Best Practice from the College of Urgent Care Medicine

Brief Resolved Unexplained Event (BRUE)

Date Reviewed

November 14, 2022


Brief Resolved Unexplained Event (BRUE) Best Practices

Patient Population

Infants < 1 year of age 


Infants are frequently brought to Urgent Care Centers after an acute event of unexpected change in breathing pattern, appearance, or behavior. Clinicians must avoid unnecessary testing, prolonged observation or transferring to Emergency Department when it is not needed. The clinical challenge is to identify and stratify patients as high or low risk for recurrence or for having an underlying condition.  


In 2016 The American Academy of Pediatrics recommended to replace the term apparent life-threatening event (ALTE) with brief resolved unexplained event (BRUE) to describe any event of transient unexpected change in breathing patterns, appearance, or behavior that remains unexplained after an appropriate individualized medical evaluation.1-5

Epidemiology is very limited as the new term was changed recently. An apparent life-threatening event includes a subset of brief resolved unexplained events accounted for approximately 0.6% to 0.8% of all Emergency Department (ED) visits and 0.6 to 2.6 per 1000 live births. 1


Evidence Based Guideline with Strength of Evidence

The term BRUE better reflects the transient nature of the event and that no clear etiology is identified.  Effective communication and detailed history and physical exam are essential interventions. Additionally, AAP has provided evidence-based recommendations:5

  1. Patient evaluation approach that is based on the risk that the infant will have a repeat event or has a serious underlying disorder.
  2. Management recommendations, or key action statements, for lower-risk infants. Effective communication, detailed history and physical exam are evidence-based interventions when assessing patients with BRUE.


BRUE is not considered a specific diagnosis, but rather a chief complaint as the term should be applied only when the infant is asymptomatic on presentation. 4 

The pathophysiology of these events is unknown, but the estimated duration of the event is usually less than one minute (and typically <20 to 30 seconds). 

Clinicians must identify infants who may benefit from further testing and prolonged observation. The stratification should be based on factors that suggest an identifiable underlying diagnosis or risk for subsequent events. This approach will mitigate the risk of unnecessary testing, monitoring, and hospital admission.4

Most but not all infants with BRUE are at low risk for recurrence or for having a serious underlying problem. 


BRUE Criteria: Sudden, brief, and now resolved episode of one or
more of the following in an infant < 1 year age:

●       Cyanosis or pallor

●       Absent, decreased or irregular breathing

●       Marked change in tone (hyper- or hypotonia)

●       Altered responsiveness

●       No explanation for the event with full history and exam


Low Risk Criteria:

●       Age > 60 days

●       Gestational Age

o   Born ≥ 32 weeks gestation and post-conception age ≥ 45 weeks

●       No CPR by trained medical provider

●       Event lasted < 1 minute

●       First event

●       No repeat events

●       No concerning history

●       No concerning physical exam 


A complete and detailed history and physical exam must be performed. History should include event characteristics, interventions, pertinent past including medical history, birth history, medications, family history and social history. See table #1. 


Concerning physical examination findings include any signs of injury, including bleeding, bruising (especially on the scalp, trunk, face, or ears), or bulging anterior fontanel; altered sensorium; fever or toxic appearance; respiratory distress; heart murmur or gallop; decreased pulses; hepatomegaly or splenomegaly; and abdominal distension or vomiting.3,4

Patients who meet low risk criteria are considered to have minimal risk for a recurrent event, serious underlying disorder, or sudden death.1,4

The main risk factors for acute events in infants are feeding difficulties, recent upper respiratory symptoms, and age younger than two months, or a history of previous episodes.4 These patients need in depth assessment, evaluation and management and transferred to a higher level of care should be considered. 

Low risk infants require minimal additional work-up or observation.



Recommended Steps:

●       Educate caregivers about BRUEs, and the low risk for infants with these characteristics.

●       Offer resources for training in cardiopulmonary resuscitation (CPR).

●       Engage in shared decision-making about further evaluation and disposition.

●       Observe for 1-2 hours while feeding. 

●       Arrange for a follow-up check with a medical provider within 24 hours to identify infants with evolving medical concerns that would require further evaluation and treatment.


Optional Steps:

●       Observation for more than 2 hours but less than 4hours with continuous pulse oximetry and serial observations.

●       12-lead electrocardiogram with attention to QT interval. Especially if concerns due to cardiac family history. 

●       Testing for pertussis (especially for infants with suggestive symptoms, unimmunized patients). 


