BENIGN FAINTING IN ADOLESCENTS AND CHILDREN
By Thomas M. Biancaniello MD
Having a child faint can be a freightening experience for parents. It is more common than most think, with 15% of kids fainting before reaching the age of 18, with most occurring after puberty begins. Fortunately it is usually not related to heart disease. It usually results from transient falls in blood pressure due to changes in body position (also called orthostatic hypotension – low blood pressure), standing (usually still) in hot environments, acutely painful episodes or periods of fear or anxiety (also called vasovagal). With sudden decreased filling of the heart, there is initial compensation by increasing heart rate, but then a reflex response from the brain can result in slowing heart rate and falling blood pressure. The medical term for this is neurocardiogenic syncope. There may be complete unconsciousness, blacking out (awake but not able to see) or visual phenomenon such as “tunnel” vision, seeing spots, or dizziness.
Whether there is complete loss of consciousness or just dizziness and uneasiness is somewhat dependent on the state of hydration. All of us can experience a bit of dizziness when we get up from a nap or sitting, but usually the feeling is transient. On the other hand, if you are dehydrated without enough fluids in your body, the bottom can drop out and you can faint. This is actually a brain protective mechanism. When not enough blood flow and oxygen are delivered to the brain, this reflex fall in heart rate and blood pressure causes the body to “go to ground” resulting in the head, the heart and the body all being at the same level making it easier from blood to return to the heart without fighting gravity and thus restoring blood flow to the brain.
It is important to recognize that this phenomenon cannot be overcome by “fighting it”. The person should sit or lie down immediately when the feeling comes on and get up slowly only when they feel better. Picking a child up after fainting can actually result in a 2nd episode. If possible someone should get them something to drink. Hyperventilation, which can occur whenever we are in distress, can make this worse, so kids should slow their breathing down by counting to five (5) as they exhale.
It is important to keep well hydrated and avoid precipitating conditions (like hot showers in the morning which dilate vessels and reduce blood flow back to the heart). We encourage kids to drink 8-12 ounces of fluid with breakfast (not just the milk left in the cereal bowl!) because most people are a bit dehydrated after a night’s sleep. We need to compensate for that early in the day. We recommend another 80 ounces during the rest of the day. The best way to judge whether you are drinking enough is the color of the urine – it should clear or light yellow, never dark after the early morning. More fluids are required with heavy physical activity and during hot weather. Kids involved in sports should be encouraged to drink more fluids if the urine remains dark despite following the recommended.
When should a parent worry that something more is going on? If dizziness or fainting occurs during the period of exertion or very shortly thereafter, further evaluation is necessary because during exercise the heart rate and blood pressure should be maintained. If there are associated complaints of palpitations or chest pain before an episode that should also trigger further evaluation. When there is any doubt, consult your physician.
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Thomas Biancaniello, MD is a Professor of Pediatrics (Cardiology) Columbia University Medical Center, Former Chief Medical Officer, Stony Brook University Hospital, Emeritus Professor of Pediatrics and Medicine, Stony Brook University