Headache

Definition

Headache is a pain in the head and neck region that may be either a disorder in its own right or a symptom of an underlying medical condition or disease. The medical term for headache is cephalalgia. Headaches are one of the most common and universal human ailments, described in the Bible as well as in medical writings from ancient Egypt, Babylonia, Greece, Rome, India, and China. Severe chronic headaches were once treated by the oldest known surgical procedure, known as trepanning or trephining, in which the surgeon drilled a hole as large as 1–2 in diameter in the patient's skull without benefit of anesthesia. Evidence of trepanning has been found in skulls from Cro-Magnon people that are about 40,000 years old.

Description

Contemporary doctors divide headaches into two large categories, primary and secondary, according to guidelines established by the International Headache Society (IHS) in 1988 and revised for republication in 2004. Primary headaches are those that are not caused by an underlying medical condition. There are three types of primary headaches: migraine, cluster, and tension headaches. More than 90% of all headaches are primary headaches. Secondary headaches are caused by disease or medical condition; they account for fewer than 10% of all headaches.

Primary headaches

MIGRAINE HEADACHES Migraine headaches are characterized by throbbing or pulsating pain of moderate or severe intensity lasting from four hours to as long as three days. The pain is typically felt on one side of the head; in fact, the English word "migraine" is a combination of two Greek words that mean "half" and "head." Migraine headaches become worse with physical activity and are often accompanied by nausea and vomiting. In addition, patients with migraine headaches are hypersensitive to lights, sounds, and odors.

The two most common types of migraines are known as classic and common migraine, respectively. Classic migraine, which accounts for 10–20% of the cases of migraine, is distinguished by a brief period of warning symptoms 10–60 minutes before an acute attack. This prodrome, which is known as an aura, may include such symptoms as seeing flashing lights or zigzag patterns, temporary loss of vision, difficulty speaking, weakness in an arm or leg, and tingling sensations in the face or hands. Common migraine is not preceded by an aura, although some patients experience mood changes, unusual tiredness, or fluid retention shortly before an attack. An attack of common migraine may include diarrhea and frequent urination, as well as nausea and vomiting.

Less common types of migraines include hemiplegic migraine, characterized by temporary paralysis on one side of the body; ophthalmoplegic migraine, in which the pain is felt in the area around the eye; basilar artery migraine, which involves a major artery at the base of the brain and primarily affects young women; and headache-free migraine, which is characterized by the gastrointestinal and visual symptoms of classic migraine, but does not involve head pain.

CLUSTER HEADACHES Cluster headaches are recurrent brief attacks of sudden and severe pain on one side of the head, usually most intense in the area around the eye. Other names for these headaches include histamine cephalalgia, Horton neuralgia, or erythromelalgia. Cluster headaches may last between five minutes and three hours; they may occur once every other day or as often as eight times per day. The IHS classifies cluster headaches as either episodic or chronic. Episodic cluster headaches occur over periods lasting from seven days to one year, with the clusters separated by headache-free intervals of at least two weeks. The average length of a cluster ranges between two weeks and three months. Chronic cluster headaches occur over a period longer than a year without a headache-free interval, or with pain-free intervals that are shorter than two weeks.

The pain of a cluster headache is excruciating; some patients describe it as severe enough to make them consider suicide. Patients with cluster headaches are restless; they may pace the floor, weep, rock back and forth, or bang their heads against a wall in desperation to stop the pain. In addition to severe pain, patients with cluster headaches often have a runny or congested nose, watery or inflamed eyes, drooping eyelids, swelling in the area of the eyebrows, and heavy facial perspiration. Because of the nasal symptoms and the relative rarity of cluster headaches, these episodes have sometimes been misdiagnosed as sinusitis.

TENSION HEADACHES Tension headaches are the most common headaches in the general population; other names for them include muscle contraction headache, ordinary headache, psychomyogenic headache, and stress headache. The IHS classifies tension headaches as either episodic or chronic; episodic tension headaches occur 15 or fewer times per month, whereas chronic tension headaches occur on 15 or more days per month over a period of six months or longer.

Tension headaches rarely last more than a few hours; 82% resolve in less than a day. The patient will usually describe the pain of a tension headache as mild to moderate in severity. The doctor will not find anything abnormal in the course of a general physical or neurological examination, although sore or tense areas (trigger points) in the

muscles of the patient's forehead, neck, or upper shoulder area may be detected.

REBOUND HEADACHES Rebound headaches, which are also known as analgesic-abuse headaches, are a subtype of primary headache caused by overuse of headache drugs. They may be associated with medications taken for tension and migraine headaches.

Secondary headaches

Secondary headaches, which are caused by diseases or disorders, are categorized as either traction or inflammatory headaches. Traction headaches result from the pulling, stretching, or displacing of structures that are sensitive to pain, as when a brain tumor presses on the outer layer of nerve tissue that covers the brain. Inflammatory headaches are caused by infectious diseases of the ears, teeth, sinuses, or other parts of the head.

Major causes of secondary headaches include the following:

• Brain tumors. Headaches associated with brain tumors usually begin as episodic nighttime headaches that are accompanied by projectile vomiting. The headaches may become continuous over time, and usually get worse if the patient coughs, sneezes, bears down while using the toilet, or does something else that increases the pressure inside the head.
• Meningitis. Meningitis is an inflammation of the meninges , the three layers of membranes that cover the brain and spinal cord. Meningitis is usually caused by bacteria or viruses, and may produce chronic headaches.
• Head trauma. Patients may complain of headaches as well as memory problems, general irritability, and fatigue for months or even years after a head injury. These symptoms are sometimes grouped together as post-concussion syndrome. In some cases, a blow on the head may cause some blood vessels to rupture and produce a hematoma, or mass of blood that displaces brain tissue, and can cause seizures or weakness as well as headaches.
• Temporal arteritis . First described in 1890, temporal arteritis is an inflammation of the temporal artery that most commonly affects people over 50. In addition to headache, patients with temporal arteritis may have fever, loss of appetite, and blurring or loss of vision. Temporal arteritis is treated with steroid medications.
• Stroke . Headaches may be associated with several conditions that may lead to stroke, including high blood pressure and heart disease. Headaches may also result from completed stroke or from the mini-strokes known as transient ischemic attacks, or TIAs.
• Lumbar puncture. About 25% of patients who undergo a lumbar puncture (spinal tap) develop a headache from the lowered cerebrospinal fluid pressure around the brain and spinal cord. Lumbar puncture headaches usually go away on their own after a few hours.
• Sinus infections. Acute sinusitis is characterized by fluid buildup inside sinus cavities inflamed by a bacterial or viral infection. Chronic sinusitis usually results from an allergic reaction to smoke, dust, animal fur, or similar irritants.
• Referred pain. This type of pain is felt in a part of the body at a distance from the injured or diseased area. Headache pain may be referred from diseased teeth; disks in the cervical spine that have been damaged by spondylosis (degeneration of the spinal vertebrae caused by osteoarthritis); or the temporomandibular joint, the small joint in front of the ear where the lower jaw is attached to the skull.
• Idiopathic intracranial hypertension. Also known as pseudotumor cerebri , this disorder is caused by increased pressure inside the skull in the absence of any abnormality of the central nervous system or blockage in the flow of the cerebrospinal fluid. In addition to headache, patients with this disorder experience diplopia (seeing double) and other visual symptoms.

Demographics

Headaches in general are very common in the adult population in North America. The American Council for Headache Education (ACHE) estimates that 95% of women and 90% of men in the United States and Canada have had at least one headache in the past 12 months. Most of these are tension headaches. Tension headaches may begin in childhood in some patients, but most commonly start in adolescence or the early 20s. The gender ratio for episodic tension headaches is about 1.4 F:1 M; for chronic tension headaches, 1.9 F:1 M.

