Syncope in Children: A Treatable Dilemma in Primary Care

Kathryn K. Collins, MD
Associate Professor, Pediatrics, University of Colorado
Director, Pediatric Arrhythmia Center and Adult Congenital Electrophysiology

Jeffrey J. Cain, MD
Associate Professor, Family Medicine, University of Colorado
Chief, Family Medicine, Children's Hospital Colorado

Fainting and syncope are common complaints for children in primary care. Although most children with syncope may be managed in primary care, syncope may also be the first symptom in serious cardiac disease that requires consultation with a pediatric cardiologist.

What are the keys in the history and physical that can help us best manage these children in our offices and when should we refer those children with more serious disease?

Syncope is defined as an abrupt loss of consciousness and postural tone followed by relatively prompt recovery over a period of minutes. It is a common occurrence in children, withthe highest incidence seen in teenage girls. As many as 10-40% of adolescents report either fainting or have significant presyncopal symptoms. At Children's Hospital Colorado Heart Institute, syncope is the referring complaint in five percent of all patients seen in a cardiac consultation in the outpatient setting. 

The syncopal conundrum is that simple fainting, also referred to as vasovagal or neurocardiogenic syncope, is a benign finding and most patients can be appropriately managed in the primary care setting with minimal evaluation or intervention. But on the other hand, there is a concern that syncope may be the first or presenting symptom for one of the more malignant diseases which can cause sudden cardiac death (Table 1).  

Although sudden cardiac death in the pediatric population is extremely low, it is always a terrible tragedy for the family and the community when a young individual who was thought to be healthy dies suddenly and unexpectedly from a previously undiagnosed cardiac cause.

How can we differentiate between benign syncope and the potential for sudden cardiac death?

Patient history for vasovagal syncope

The classic story for vasovagal syncope would be for a pre-teen or teenager who reports prolonged standing on a hot day, such as at choir or band practice. Alternately, the patient may also report prolonged sitting and then an abrupt position change to standing. Commonly there is often a report of not having eaten or drank much on that specific day. Usually children with vasovagal syncope will complain of prodromal symptoms of feeling warm, slight dizziness, seeing spots, tunnel vision or a general sense of unease. During the syncopal episode, the patient will pass out for a brief period of time and then recover without intervention. When the patient recovers from the loss of consciousness, they may continue to be pale, somewhat dizzy and typically quite exhausted.

Other classic stories for vasovagal syncope include specific triggers such as the sight of blood, having blood drawn, or a noxious stimuli like hitting their elbow. Hair grooming syncope or micturition syncope have been reported. In a toddler, the story may include crying uncontrollably followed by pallid breath-holding spells. 

Patient history for cardiac syncope

In contrast to vasovagal syncope stories, patient histories for sudden or aborted cardiac death involve abrupt collapse with few or no prodromal symptoms. A typical story would be a previously healthy young athlete who was running down the basketball court and then drops to the floor in mid-stride. These patients are not even able to try to catch themselves as they fall and may sustain injuries secondary to the fall. Several cardiac conditions with no previous symptoms can present with exercise-associated syncope, including hypertrophic, dilated and electrical myopathies. While symptoms of palpitations, urinary incontinence, onset with exercise, or onset while sitting or supine could raise the suspicion of serious arrhythmia, none are diagnostic. 

Thus, all patients with syncope during or around exercise deserve prompt cardiac referral and additional testing. 

Other important factors that may indicate cardiac sources could be syncope associated with loud noises or with extreme emotion and is often associated with prolonged QT syndrome. 

Because many cardiac diseases in children have a genetic background, it is important to gather any pertinent family history relating to early, sudden or unexplained deaths. And, in reverse, a sudden or unexplained death in another family member should prompt consideration for screening other family members.

Cardiac evaluation

The diagnosis of neurocardiogenic syncope can be confidently made in most children with a detailed history, physical examination and electrocardiogram. In one study of patients 

referred to a pediatric cardiology practice for evaluation of syncope, five percent were found to have cardiac syncope. Of those, almost all could be identified by syncope with exercise, an abnormal electrocardiogram, a family history of arrhythmia, or an abnormal physical examination. Family history should focus on sudden or unexplained death prior to age 40, congenital deafness, or cardiomyopathy. Physical examination should focus on orthostatic vital signs, a detailed cardiac examination for murmurs, and a neurologic examination. Examination should also explore for any signs of systemic disease, such as connective tissue disease like Marfan syndrome.

The electrocardiogram is a good screening tool that can show signs of left ventricular hypertrophy (suggestive of hypertrophic cardiomyopathy), Wolff-Parkinson-White syndrome, conduction defects, and electrical myopathies such as long QT syndrome but does not screen for coronary abnormalities. Further evaluation with 24-hour Holter monitoring, event recorders, or loop recorders can be used as a means to correlate symptoms with any cardiac rhythm abnormality.

Routine echocardiographic screening for syncope has very low yield. In most instances, the reason to do an echocardiogram is to demonstrate absence of serious disease. If the history or electrocardiogram demonstrates some abnormality, then an echocardiogram would be the next step for determining such diagnoses as hypertrophic cardiomyopathy or abnormal coronary artery origins.

Treatment and clinical course for vasovagal syncope

Initial treatment for vasovagal syncope is volume expansion through increasing salt and water consumption. Patients can also learn to be more aware of prodromal symptoms and can choose to sit or lie down in order to avoid a frank syncopal episode. Behavioral therapy has been supported in the literature. Pharmacologic management is also available, albeit very imperfect, through medications such as fludrocortisones, betablockers, midodrine or serotonin reuptake inhibitors. Neurally mediated syncope is not associated with any increased risk for mortality. Most adolescents appear to outgrow their episodes over several years.

Summary

Neurocardiogenic syncope, or vasovagal syncope, is a common occurrence in childhood. A thorough patient history, family history and physical examination are the main means of diagnosing this condition which can be managed in primary care. A referral to a pediatric cardiology clinic should be made if there is syncope with exercise, a family history of sudden or unexplained death or abnormal physical examination findings.