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Headaches: Tension-Type

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of common headaches.

Causes

Because of its high prevalence in developed nations, headaches are among the most costly diseases from lost work days and low productivity in the US and Europe. With tension headaches being the most common, it is surprising that so little scientific attention has been focused on determining the cause of this widespread problem. In any case, there does not appear to be a single cause of chronic tension-type; rather, many factors are likely involved.

Muscle Contractions and Tenderness

One of the most popular theories on the cause of tension-type headaches involves muscle contraction in the head, neck, and shoulders. There are a number of ideas about how muscle tension may produce these headaches.

Tension-type headache
The most common cause of tension-type headaches is muscle contraction in the head, neck or shoulders.

Studies have suggested that tension-type headache sufferers may have higher-than-average muscle tenderness in the face and head that make them more susceptible to headache after muscle contractions. A few studies suggest that some patients with chronic headaches may be overly sensitive to pain in general or may overestimate muscle contraction pain.

One theory suggests that sustained tension or stress that produces muscle contractions in the tender areas around the skull constrict blood vessels. Blood flow is reduced so oxygen is blocked and waste matter builds up, resulting in pain.

Still, pain can last long after the muscles have relaxed and clear evidence is lacking on how or even if muscle contractions are a major cause of tension headache.

Sensitivity in the Central Nervous System and a Common Theory of Primary Headaches

Researchers are increasingly finding evidence to support factors that are common to both migraine and tension-type headache. Some research suggests that both problems may result from a continuum of abnormalities in the central nervous system (the nerves in the brain and spine). Such changes trigger a progression of symptoms starting with mild sensations, developing into tension headache, and finally, progressing in some people to a migraine.

Serotonin and Other Neurotransmitter Levels. Neurotransmitters are chemical messengers in the brain. Serotonin is a neurotransmitter (chemical messenger in the brain) that is important for sleep, well being, and other factors that affect quality of life. Abnormalities in serotonin levels have been observed in both tension-type and migraine headache sufferers. Altered levels of other neurotransmitters, importantly dopamine and stress hormones, also occur with migraine and tension-type headaches.

Dopamine, for example, may act as a stimulant of the migraine process. Some evidence suggests that certain genetic factors make people over-sensitive to the effects of dopamine, which include nerve cell excitation. Such nerve-cell over-activity could trigger the events in the brain leading to migraine. The prodromal symptoms (mood changes, yawning, drowsiness), for example, have been associated with increased dopamine activity. Dopamine receptors are also involved in regulation of blood flow in the brain.

Reduced Magnesium Levels. Magnesium deficiencies have been observed in people with both tension-type and migraine headaches. Researchers have noted a drop in magnesium levels before or during a migraine attack. Magnesium plays a role in nerve cell function; reduced levels could be a destabilizing factor, causing the nerves in the brain to misfire, possibly even accounting for the auras that many sufferers experience.

Nitric Oxide. Other research suggests that over-excitable neurons release nitric oxide, a small molecular messenger, which may be important in triggering in most primary headaches (tension-type, cluster, and migraines). Elevated levels have been observed in blood cells of patients with tension-type headache. There is some evidence that the release of this molecule in blood vessels may activate nerve pathways in the brain, muscles, or elsewhere and increase pain. More research is warranted.

Estrogen Fluctuations in Women. Tension-type headaches and migraine headaches are slightly more common in females during adolescence and adulthood. Most likely hormone fluctuations, rather than whether levels are elevated or low, trigger headaches. Some research suggests that fluctuations in estrogen levels may impact levels of serotonin and other pain-modulating substances that affect these headaches.

Inflammation in the Maxillary Nerve. Early studies suggest that some chronic tension-type and migraine headaches may be caused by inflammation in the nerve that runs behind the cheekbone (the maxillary nerve)--not around the covering of the brain. In fact, some work using ice water for reducing swelling in areas of the gums above the last upper molars has relieved some severe migraine and tension-type headaches.

Genetic Factors

Genetic factors appear to play a role in predisposing people to recurrent tension headaches. One study of twins suggested that the chances of inheriting the susceptibility to recurring headaches (both migraine and tension) were about 70% in close relatives. The trait is equal in both boys and girls. Because such headaches tend to occur in females, however, hormonal, social, psychological, or other factors must play a role in their development.

Stress and Psychological Factors

Tension-type headache has been highly associated with an intense response to stress. Some studies suggest that patients with chronic tension-type headaches have more general feelings of anxiety or depression and are less able to express their emotions, and a 2001 study indicated that patients with tension headaches tend to perceive everyday events as more stressful than those without headaches. Some research even suggests that tension-type headache victims may have some biological predisposition for translating stress into muscle contraction. Still, the link between stress and tension-type headaches is not fully understood and some evidence challenges any causal association.

Head and Neck Injuries

Whiplash, concussions, and other head and neck injuries, even mild ones, may result in persistent tension-type or migraine headaches in both adults and children. Such headaches should be treated as if they were the primary types. The risk for tension headaches may persist for years after the injury. For example, a 2002 survey of 26 year olds noted that tension headaches were significantly associated with neck or back injuries before the age of 13.

Other Major Causes of Chronic Daily Headaches

Medication Overuse (Rebound) Headache. About a third of persistent headaches--whether chronic migraine or tension-type--are medication-overuse headaches (MOHs). These are the result of a rebound effect caused by the regular overuse of headache medications. Nearly any headache medication can produce this effect. In one study of headache sufferers, MOH developed after an average of 1.7 years of regular use of triptans (18 doses a month), after 2.7 years of ergot use (37 doses as month), and after 4.8 years using pain killers (114 doses a month). It should be noted that regular use of pain killers for any chronic problem (such as arthritis) poses a 2% risk for medication-overuse headache, with risk being highest in people who already have primary headaches, especially migraines.

