See also
Afebrile Seizures
Supraventricular Tachycardia
Coma
Key points
- An arrhythmia should be considered in all children with syncope
- Most paediatric syncope is vasovagal
- A thorough history is the best strategy to determine the cause of syncope and guide further investigation
Background
- Syncope is a brief and sudden loss of consciousness associated with loss of postural tone with spontaneous recovery
- Paediatric syncope is common, with about 15% of children experiencing an episode before the end of adolescence
- Most paediatric syncope is benign and has an autonomic cause (ie vasovagal or orthostatic)
- Syncope is less commonly caused by life-threatening cardiac conditions such as structural abnormalities and arrhythmia
- Neurological conditions such as seizure and migraine may mimic syncope
Assessment
Causes and Differential diagnoses
Autonomic |
Vasovagal syncope (also called neurocardiogenic)
Orthostatic hypotension
Postural orthostatic tachycardia syndrome
Breath-holding spells |
Cardiac |
Brady/tachyarrhythmia
Long QT syndrome
Brugada syndrome
Wolff-Parkinson-White syndrome
Structural abnormalities (eg aortic stenosis, hypertrophic cardiomyopathy) |
Other |
Functional disorder
Hypoglycaemia
Seizure
Migraine
Anaemia
Narcolepsy
Toxic exposure (eg carbon monoxide, clonidine) |
History
The child’s medical history and description of the event, including any previous episodes, is essential in identifying the cause of syncope.
Key features and useful features to differentiate from a seizure:
Feature |
Syncope
(including cardiac and autonomic causes) |
Seizures |
Precipitating events:
Including preceding symptoms and the position in which episode occurred |
Sudden or prolonged standing, painful or emotional stimulus, palpitations |
Usually none |
Period of unconsciousness |
Usually seconds |
Usually more than a few seconds, up to minute |
Incontinence |
Absent |
May be present |
Confusion on waking |
Absent |
Marked for 20-30 mins |
Tonic-clonic movements, presence and timing |
Occasionally & brief particularly if unconsciousness is prolonged (syncopal seizure) |
Frequently present |
Vasovagal syncope is typically preceded by a painful or emotional stimulus and prodromal symptoms such as dizziness, weakness and visual changes.
Red flags for potential cardiac aetiology are:
- lack of prodrome
- palpitations or chest pain
- exercise-induced syncope
- past cardiac history
- family history of early cardiac death, arrhythmia or sudden death
Examination
- Orthostatic heart rate and blood pressure measurements
- Complete cardiac and neurological examination
Management
Investigations
An ECG should be obtained in all children at least once. May not be required if
done previously and there is no additional concern. (see
ECG interpretation)
- A blood glucose level can be useful if the child is seen shortly after the event
- Obtain a full blood count if anaemia is suspected
- Consider pregnancy testing
Treatment
*There may be brief tonic-clonic movements with vasovagal syncope
Children with frequent and/or problematic vasovagal or orthostatic syncope often achieve symptom control by avoiding usual triggers and increasing their fluid and salt intake.
Consider consultation with a local paediatric team when
- Children with a suspicion of cardiac syncope on history, examination or ECG should be urgently referred to a paediatrician or cardiologist
- Children with recurrent vasovagal or orthostatic syncope that do not respond to non-pharmacological treatment could be referred to a paediatrician or cardiologist
- Children with presentations suspicious for seizures should be referred to a paediatrician or neurologist
Consider transfer when
- Children that are persistently symptomatic when seen and/or requiring care beyond the level of comfort of the local hospital
- Children with clustering of syncope with cardiac features
For emergency advice and paediatric or neonatal ICU transfers, call the Paediatric Infant Perinatal Emergency Retrieval (PIPER) Service: 1300 137 650
Consider discharge when
The most likely cause of syncope has been identified and follow up has been arranged
Last updated August 2018