| Introduction*
Headaches are a very common medical problem and a common cause of disability among men and women. Headaches interfere with the ability to work and to perform daily tasks. Some people have frequent headaches; other people hardly ever have them. |
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Causes
Although headaches can be painful and distressing, they rarely indicate a serious condition. Most headaches — tension-type, migraine, and cluster headaches are not caused by another identifiable disorder. Tension-type headaches are the most common.
Less commonly, headaches result from another disorder. Usually, the disorder is not serious. Disorders that cause headaches are often minor or temporary ones that affect the eyes, nose, throat, sinuses, teeth, jaws, ears, or neck.
Rarely, headaches are caused by a serious disorder. Such disorders include a head injury, stroke, bulge in the wall of an artery supplying the brain (cerebral aneurysm), brain infection (brain abscess, meningitis, and encephalitis), and blood vessel (arteriovenous) malformation near the brain. Infections such as tuberculosis may affect the brain and cause headaches. Disorders that increase pressure within the skull can cause headaches by putting pressure on the brain. Examples are a brain tumor, bleeding (hemorrhage), an accumulation of blood (hematoma), and pseudotumor cerebri, in which pressure within the skull increases but no cause can be identified.
Other serious diseases that may cause headache include very high blood pressure, which may produce a throbbing sensation in the head. (However, high blood pressure does not usually cause headaches.) Lung disorders (such as emphysema) that reduce the oxygen supply to the brain may cause headaches, as may sleep apnea, which temporarily increases levels of carbon dioxide in the blood. Inflammation of large arteries (temporal arteritis), usually in the neck and head, may cause headaches. Temporal arteritis affects older people primarily. Severe cases of influenza and high fever may cause headaches. Lyme disease in its early stages commonly causes headaches.
Headaches commonly result from withdrawal of caffeine, withdrawal of analgesics after long-term use, and use of certain drugs that widen blood vessels (such as nitroglycerin
Diagnosis
Usually, doctors can determine the type or cause of headaches on the basis of the person's medical history, the characteristics of the headache, and results of a physical examination. Characteristics of the headache include its frequency, duration, location, severity, and associated symptoms.
The following characteristics may indicate that a serious disorder is the cause of headaches, and prompt medical attention is required:
| • | Frequent headaches in a person who rarely has headaches |
| • | Mild headaches that become severe |
| • | Headaches that awaken a person from sleep |
| • | Any change in the pattern or nature of headaches |
| • | Headaches associated with symptoms such as a fever and a stiff neck, changes in sensation or vision, weakness, loss of coordination, or fainting. For example, a severe headache with a fever and a stiff neck suggests meningitis - a life-threatening infection of the layers of tissue covering the brain and spinal cord (meninges). A headache that occurs suddenly and that is more severe than any others the person has experienced suggests a subarachnoid hemorrhage—often due to a ruptured aneurysm. |
When doctors suspect a serious disorder, additional diagnostic procedures are usually performed. If meningitis is suspected, a spinal tap (lumbar puncture) is performed immediately. A spinal tap may also be performed if doctors suspect a ruptured aneurysm. Occasionally, blood tests are performed to check for a disorder such as Lyme disease. The erythrocyte sedimentation rate (ESR—the rate at which red blood cells settle to the bottom of a test tube containing blood) may be determined to check for temporal arteritis. A high ESR suggests inflammation.
If doctors suspect a tumor, stroke, hemorrhage, or another structural brain disorder, computed tomography (CT) or magnetic resonance imaging (MRI) of the head is performed.
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* The Merck Manual - Second Home Edition, online version.
