Fainting (Syncope)

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

If the brain lacks adequate blood supply, the body immediately does what it can to get more blood (which carries oxygen) to the brain. When a person faints, they usually fall over and/or lie down. 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.

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, paediatricians will recommend that children who have fainted simply drink more. They may also recommend increased salt intake, not skipping meals, and eliminating caffeine. Often this will “cure” the problem.

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

• Arrhythmias: abnormal electrical signals that control the heartbeat (for example, long QT syndrome).
• Structural abnormalities in the heart: problems with the heart’s valves, chambers or vessels (for example, hypertrophic cardiomyopathy or coarctation of the aorta).

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)
• Become pale.

Finally, the person loses consciousness (faints) and can fall over.

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

If your child is healthy and faints once, make an appointment with your paediatrician. Explain exactly what happened. Tell your paediatrician 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 your paediatrician again. 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 paediatrician may also refer you to a paediatric cardiologist, a doctor who specializes in heart problems in children. The paediatric 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), 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 Holter monitor (24 hour record of ECG) or a head-up tilt table test (HUTT test).

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