Migraine and cluster headaches have distinctive demographic patterns. Migraine headaches are less common than tension headaches, affecting about 11% of the population in the United States and 15% in Canada. Several studies done in the United Kingdom and the United States, however, indicate that doctors tend to underdiagnose migraine headache; thus the true number of patients with migraine may be considerably higher than the usual statistics indicate. Migraines are a major economic burden; it is estimated that the annual cost of time lost from work due to migraines in the United States alone is $17.2 billion. Most people who experience migraines have their first episode in childhood or adolescence, although some experience their first migraine after age 20. Migraines occur most frequently in adults between the ages of 25 and 55; the gender ratio is about 3 F:1 M. Although migraine headaches occur in people of all races and ethnic groups, they are thought to affect Caucasians more often than African or Asian Americans.

Currently, migraine is the only type of primary headache known to run in families. A child with one parent affected by migraines has a 50% chance of developing migraines as an adult; if both parents are affected, the risk rises to 70%. Although geneticists think that a number of different genes are involved in transmitting a susceptibility to migraine, they have recently identified two specific 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 common migraine.

Cluster headaches are the least common type of primary headaches, affecting about 0.4% of adult males in the United States and 0.08% of adult females. The gender ratio is 5–7.5 M:1 F. Cluster headaches occur most commonly in adults between the ages of 20 and 40. It is not currently known whether cluster headaches are more common in some racial or ethnic groups than in others; however, many patients with cluster headaches have a history of face or head trauma.

The demographics of secondary headaches vary depending on the disease or disorder that causes the headache.

Causes and symptoms

Causes

PHYSICAL A person feels headache pain when specialized nerve endings known as nociceptors are stimulated by pressure on or injury to any of the pain-sensitive structures of the head. Most nociceptors in humans are located in the skin or in the walls of blood vessels and internal organs; the bones of the skull and the brain itself do not contain nociceptors.

The specific parts of the head that are sensitive to pain include:

• the skin that covers the skull and cervical spine
• the 5th, 9th, and 10th cranial nerves and the nerves that supply the upper part of the neck the venous sinuses inside the head
• the large arteries at the base of the brain
• the large arteries that supply the dura mater, which is the outermost of the three meninges (membranes) that cover the brain and spinal cord
• the portion of the dura mater at the base of the skull

Tension headaches typically result from tightening of the muscles of the face, neck, and scalp as a result of emotional stress; physical postures that cause the head and neck muscles to tense (e.g., holding a phone against the ear with one's shoulder); depression or anxiety; temporomandibular joint dysfunction (TMJ); or degenerative arthritis of the neck. The tense muscles put pressure on the walls of the blood vessels that supply the neck and head, which stimulates the nociceptors in the tissues that line the blood vessels. In addition, the nociceptors in patients with chronic tension headaches appear to be abnormally sensitive to stimulation.

The pathophysiology of migraine headaches has been debated among doctors since the 1940s. Some researchers think that migraines are the end result of a magnesium deficiency in the brain or of hypersensitivity to a neuro-transmitter known as dopamine. Another theory holds that certain nerve cells in the brain cortex become unusually excitable and depolarize (lose their electrical potential) spontaneously, releasing potassium and glutamate, an amino acid. These substances then depolarize nearby nerve cells, resulting in a chain reaction known as cortical-spreading depression (CSD). CSD then leads to changes in the amount of blood flowing through the blood vessels and stimulation of their nociceptors, resulting in severe headache. More recently, the discovery of specific genes associated with migraine indicates that genetic mutations are responsible for the abnormal excitability of the nerve cells in the brains of patients with migraine.

Little is known about the causes of cluster headaches or changes in the central nervous system that produce them.

PSYCHOLOGICAL Chronic headaches are often associated with anxiety, depression, or a specific group of mental disorders known as somatoform disorders. These disorders include hypochondriasis and pain disorder; they are characterized by physical symptoms (frequently headache) that suggest that the patient has a general medical condition, but there is no diagnosable disease or disorder that fully accounts for the patient's symptoms. The relationship between psychological and physical factors in headaches is complex in that headaches may be either the cause or result of emotional disturbances, or both. Some patients find that chronic headaches disappear completely after a stressful family- or job-related situation has been resolved.

Warning symptoms

Most headaches are not associated with serious or life-threatening illnesses. Patients should, however, immediately call their primary physician if they have any of the following symptoms:

• three or more headaches per week
• need for a pain reliever every day or almost every day
• need for greater than recommended doses of over-thecounter medications (OTCs)
• stiff neck or fever accompanying the headache
• shortness of breath, hearing problems, blurry vision, or severe sore throat
• dizziness, weakness, slurred speech, mental confusion, or drowsiness headache following a head injury that is not relieved by OTCs
• headache triggered by exercise , coughing, sexual activity, or bending over
• persistent or violent vomiting
• change in the character of the headaches—for example, persistent severe headaches in a person who has previously had only mild headaches of brief duration
• recurrent headaches in a child
• recurrent severe headaches, beginning after age 50

Diagnosis

Patient history

The differential diagnosis of headaches begins with a complete patient history, including a family history. In many cases, a primary care physician can make the diagnosis on the basis of the history. The doctor will ask the patient about head injuries or surgery on the head; eye problems or disorders; sinus infections; dental problems or extensive oral surgery; and medications that the patient is taking regularly.

After taking the history, the doctor will ask the patient to describe the location and type of pain that he or she experiences during the headache. People who have tension headaches will typically describe the pain as "viselike," "tightening," "pressing," or as a steady or constant ache. Patients with migraine headaches, on the other hand, will usually say that the pain has a "throbbing" or "pulsating" character, while patients with cluster headaches describe the pain as "penetrating" or "piercing." About 85% of patients with tension headaches experience pain on both sides of the head, most commonly in the area around the forehead and temples. Patients with migraine or cluster headaches, however, are more likely to feel pain on only one side of the head.

Some primary care physicians give the patient a printed questionnaire that consists of 50–55 brief yes/no questions that cover such matters as the timing and frequency of the headaches; whether other family members have the same type of headache; whether the patient feels depressed; whether the headaches are related to changes in the weather; and so on. The answers to the questions will usually fall into a pattern that tells the doctor whether the patient has migraines, tension headaches, cluster headaches, or headaches with other causes. The doctor may also ask the patient to keep a headache diary to help identify foods, stress, lack of sleep, weather, and other factors that may trigger headaches.

It is possible for patients to have more than one type of headache. For example, patients with chronic tension headaches often have migraine headaches as well.

Physical examination

The physical examination helps the doctor identify other symptoms and signs that may be relevant to the diagnosis, such as fever; difficulty breathing; nausea or vomiting; stiff neck; changes in vision or hearing; watering or inflammation of the nose and eyes; evidence of head trauma; skin rashes or other indications of an infectious disease; and abnormalities in the structure or alignment of the patient's spinal column, teeth or jaw. In some cases, the doctor may refer the patient to a dentist, oral surgeon, or endodontist for a more detailed evaluation of the patient's mouth and jaw.

Special studies

Some laboratory tests are useful in identifying headaches caused by infections or by such disorders as anemia or thyroid disease. These tests include a complete blood count (CBC); erythrocyte sedimentation rate (ESR); and blood serum chemistry profile.

Patients who report visual disturbances and other neurologic symptoms may be given visual field tests and have the pressure of the fluid inside their eyes (intraocular pressure) tested to check for glaucoma. A lumbar puncture (spinal tap) may be done to confirm a diagnosis of idiopathic intracranial hypertension.

Imaging studies may include x rays of the sinuses to check for sinus infections; and CT or MRI scans, which are done to rule out brain tumors and cerebral aneurysms .

Patients whose symptoms cannot be fully explained by the results of physical examinations and tests may be referred to a psychiatrist for evaluation of psychological factors related to their headaches.

