Migraine Headache

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Migraine Headache

Definition

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. 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. More than three million women and one million men have one or more severe headaches every month. 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 and symptoms

Causes

The physiological basis of migraine has proved difficult to uncover. Genetics appear to play a part for many, but not all, people with migraine. 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 other nearby nociceptors.

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 constricting the enclosed blood vessels and stimulating adjacent pain receptors. 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 though 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.

Common food triggers include:

cheese
alcohol
caffeine products, and caffeine withdrawal
chocolate
intensely sweet foods

dairy products
fermented or pickled foods
citrus fruits
nuts
processed foods, especially those containing nitrites, sulfites, or monosodium glutamate (msg)

Environmental and event-related triggers include:

stress or time pressure
menstrual periods, menopause
sleep changes or disturbances, oversleeping
prolonged overexertion or uncomfortable posture
hunger or fasting
odors, smoke, or perfume
strong glare or flashing lights

Drugs which may trigger migraine include:

oral contraceptives
estrogen replacement therapy
nitrates
theophylline
reserpine
nifedipine
indomethicin
cimetidine
decongestant overuse
analgesic overuse
benzodiazepine withdrawal

Symptoms

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 is 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.

The pain of migraine 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 common.

Migraine 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

Once a migraine begins, the person will usually seek out a dark, quiet room to lessen painful stimuli. Several drugs may be used to reduce the pain and severity of the attack.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are helpful for early and mild headache. NSAIDs include acetaminophen, ibuprofen, naproxen, and others. A recent study concluded that a combination of acetaminophen, aspirin, and caffeine could effectively relieve symptoms for many migraine patients. One such over-the-counter preparation is available as Exedrin Migraine.

More severe or unresponsive attacks may be treated with drugs that act on serotonin receptors in the smooth muscle surrounding cranial blood vessels. Serotonin, also known as 5-hydroxytryptamine, constricts these vessels, relieving migraine pain. Drugs that mimic serotonin and bind to these receptors have the same effect. The oldest of them is ergotamine, a derivative of a common grain fungus. Ergotamine and dihydroergotamine are used for both acute and preventive treatment. Derivatives with fewer side effects have come onto the market in the past decade, including sumatriptan (Imitrex). Some of these drugs are available as nasal sprays, intramuscular injections, or rectal suppositories for patients in whom vomiting precludes oral administration. Other drugs used for acute attacks include meperidine and metoclopramide.

Studies are showing that rizatriptan is a promising drug for the treatment of migraines. One study showed that 10mg of rizatriptan provided relief to 90% of the patients in the study group and kept 50% of them pain-free 2 hours after taking the medication. Sumatriptan has been on the market since 1993, while rizatriptan became available in 1998.

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.

Alternative treatments

Alternative treatments are aimed at prevention of migraine. 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. Herbal therapy with feverfew (Chrysanthemum parthenium ) may lessen the frequency of attacks. Learning to increase the flow of blood to the extremities through biofeedback training may allow a patient to prevent some of the vascular changes once a migraine begins. During a migraine, keep the lights low; put the feet in a tub of hot water and place a cold cloth on the occipital region (the back of the head). This treatment draws the blood to the feet and decreases the pressure in the head.

Prognosis

Most people with migraines can bring their attacks under control through recognizing and avoiding triggers, and by use of appropriate drugs when migraine occurs. 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 may be lessened by avoiding triggers. It is useful to keep a headache journal, recording the particulars and noting possible triggers for each attack. Specific measures which may help include:

Eating at regular times, and not skipping meals.
Reducing the use of caffeine and pain-relievers.
Restricting physical exertion, especially on hot days.
Keeping regular sleep hours, but not oversleeping.
Managing one's time efficiently in order to avoid stress at work and home.

Some drugs can be used for migraine prevention, including specific members of these drug classes:

beta blockers
tricyclic antidepressants
calcium channel blockers
selective serotinin reuptake inhibitors (SSRIs)
monoamine oxidase inhibitors (MAOIs)
serotonin antagonists

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.

KEY TERMS

Aura— A group of visual or other sensations that precedes the onset of a migraine attack.

Coenzyme Q₁₀— A substance used by cells in the human body to produce energy for cell maintenance and growth. It is being studied as a possible preventive for migraine headaches.

Nociceptor— A specialized type of nerve cell that senses pain.

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.

Anti-epileptic drugs, which are also known as anticonvulsants, are also being studied as possible migraine preventives. As of 2003, sodium valproate (Epilim) is the only drug approved by the Food and Drug Administration (FDA) for prevention of migraine. Such newer anticonvulsants as gabapentin (Neurontin) and topiramate (Topamax) are presently being evaluated as migraine preventives.

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.

Resources

BOOKS

Beers, Mark H., MD, and Robert Berkow, MD, editors. "Migraine." Section 14, Chapter 168. In The Merck Manual of Diagnosis and Therapy. Whitehouse Station, NJ: Merck Research Laboratories, 2004.

Pelletier, Kenneth R., MD. The Best Alternative Medicine, Part II, "CAM Therapies for Specific Conditions: Headaches." New York: Simon & Schuster, 2002.

Rakel, Robert. Conn's Current Therapy: Latest Approved Methods of Treatment for the Practicing Physician. Philadelphia: W.B. Saunders Company, 2001.

Tierney, Lawrence, et al. Current Medical Diagnosis and Treatment. Los Altos, CA: Lange Medical Publications, 2001.

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.

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.

Tepper, S. J., and D. Millson. "Safety Profile of the Triptans." Expert Opinion on Drug Safety 2 (March 2003): 123-132.