, especially in the early morning hours. Rebound headache can be avoided by using antimigraine drugs under a doctor's supervision, with the minimum dose necessary to treat symptoms. Tizanidine (Zanaflex) has been reported to be effective in treating rebound headaches when taken together with an NSAID.
Expected results
Most people can control migraines through recognizing and avoiding triggers, and by using effective treatments. Some people with severe migraines do not respond to preventive or drug therapy. Migraines usually wane in intensity by age 60 and beyond.
Prevention
The frequency of migraine headaches may be lessened by avoiding triggers. It is useful to track these triggers by keeping a headache journal.
One substance that is being studied as a possible migraine preventive is coenzyme Q10, a compound used by cells to produce energy needed for cell growth and maintenance. Coenzyme Q10 has been studied as a possible complementary treatment for cancer. Its use in preventing migraines is encouraging and merits further study.
A study published in early 2003 reported that three drugs currently used to treat disorders of muscle tone are being explored as possible preventive treatments for migraine. They are botulinum toxin type A (Botox), baclofen (Lioresal), and tizanidine (Zanaflex). Early results of open trials of these medications are positive.
A natural preparation made from butterbur root (Petasites hybridus) has been sold in Germany since the 1970s as a migraine preventive under the trade name Petadolex. Petadolex has been available in the United States since December 1998 and has passed several clinical safety and postmarketing surveillance trials.
Other possible preventive measures include: eating at regular times, not skipping meals, reducing the use of caffeine and pain-relievers, restricting physical exertion (especially on hot days), and keeping regular sleep hours, but not oversleeping. Other measures include:
Aerobic exercise, which can reduce the frequency of migraines.
Biofeedback thermal control was found to be as effective as medications in preventing migraines.
Celery juice consumed twice daily may help to prevent migraines.
Feverfew was shown to reduce the severity and frequency of migraines. This herb should not, however, be used during pregnancy or by people taking blood-thinning medications.
Supplementation with magnesium and riboflavin was shown to prevent migraines.
BOOKS
American Council on Headache Education. Migraine: The Complete Guide. New York: Dell, 1994.
"Migraine. " Section 14, Chapter 168 in The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 1999.
Pelletier, Kenneth R., MD. The Best Alternative Medicine, Part II, "CAM Therapies for Specific Conditions: Headaches." New York: Simon & Schuster, 2002.
PERIODICALS
Bendtsen, L. "Sensitization: Its Role in Primary Headache." Current Opinion in Investigational Drugs 3 (March 2002): 449–453.
Corbo, J. "The Role of Anticonvulsants in Preventive Migraine Therapy." Current Pain and Headache Reports 7 (February 2003): 63–66.
Danesch, U., and R. Rittinghausen. "Safety of a Patented Special Butterbur Root Extract for Migraine Prevention." Headache 43 (January 2003): 76–78.
Diamond, S., and R. Wenzel. "Practical Approaches to Migraine Management." CNS Drugs 16 (2002): 385–403.
Freitag, F. G. "Preventative Treatment for Migraine and Tension-Type headaches : Do Drugs Having Effects on Muscle Spasm and Tone Have a Role?" CNS Drugs 17 (2003): 373–381.
Lea, R. A., A. G. Shepherd, R. P. Curtain, et al. "A Typical Migraine Susceptibility Region Localizes to Chromosome 1q31." Neurogenetics 4 (March 2002): 17–22.
Lipton, R. B., A. I. Scher, T. J. Steiner, et al. "Patterns of Health Care Utilization for Migraine in England and in the United States." Neurology 60 (February 11, 2003): 441–448.
Marconi, R., M. De Fusco, P. Aridon, et al. "Familial Hemiplegic Migraine Type 2 is Linked to 0.9Mb Region on Chromosome 1q23" Annals of Neurology 53 (March 2003): 376–381.
Pryse–Phillips, William E.M., et al. "Guidelines for the Nonpharmacologic Management of Migraine in Clinical Practice." Canadian Medical Association Journal 159 (July 14, 1998): 47–54.
Rozen, T. D., M. L. Oshinsky, C. A. Gebeline, et al. "Open Label Trial of Coenzyme Q10 as a Migraine Preventive." Cephalalgia 22 (March 2002): 137–141.
Sheftell, F. D., and S. J. Tepper. "New Paradigms in the Recognition and Acute Treatment of Migraine." Headache 42 (January 2002): 58–69.
Sinclair, Steven. "Migraine Headaches: Nutritional, Botanical and Other Alternative Approaches." Alternative Medicine Review 4 (1999): 86–95.
Soragna, D., A. Vettori, G. Carraro, et al. "A Locus for Migraine Without Aura Maps on Chromosome 14q21.2-q22.3." American Journal of Human Genetics 72 (January 2003): 161–167.
Stetter, F., and S. Kupper. "Autogenic Training: A Meta-Analysis of Clinical Outcome Studies." Applied Psychophysiology and Biofeedback 27 (March 2002): 45–98.
Tepper, S. J., and D. Millson. "Safety Profile of the Triptans." Expert Opinion on Drug Safety 2 (March 2003): 123–132.
ORGANIZATIONS
American Council for Headache Education. 19 Mantua Road, Mt. Royal, NJ 08061. (609) 423-0043 or (800) 255-2243. <http://www.achenet.org>.
National Headache Foundation. 428 West St. James Place, Chicago, IL 60614. (773) 388-6399 or (800) 843-2256. <http://www.headaches.org>.
U. S. Food and Drug Administration (FDA). 5600 Fishers Lane, Rockville, MD 20857. (888) 463-6332. <http://www.fda.gov>.
