Apparent Life Threatening Events


A 6-month old infant is presented to the Emergency Department by his parents with a history of a ‘floppy’ episode approximately 30 seconds in duration. It was noted that he did not respond to his mother’s voice and she was concerned enough to call an ambulance.

Transport to hospital by ambulance, was reported as uneventful by the paramedic attending the family.

A full history including; extensive maternal antenatal, birth and family history should be explored in detail in order to exclude potential differential diagnosis (see later). Along with careful head-to-toe clinical examination of the infant, which with this presentation will often expose little with regard to signs and symptoms at the point of assessment, as generally the child’s condition will have completely resolved.

So what?

The term Apparent Life Threatening Event (ALTE) originated to replace the term ‘near miss sudden infant death syndrome’ (NIH, 1986). This term was originally changed as its clinical application potentiated parental concern and challenged the clinician’s evaluation of these presentations. Further research has subsequently found that for the majority of infants, who appear well after the event, the risk of serious underlying disorder or recurrent event is extremely low (McGovern & Smith, 2004).

Also known as Brief Resolved Unexplained Event (BRUE) as described by Tieder, J. S. et al (2016), the application of both terms are dependent on the subjective experience of parents (caregivers) who witness the event. Defined clinically as an event lasting <1 minute in an infant <1 year of age, that is associated (as ALTE) with some combination of signs and symptoms as listed below (Tieder et al, 2016).

– frightening to the observer
– apnoea (central or obstructive) – absent, decreased, or irregular breathing
– colour change (cyanosed or pallid) or occasionally redness (i.e. erythematous or plethoric) – cyanosis or pallor
– marked limpness – marked change in muscle tone (hypertonia or hypotonia)
– choking or gagging – altered level of responsiveness

ALTE and BRUE are both diagnoses of exclusion and reached only when there is no qualifying explanation for the witnessed event, and where consideration of alternative differential diagnosis has been undertaken following comprehensive history-taking and clinical examination by a competent and experienced paediatric clinician.

Differential Diagnosis:

  • Child Abuse (e.g. Non Accidental Injury, Fabricated Illness)
  • Congenital Abnormality (examination should also include looking for signs of dysmorphia for eaxmple)
  • Central Nervous System Disease (e.g.Epilepsy)
  • Metabolic Disorders (Inborn)
  • Infection/Sepsis

Or symptoms may have characteristics of a less concerning event (which can include):

  • periodic breathing of the newborn
  • dysphagia
  • gastroesophageal reflux disease (GORD)

It should be remembered that there is no clinical practice without risk, but in order to determine a lower risk BRUE the following criteria should be met (figure 1). This contrasts with the higher risk presentations, which require immediate referral for further investigation and management.

Figure 1. Developed from Tieder et al (2017)

– Age >60 days – Age <60 days
– Gestational age ≥32 weeks and post-conceptional age ≥45 weeks – Gestational age <32 weeks and post-conceptional age <45 weeks
– First episode – Previous episodes
No health professional cardiopulmonary resuscitation (CPR) required – Health professional Cardiopulmonary resuscitation (CPR) undertaken
No features in the history of concern


– Features in the history of concern (e.g. possible child abuse, family history of sudden unexplained death, toxic exposures)
No worrisome physical exam findings


– Worrisome physical exam findings (e.g. bruising, cardiac murmurs, organomegaly)

Discharge of infants assessed as fitting the lower risk criteria is not without risk and consideration for appropriate paediatric follow-up and parental training in cardiorespiratory resuscitation (CPR) should be available prior to discharge.

Now what?

Infants less than 1-year of age presenting to the ED with features of ALTE/BRUE should be assessed by a clinician with Paediatric training and experience. Early reference to local clinical pathways should ensure either safe discharge or access to appropriate further investigation and management. For some departments this will mean automatic referral to Paediatric services.

Shiela Pantrini


For further FOAMed (from the always excellent FOAMCAST), access the link below;




Driscoll, J. (2007) Practicing clinical supervision: a reflective approach for healthcare professionals (2nd edition). Elsevier, Edinburgh.

McGovern, M.C. & Smith, M.B. (2004) Causes of apparent life threatening events in infants: a systematic review. Archives of Disease Child 89(11):1043-48.

National Institute of Health (NIH)(1986) Infantile apnea and home monitoring. [on-line] National Institute of Health Consensus: Development Conference Consensus Statement 6(6):1-10 (accessed 31st March 2017)

Tieder, J.S., Bonkowsky, J.L., Etzel, R., Franklin, W.H., Gremse, D.A., Bruce, E., Katz, E.S., Krilov, L.R., Merritt, J.L., Norlin, C., Percelay, J., Sapien, R.E., Shiffman, R.E., Smith, M.B.H. (2016) Brief Resolved Unexplained Events (BRUE) formerly Apparent Life-Threatening Events (ALTE) and evaluation of lower risk infants. American Academy of Pediatrics. 137(2)

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