Evidence Based Strategies: Sudden Scares: Understanding Brief Resolved Unexplained Events (BRUE)

Column Author: Tess Schultz, DO | Resident PGY 3

Column Editor: Angela D. Etzenhouser, MD, FAAP | Associate Director, Pediatric Residency Program

A brief resolved unexplained event (BRUE) is a term used to describe a sudden, brief episode in an infant that involves a change in breathing, color, muscle tone or responsiveness that resolves on its own and cannot be explained after a thorough medical evaluation. Primary care providers need to understand BRUE in order to effectively manage it and, when appropriate, reassure concerned families. 

Definition and Diagnostic Criteria: 

BRUE, previously known as apparent life-threatening event (ALTE), is defined by the American Academy of Pediatrics (AAP) as an event occurring in an infant younger than 1 year of age when the observer reports a sudden, brief (less than one minute) and then resolved episode of one or more of the following: cyanosis or pallor; absent, decreased, or irregular breathing; marked change in tone (hyper- or hypotonia); or altered level of responsiveness.4 

Risk Stratification: 

Risk stratification is an important initial step in the evaluation and management of BRUE. Infants are categorized into lower-risk and higher-risk groups based on factors such as age, event characteristics and medical history. Lower-risk infants typically do not require extensive testing or hospitalization, while higher-risk infants may need further evaluation and monitoring. Lower-risk BRUE criteria include age >60 days, gestational age at birth >32 weeks AND postconceptional age >45 weeks, no history of BRUE, single event, duration of event less than one minute, no CPR required by trained medical provider, and no concerning historical features or physical exam findings.2,5 

Evaluation and Management: 

The evaluation of BRUE involves a detailed history and physical examination for risk stratification and identification of any underlying causes. For lower-risk infants, detailed recommendations on evaluation and management from the AAP can be found here: https://publications.aap.org/pediatrics/article/137/5/e20160590/52195/Brief-Resolved-Unexplained-Events-Formerly5 

In general, this clinical practice guideline recommends against extensive laboratory testing, imaging and diagnostic studies for infants at lower risk and emphasizes parental education on BRUE, provision of resources, and shared decision-making. There is no formal guideline for management of higher-risk BRUE, but initial investigation should be prompt and guided by the history and physical exam. Evaluation may require prolonged vital sign monitoring, laboratory studies, imaging and possibly admission for observation.4 

Prognosis and Follow-Up: 

Most infants who experience a BRUE have a good prognosis. A meta-analysis by Brand and Fazzari (2018) emphasized that the risk of death in infants who experienced a BRUE is low, especially in those categorized as lower risk.1 Infants presenting with lower-risk BRUE may not require hospitalization, but close follow-up within 24 hours of the initial visit is recommended.5 Follow-up care should include educating parents about recognizing and responding to potential future events, including CPR education.   

Understanding BRUE and its management is vital for primary care providers. By following the guidelines for risk stratification and evaluation, health care professionals can provide appropriate care and reassurance to families, ensuring the wellbeing of their infants. 

For additional evidence-based guidance, Children’s Mercy’s clinical pathway for the evaluation and management of BRUE can be found at Brief Resolved Unexplained Event (BRUE) | Children's Mercy Kansas City (childrensmercy.org).

References: 

1. Brand DA, Fazzari M Risk of death in infants who have experienced a brief resolved unexplained event: a meta-analysis. J Pediatr. 2018;197:63-67. doi:10.1016/j.jpeds.2017.12.028

2. Colombo M, Katz ES, Bosco A, Melzi ML, Nosetti Brief resolved unexplained events: retrospective validation of diagnostic criteria and risk stratification. Pediatr Pulmonol. 2019;54(1):61-65. doi:10.1002/ppul.24195

3. Fu LY, Moon R Apparent life-threatening events: an update. Pediatr Rev. 2012;33(8):361-368. doi:10.1542/pir.33-8-361

4. Merritt JL II, Quinonez RA, Bonkowsky JL, et al. A framework for evaluation of the higher-risk infant after a brief resolved unexplained event. Pediatrics. 2019;144(2):e  

5. Tieder JS, Bonkowsky JL, Etzel RA, et al. Brief resolved unexplained events (formerly apparent life-threatening events) and the evaluation of lower-risk infants. Pediatrics. 2016;137(5):e