Treatment

Medical

TENSION HEADACHES Episodic tension headaches are usually relieved fairly rapidly by such over-the-counter analgesics as aspirin (300–600 mg every four hours), acetaminophen (650 mg every four hours), or another nonsteroidal anti-inflammatory drug (NSAID), usually ibuprofen (Advil) or naproxen (Naprosyn, Aleve). The doctor may prescribe a tricyclic antidepressant or benzodiazepine tranquilizer in addition to a pain reliever for patients with chronic tension headaches. A newer treatment for chronic tension headaches is botulinum toxin (Botox type A), which appears to work very well for some patients. As of 2003, however, Botox has not yet been evaluated in controlled multicenter studies as a treatment for chronic headaches; the data obtained so far are derived from case reports and open-label studies.

MIGRAINE HEADACHES Medications can be prescribed to prevent migraines as well as to treat the symptoms of an acute attack. Drugs that are given for migraine prophylaxis (to prevent or lower the frequency of migraine attacks) include tricyclic antidepressants, beta-blockers, and anti-epileptic drugs, which are also known as anti-convulsants . As of 2003, sodium valproate (Epilim) is the only anticonvulsant 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. Moreover, a new study reported that three drugs currently used to treat disorders of muscle tone are being explored as possible preventives for migraine—Botox, baclofen (Lioresal), and tizanidine (Zanaflex). Early results of open trials of these medications are positive.

Nonsteroidal anti-inflammatory drugs acetaminophen (Tylenol), ibuprofen (Motrin), and naproxen (Aleve) are helpful for early or mild migraines. More severe or unresponsive attacks may be treated with dihydroergota-mine; a group of drugs known as triptans; beta-blockers and calcium channel-blockers; antiseizure drugs; antidepressants (SSRIs); meperidine (Demerol); or metoclopramide (Reglan). Some of these are also available as nasal sprays, intramuscular injections, or rectal suppositories for patients with severe vomiting. Sumatriptan and the other triptan drugs (zolmitriptan, rizatriptan, naratriptan, almotriptan, and frovatriptan) should not be taken by patients with vascular disease, however, because they cause narrowing of the coronary arteries.

About 40% of all migraine attacks do not respond to treatment with triptans or any other medication. If the headache lasts longer than 72 hours—a condition known as status migrainosus—the patient may be given narcotic medications to bring on sleep and stop the attack. Patients with status migrainosus are often hospitalized because they are likely to be dehydrated from severe nausea and vomiting.

CLUSTER HEADACHES Medications that are given as prophylaxis for cluster headaches include verapamil (Calan, Isoptin, Verelan), which is a calcium channel blocker, and methysergide (Sansert), which is a derivative of ergot. A new study indicates that topiramate (Topamax), an anticonvulsant, is also effective in preventing cluster headaches. Sumatriptan (Imitrex) or indomethacin (Indameth, Indocin) may be prescribed to suppress an attack.

REBOUND HEADACHES Continued use of some pain relievers or antimigraine drugs can lead to rebound headaches, which may be frequent or chronic and often occur in the early morning hours. Rebound headache can be avoided by using antimigraine drugs or analgesics under a doctor's supervision, using only 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; Botox has also been used successfully in some patients.

Diet and lifestyle modifications

One measure that people can take to lower the risk of episodic tension headaches is to get enough sleep and eat nutritious meals at regular times. Skipping meals, using unbalanced fad diets to lose weight, and having insufficient or poor-quality sleep can bring on tension headaches. In fact, the common association of tension headaches with hunger, lack of sleep, heat, and sudden temperature extremes has led some researchers to suggest that headaches developed over the course of human evolution as an internal protective response to stress from the environment.

Changes in diet may be helpful to some patients with migraine, although some experts think that the role of foods in triggering migraines has been exaggerated. Women with migraines, however, often benefit by switching from oral contraceptives to another method of birth control or by discontinuing estrogen replacement therapy.

Patients with cluster headaches are advised to quit smoking and minimize their use of alcohol, because nicotine and alcohol appear to trigger cluster headaches. Currently, the precise connection between these chemicals and cluster attacks, however, is not completely understood.

Surgical

Headaches that are caused by brain tumors, post-injury hematomas, dental problems, or disorders affecting the spinal disks usually require surgical treatment. Surgery may also be used to treat cases of idiopathic intracranial hypertension that do not respond to treatment with steroids, repeated lumbar punctures, or weight reduction.

Some plastic surgeons have reported success in treating patients with chronic migraines by removing some muscle tissue near the eyebrows, cutting a branch of the trigeminal nerve, and repositioning the soft tissue around the temples.

Psychotherapy

Psychotherapy may be helpful to patients with chronic headaches by interrupting the "feedback loop" between emotional upset and the physical symptoms of headaches. One type of psychotherapy that has been shown to be effective is cognitive restructuring, an approach that teaches people to reframe the problems in their lives—that is, to change their conscious attitudes and responses to these stressors. Some psychotherapists teach relaxation techniques, biofeedback, or other approaches to stress management as well as cognitive restructuring.

Complementary and alternative (CAM) treatments

There are a number of different CAM treatments for headache, but most fall into two major groups: those intended as prophylaxis or pain relief, and those that reduce the patient's stress level.

CAM therapies intended to prevent headaches or relieve discomfort include:

• Feverfew (Tanacetum parthenium ). Feverfew is an herb related to the daisy that is traditionally used in England to prevent migraines. Published studies indicate that feverfew can reduce the frequency and intensity of migraines. It does not, however, relieve pain once the headache has begun.
• Butterbur root (Petasites hybridus ). Petadolex is a natural preparation made from butterbur root that has been sold in Germany since the 1970s as a migraine preventive. Petadolex has been available in the United States since December 1998.
• Brahmi (Bacopa monnieri ). Brahmi is a herb used in Ayurvedic medicine to treat headaches related to anxiety.
• Acupuncture . Studies funded by the National Center for Complementary and Alternative Medicine (NCCAM) have found that acupuncture is an effective treatment for headache pain in many patients.
• Naturopathy. Naturopaths include dietary advice and nutritional therapy in their approach to treatment, which is often effective for patients with episodic or chronic tension headaches.
• Chiropractic. Some patients with tension or migraine headaches find spinal manipulation effective in relieving their pain; however, no controlled studies of the long-term effectiveness of chiropractic in treating headaches have been done as of 2003.

CAM therapies that are reported to be effective in reducing emotional stress related to headaches include:

• yoga and t'ai chi
• prayer and meditation
• aromatherapy
• hydrotherapy, particularly whirlpool baths
• Swedish massage and shiatsu
• pet therapy
• humor therapy
• music therapy

Clinical trials

As of late 2003, there were three National Institutes of Health (NIH) trials recruiting patients with headaches: a study evaluating a new intranasal drug (civamide) for cluster headaches; a study of the effectiveness of biofeedback and relaxation training in patients with chronic migraine or tension headaches; and a study of migraine headaches in children.

Prognosis

The prognosis of primary headaches varies. Episodic tension headaches usually resolve completely in less than a day without affecting the patient's overall health. According to NIH statistics, 90% of patients with chronic tension or cluster headaches can be helped. The prognosis for patients with migraines, however, depends on whether the patient has one or more of the other disorders that are associated with migraine. These disorders include Tourette's syndrome, epilepsy , ischemic stroke, hereditary essential tremor, depression, anxiety, and others. For example, migraine with aura increases a person's risk of ischemic stroke by a factor of six.

The prognosis of secondary headaches depends on the seriousness and severity of their cause.

Resources

BOOKS

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revision. Washington, DC: American Psychiatric Association, 2000.

" Headache." The Merck Manual of Diagnosis and Therapy. Edited by Mark H. Beers and Robert Berkow. Whitehouse Station, NJ: Merck Research Laboratories, 2002.

