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Fainting, also known by the medical term
syncope, is the temporary loss of consciousness, often
accompanied by falling down or a strong urge to lie down, followed by spontaneous
recovery. The most common reason for fainting is a temporary decrease in blood
flow to the brain. Except for the risk of physical injury from falling, fainting
itself is often not a serious health problem. However, sometimes fainting
can be a sign of a serious underlying disorder, so determining the cause is
important. The September 8, 2004, issue of JAMA includes
an article about fainting after exercise.
Drop in blood pressure due to change in position or blood loss
Heat or dehydration
Arrhythmias (abnormal heart rhythms)
An oversensitive region in an artery in the neck called the carotid artery
Blood clots in the lung
Field of vision either whites out or blacks out
A physical examination and a careful history of what happens just before
and during fainting are very important in determining the cause. Individuals
who faint often should be tested for abnormal heart rhythms using an electrocardiogram (ECG), a machine that records the electrical
impulses of the heart. They generally should also be evaluated with an echocardiogram (ultrasound of the heart) to see if there
are abnormalities in the heart muscle or valves. In some cases, other tests
may be performed, such as a Holter monitor (a 24-hour
recording of the heart rhythm) or a tilt test, in
which blood pressure and heart rate are measured while the person is lying
down on a table and again after the patient stands up or the table is tilted
Treatment for fainting depends on its underlying cause. If no serious
cause is found, the only interventions that may be necessary are avoiding
situations that lead to fainting and protection from injury from falling.
If a more serious cause is found, treatment is directed at the responsible
National Heart, Lung, and Blood Institute 301/592-8573 http://www.nhlbi.nih.gov
National Institute of Neurological Disorders and Stroke 800/352-9424 http://www.ninds.nih.gov
To find this and other JAMA Patient Pages, go to the Patient Page link
on JAMA's Web site at http://www.jama.com.
A Patient Page on electrocardiograms was published in the April 23, 2003,
Sources: National Heart, Lung, and Blood Institute; National Institute
of Neurological Disorders and Stroke; American Heart Association; Centers
for Disease Control and Prevention
The JAMA Patient Page is a public service of JAMA. The information and recommendations appearing on this page are appropriate
in most instances, but they are not a substitute for medical diagnosis. For
specific information concerning your personal medical condition, JAMA suggests that you consult your physician. This page may be photocopied
noncommercially by physicians and other health care professionals to share
with patients. Any other print or online reproduction is subject to AMA approval.
To purchase bulk reprints, call 718/946-7424.
Parmet S, Lynm C, Glass RM. Fainting. JAMA. 2004;292(10):1260. doi:10.1001/jama.292.10.1260
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