Authors: Hiba Ahmed / Editor: Liz Herrieven / Codes:  / Published: 09/08/2022

Tommy is a 5-month-old infant brought in by ambulance after an episode at home where he went floppy and dusky in colour, witnessed by his parents. They were about to start mouth to mouth when Tommy started moving again and his colour improved.

Tommy was born preterm at 33 weeks gestation and discharged from the neonatal unit in good condition with no prematurity complications.

Tommy, now in the ED, looks alert and pink and is smiling at his mum.

His heart rate is 110/min, respiratory rate 36/min, temp 37.1 C, SPO2 97% on air and youve even got a BP, which is 95/45.

What is your approach? What red flags do you need to consider? Are you going to carry out any investigations? If yes, which ones? Does Tommy need admission or can he be sent home?

History is key. Ideally it should be first-hand, from someone who observed the infant during or immediately after the event. Key features of the history should include:


Circumstances and environment prior to event

  • Awake or asleep?
  • Relationship of the event to feeding and any history of vomiting
  • Position (prone/supine/on their side)
  • Environment: sleeping arrangement, co-sleeping, temperature, bedding
  • Objects nearby that could be swallowed, or cause choking or suffocation
  • Illness in preceding days


Description of event

  • Choking, gagging?
  • Breathing: struggling to breathe, any pauses, apnoea?
  • Colour and colour distribution: normal, cyanosis, pallor, plethora
  • Any distress?
  • Conscious state: were they responsive to voice, touch, or visual stimulus?
  • Tone: did they feel stiff, floppy or normal?
  • Movement (including eyes): Purposeful? Repetitive?

End of event

  • Duration of event
  • Circumstances of cessation: self-resolved, repositioned, stimulation, mouth to mouth and/or chest compressions
  • Recovery phase: rapid or gradual.

Any safeguarding concerns?

  • Multiple or changing versions of the history?
  • Any delay in seeking help?
  • Inconsistencies with developmental age of the child?
  • Unexplained bruising? Unexplained bleeding from the nose or mouth?
  • Does the infant have a Child Protection Plan?

Other history

  • Past medical history including previous similar events
  • Preceding/intercurrent illness
  • Sick contacts
  • Family history of sudden death or significant childhood illness
  • Patient medications, plus medications or other drugs within the home
  • Social history parental support, psychosocial assessment

Examination is next, including a full A to E assessment, observations and, ideally, plotting weight, length and head circumference.

Could this be a BRUE? A BRUE is a brief, resolved, unexplained event.

Before diagnosing it, you need to consider the alternatives.

  • Infection: bacterial: meningitis, septicaemia, viral: URTI, pertussis, RSV, etc.
  • Airway obstruction: congenital abnormalities, infection, hypotonia, gastro-oesophageal reflux, vascular ring
  • Metabolic problems: hypoglycaemia, hypocalcaemia
  • Cardiac disease: congenital heart disease, arrhythmias
  • Toxin / Drugs: accidental or non-accidental
  • Neurological causes: head injury, seizures, infections
  • Inflicted injury: shaken baby, drug overdose, fabricated or fictitious illness (members only learning session here)

Your history and examination should be able to exclude many of these.

The next thing to consider is whether this is a high or low risk event. Those at higher risk are infants under two months of age, those born earlier than 32 weeks gestation and those who have had more than one episode. High risk events also include those in which CPR was given by a healthcare professional (as they were obviously concerned enough to start it) and those lasting longer than one minute.

Infants presenting at low risk dont usually need any investigations, although you may consider a blood glucose and/or urinalysis depending on the situation. Those at higher risk should be discussed with a senior ED or Paediatric doctor. You might consider FBC, U&Es, CRP, glucose, blood gas (capillary or venous) and ECG, for starters.

Often, parents feel as if their child has nearly died during these events, which can cause enormous anxiety and fear in the family.

BRUE patients at low risk may be discharged safely if their parents are confident they can take care of their child at home after the episode. If discharged, it is recommended that these infants have early medical follow-up. In practice, many infants with a low-risk BRUE are admitted to the hospital for observation for parental reassurance. Clinicians should also educate caregivers about BRUEs and engage in shared decision making to guide management and follow-up.

High-risk BRUE infants may have benign causes for their symptoms but should be admitted for observation, pulse oximetry (or cardiac telemetry if there is a suspicion of arrhythmia) and paediatric review.


What do I need to know?

What should I stop doing?

  • Stop using the term ALTE (its especially scary for parents)
  • Avoid admitting infants to hospital for observation beyond 14hours in low-risk BRUE where possible.
  • Dont routinely perform a blood gas or other blood tests in low-risk BRUEs.

What should I start doing?

  • Reassure parents and be confident in conservative management.
  • Recognise that the BRUE definition is more precise. Cough, fever, reflux, symptoms of viral upper respiratory tract infection, unresolved episodes or significant family history all need managing separately from these guidelines.

What can I continue to do as before?

  • Consider alternative diagnoses throughout assessment.
  • Continue to be vigilant to safeguarding concerns.
  • Continue to involve parents in agreed management plans.
  • Continue to offer life support training to parents.

Other RCEMLearning Resources


  1. Melbourne, T., n.d. Clinical Practice Guidelines: Brief Resolved Unexplained Event BRUE. [online] [Accessed 7 April 2022].
  2. Starship Child Health, BRUE brief resolved unexplained events. [Accessed April 2022].
  3. S Farquharson, S Foster, Brief resolved unexplained event or BRUE (ALTE guideline update). [Accessed May 2020].
  4. Tieder JS, Bonkowsky JL, Etzel RA, Franklin WH, Gremse DA, et al., Brief Resolved Unexplained Events (Formerly Apparent Life-Threatening Events) and Evaluation of Lower-Risk Infants. Pediatrics. 2016 May;137(5):e20160590.
  5. Tate C, Sunley R. Brief resolved unexplained events (formerly apparent life-threatening events) and evaluation of lower-risk infants. Arch Dis Child Educ Pract Ed. 2018 Apr;103(2):95-98.
  6. Landing page image by Aditya Romansa on Unsplash.

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