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

"Psychogenic Pain Syndromes." The Merck Manual of Diagnosis and Therapy. Edited by Mark H. Beers and Robert Berkow. Whitehouse Station, NJ: Merck Research Laboratories, 2002.

PERIODICALS

Argoff, C. E. "The Use of Botulinum Toxins for Chronic Pain and Headaches." Current Treatment Options in Neurology 5 (November 2003): 483–492.

Astin, J. A., and E. Ernst. "The Effectiveness of Spinal Manipulation for the Treatment of Headache Disorders: A Systematic Review of Randomized Clinical Trials." Cephalalgia 22 (October 2002): 617–623.

Corbo, J. "The Role of Anticonvulsants in Preventive Migraine Therapy." Current Pain and Headache Reports 7 (February 2003): 63–66.

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.

Guyuron, B., T. Tucker, and J. Davis. "Surgical Treatment of Migraine Headaches." Plastic and Reconstructive Surgery 109 (June 2002): 2183–2189.

Headache Classification Subcommittee of the International Headache Society. "The International Classification of Headache Disorders," 2nd ed. Cephalalgia 24 (2004) (Supplement 1): 1–150.

Lainez, M. J., J. Pascual, A. M. Pascual, et al. "Topiramate in the Prophylactic Treatment of Cluster Headache." Headache 43 (July-August 2003): 784–789.

Lenaerts, M. E. "Cluster Headaches and Cluster Variants." Current Treatment Options in Neurology 5 (November 2003): 455–466.

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.

Mendizabai, Jorge, MD. "Cluster Headache." eMedicine, 26 September 2003. <http://www.emedicine.com/neuro/topic70.htm>.

Sahai, Soma, MD, Robert Cowan, MD, and David Y. Ko, MD. "Pathophysiology and Treatment of Migraine and Related Headache." eMedicine, April 30, 2002 (February 16, 2004). <http://www.emedicine.com/neuro/topic517.htm>.

Singh, Manish K., MD. "Muscle Contraction Tension Headache." eMedicine, October 5, 2001 (February 16, 2004). <http://www.emedicine.com/neuro/topic231.htm>.

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.

OTHER

Migraine Information Page. NINDS. 2003 (February 16, 2004). <http://www.ninds.nih.gov/health_and_medical/pubs/migraineupdate.htm>.

National Institute of Neurological Disorders and Stroke (NINDS). "Headache—Hope Through Research." Bethesda, MD: NINDS, 2001. (February 16, 2004.) <http://www.ninds.nih.gov/health_and_medical/pubs/headache_htr>.

ORGANIZATIONS

American Academy of Neurology (AAN). 1080 Montreal Avenue, Saint Paul, MN 55116. (651) 695-2717 or (800) 879-1960; Fax: (651) 695-2791. memberservices@aan.com. <http://www.aan.com>.

American Council for Headache Education (ACHE). 19 Mantua Road, Mt. Royal, NJ 08061. (856) 423-0258; Fax: (856) 423-0082. achehq@talley.com. <http://www.achenet.org>.

International Headache Society (IHS). Oakwood, 9 Willowmead Drive, Prestbury, Cheshire SK10 4BU, United Kingdom. +44 (0) 1625 828663; Fax: +44 (0) 1625 828494. rosemary@ihs.u-net.com. <http://216.25.100.131>.

National Headache Foundation. 820 North Orleans, Suite 217, Chicago, IL 60610. (773) 525-7357 or (888) NHF-5552. <http://www.headaches.org>.

NIH Neurological Institute. P. O. Box 5801, Bethesda, MD 20824. (301) 496-5751 or (800) 352-9424. <http://www.ninds.nih.gov>.

Rebecca J. Frey, PhD

Headache

Definition

A headache is a pain in the head and neck region that may be either a disorder in its own right or a symptom

of an underlying medical condition or disease. The medical term for headache is cephalalgia.

Description

Headaches are divided into two large categories, primary and secondary, according to guidelines established by the International Headache Society (IHS) in 1988 and revised for republication in 2004. Primary headaches—accounting for more than 90% of all headaches—are not caused by an underlying medical condition. There are three major types of primary headaches: migraine, cluster, and tension. Secondary headaches are caused by another disease or medical condition, and account for fewer than 10% of headaches.

Rebound headaches, also known as analgesic abuse headaches, are a subtype of primary headache caused by overuse of headache drugs. They may be associated with medications taken for tension or migraine headaches.

Secondary headaches are classified as either traction or inflammatory headaches. Traction headaches result from the pulling, pushing, or stretching of pain-sensitive structures, such as a brain tumor pressing upon the outer layer of tissue that covers the brain. Inflammatory headaches are caused by infectious diseases of the ears, teeth, sinuses, or other parts of the head.

Headaches are very common in the North American adult population. The American Council for Headache Education (ACHE) estimates that 95% of women and 90% of men in the United States and Canada have had at least one headache in the past 12 months. Most of these are tension headaches. Migraine headaches are less common, affecting about 11% of the population in the United States and 15% in Canada. Several studies indicate that doctors tend to underdiagnose migraine headaches; thus the true number of patients with migraines may be considerably higher than the reported statistics. Cluster headaches are the least common type of primary headaches, affecting about 0.4% of adult males in the United States and 0.08% of adult females. Cluster headaches occur most commonly in adults between the ages of 20 and 40.

It is possible for patients to suffer from more than one type of headache. For example, patients with chronic tension headaches often have migraine headaches as well.

Causes & symptoms

Causes

A person feels headache pain when specialized nerve endings, known as nociceptors, are stimulated by pressure on or injury to any of the pain-sensitive structures of the head. Most nociceptors in humans are located in the skin or on the walls of blood vessels and internal organs. The bones of the skull and the brain itself do not contain these specialized pain receptors. The parts of the head that are sensitive to pain include the skin that covers the skull and upper spine; the 5th, 9th, and 10th cranial nerves, and the nerves that supply the upper part of the neck; and the large arteries located at the base of the brain, as well as those that supply the membranes covering the brain and spinal cord.

Tension headaches typically result from tightening of the face, neck, and scalp muscles as a result of emotional stress; physical postures that cause the head and neck muscles to tense (e.g., holding a phone against the ear with one's shoulder); emotional depression or anxiety ; temporomandibular joint (TMJ) dysfunction; or arthritis of the neck. The tense muscles put pressure on the walls of the blood vessels that supply the neck and head, which stimulates the nociceptors in the tissues that line the blood vessels.

The causes of migraine headaches have been debated since the 1940s. Some researchers think that migraines are the end result of a magnesium deficiency in the brain, or of hypersensitivity to a neurotransmitter (brain chemical) known as dopamine. Another theory is that certain nerve cells in the brain become unusually excitable, setting off a chain reaction that leads to changes in the amount of blood flowing through the blood vessels and stimulation of their nociceptors. Specific genes associated with migraines were recently discovered. This finding suggests that genetic mutations may be responsible for the abnormal excitability of the nerve cells in the brains of patients with migraine headaches.

As of 2004, little is known about the causes of cluster headaches or changes in the central nervous system that produce them. Patients with cluster headaches are advised to quit smoking and minimize their use of alcohol because nicotine and alcohol appear to trigger these headaches. The precise connection between these chemicals and cluster attacks is not yet completely understood.

Symptoms

Tension headaches are less severe than other types of primary headache. They rarely last more than a few hours; 82% resolve in less than a day. Patients usually describe the pain of a tension headache as mild to moderate. The doctor will not find anything abnormal in the course of a general physical examination, although he or she may detect sore or tense areas (trigger points) in the muscles of the patient's forehead, neck, or upper shoulder area.

Migraine headaches are characterized by throbbing or pulsating pain of moderate or severe intensity lasting from four hours to as long as three days. The pain is typically felt on one side of the head; in fact, the English word "migraine" is a combination of two Greek words that mean "half" and "head." Migraine headaches worsen

with physical activity, and are often accompanied by nausea and vomiting . Patients with migraine headaches are hypersensitive to lights, sounds, and odors.

