Story by: Christopher L. Johnsrude, M.D. on April 23, 2019
Anytime a child or teenager faints, “passes out” or loses consciousness, family members — as well as the child or teen — often worry there might be something terribly wrong. The good news is that fainting or syncope (pronounced sin-koh-pee) in most older children and teenagers who are otherwise healthy does not automatically mean that they have a life-threatening condition. Having said that, even a harmless (benign) faint can cause problems, such as getting hurt after falling down or not being able to play sports because parents and coaches worry something bad might happen. Also, it is important to realize that in some rare circumstances, syncope actually may be due to a more serious underlying condition.
To understand why someone who is otherwise healthy might lose consciousness, think about what happens whenever you stand upright from a sitting or lying down position. As soon as you stand up, gravity tends to force much of your blood down into the blood vessels of your legs and feet. If your body didn’t respond appropriately, the blood would pool down there, so less blood would flow up to your brain. If your brain didn’t have the right amount of blood flow, you would first start to feel lightheaded or dizzy. If blood flow to the brain didn’t improve soon, you may see spots or graying out, and your hearing may become muffled. Next, you’d feel like you were about to faint, and then you actually would faint, and fall to the ground. Once flat on the ground, the force of gravity wouldn’t be a problem anymore, blood flow to the brain would be restored, and you’d wake up soon thereafter, usually feeling dizzy, disoriented and tired.
Fortunately, our bodies have intrinsic mechanisms to not let this happen every time we stand up. The first thing that happens upon standing is that the nervous system detects the gravity-related displacement of blood to the lower parts of the body. The nervous system then “tells” the blood vessels in the legs to tighten up, which starts to “milk” the blood back up to the head. In addition, the nervous system “tells” the heart to beat harder and faster, also helping to pump blood up to the head. When working correctly, all of these things happen automatically, without you even noticing it.
The most common reason that otherwise healthy young people experience profound dizziness or faint when upright is that the nervous system gets its signals crossed, not coordinating the blood vessels and heart like it should. In some people, this cross-firing may be triggered by other factors such as a hot shower, the sight of blood, hair combing, etc. This condition has many names in the medical literature, including:
Most people who have this problem don’t get dizzy or pass out every single time they get up, take a shower, etc. Instead, they often have good days (when they feel pretty good with minimal symptoms all day long) and bad days (when they have more problems with dizziness, fatigue, fainting and afternoon headaches).
Although feeling really dizzy or fainting certainly can be uncomfortable, usually it can be treated with some self-awareness and attention to nutrition and behavior. Some patients only feel better when using medications. The good news is that this condition is usually temporary, and most children and teenagers eventually outgrow it over time.
Rarely, a child or teenager faints from a serious underlying heart condition, when the heart has temporarily stopped or not pumped effectively, resulting in a brief period of diminished blood flow to the brain. Numerous kinds of heart disease can cause this. Some of the conditions interfere with normal contractions or the “plumbing” of the heart are: cardiomyopathy, aortic stenosis, pulmonary hypertension and others. Other conditions interrupt normal cardiac rhythm: heart block, Wolff-Parkinson-White (WPW) syndrome, Long QT Syndrome, catecholaminergic polymorphic ventricular tachycardia and others. The primary concern for patients with a true heart condition is that the faint represented a temporary problem with the heart’s pumping function, and what would happen if that lasted longer or didn’t stop?
The primary purpose of the initial evaluation for anyone who has fainted is to decide whether there is a serious underlying condition. The keys to sorting this out are taking a careful health history (focusing on the exact details of what the patient experienced before, during and after the faint) and performing a careful physical exam. Things that may point to a serious problem include:
Depending on the circumstances of each patient, sometimes tests help to confirm or rule out serious conditions. Such tests for children and teens who have fainted can include: electrocardiogram, echocardiogram, treadmill stress test, Holter or event monitor, electroencephalogram (EEG), brain magnetic resonance imaging (MRI) scan, and blood and urine lab work.
For individuals who faint or have significant dizziness while standing (so-called orthostatic dizziness), there are several ways to improve symptoms and reduce the chance of future episodes. Our main recommendation is for the patient to markedly increase fluid intake each day: We often recommend a teenager drink at least two 12-ounce glasses of noncaffeinated beverage at breakfast, lunch and supper, and try to drink even more between meals. It is important to start the day with fluids, not to skip meals, to allow the child/teen to have a water bottle at school, and to understand he or she may need to use the bathroom more often than others. Another dietary recommendation is increasing salt in the diet (sodium, not potassium). Salt helps the body hold onto fluids; caffeine, on the other hand, is a diuretic that makes it harder for the body to hold onto fluids. Please note, increasing salt may not be a good idea for patients with pre-existing hypertension, heart failure or kidney disease – most childhood fainters who are otherwise healthy don’t have those problems.
We also emphasize that the patient try to recognize the early warning signs of an impending faint. For example, if the child feels dizzy and it progresses, a faint may be coming soon, so he or she should sit down or lie down until the dizziness passes. Some people have fewer symptoms by avoiding long hot showers first thing in the morning, instead taking shorter and less hot showers after supper the night before, when they’ve had plenty to eat and drink all day long. In addition, regular exercise (emphasizing the legs) is also recommended, as that improves the body’s ability to handle blood flow to the brain when you’re upright. Patients who continue to have symptoms despite these recommendations often benefit from one or more medications such as fludrocortisone, midodrine, beta blockers, selective serotonin reuptake inhibitor (SSRI) agents, etc.
Unfortunately, patients who have fainted and have serious cardiac conditions often do not improve with these treatments, and instead may require more invasive treatments such as other more potent medications, catheter-based intervention, implantation of a pacemaker or cardioverter-defibrillator, and/or cardiac surgery.
Christopher L. Johnsrude, M.D.,is an associate professor in the University of Louisville Department of Pediatrics and serves as director of the pediatric arrhythmia service at Norton Children’s Hospital.