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Brief Resolved Unexplained Event BRUE

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

  • See also

    Gastrooesophageal reflux in infants
    Afebrile seizures

    Key Points

    1. A BRUE (Brief Resolved Unexplained Event) is an event in an infant that is characterised by a marked change in breathing, tone, colour or altered level of consciousness, that is followed by a complete return to a baseline state, and that cannot be explained by a medical cause.
    2. A BRUE is a diagnosis of exclusion.  There are many diagnosable conditions that cause symptoms similar to that of a BRUE.
    3. Infants that have had a BRUE can be stratified into groups of lower and higher risk of having a repeat event or a serious underlying disorder.  Lower risk BRUE may be safely managed in an outpatient setting.  


    The BRUE guideline replaces the Apparent Life Threatening Event (ALTE) guideline. The ALTE is an older descriptive term for events that are characterised by some combination of “apnoea, colour change, change in muscle tone, or choking and gagging and are frightening to the observer”.  This term has been replaced as it described events that ranged from normal physiological events to pathological events and so was not useful in determining diagnosis, treatment or prognosis.   

    A BRUE (Brief Resolved Unexplained Event) refers to an episode in an infant less than 12 months old which is:

    • Less than one minute duration but typically 20–30 seconds.
    • Accompanied by a return to a baseline state
    • Not explained by identifiable medical conditions.
    • Characterised by  ≥1 of the following
      • Central cyanosis or pallor
      • Absent, decreased or irregular breathing
      • Marked change in tone. (hypertonia or hypotonia)
      • Altered level of consciousness  


    The assessment of the event should be directed at determining the cause of the event and assess for risk factors for recurrence. The differential diagnoses of these events are broad.

    Differential diagnoses

    • Normal physiological response:  laryngospasm, gagging
    • Inflicted injury: (shaken baby, drug overdose, Factitious illness by proxy or intentional suffocation)
    • Infection : Pertussis, septicaemia, pneumonia, meningitis,
    • Airway obstruction: congenital abnormalities, infection, hypotonia
    • Abdominal: intussusception, strangulated hernia, testicular torsion
    • Metabolic problems: hypoglycaemia, hypocalcaemia, hypokalaemia, other inborn errors of metabolism
    • Cardiac disease: congenital heart disease, arrhythmias, vascular ring, prolonged QT. 
    • Respiratory: inhaled FB
    • Toxin / Drugs: accidental or non-accidental
    • Neurological causes: head injury, seizures, infections, cerebral malformations etc.


    History should be taken, ideally first-hand, from persons who observed the infant during or immediately after the event.

    1. Description of event:
      1. Choking, gagging
      2. Breathing: yes/no or attempting to breathe
      3. Colour and colour distribution: normal, cyanosis, pallor, plethora
      4. Distress
      5. Conscious state: responsive to voice, touch, or visual stimulus.
      6. Tone: stiff, floppy, or normal
      7. Movement including eye movements: purposeful, repetitive, or flaccid
    2. Circumstances and environment prior to event:
      1. Awake or asleep and position (prone / supine / side)
      2. Relationship of the event to feeding and history of vomiting
      3. Environment: sleeping arrangement, temperature, bedding
      4. Availability of items that could be swallowed, cause choking or suffocation.
      5. Illness in preceding days
    3. End of event
      1. Duration of event
      2. Circumstances of cessation: self-resolved, repositioned, stimulation, mouth to mouth, chest compressions
      3. Recovery phase: Rapid or gradual
      4. Residual symptoms
    4. Other history:
      1. Past medical history including previous events
      2. Sick contacts
      3. Family history of sudden death or significant childhood illness.


    A detailed general physical examination is required, bearing in mind the differential diagnoses.

    Risk stratification

    It is common for no specific diagnosis to be made after evaluation and a period of observation.  The most common cause of these events is thought to be exaggerated airway reflexes in the setting of feeding, reflux, or increased upper airway secretions.

    If the infant has fully recovered, has benign examination findings and the event meets the criteria for a BRUE, the event can be risk stratified.

    A lower risk BRUE occurs when there are no concerning features on history or examination AND:

    • Age >60 days
    • Born ≥32 weeks gestation and corrected gestational age ≥45 weeks
    • No CPR by trained healthcare professional
    • First event (cannot be lower risk if event has been repeated)
    • event lasted <1 minute

    A lower risk BRUE is unlikely to represent a presentation of a severe underlying disorder and is unlikely to recur.  



    A lower risk BRUE does not require any investigations.  Depending on clinical suspicion, an ECG and pertussis swab may be performed.

    For similar events that fall outside the lower risk BRUE criteria, consider performing the following investigations

      • Full blood examination
      • Urea & electrolytes
      • Blood glucose
      • Nasopharyngeal sample for viruses & pertussis.
      • ECG (measure QT interval)


    If the infant requires ongoing acute treatment, the event is not considered to be a BRUE. 

    Infants who have had a lower risk BRUE may be discharged safely if their parents feel reassured and capable of caring for their infant at home.  It should be acknowledged with the family, that these events are highly anxiety provoking and parents often feel that their child has nearly died.  

    If discharged, it is recommended that these infants have early medical follow up.  In practice, many infants with a lower risk BRUE are admitted to hospital for observation.

    Patients with a higher risk BRUE may still have a benign cause for their symptoms but should be admitted for observation, cardiorespiratory monitoring and paediatric review.   


    Consider consultation with local paediatric team when:

    The event does not meet lower risk BRUE criteria.

    Consider transfer when:

    There is a concern of a serious underlying disorder.

    For emergency advice and paediatric or neonatal ICU transfers, call the Paediatric Infant Perinatal Emergency Retrieval (PIPER) Service: 1300 137 650.

    Consider discharge when:

    There is low clinical suspicion of a serious underlying disorder and the parents are reassured.

    Last Updated August, 2017