Cluster headaches are recurrent brief attacks of sudden and severe pain on one side of the head. The pain is usually most intense in the area around the eye. Cluster headaches may last between five minutes and three hours, and may occur once every other day or as often as eight times per day. Some patients describe it as severe enough to make them consider suicide. Patients may pace the floor, weep, rock back and forth, or bang their heads against a wall in desperate attempts to stop the pain. In addition to severe pain, patients often have a runny or congested nose, watery or inflamed eyes, drooping eyelids, swelling in the area of the eyebrows, and heavy facial perspiration. Because of the nasal symptoms and the relative rarity of cluster headaches, they are sometimes misdiagnosed as sinusitis.

Diagnosis

Patient history

The differential diagnosis of headaches begins with a careful patient history that includes information about head injuries or surgery on the head; eye problems or disorders; sinus infections ; dental problems or extensive oral surgery; and medications that the patient takes regularly. Some primary care physicians give the patient a printed questionnaire that consists of 50–55 brief questions covering such matters as the timing and frequency of the headaches; family history of the same type of headache; signs of depression; correlation between headaches and weather changes; and so on. The doctor may also ask the patient to keep a headache diary to help identify foods, stress, lack of sleep, weather, and other factors that may trigger the pain.

Physical examination

A physical examination helps the doctor identify signs and symptoms that may be relevant to the diagnosis such as fever ; difficulty breathing; nausea or vomiting; stiff neck; changes in vision or hearing; watering or inflammation of the nose and eyes; evidence of head trauma; skin rashes or other indications of an infectious disease; and abnormalities in the structure or alignment of the spinal column, teeth or jaw. In some cases, the doctor may refer the patient to a dentist or oral surgeon for a more detailed evaluation of the mouth and jaw.

Special tests and imaging studies

Laboratory tests are useful in identifying headaches caused by infections, anemia , or thyroid disease. These tests include a complete blood count (CBC); erythrocyte sedimentation rate (ESR); and blood serum chemistry profile. Patients who report visual disturbances and other neurologic symptoms may be given visual field tests and screened for glaucoma (a condition involving high fluid pressure inside the eye). Imaging studies may include x rays of the sinuses to check for infections; and CT or MRI scans, which can rule out brain tumors and cerebral aneurysms. Patients whose symptoms cannot be fully explained by the results of physical examinations and tests may be referred to a psychiatrist for evaluation of psychological factors related to their headaches.

Warning symptoms

There are warning signs associated with headache that indicate the need for prompt medical attention. Patients with any of the following symptoms should see a physician at once:

• Three or more headaches per week.
• Need for a headache pain reliever every day or almost every day.
• Need for greater than recommended doses of over-the-counter (OTC) headache medications.
• Headache accompanied by one-sided weakness, numbness, visual loss, speech difficulty, or other signs.
• Headache that becomes worse over a period of six months, especially if most prominent in the morning or if accompanied by neurological symptoms.
• Sudden onset of headache accompanied by fever and stiff neck.
• Change in the character of the headaches—for example, persistent severe headaches in a person who has previously had only mild headaches of brief duration.
• Recurrent headaches in a child.
• Recurrent severe headaches beginning after age 50.

Treatment

Alternative remedies can lessen the frequency and severity of headaches. Common treatments include:

• Acupressure. The stomach 3 and large intestine 4 points relieve sinus headaches.
• Acupuncture . A National Institutes of Health (NIH) panel concluded that acupuncture may be a useful treatment for headache.
• Aerobic exercise. Regular aerobic exercise reduces the frequency and intensity of headaches.
• Aromatherapy. Massage using the essential oils of lavender, rosemary , or peppermint relieves headache.
• Autogenic therapy. Headache may be relieved by learning to put oneself in a semi-hypnotic state.
• Chiropractic. Cervical manipulation may relieve tension headaches.
• Heat and/or cold. A hot shower or bath can ease tension headaches. Vascular headache may be relieved by placing an ice pack on the forehead, or the feet in hot water and a cold pack on the forehead (hydrotherapy treatment).
• Herbals. Feverfew (Chrysanthemum parthenium ) can be used for migraine; goldenseal (Hydrastis canadensis ) for sinus headache; valerian (Valeriana officinalis ), skullcap (Scutellaria lateriflora ), or passionflower (Passiflora incarnata ) for tension headache; and cayenne (in nostrils) for cluster headache. A German remedy made from butterbur root (Petasites hybridus ) is now available in the United States under the brand name Petadolex. The herb, Brahmi (Bacopa monnieri ), is used in Ayurvedic medicine to treat headaches related to anxiety.
• Holistic medicine. Headaches may be caused by constipation and liver malfunction. Apple-spinach juice relieves constipation, and a blend of carrot, beet, celery, and parsley juices treats the liver.
• Homeopathy. Remedies are chosen for each patient and may include Belladonna (throbbing headache), Bryonia (splitting headache), Kali bichromicum (sinus headache), and Nux vomica (tension headache with nausea and vomiting).
• Massage. Firm massage of the forehead, neck, and scalp may relieve headache.
• Osteopathy. Headache is treated with neuromuscular manipulation and massage of the head, neck, and upper back.
• Pressure. A headband tied tightly around the head may relieve migraines in some patients.
• Reflexology. Headache is treated using the solar plexus, ear, eye, and head points.
• Relaxation techniques. Meditation, biofeedback, and yoga may relieve headache.
• Supplements. Vitamins B₂ and B₁₂, niacin , and magnesium (a mineral) may help treat or prevent headache.
• Transcutaneous electrical nerve stimulation (TENS). This effective headache treatment electrically stimulates nerves and blocks pain transmission.
• Visualization. This relaxation technique controls the images in the mind, replacing negative thoughts and images with positive ones that enhance relaxation.

Allopathic treatment

Medical

Tension headaches are usually relieved fairly rapidly by such over-the-counter analgesics as aspirin (300–600 mg every four hours), acetaminophen (650 mg every four hours), or other nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (brands include Advil or Motrin) or naproxen (brands such as Naprosyn or Aleve). For patients with chronic tension headaches, the doctor may prescribe a tricyclic antidepressant or benzodiazepine tranquilizer in addition to a pain reliever. A newer treatment for chronic tension headaches is botulinum toxin (Botox type A), which appears to work quite well for some patients.

Nonsteroidal anti-inflammatory drugs, including acetaminophen (e.g. Tylenol), ibuprofen, and naproxen are helpful for early or mild migraines. More severe attacks may be treated with dihydroergotamine; a group of drugs known as triptans; beta-blockers and calcium channel-blockers; antiseizure drugs; antidepressants (SSRIs); meperidine (Demerol); or metoclopramide (Reglan). Some of these medications are also available as nasal sprays, intramuscular injections, or rectal suppositories for patients with severe vomiting.

Sumatriptan (known as the brand Imitrex) or indomethacin (Indameth or Indocin) may be prescribed to suppress a cluster headache.

Surgical

Headaches that are caused by brain tumors, head trauma, dental problems, or disorders affecting the spinal discs usually require surgical treatment. In addition, some plastic surgeons have reported success in treating chronic migraine patients by removing some muscle tissue near the eyebrows, cutting a branch of the trigeminal nerve, and repositioning the soft tissue around the temples (sides of the head).

Psychotherapy

Psychotherapy may be helpful to patients with chronic headaches by interrupting the "feedback loop" between emotional upset and the physical symptoms of headaches.

Expected results

The prognosis for primary headaches varies. Episodic tension headaches usually resolve completely in less than a day without affecting the patient's overall health. The long-term outlook for patients with migraines depends on whether they have one or more of the other disorders associated with migraine. These disorders include Tourette's syndrome, epilepsy , ischemic stroke , hereditary essential tremor, depression, anxiety, and others. For example, migraine with aura increases a person's risk of ischemic stroke by a factor of six.

