Pediatric Syncope

Syncope is a brief loss of consciousness and muscle tone (or posture) that can occur when not enough blood gets to the brain. Syncope is commonly called fainting. In most children, it’s usually harmless. But in a few children, syncope is serious. Fainting may be due to a heart problem, or sometimes a neurological problem.

The common reason behind each fainting episode is a temporary lack of oxygen-rich (red) blood getting to the brain. However, many different problems can cause a decrease in blood flow to the brain. Some causes of syncope include:

• Vasovagal syndrome (neurocardiogenic syncope). A sudden drop in blood pressure with or without a decrease in heart rate. It's caused by a problem with overstimulating the nerves that have direct input on the heart and blood vessels. This is the most common cause of syncope and can follow periods of extreme emotion. It's generally a benign condition.
• Heart rhythm problem (arrhythmia). A heart rate that is too slow, too fast, or too irregular to keep enough blood flow to the body, including the brain. This is a fairly rare cause of syncope, especially in children.
• Structural heart disease (muscle or valve defects). There may be problems with the heart muscle or one or more of the heart valves. This may cause a decrease of blood flow to the body, including the brain. Inflammation of the heart muscle, known as myocarditis, can also cause fainting. The heart muscle becomes weak and is not able to pump as well as normal. The body again reacts to decreased blood flow to the brain by fainting.
• Orthostatic hypotension. This is a drop in blood pressure that occurs when a person has been standing for a while, or changes from a sitting to a standing position. Blood pools in the legs, preventing a normal amount of blood from being pumped to the brain. This brief drop in blood flow to the brain causes a person to faint. This more commonly occurs in older adults.

Other situations or illnesses that can cause syncope or mimic syncope include:

• Head injury
• Seizure
• Stroke
• Inner ear problems
• Dehydration
• Low blood sugar
• Breath-holding episodes (typically in children 6 month to 2 years of age)
• Pregnancy
• Anemia 
• Brain mass
• Aneurysm or abnormality of the blood vessels of the brain
• Urination
• Having a bowel movement
• Coughing

Certain symptoms that occur with syncope may suggest a more serious problem. These include:

• Syncope occurring during exercise or strenuous physical exertion
• Syncope that is accompanied by palpitations or a sensation of rapid heartbeats
• If you have syncope and you have a family history of sudden cardiac death

Some children will have symptoms before they faint. A child may have:

• Dizziness
• Lightheadedness
• Nausea
• Changes in their vision
• Cold, damp skin

There may be enough warning signs that your child will have time to sit or lie down before fainting occurs. This can prevent injuries that may happen from falling during syncope, such as head injury.

The healthcare provider will ask about your child’s symptoms and health history. They will give your child a physical exam. Helpful details you can provide include answers to these questions:

• How often does syncope occur?
• What your child was doing before the syncope?
• Did your child have any symptoms before the syncope?
• What did they eat before the syncope?
• What happened during and after the syncope? Was there any loss of bowel or bladder control?
• Was the syncope witnessed?
• How long did the period of loss of conscious persist after syncope?

Your child's provider will check your child's blood pressure and heart rate. Your child’s blood pressure is usually checked more than once in different positions. It may be taken while your child is lying down, sitting and standing. Your child's provider will look for changes in blood pressure that occur with orthostatic hypotension.

Often your child will not need any tests. If your child's provider thinks there may be a serious problem, they may refer you to a pediatric cardiologist. This is a doctor with special training to treat heart problems in children. They may order tests, such as:

• Electrocardiogram (ECG). This test records the electrical activity of the heart. It shows any abnormal rhythms (arrhythmias).
• Tilt table test. This test checks a child's blood pressure and heart rate while they are in different positions. 
• Holter monitor. This test uses a portable monitor that your child wears for 24 hours or longer. It's used to evaluate irregular, fast or slow heart rhythms while your child does their normal activities, even while away from the provider's office.
• Echocardiogram (echo). This test studies the heart's function. It uses sound waves (ultrasound) to make a moving picture of the heart and heart valves, pumping function and blood flow through the heart.

After an episode of syncope, your child should lie down for 10 to 15 minutes. Or your child can sit with their head between their knees. Give your child a drink of water.

Work with your child's healthcare provider to figure out the cause and ways to prevent further syncope.

If a heart problem is the cause of syncope, the pediatric cardiologist will figure out what treatment is needed. Occasionally, the problem can also be due to a brain problem and may require consultation with a pediatric neurologist.

Most syncope in children is harmless. In a small number of children, serious heart problems may be the cause of syncope. Sudden death can occur.

To prevent passing out caused by dehydration:

• Be sure your child stays well hydrated. Encourage them to drink plenty of water.
• Increase salt intake. Try nonfat salty snacks such as pretzels or crackers.

If passing out occurs when standing too long:

• Advise your child not to lock their knees when standing.
• Advise your child to promote blood flow by relaxing and tightening the leg muscles.

If your child has passed out upon standing:

• Make sure your child sits up slowly and lets their legs hang off the bed. Tell them to wiggle their toes and take a few deep breaths before standing up.

If your child feels like they may pass out, advise them to sit or lie down quickly.

Call your child's provider if they have syncope, especially if:

• It continues even with preventive efforts
• It occurs with irregular heartbeats
• It occurs with exercise
• You have a family history of syncope
• There is no known cause
• It occurs unpredictably and in dangerous situations
• Injuries occur afterwards