Infants who do not meet these low-risk criteria are thought to be at higher risk for a recurrence or serious underlying disorder and require more extensive evaluation. 4


Not Recommended:

●       The American Academy of Pediatrics guideline specifically recommends against evaluating for systemic infection (white blood cell count, blood culture, or cerebrospinal fluid analysis or culture); laboratory testing for anemia; metabolic disease (electrolytes, calcium, ammonia, urine organic acids, plasma amino acids or acylcarnitines); respiratory disease (chest radiograph or blood gas testing); echocardiogram; electroencephalogram (EEG); or studies for gastroesophageal reflux (GER). 

●       RSV testing or respiratory panels.

●       Routine testing with a urinalysis, blood tests (glucose, bicarbonate, or lactic acid), or neuroimaging, or admission to the hospital only for cardiorespiratory monitoring.

●       Home cardiorespiratory monitoring. 

●       There is no role for medications including acid reflux reducers or epilepsy treatment or specialist consultations.


Disposition Considerations

●       No repeat event during ED stay

●       Successful PO trial

●       Evaluation negative for any concerning illness

●       Parent comfortable with discharge to home

●       Safe sleep, co-sleeping teaching

●       Close follow up is available


Approximately 4% of infants presenting with BRUE have a serious underlying cause. BRUE and ALTEs are not considered a precursor to, or risk factor for, SIDS. The vast majority of SIDS victims do not experience apnea prior to death, and the epidemiology and risk factors for SIDS are very different from those for BRUE and ALTE. Clinicians must be familiarized with the evaluation of patient presents after a sudden event and categorize patients as high or low risk to avoid unnecessary tests or transfer to emergency room. Shared decision-making with caregivers should be part of the overall management strategy.


  1. Kondamudi NP, Virji M. Brief Resolved Unexplained Event. [Updated 2022 Aug 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from:
  2. Merritt JL, Quinonez RA, Bonkowsky JL, et al. Framework for evaluation of the higher-risk infant after a brief resolved unexplained event. American Academy of Pediatrics. Published August 1, 2019. Accessed November 9, 2022. 
  3. The Children’s Hospital of Philadelphia. Brief resolved unexplained event clinical pathway – emergency and inpatient. Brief Resolved Unexplained Event Clinical Pathway – Emergency and Inpatient. Published March 16, 2017. Accessed November 9, 2022. 
  4. Corwin MJ. Acute events in infancy including brief resolved unexplained event (BRUE). UpToDate.! Accessed November 9, 2022. 
  5. Brief Resolved Unexplained Events (Formerly Apparent Life-Threatening Events) and Evaluation of Lower-Risk Infants. Accessed November 9, 2022. 
  6. Mittal, M. K., Sun, G., & Baren, J. M. (2012). A clinical decision rule to identify infants with apparent life-threatening event who can be safely discharged from the emergency department. Pediatric emergency care, 28(7), 599-605.
  7. Kaji, A. H., Claudius, I., Santillanes, G., Mittal, M. K., Hayes, K., Lee, J., & Gausche-Hill, M. (2013). Apparent life-threatening event: multicenter prospective cohort study to develop a clinical decision rule for admission to the hospital. Annals of emergency medicine, 61(4), 379-387.


Cesar Mora Jaramillo, MD FAAFP FCUCM

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Table #1: BRUE Detailed History

Event Characteristics

●       Preceding illness or injury

●       Event Description

o   Location, position, feeding, environment, timing of the event

o   Choking, gagging

o   Tone, movement

o   Mental status

o   Level of distress

o   Color change – pallor, red, blue

o   Breathing ability – apnea, shallow breathing, or difficulty breathing

o   Duration

o   Interventions

o   Return to baseline


Pertinent Past

●       Prematurity (gestational age < 32 weeks)

●       Previous episode, BRUE diagnosis

●       Newborn screening results

●       Growth and development

●       Breathing problems

●       Reflux

●       Medications


●       Sudden unexplained death

●       Cardiac disease, arrhythmias

●       Metabolic/genetic disease

●       Households with similar events


●       Environment, exposures, illness contacts

●       Family structure, individuals in home

●       Caretakers

●       Stressors

●       Specific/relevant social history (e.g., sleeping/co-sleeping, sleep surface)

●       Consideration for possible child abuse:

o   Previous children service/law involvement

o   Inconsistency of event history, history not compatible with age

o   Unexplained PE findings (bruising)