Chronic Migraines. In some cases, migraines naturally evolve into chronic, daily headaches referred to as transformed migraines. [For more information, seeWell-Connected Report #97, Migraine.]

CAUSES OF SECONDARY HEADACHES

About 90% of people seeking help for headaches have a primary headache. The balance of cases are secondary headaches, caused by an underlying disorder that produces headache as a symptom. More than 300 conditions can cause headaches. Some of the most common are listed below.

Sinus Headaches. Many primary headaches, including migraines, are misdiagnosed as sinus headaches. Sinus headaches can occur in the front of the face, usually around the eyes, across the cheeks, or over the forehead. They are usually mild in the morning and increase during the day and are usually accompanied by fever, runny nose, congestion, and general debilitation. Sinus headaches spread over a larger area of the head than migraines, but it is often difficult to tell them apart, particularly if headache is the only symptom of sinusitis; they even coexist in many cases. Often, the visual changes associated with migraine can rule out sinusitis, but such visual changes do not occur with all migraines. (In rare cases, sinusitis can cause double vision and even vision loss, a sign of very serious infection.) [For more information, see the Well-Connected Report #62, Sinusitis.]

Headaches that Originate in the Neck. Some headaches may be caused by abnormalities of the neck muscles (called cervicogenic headaches). Nerves in the neck converge in the trigeminal nerve, which is the largest nerve in the skull. It originates in the brain stem and supplies sensation to the face. This nerve can generate pain signals to the facial area that the brain may interpret as headache. Pain is usually on one side; even if it affects both sides of the head it is usually more severe on one side. The quality of the headache may be difficult to distinguish from an aching tension headache or a mild migraine without aura. Cervicogenic headaches can result from prolonged poor posture (such as that caused by sitting in front of a computer keyboard or driving daily for long periods), arthritis, injuries of the upper spine, or abnormalities in the cervical spine (the spinal bones in the neck). Whiplash injuries involve the neck and can cause headaches, which, according to a 2001 British study, resolve within three weeks in 85% of patients.

Temporomandibular Joint Disorder (TMJ, also called TMD). Muscle contractions that cause headaches may be a result of temporomandibular joint dysfunction, which is caused by clenching the jaws or grinding the teeth (usually during sleep), or by abnormalities in the jaw joints themselves. The diagnosis is easy if chewing produces pain or if jaw motion is restricted or noisy. TMJ pain can occur in the ear, cheek, temples, neck, or shoulders. This condition often coexists with chronic tension headache.

Click the icon to see an image of temporomandibular joint dysfunction.

Glaucoma. Acute glaucoma is caused by increased pressure in the eye and requires immediate medical attention. Throbbing pain may be felt around or behind the eyes or in the forehead. Patients have redness in the eye and may see halos or rings around lights.

Brain Tumor. Fear of brain tumor is common among people with headaches, but headache is almost never the first or only sign of a tumor. Changes in personality and mental functioning, vomiting, seizures, and other symptoms are more likely to appear first. When the headache does develop, it is often worse early in the morning or may awaken sufferers during the night.

Neuralgia. Neuralgia is pain due to nerve abnormalities, which can occur in the facial area and resemble migraines or sinus headaches.

Hypertension. Although many people attribute headaches to high blood pressure, the weight of evidence suggests that hypertension does not cause headaches. An exception is malignant hypertension, an uncommon medical emergency in which the blood pressure abruptly rises to extreme levels, causing damage to blood vessels in the brain, heart, and kidneys.

Strokes Caused by Blood Clots or Hemorrhages. A blood clot or hemorrhage in the brain leading to a stroke can cause a severe headache, sometimes referred to as a thunderclap headache when it is very sudden and severe. The onset of such a headache, particularly if it is associated with confusion, stupor, or other neurologic symptoms, mandates prompt medical attention.

Epilepsy. Severe headaches that can last 12 hours or longer are very common in epilepsy. Migraine is particularly associated with epilepsy.

Head Injuries. It is obvious that a significant blow to the head will cause pain. In most cases, the pain is similar to tension-type headache and is treated in the same way as the primary headache. Post-injury headaches, however, can reflect serious damage, ranging from skull fractures to internal bleeding, and monitoring is important.

Disorders of the Meninges. The meninges are the membranes covering the brain and the spinal cord. Meningitis, which is an infection or irritation of these membranes, is an uncommon but potentially serious cause of severe headache. Other symptoms include nausea and stiffness or pain in the neck.

Gynecologic Problems. Many clinicians have anecdotally linked gynecologic problems, such as ovarian cysts and menstrual disorders, to chronic headaches, and new data are emerging to support this association.

Temporal (Giant Cell) Arteritis. Certain causes of headaches are unique to the elderly, such as temporal arteritis, also called giant cell arteritis. Inflammation in arteries that carry blood to the head, neck, and sometimes the upper part of the body can cause very severe headaches. The risk for this headache is highest in people over age 70, especially among women, people of European heritage, and patients with polymyalgia rheumatica.

Miscellaneous Causes of Benign Headaches. Rapid consumption of ice cream or other very cold foods or beverages is the most common trigger of sudden headache pain, which may be prevented by warming the food or drink for a few seconds in the front of the mouth before swallowing. Other common benign causes of headache include eyestrain, dental problems, allergies, systemic infections, and caffeine withdrawal. Headaches may be induced by sexual activity or intense physical exertion. Leakage from spinal cord fluid is rare but can cause headaches that may be mistaken for brain tumors.

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