The prognosis for secondary headaches depends on the seriousness and severity of the cause.

Prevention

Lifestyle modification is one measure that people can take to lower their risk of tension headaches. They should get enough sleep and eat nutritious meals at regular times. Skipping meals, using unbalanced fad diets to lose weight, and insufficient or poor-quality sleep can bring on tension headaches.

Some headaches may be prevented by avoiding substances and situations that trigger them, or by employing alternative therapies, such as yoga and regular exercise. Proper lighting may prevent headaches caused by eyestrain. Because food allergies are often linked with headaches, especially cluster strain headaches and migraines, identification and elimination of the allergycausing food(s) from the diet can be an important preventive measure. Women with migraines often benefit by switching from oral contraceptives to another method of birth control, or by discontinuing estrogen replacement therapy. Prophylactic treatments for migraine include prednisone, calcium channel blockers, and methysergide.

Resources

BOOKS

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4th ed., text revision. Washington, DC: American Psychiatric Association, 2000.

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

Rapoport, Alan M., and Fred D. Sheftell. Headache Disorders: A Management Guide for Practitioners. Philadelphia: W.B. Saunders Company, 1996.

Somerville, Robert. The Alternate Advisor: The Complete Guide to Natural Therapies and Alternative Treatments. Alexandria, VA: Time-Life Books, 1997.

Ying, Zhou Zhong, and Jin Hui De. Clinical Manual of Chinese Herbal Medicine and Acupuncture. New York: Churchill Livingston, 1997.

PERIODICALS

Guyuron, B., T. Tucker, and J. Davis. "Surgical Treatment of Migraine Headaches." Plastic and Reconstructive Surgery 109 (June 2002): 2183-9.

Headache Classification Subcommittee of the International Headache Society. "The International Classification of Headache Disorders," 2nd ed. Cephalalgia 24 (2004) (Supplement 1): 1–150.

Mendizabai, Jorge, M.D. "Cluster Headache." eMedicine, 26 September 2003. <http://www.emedicine.com/neuro/topic70.htm>.

Sahai, Soma, M.D., Robert Cowan, M.D., and David Y. Ko, M.D. "Pathophysiology and Treatment of Migraine and Related Headache." eMedicine, 30 April 2002. <http://www.emedicine.com/neuro/topic517.htm>.

Singh, Manish K., M.D. "Muscle Contraction Tension Headache." eMedicine, 5 October 2001. <http://www.emedicine.com/neuro/topic231.htm>.

Vernon, H., C. S. McDermaid, and C. Hagino. "Systematic Review of Randomized Clinical Trials of Complementary/Alternative Therapies in the Treatment of Tension-Type and Cervicogenic Headache." Complementary Therapies in Medicine. (1999): 142–55.

ORGANIZATIONS

American Council for Headache Education (ACHE). 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. (800) 843-2256. <http://www.headaches.org/>.

OTHER

National Institute of Neurological Disorders and Stroke (NINDS). "Headache—Hope Through Research." Bethesda, MD: NINDS, <http://www.ninds.nih.gov/health_and_medical/pubs/headache_htr>.

NINDS. "Migraine Information Page." Bethesda, MD: NINDS, 2003. <http://www.ninds.nih.gov/health_and_medical/pubs/migraineupdate.htm>.

Rebecca J. Frey, PhD

Headache

Definition

A headache involves pain in the head which can arise from many disorders or may be a disorder in and of itself.

Description

There are three types of primary headaches: tension-type (muscular contraction headache), migraine (vascular headaches), and cluster. Virtually everyone experiences a tension-type headache at some point. An estimated 18% of American women suffer migraines, compared to 6% of men. Cluster headaches affect fewer than 0.5% of the population, and men account for approximately 80% of all cases. Headaches caused by illness are secondary headaches and are not included in these numbers.

Approximately 40-45 million people in the United States suffer chronic headaches. Headaches have an enormous impact on society due to missed workdays and productivity losses.

Causes and symptoms

Traditional theories about headaches link tension-type headaches to muscle contraction, and migraine and cluster headaches to blood vessel dilation (swelling). Pain-sensitive structures in the head include blood vessel walls, membranous coverings of the brain, and scalp and neck muscles. Brain tissue itself has no sensitivity to pain. Therefore, headaches may result from contraction of the muscles of the scalp, face or neck; dilation of the blood vessels in the head; or brain swelling that stretches the brain's coverings. Involvement of specific nerves of the face and head may also cause characteristic headaches. Sinus inflammation is a common cause of headache. Keeping a headache diary may help link headaches to stressful occurrences, menstrual phases, food triggers, or medication.

Tension-type headaches are often brought on by stress, overexertion, loud noise, and other external factors. The typical tension-type headache is described as a tightening around the head and neck, and an accompanying dull ache.

Migraines are intense throbbing headaches occurring on one or both sides of the head, usually on one side. The pain is accompanied by other symptoms such as nausea, vomiting, blurred vision, and aversion to light, sound, and movement. Migraines often are triggered by food items, such as red wine, chocolate, and aged cheeses. For women, a hormonal connection is likely, since headaches occur at specific points in the menstrual cycle, with use of oral contraceptives, or the use of hormone replacement therapy after menopause. Research shows that a complex interaction of nerves and neurotransmitters in the brain act to cause migraine headaches.

Cluster headaches cause excruciating pain. The severe, stabbing pain centers around one eye, and eye tearing and nasal congestion occur on the same side. The headache lasts from 15 minutes to four hours and may recur several times in a day. Heavy smokers are more likely to suffer cluster headaches, which also are associated with alcohol consumption.

Diagnosis

Since headaches arise from many causes, a physical exam assesses general health and a neurologic exam evaluates the possibility of neurologic disease as a cause for the headache. If the headache is the primary illness, the doctor asks for a thorough history of the headache. Questions revolve around its frequency and duration, when it occurs, pain intensity and location, possible triggers, and any prior symptoms. This information aids in classifying the headache.

Warning signs that should point out the need for prompt medical intervention include:

• "Worst headache of my life." This may indicate subarachnoid hemorrhage from a ruptured aneurysm (swollen blood vessel) in the head or other neurological emergency.
• Headache accompanied by one-sided weakness, numbness, visual loss, speech difficulty, or other signs. This may indicate a stroke. Migraines may include neurological symptoms.
• Headache that becomes worse over a period of 6 months, especially if most prominent in the morning or if accompanied by neurological symptoms. This may indicate a brain tumor.
• Sudden onset of headache. If accompanied by fever and stiff neck, this can indicate meningitis.

Headache diagnosis may include neurological imaging tests such as computed tomography scan (CT scan) or magnetic resonance imaging (MRI).

Treatment

Headache treatment is divided into two forms: abortive and prophylactic. Abortive treatment addresses a headache in progress, and prophylactic treatment prevents headache occurrence.

Tension-type headaches can be treated with aspirin, acetaminophen, ibuprofen, or naproxen. In early 1998, the FDA approved extra-strength Excedrin, which includes caffeine, for mild migraines. Physicians continue to investigate and monitor the best treatment for migraines and generally prefer a stepped approach, depending on headache severity, frequency and impact on the patient's quality of life. A group of drugs called triptans are usually preferred for abortive treatment. About seven triptans are available in the United States and the pill forms are considered most effective. They should be taken as early as possible during the typical migraine attack. The most common prophylactic therapies include antidepressants, beta blockers, calcium channel blockers and antiseizure medications. Antiseizure medications have proven particularly effective at blocking the actions of neurotransmitters that start migraine attacks. Topiramate (Topamax) was shown effective in several combined clinical trials in 2004 at 50 to 200 mg per day.

