Diagnosis

What Tests Are Used to Diagnose Headache?

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.