Brief Resolved Unexplained Events (BRUE) Criteria

Classifies unexplained events in infants and replaces the Apparent Life Threatening Events (ALTE) classification.

Refer to the text below the calculator for more information on the BRUE criteria and its usage in pediatric patients.

The BRUE criteria is to be used in infants aged less than 12 months who are asymptomatic and in their normal state of health at the time of evaluation, where they have been brought in after a brief, unexplained, and now resolved event, consisting of at least 1 of the following:

■ Cyanosis or pallor.

■ Absent, decreased, or irregular breathing.

■ Marked change in tone.

■ Altered level of responsiveness.

Where the BRUE criteria (at least 1 of cyanosis or palor; absent, decreased, or irregular breathing; marked change in tone; altered level of responsiveness) is fulfilled, if all of the following 5 are also met, then the BRUE is considered lower risk.

Episode duration <1 minute

Age >2 months

No history of prematurity (≥32 weeks gestational age or ≥45 weeks postconceptional age)

No prior BRUE

No need for CPR by medical provider


Entry criteria

All four needed to evaluate for BRUE
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About the BRUE risk stratification

In 2016, the American Academy of Pediatrics published a clinical practice guideline that consists of BRUE criteria and a risk stratification algorithm. The guidelines were aimed at updating the previously used term of “apparent life-threatening event (ALTE)” to “brief resolved unexplained events (BRUE)” and at allowing stratification of the infant patients between low and high risk categories.

To be classified as a brief resolved unexplained events (BRUE), all of the following must be true:

Infant <1 year old;

Asymptomatic on presentation (no URI symptoms, no fever);

No explanation for the event after conducting history and physical (e.g. GER, feeding difficulties).

History of sudden, brief, and now resolved episode consisting of ≥1 of the following:

- Cyanosis or pallor;

- Absent, decreased, or irregular breathing;

- Marked change in tone (hyper or hypotonia)

- Altered level of responsiveness.

Then, for a BRUE to be classified as low risk, all five of the following must also be met:

Episode duration <1 minute;

>2 months of age;

No history of prematurity (≥32 weeks gestational age or ≥45 weeks postconceptional age for infants born at <32 weeks);

No prior BRUE;

No need for CPR by medical provider.

Risk in infants presenting with a BRUE was defined by risk of either adverse recurrent events or potential subsequent diagnosis of the infant with a serious underlying disorder. A low risk event is unlikely to represent a severe underlying disorder; and is unlikely to recur.

By using the BRUE definition and framework, infants younger than 1 year who present with a BRUE are categorized either as:

(1) a lower-risk patient on the basis of history and physical examination for whom evidence-based recommendations for evaluation and management are offered;


(2) a higher-risk patient whose history and physical examination suggest the need for further investigation and treatment;

BRUE Criteria Flow Diagram

Source: American Academy of Pediatrics; Brief resolved unexplained events (formerly Apparent life-threatening events) and evaluation of lower risk infants. Pediatrics 2016, 137(5): e20160590.

Examples of possible conditions for BRUE differential diagnosis include:

Cardiac: congenital heart disease, arrhythmias, prolonged QT, vascular ring;

Respiratory: inhaled foreign bodies, airway obstruction incl. laryngomalacia, congenital malformation;

Infection: pertussis, pneumonia, meningitis/encephalitis, uterine tract infection, septicaemia, gastroenteritis;

Gastrointestinal: gastro-oesophageal reflux;

Neurological: head injury, seizures, cerebral malformations;

Metabolic: hypoglycaemia, hypocalaemia, hypokalaemia;

Non-accidental injury: inflicted injury (ex. drug ingestion).

Factors to consider when taking patient history:

General description of event (during, throughout and after);

Past medical history;

Family history;

Social & Environmental history.


BRUE criteria as extracted from other studies

Even before the development of the current BRUE criteria, several studies have looked at the management of apparent life-threatening events in infants, and have sourced different predictive variables of the risk for such event to occur.

The retrospective cohort study (625 patients) of Al-Kindy et al. identified risk factors for “extreme” vital sign changes:

sustained bradycardia;


or desaturation;

post-conceptional age <43 weeks;

premature birth;

upper respiratory infection symptoms;

The study by Mittal et al. on infant ER presentations with ALTE (300 patients) identified the following risk factors and predictors for hospital admission:


abnormal physical examination;

cyanotic color change;

the absence of URI symptoms;


A larger study by Kaji et al. on 832 infants with ALTE presentation retrieved the following indicators:

a significant medical history (e.g. cardiopulmonary or neuromuscular disease);

the presence of >1 event in the preceding 24 hours identified the majority of patients requiring admission.



Original reference

Tieder JS, Bonkowsky JL, Etzel RA, et al. Brief Resolved Unexplained Events (Formerly Apparent Life-Threatening Events) and Evaluation of Lower-Risk Infants. Pediatrics. 2016;137(5)

Other references

Al-kindy HA, Gélinas JF, Hatzakis G, Côté A. Risk factors for extreme events in infants hospitalized for apparent life-threatening events. J Pediatr. 2009;154(3):332-7, 337.e1-2.

Mittal MK, Sun G, Baren JM. A clinical decision rule to identify infants with apparent life-threatening event who can be safely discharged from the emergency department. Pediatr Emerg Care. 2012;28(7):599-605.

Kaji AH, Santillanes G, Claudius I, et al. Do infants less than 12 months of age with an apparent life-threatening event need transport to a pediatric critical care center? Prehosp Emerg Care. 2013;17(3):304-11.

Tieder JS, Altman RL, Bonkowsky JL, et al. Management of apparent life-threatening events in infants: a systematic review. J Pediatr. 2013;163(1):94-9.e1-6.

Specialty: Pediatrics

Objective: Assessment

No. Of Criteria: 13

Year Of Study: 2016

Abbreviation: BRUE

Article By: Denise Nedea

Published On: April 22, 2020

Last Checked: April 22, 2020

Next Review: April 22, 2025