In 2004, a new, large study added evidence to show the effectiveness of botulinum toxin type A (Botox) treatment to prevent headache pain for those with frequent, untreatable tension and migraine headaches. Patients were treated every three months, with two to five injections each time. They typically received relief within two to three weeks.

Cluster headaches may also be treated with ergotamine and sumatriptan, as well as by inhaling pure oxygen. Prophylactic treatments include prednisone, calcium channel blockers, and methysergide.

Alternative treatment

Alternative headache treatments include:

• acupuncture or acupressure
• biofeedback
• chiropractic
• herbal remedies using feverfew (Chrysanthemum parthenium ), valerian (Valeriana officinalis ), white willow (Salix alba ), or skullcap (Scutellaria lateriflora ), among others
• homeopathic remedies chosen specifically for the individual and his/her type of headache
• hydrotherapy
• massage
• magnesium supplements
• regular physical exercise
• relaxation techniques, such as meditation and yoga
• transcutaneous electrical nerve stimulation (TENS) (A procedure that electrically stimulates nerves and blocks the signals of pain transmission.)

Prognosis

Headaches are typically resolved through the use of analgesics and other treatments. Research in 2004 showed that people who have migraine headaches more often than once a month may be at increased risk for stroke.

Prevention

Some headaches may be prevented by avoiding triggering substances and situations, or by employing alternative therapies, such as yoga and regular exercise. Since food allergies often are linked with headaches, especially cluster headaches, identification and elimination of the allergy-causing food(s) from the diet can be an important preventive measure.

KEY TERMS

Abortive— Referring to treatment that relieves symptoms of a disorder.

Analgesics— A class of pain-relieving medicines, including aspirin and Tylenol.

Biofeedback— A technique in which a person is taught to consciously control the body's response to a stimulus.

Chronic— Referring to a condition that occurs frequently or continuously or on a regular basis.

Prophylactic— Referring to treatment that prevents symptoms of a disorder from appearing.

Transcutaneous electrical nerve stimulation— A method that electrically stimulates nerve and blocks the transmission of pain signals, called TENS.

Resources

PERIODICALS

Kruit, Mark C., et al. "Migraine as a Risk Factor for Subclinical Brain Lesions." JAMA, Journal of the American Medical Association January 28, 2004: 427-435.

Norton, Patrice G. W. "Botox Stops Headache Pain in Recalcitrant Cases." Clinical Psychiatry News March 2004: 72.

Taylor, Frederick, et al. "Diagnosis and Management of Migraine in Family Practice." Journal of Family Practice January 2004: S3-S25.

ORGANIZATIONS

American Council for Headache Education (ACHE). 19 Mantua Road, Mt. Royal, NJ 08061. (800) 255-2243. 〈http://www.achenet.org〉.

National Headache Foundation. 428 W. St. James Place, Chicago, IL 60614. (800) 843-2256. 〈http://www.headaches.org〉.

headache is arguably the commonest of the human ills, and perhaps, in proportion to its impact, one of the least well understood.

There are many different types of headache, whether considered as to how they behave or as to how they are caused. Headache may broadly be classified as primary or secondary: there are situations in which headache itself is the problem (primary headache), and others in which headache is a symptom of some other condition (secondary headache). Headache has been classified in detail by the International Headache Society, and whole textbooks have been written about it.

The main types of primary and secondary headache are listed in the table, which is based on a population survey. The main primary headaches are migraine (which is considered separately under that heading) and ‘tension-type headache — which is the commonest of all. It is often dull, both-sided, mild but otherwise featureless. It is surprisingly poorly understood. One of the most severe forms of headache, and one of the most difficult to treat, is ‘chronic daily headache’, which involves having headache most days of the week for most of the day. This may be either a form of chronic migraine or of tension-type headache; it is probably experienced in some form by up to 4% of the population, and is often associated with analgesic (painkiller) overuse. The daily headache syndrome is often due in part to the constant cycle of taking painkillers and then having their effects wear off: so-called rebound headache. Regular use of painkillers, particularly those containing more than one ingredient, such as mixtures with codeine, caffeine, or barbiturates, is a potent cause of difficulty in the treatment of headache. Also any regular intake of anti-migraine drugs, including ergotamine and triptans (sumatriptan and related compounds), may potentially cause or aggravate this problem.

Headache does not have any single cause. Just as there are many types of headache, there are many causes of the problem. With respect to the cause of the pain the mechanisms are much less well understood for the primary than for the secondary headaches. Whereas the pain due to injury to the skin, for example, is well understood as being due to stimulation of specific nerve endings in conjunction with local inflammatory events, it is not clear in primary head pain whether the nerves are firing normally or abnormally in response to various stimuli. Much work is to be to done, especially in regard to understanding tension-type headache.

Headache due to serious disease is rare, but a sufferer should be concerned about a headache when it has certain features. These include: sudden onset or sudden worsening, such as a severe headache never previously experienced; headache associated with fever, together with neck stiffness or altered consciousness, such as drowsiness; headache that is gradually worsening over a short period — say one to two months; or headache associated with pain in the temples, and pain on chewing, particularly if there is any visual disturbance. These latter symptoms are very important and a sufferer should seek immediate medical attention.

Most countries have established flourishing patient groups, which can be contacted by reference to telephone directories, such as the Migraine Trust in the UK and the American Council for Headache Education in the US.

Peter J. Goadsby

Bibliography

Goadsby, P. J. and Silberstein, S. D. (ed.) (1997). Headache. Butterworth–Heinemann, New York. ( Asbury, A. and Marsden. C. D. (ed.) Blue books in practical neurology, Vol. 17.)
Lance, J. W. and and Goadsby, P. J. (1998). Mechanism and management of headache, (6th edn). Butterworth–Heinemann, London.

Headache

What Are Headaches?

Causes and Types of Headaches

Tension Headaches

Migraine

Cluster Headaches

Should I See a Doctor?

How Are Headaches Treated?

Headache is a pain or discomfort of the head. It is not a disease but a symptom of some other problem in the body, and there are many possible causes. When someone gets a headache it usually is temporary, and only very rarely is it a sign of serious illness.

KEYWORDS

for searching the Internet and other reference sources

Cephalagia

Inflammation

Migraine

Neurology

What Are Headaches?

Headaches are so common that it is hard to imagine someone who has not had a headache, unless perhaps it is a newborn baby. Although there are dozens of causes of headaches, most headaches are due to tension or stress. About 20 percent of people in the United States at some point in their lives may have a recurrent, often severe type of headache known as migraine.

Up to 50 million people in America seek medical help for migraine and other severe headaches each year. It has been estimated that more than 180 million workdays are lost due to headache annually, and that more than a billion dollars are spent for over-the-counter remedies to relieve headaches.

Chronic headaches may accompany emotional disturbances such as depression. Many times, headaches are just one of a number of symptoms, such as fever or dizziness, that are brought on by various diseases or injuries. Migraine headaches frequently are accompanied by nausea and other symptoms that are characteristic of it.

Causes and Types of Headaches

The pain of headache may be mild, extremely severe, or anywhere in between. It may involve the entire head, one side only, the forehead, the base of the skull, or it may seem to move around. The pain may be sharp, a dull ache, or throbbing. A headache may last a few minutes or hours. It may recur from time to time, or may become chronic, coming back many times over an extended period.

How Did Migraine Get Its Name?

Aretaeus of Cappadocia, a medical writer in Greece in the second century A.D., is believed to have been the first to recognize migraine as a one-sided headache with stomach and visual disturbances. Galen, a contemporary of Aretaeus, gave this affliction the name hemikrania meaning “half of the head,” referring to the way it typically affects people. In Old English, the term became megrim, and finally evolved to “migraine.”

An Ancient, and Drastic, Treatment

Prehistoric peoples are known to have surgically cut holes in the skulls of living persons, presumably to relieve some ailment. The purpose of this operation is not known with certainty. Perhaps it was carried out to relieve the pressure of a blood clot under the skull caused by a blow to the head. However, it is believed that in some instances it may have been done in an attempt to cure headaches by releasing evil spirits. Stone Age patients who underwent this surgery apparently often survived, because many of the skulls found by scientists showed new growth of bone around the holes.

