Understanding fainting

Fainting, also known as syncope, can be a scary thing. What does it mean? Is it a sign of a more serious issue? Fainting is actually most common in teens and young adults. Thomas Yohannan, MD, a Le Bonheur pediatric cardiologist, weighs in.

What is syncope?

Syncope is the medical term for fainting or passing out. It is most prevalent in the teenagers and occurs most often in the summer months.

What causes syncope?

A transient and temporary decrease in blood flow to the brain results in a fainting spell.

Symptoms

A syncopal episode may be preceded by premonitory symptoms like chest pain, palpitations, nausea and dizziness. The child or teenager may complain of these symptoms before the actual episode occurs. Or the child may not have any of these presyncopal symptoms and will simply faint.

What are the different types of syncope?

• Vasovagal syncope: The most common cause of syncope irrespective of age, sex or comorbidity is vasovagal. This is usually triggered by pain, fatigue, heat, exercise, stress and even extreme emotions like hearing bad news or excitement while playing video games or watching scary movies. It is common to see a family history of vasovagal syncope in many of these patients.

• Orthostatic syncope: This is secondary to pooling of blood in the legs and occurs mainly when there is a change in position (from sitting or lying down to standing). This type of syncope is exacerbated by immaturity of the vascular tone and autonomic dysfunction.

• Cardiac syncope: Though majority of syncopal episodes in children and teenagers are secondary to benign causes, they could occasionally be linked to a cardiac problem. Cardiac syncope could be secondary to structural heart defect like hypertrophic cardiomyopathy (thickened heart muscle) or aortic stenosis (narrowing of the aortic valve); an irregular heart rhythm caused by Long QT syndrome or other inherited cardiac arrhythmias; or a congenital defect of the coronary arteries (blood vessels that supply the heart).

Other causes of syncope may include seizures, certain kinds of stroke and even something as simple as low blood sugar and dehydration.

When to worry about syncope?

Syncope episodes during exertion or physical activity (like lifting weights, working out in gym, actively playing in the field ) are worrisome and could be due to a cardiac problem as mentioned above. You should also see a doctor about recurrent episodes of syncope or absence of preceding symptoms.

To rule out any serious issues, a visit to a pediatrician is essential to exactly find out the cause of the syncopal episode.

What to expect when referred to a pediatric cardiologist for syncope?

A pediatric cardiologist will need a detailed history and family history as well as a physical examination to determine the cause of syncope. Tests like an electrocardiogram (EKG) and Holter monitor may be ordered to find out rhythm abnormalities. An echocardiogram (ultrasound of the heart) can detect any structural heart defects. In a few cases, a heart catheterization or an electrophysiology study with ablation may be necessary.

More information about syncope can be found at www.healthychildren.org sponsored by the American Academy of Pediatrics.