Headache

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.

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-thecounter (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 channelblockers; 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.