Cardiac Center

Syncope (Fainting) in Children and Teenagers

What is syncope (fainting)?

Syncope is the medical term for fainting. A person faints when the brain isn’t getting enough blood pressure.

If the brain lacks adequate blood pressure, the body immediately does what it can to get more blood (which carries oxygen) to the brain. Before fainting, a person may feel dizzy, see spots or dark vision, hear ringing or muffled sounds, feel nauseated, feel hot or cold, notice their heart rate going very fast (or very slow), or become pale. Finally, the person loses consciousness (faints) and can fall over. It ends up being easier for blood to get to the brain when a person is lying flat; when a person is standing, blood must move up against gravity to reach the brain from the heart.


What are some causes of syncope (fainting)?

In the majority of cases, fainting is not a sign of a dangerous medical condition. Fainting in adolescents is somewhat common. However, it should not be ignored.

Dehydration is the most common cause of fainting in children. When the body doesn’t get enough fluid intake, the blood pressure can drop, which can cause inadequate blood flow to the brain. In many cases, as a first step, pediatricians will recommend that children who have fainted simply drink more. They may also recommend increased salt intake, not skipping meals, and eliminating caffeine intake. Often this will “cure” the problem.

Fear and pain, crowded or hot rooms, the sight of blood, or a hot shower can also cause fainting, as can certain medications and illegal drugs.

There are serious medical conditions that can cause fainting. They include anemia (insufficient iron in the blood), blood clots, and heart defects or heart problems, such as:

After a child faints, parents are understandably concerned. Some worry their child has a heart problem that could lead to sudden death. This is very unlikely — most children who faint do not have underlying heart problems. However, do not ignore fainting. It is important to see a doctor if your child faints even once.


What should I do if my child has fainted once or repeatedly?

If your child has been treated for a heart defect and he or she faints, you should call your pediatrician or pediatric cardiologist immediately.

If your child is healthy and faints once, make an appointment with your pediatrician. Explain exactly what happened. Tell your pediatrician if your child has other symptoms that might indicate a heart problem and if there is a family history of known heart abnormalities or sudden death before age 50 (including sudden infant death syndrome).

If your child faints again, call the pediatrician. A more comprehensive evaluation may be necessary. It isn’t always possible to figure out why a child is fainting. However, doctors can check for some of the serious medical conditions that might be causing the fainting. Your pediatrician may refer you to a pediatric cardiologist, a doctor who specializes in heart problems in children.


What should I expect if my child is referred to a pediatric cardiologist after fainting?

The pediatric cardiologist will listen to your child’s heart and ask questions about the circumstances that led to fainting, your child’s medical history and your family's medical history. The doctor may order an electrocardiogram (ECG or EKG), a record of the electrical activity of your child’s heart, to determine whether a heart problem may have caused the fainting.

The cardiologist might order other tests, such as an exercise stress test, a transtelephonic monitor or a Holter monitor.

If your child’s fainting episodes are caused by a heart problem, medications, implantable pacemakers or defibrillators, or, rarely, treatment by catheterization or surgery may be required.


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Contact the Cardiac Center at The Children's Hospital of Philadelphia for a second opinion or for more information.

Reviewed by: Jeffrey R. Boris, MD
Date: May 2013

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