Introduction

For 2 years, Jim suffered the excruciating pain of cluster headaches. Night after night he paced the floor, the pain driving him to constant motion. He was only 48 years old when the clusters forced him to quit his job as a systems analyst. One year later, his headaches are controlled. The credit for Jim's recovery belongs to the medical staff of a headache clinic. Physicians there applied the latest research findings on headache, and prescribed for Jim a combination of new drugs.

Joan was a victim of frequent migraine. Her headaches lasted 2 days. Nauseous and weak, she stayed in the dark until each attack was over. Today, although migraine still interferes with her life, she has fewer attacks and less severe headaches than before. A specialist prescribed an antimigraine program for Joan that included improved drug therapy, a new diet and relaxation training.

An avid reader, Peggy couldn't put down the new mystery thriller. After 4 hours of reading slumped in bed, she knew she had overdone it. Her tensed head and neck muscles felt as if they were being squeezed between two giant hands. But for Peggy, the muscle-contraction headache and neck pain were soon relieved by a hot shower and aspirin.

An estimated 45 million Americans experience chronic headaches. For at least half of these people, the problem is severe and sometimes disabling. It can also be costly: headache sufferers make over 8 million visits a year to doctor's offices. Migraine victims alone lose over 157 million workdays because of headache pain.

Understanding why headaches occur and improving headache treatment are among the research goals of the National Institute of Neurological Disorders and Stroke (NINDS). As the leading supporter of brain research in the Federal Government, the NINDS also supports and conducts studies to improve the diagnosis of headaches and to find ways to prevent them.

What hurts when you have a headache? Several areas of the head can hurt, including a network of nerves which extends over the scalp and certain nerves in the face, mouth, and throat. Also sensitive to pain, because they contain delicate nerve fibers, are the muscles of the head and blood vessels found along the surface and at the base of the brain.

The bones of the skull and tissues of the brain itself, however, never hurt, because they lack pain-sensitive nerve fibers.

The ends of these pain-sensitive nerves, called nociceptors, can be stimulated by stress, muscular tension, dilated blood vessels, and other triggers of headache. Once stimulated, a nociceptor sends a message up the length of the nerve fiber to the nerve cells in the brain, signaling that a part of the body hurts. The message is determined by the location of the nociceptor. A person who suddenly realizes "My toe hurts," is responding to nociceptors in the foot that have been stimulated by the stubbing of a toe.

A number of chemicals help transmit pain-related information to the brain. Some of these chemicals are natural painkilling proteins called endorphins, Greek for "the morphine within." One theory suggests that people who suffer from severe headache and other types of chronic pain have lower levels of endorphins than people who are generally pain free.

Not all headaches require medical attention. Some result from missed meals or occasional muscle tension and are easily remedied. But some types of headache are signals of more serious disorders, and call for prompt medical care. These include:

• Sudden, severe headache
• Headache associated with convulsions
• Headache accompanied by confusion or loss of consciousness
• Headache following a blow on the head
• Headache associated with pain in the eye or ear
• Persistent headache in a person who was previously headache free
• Recurring headache in children
• Headache associated with fever
• Headache which interferes with normal life

A headache sufferer usually seeks help from a family practitioner. If the problem is not relieved by standard treatments, the patient may then be referred to a specialist--perhaps an internist or neurologist. Additional referrals may be made to psychologists.

Diagnosing a headache is like playing Twenty Questions. Experts agree that a detailed question-and-answer session with a patient can often produce enough information for a diagnosis. Many types of headaches have clear-cut symptoms which fall into an easily recognizable pattern.

Patients may be asked: How often do you have headaches? Where is the pain? How long do the headaches last? When did you first develop headaches? The patient's sleep habits and family and work situations may also be probed.

Most physicians will also obtain a full medical history from the patient, inquiring about past head trauma or surgery and about the use of medications. A blood test may be ordered to screen for thyroid disease, anemia, or infections which might cause a headache. X-rays may be taken to rule out the possibility of a brain tumor or blood clot.

A test called an electroencephalogram (EEG) may be given to measure brain activity. EEG's can indicate a malfunction in the brain, but they cannot usually pinpoint a problem that might be causing a headache. A physician may suggest that a patient with unusual headaches undergo a computed tomographic (CT) scan and/or magnetic resonance imaging (MRI). The CT scan produces images of the brain that show structures or variations in the density of different types of tissue. The scan enables the physician to distinguish, for example, between a bleeding blood vessel in the brain and a brain tumor, and is an important diagnostic tool in cases of headache associated with brain lesions or other serious disease. MRI uses magnetic fields and radio waves to produce an image that provides information about the structure and biochemistry of the brain.

An eye exam is usually performed to check for weakness in the eye muscle or unequal pupil size. Both of these symptoms are evidence of an aneurysm--an abnormal ballooning of a blood vessel. A physician who suspects that a headache patient has an aneurysm may also order an angiogram. In this test, a special fluid which can be seen on an X-ray is injected into the patient and carried in the bloodstream to the brain to reveal any abnormalities in the blood vessels there.

Thermography, an experimental technique for diagnosing headache, promises to become a useful clinical tool. In thermography, an infrared camera converts skin temperature into a color picture or thermogram with different degrees of heat appearing as different colors. Skin temperature is affected primarily by blood flow. Research scientists have found that thermograms of headache patients show strikingly different heat patterns from those of people who never or rarely get headaches.

A physician analyzes the results of all these diagnostic tests along with a patient's medical history in order to arrive at a diagnosis.

Headaches are diagnosed as

• Vascular
• Muscle contraction (tension)
• Traction
• Inflammatory

Vascular headaches--a group that includes the well-known migraine--are so named because they are thought to involve abnormal function of the brain's blood vessels or vascular system. Muscle contraction headaches appear to involve the tightening or tensing of facial and neck muscles. Traction and inflammatory headaches are symptoms of other disorders, ranging from stroke to sinus infection. Some people have more than one type of headache.

May 20, 1997

Information provided by NIH.