Many people believe that the brain itself is involved in headaches, but neither the brain nor the skull has nerves that register pain. The sources of head pain are the nerve endings in the blood vessels and muscles in and around the head. Pain may be felt when these tissues become stretched, inflamed, or damaged. Headaches can arise in blood vessels within the brain, as well as in the meninges (me-NIN-jeez), which are the sensitive membranes that cover the brain.

Mild headaches may arise from such things as a change in the weather or hunger. Common causes of mild to severe headache pain include disorders of the eyes, ears, and sinuses. For example, eyestrain and diseases such as glaucoma can produce pain in the front of the head and around the eye. Mastoiditis, an inflammation of bone behind the ear, can cause severe pain on the affected side of the head. Sinusitis can cause sharp headaches in the front of the head (often called sinus headaches). A jaw or bite that does not close properly also can cause headache.

Many types of infection with fever, such as influenza (flu), cause headache. Other causes include drinking too much alcohol, heavy smoking, withdrawal from caffeine, or inhaling a noxious gas, such as carbon monoxide. Contrary to popular belief, high blood pressure rarely is a direct cause of headache.

Headache is one of the symptoms of concussion, and sometimes becomes chronic following this injury.

Rarely, headaches may be caused by brain abscesses, brain tumors, bleeding into the brain, and meningitis (an inflammation of the membranes covering the brain).

Physicians often classify headaches as those caused by disease or injury (described above); tension headaches; and vascular* headache . Vascular headaches include migraine and a type called cluster headaches. Tension and migraine headaches are very common.

* vascular

refers to veins and arteries (the blood vessels).

Tension Headaches

Headaches that are associated with emotional stress or muscular tension are called tension headaches. The muscular tension may be in the neck, face, or scalp. It may be the result of poor posture or of constantly bending over one’s work. These headaches are extremely common, and almost everyone has them at one time or another. A person may have one after working on the computer too long or bending over while doing homework.

Pressures from school, friends, or family may play a role. Adults may develop tension headaches because of stress at work. Tension headaches may be mild to moderate and occur in various parts of the head. The feeling has been described as a steady ache or as a tight sensation.

The pain of tension headaches can be chronic or recurrent, sometimes coming on every day. Muscles near the site of the pain, such as at the back of the neck, or on the sides of the head, are often tense and tender. Sometimes chronic tension headache is a symptom of depression.

Migraine

Migraine is a moderate to severe headache that can interfere with a person’s life. The pain is typically, although not always, in one side of the head, at least at the beginning, and may last from hours to days. Migraine headaches occur every so often, usually beginning in adolescence or early adult life. They tend to become less frequent with age, and tend to be rare or absent after the age of 40 to 50.

Migraine is one of the most common types of headaches, affecting about 20 million people in the United States alone. Women are four times more likely to experience migraine than men. People in all walks of life have been afflicted, including Sigmund Freud, Thomas Jefferson, Charles Darwin, and Lewis Carroll, the author of Alice in Wonderland. Contemporary sufferers have included the late Princess Diana of Great Britain and the basketball player, Kareem Abdul-Jabbar.

The cause or causes of migraine headaches are not known with certainty. They are classified as vascular headaches because blood vessels in the head dilate, or expand, during an attack. It is believed that certain chemical substances in the nerve cells surrounding the vessels are involved in the attack. The precise mechanism is not fully understood, however.

Migraine headaches tend to run in families. However, one does not catch this headache from someone else.

Most migraine attacks begin without warning. Typically, the pain is throbbing, often growing in intensity. It usually is accompanied by nausea and sometimes vomiting. The slightest noise or movement can make it worse. Ordinary light coming through a window may seem unbearable.

The Aura

In about 15 percent of people who get migraines, the headaches are preceded by a distinctive type of warning called an aura (OR-uh). An aura can be a blank spot in the vision bordered by zigzag and flashing lights or numbness or weakness in parts of the body. After several minutes, the aura goes away and the pain of the headache begins. Migraine preceded by an aura has been called a classic migraine, or migraine with aura.

Triggers

In a number of individuals, certain factors, or triggers, can bring on a migraine attack. Common examples include red wine and foods such as cheese, nuts, chocolate, and citrus fruit. Nitrites, which are used as meat preservatives in products such as bacon or cold cuts, are another recognized trigger. Other triggers include excessive sleep, relaxation after exercise, fatigue, and stress. Still others are related to hormonal changes, such as those that occur at the onset of menstruation. Sometimes the trigger is not known.

Cluster Headaches

Intensely painful headaches that occur one or more times daily are called cluster headaches. These headaches may keep recurring for weeks or months, then not return for years. The pain is centered on one side of the head around the eye. Besides pain, the symptoms include a watery eye and a runny nose on the affected side.

Cluster headaches occur in men more often than in women, and usually first appear about age 40. Their cause is unknown.

Should I See a Doctor?

Most headaches, although unpleasant, are not signs of serious health problems. A person should see a doctor if the headaches are unusually persistent or severe, if there are any changes in vision or speech, or if there is weakness or numbness in any body part.

How Are Headaches Treated?

Over-the-counter pain-relieving drugs, such as acetaminophen, may ease mild headaches. Relief also may come from such simple measures as getting some fresh air, taking a hot bath, getting a muscle massage, or just lying down for a while. Tension headaches can be dealt with by addressing the cause of the emotional or physical stress.

For severe headaches, such as migraine, the best approach is prevention, that is, avoiding the factors that the individual knows are most likely to trigger an attack. Once an attack begins, pain-relieving drugs may help to ease symptoms. The doctor also can prescribe medicines that will narrow the blood vessels in the brain that have dilated during an attack. If migraine attacks occur frequently, the doctor can prescribe medications to prevent the migraine. Biofeedback, a relaxation technique, has proven helpful in relieving and avoiding some headaches.

Cluster headache attacks may be over before pain-relieving drugs can take effect. However, some prescription medicines may be useful in prevention.

Many common headaches can, of course, be prevented by maintaining a healthy lifestyle, including regular eating and sleeping habits, and avoidance of excess alcohol and caffeine intake.

See also

Concussion

Glaucoma

Sinusitis

head·ache / ˈhedˌāk/ • n. a continuous pain in the head. ∎ inf. a thing or person that causes worry or trouble; a problem: an administrative headache. DERIVATIVES: head·ach·y / -ˌākē/ adj.

headache (hed-ayk) n. pain felt deep within the skull. Most headaches are caused by emotional stress or fatigue but some are symptoms of serious intracranial disease. See also cluster headache, migraine.

headache Pain felt in the skull. Most frequently caused by stress or tension, it may also signal other diseases, especially if associated with fever. See also migraine

headache •ache, awake, bake, betake, Blake, brake, break, cake, crake, drake, fake, flake, forsake, hake, Jake, lake, make, mistake, opaque, partake, quake, rake, sake, shake, sheikh, slake, snake, splake, stake, steak, strake, take, undertake, wake, wideawake •bellyache • clambake • headache •backache • pancake • teacake •seedcake • beefcake • cheesecake •fishcake • johnnycake • tipsy cake •rock cake • shortcake • oatcake •oilcake • fruitcake • cupcake •pat-a-cake • cornflake • snowflake •rattlesnake • handbrake • mandrake •heartbreak • airbrake • daybreak •jailbreak • canebrake • windbreak •tiebreak • corncrake • outbreak •footbrake • muckrake • earache •firebreak • namesake • keepsake •handshake • milkshake • heartache •beefsteak • sweepstake • stocktake •out-take • uptake • grubstake •wapentake • toothache • seaquake •kittiwake • moonquake • earthquake