Syncope


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    This guideline has been adapted for statewide use with the support of the Victorian Paediatric Clinical Network

  • See also

    Afebrile Seizures guideline
    Supraventricular Tachycardia guideline
    Coma guideline

    Key Points

    1. An arrhythmia should be considered in all children with syncope.
    2. Most paediatric syncope is vasovagal
    3. 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 (i.e. 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 (e.g. aortic stenosis, hypertrophic cardiomyopathy)

    Other

    Functional disorder
    Hypoglycaemia
    Seizure
    Migraine
    Anaemia
    Narcolepsy
    Toxic exposure (e.g. 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

    syncope diagram

    *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