From the Guidelines
Vasovagal syncope (VVS) is the most common cause of syncope in pediatrics, occurring in 33% to 80% of children with syncope. The evaluation of pediatric syncope should include a detailed medical history, physical examination, family history, and a 12-lead ECG, as recommended by the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1. Other common causes of syncope in pediatrics include cardiac arrhythmias, such as long QT syndrome and catecholaminergic polymorphic ventricular tachycardia, as well as structural heart disease and neurologic conditions.
Some key characteristics that differentiate VVS from cardiac causes of syncope include:
- The presence of prodromal symptoms, such as nausea, vomiting, and sweating
- The occurrence of syncope in response to specific triggers, such as prolonged standing or emotional stress
- The absence of preceding palpitations or other cardiac symptoms
- A family history of VVS or early sudden cardiac death (SCD) 1
The management of pediatric syncope depends on the underlying cause, with VVS typically managed conservatively through:
- Education on symptom awareness and avoidance of triggers
- Increased fluid and salt intake
- Reassurance about the generally benign nature of the condition 1 In cases where the diagnosis is unclear, tilt-table testing may be useful, and midodrine may be prescribed for patients with VVS who do not respond to lifestyle measures 1.
It is essential to note that while VVS is the most common cause of pediatric syncope, cardiac syncope does represent 1.5% to 6% of pediatric cases, and a thorough evaluation is necessary to rule out potentially life-threatening cardiac causes 1.
From the Research
Common Causes of Syncope in Pediatrics
The most common causes of syncope in pediatrics can be categorized into:
- Neural causes
- Cardiovascular causes
- Other non-cardiovascular causes 2 These causes often lead to a transient global hypoperfusion of the brain, resulting in a sudden, self-limited loss of consciousness and postural tone.
Specific Causes of Syncope
Some specific causes of syncope include:
- Vasovagal (reflex) syncope, which is the most common form of syncope 3
- Orthostatic hypotension, which can be a confounder of vasovagal syncope 4
- Cardiac causes, such as valvular heart disease, cardiomyopathies, and arrhythmias 4, 5
- Vascular causes, such as pulmonary embolism, subclavian steal, and aortic dissection 5
Diagnosis and Management
Diagnosis of syncope is primarily clinical, with objective laboratory investigations adding little to the diagnosis in children, especially in the neurocardiogenic subtype 2. Management depends on the underlying cause of syncope, with cardiac causes requiring early referral to a pediatric cardiology specialist, and neurocardiogenic syncope requiring behavior and lifestyle modifications, followed by drugs in refractory cases 2.