Few things are as scary to parents as seeing their child faint and crumple to the ground.

In my practice I am frequently asked to see children who faint. They may be young children who are upset or crying or growing adolescents who faint in the morning when getting out of bed. Often these fainting episodes are harmless. But they could indicate an underlying problem.

Dr. Ronald Kanter discusses some of these conditions and what to look for in case it is something more serious.

-- Dennis Clements, MD, PhD, MPH

Ronald J. KanterWhen a child or teen faints, especially at school and in the presence of peers, it is often very upsetting to other children and can be a source of great embarrassment to the child who has fainted.

There are many causes of syncope -- the medical term for fainting -- in the young, and happily, most do not represent a life-threatening condition.

But less common -- and far more dangerous -- conditions may first show themselves as syncope. Because of this, children who have fainted need to be seen by a health care professional to rule out serious causes and to recommend therapy to limit or eliminate further fainting events.

Syncope (pronounced: sĭng’-kə-pē) occurs at least once during childhood in over 15 percent of youth, especially teenagers. Syncope is said to have occurred when a child suddenly loses consciousness and the ability to maintain upright posture and then spontaneously recovers.

Syncope happens when there is sudden interruption of necessary nutrients to the brain, especially oxygen. Since oxygen is carried by the bloodstream, any condition which causes a sudden drop in blood pressure to the brain may therefore cause syncope.

If such a circumstance sustains, sudden death may ensue (such uncommon diseases will be discussed later in this article). Far more commonly, sudden drops in blood pressure occur as an exaggerated reflex or due to suddenly rising from a lying or sitting position.

Once the fainting youngster becomes horizontal on the ground, blood returns to the heart and brain, and he or she quickly regains consciousness.

Causes of Syncope

What causes the “common faint” is actually a kind of reflex that is theoretically hard-wired into all humans, and, in fact, many mammals. When we use the word “reflex”, we refer to an automatic reaction by the body to a particular stimulus.

In this instance, the automatic reaction is a sudden drop in heart rate or blood pressure, as mentioned above. The provocative stimulus most commonly is an exaggerated and sudden adrenalin effect on the heart due to any of a variety of events:

• Posture-related pooling of the circulating blood volume while sitting or standing for prolonged periods
• Unexpected minor trauma; the sight of blood or injury (“blood/injury syncope”)
• Even listening to a discussion of frightening or graphic subjects

These together are called “vasovagal syncope”, also known as “neurally-mediated syncope” or “neurocardiogenic syncope.” All three terms are synonyms.

Less commonly, syncope may reflexively occur during brushing of one’s hair (“hair-groomer’s syncope”), vigorous arching of the back and extending the neck while stretching (“stretch syncope”), urination (“micturition syncope”), and even chewing food (“deglutition syncope”).

Reflexive syncopes of the types described above always spontaneously terminate, and are therefore only dangerous if they cause head trauma during the syncopal episode.

“Pallid breath-holding spells” are a form of vasovagal syncope that affect toddlers in response to sudden fright, frustration, or mild head trauma. They are not any more serious than the teenage forms.

Syncope may have an emotional basis, including hyperventilation or syncope-like events caused by more severe psychologic conditions (so-called “conversion reaction”). These children and teens typically faint in the presence of others and not while alone.

Syncope that occurs during physical exertion, especially when actually in motion, may have a more serious cause and may be due to a primary heart condition. Such events may be preceded by palpitations or chest pain and always warrant a more complete evaluation, often by a pediatric cardiologist.

Evaluation of the Child Who Faints

Among reflexive forms of syncope, your health care professional can usually make the correct diagnosis from a description of the event by the patient and parents.

In particular, vasovagal syncope is typically preceded by a brief period of such symptoms as dizziness, lightheadedness, nausea, changes in vision or hearing, or a feeling of warmth.

After recovery from a fainting event, children are almost always fully oriented, but may feel weak, nauseous, or tired for minutes to hours.

Reflexive syncope may even be associated with seizure activity or urinary incontinence, although such events often warrant a more complete evaluation by a pediatric neurologist or cardiologist.

After the first fainting event, the provider will also always obtain a family history, perform a complete physical examination, and may perform an electrocardiogram. Vasovagal syncope often runs in families, and certain serious heart diseases which cause syncope may also be genetic.

Children who faint during sports participation should not be permitted to return to strenuous activities until they have been fully evaluated and cleared by a qualified provider. In addition to the aforementioned evaluation, echocardiography, exercise testing, ambulatory heart rhythm monitoring, and even cardiac catheterization may be necessary.

Treatment of the Child Who Faints

Vasovagal syncope is most commonly treated by such simple strategies as improving daily fluid intake and reducing chronic physical or emotional stresses.

If this approach fails, evaluation by a cardiologist or neurologist is imperative. They will likely perform an electroencephalogram (EEG) or an electrocardiogram (ECG) and a “tilt table test."

A tilt table test is an out-patient procedure, during which the child is comfortably secured to a special table capable of propping him or her up to an almost standing posture but without the ability to move or shift their weight. It tends to provoke vasovagal symptoms during continuous heart rhythm and blood pressure monitoring in those prone to vasovagal syncope, all in a safe and controlled environment.

After those tests, medications may be prescribed to help minimize symptoms. Finally, emotional causes of syncope require intervention by a mental health expert.

Ronald J. Kanter, MD, is an associate professor of pediatrics and director of pediatric electrophysiology. His team takes care of infants, children, teenagers, and young adults who have or potentially have abnormal heart rhythms, pacemakers, or automatic defibrillators.

Dennis Clements, MD, PhD, MPH, is the chief of primary care pediatrics at Duke Children's Hospital.