Essentials Masterclass: BRUE

A BRUE is a sudden, brief, resolved event in an infant under 1 year with cyanosis or pallor, abnormal breathing, tone change, or altered responsiveness—and if history or exam reveals a cause, it is not a BRUE. Most low-risk infants need little testing, while non-low-risk cases hinge on targeted evaluation and disposition.

BRUE Definition and Risk Stratification

• Core BRUE definition: BRUE applies only to infants under 1 year after a sudden, brief, fully resolved episode with cyanosis or pallor, abnormal breathing, marked tone change, or altered responsiveness.
• Not a BRUE clues: A diagnosis from the history or exam takes the child out of the BRUE bucket; choking or gagging is one of the most common mimics, and a symptomatic infant at presentation is not a BRUE.
• Low-risk criteria framework: Only about 15% of infants meet low-risk BRUE criteria, which require an older infant, a single short event, no concerning history, and a reassuring physical exam. We walk through the practical risk split in the episode.
• Abuse red flags: Non-accidental trauma remains a key alternative diagnosis, with concerning bruising, injury patterns, or social risk factors carrying special weight in a preverbal infant.
• High-risk clinical context: Age under 2 months, prematurity, recurrent episodes, provider-delivered CPR, or preceding fever, poor feeding, lethargy, or URI symptoms should push evaluation beyond the low-risk pathway.

Evaluation, Etiologies, and Disposition

• Low-yield routine testing: For low-risk BRUE, routine diagnostic testing has low utility; the two studies with the best yield are an ECG and pertussis testing.
• Common final diagnoses: When a final diagnosis is eventually found, about two-thirds are gastroesophageal reflux and roughly 10% are seizures, with feeding problems and laryngomalacia also showing up.
• Serious alternate diagnoses: Seizures, airway anomalies, serious bacterial infection, inborn errors of metabolism, toxin exposure, and non-accidental trauma make up the dangerous minority, especially in non-low-risk infants.
• Observation and discharge: Low-risk infants can usually go home with follow-up within 24 hours, while non-low-risk infants may need a short ED observation period or discharge after a targeted workup and shared decision-making.
• Counseling and follow-up: Discharge counseling should cover safe sleep, recurrence precautions, and the fact that home cardiorespiratory monitors are not routinely recommended. The return-precaution language is worth hearing in the chapter.

References:

1. Pitetti R. Defining Risk Factors for Children Following a BRUE: The Need to Revisit the AAP BRUE Guideline. Pediatrics. 2021 Jul;148(1):e2021049933. PMID: 34168060.
2. Bochner R, et al; BRIEF RESOLVED UNEXPLAINED EVENT RESEARCH AND QUALITY IMPROVEMENT NETWORK. Explanatory Diagnoses Following Hospitalization for a Brief Resolved Unexplained Event. Pediatrics. 2021 Nov;148(5):e2021052673. PMID: 34607936.
3. Tieder JS,et al; Brief Resolved Unexplained Event Research and Quality Improvement Network. Risk Factors and Outcomes After a Brief Resolved Unexplained Event: A Multicenter Study. Pediatrics. 2021 Jul;148(1):e2020036095. PMID: 34168059.
4. Ramgopal S, et al. Brief resolved unexplained events: a new diagnosis, with implications for evaluation and management. Eur J Pediatr. 2022 Feb;181(2):463-470. PMID: 34455524.
5. Maksimowski K, et al. Pediatrician Perspectives on Brief Resolved Unexplained Events. Hosp Pediatr. 2021 Sep;11(9):996-1003. PMID: 34429345. 
6. Gerber NL, et al. Brief Resolved Unexplained Event: Not Just a New Name for Apparent Life-Threatening Event. Pediatr Emerg Care. 2021 Dec 1;37(12):e1439-e1443. PMID: 32472924.
7. Haddad R, et al. Diagnostic Evaluation Low Yield for Patients with a Lower-Risk Brief Resolved Unexplained Event. Glob Pediatr Health. 2021 Feb 1;8:2333794X20967586. PMID: 33614835.