A Brief Resolved Unexplained Event (BRUE) describes a sudden episode in an infant that resolves completely without a clear medical explanation. The occurrence of a BRUE can be alarming for parents, as the infant briefly displays worrisome signs before returning to normal health. This clinical classification guides the medical evaluation process for infants under one year of age. The primary goal of assessment is to determine the infant’s risk level and rule out any underlying serious health issues.
Defining the Brief Resolved Unexplained Event
The American Academy of Pediatrics (AAP) precisely defines the term BRUE, which replaced the older diagnosis of Apparent Life-Threatening Event (ALTE) in 2016. A BRUE is characterized by an observed episode that is sudden, brief, and completely resolved before the infant is seen by a healthcare professional. The diagnosis is one of exclusion, meaning no underlying medical cause is found after a thorough history and physical examination. The episode typically lasts less than one minute, often 20 to 30 seconds. The transition to BRUE reflects the transient nature of these events and avoids the “life-threatening” label, which often led to unnecessary testing.
The event must include at least one of four specific elements observed by the caregiver:
- A change in skin color, such as cyanosis (blue) or pallor (pale).
- Absent, decreased, or irregular breathing.
- A marked change in muscle tone, either hypertonia (stiff) or hypotonia (floppy).
- An altered level of responsiveness.
Distinguishing Low-Risk Versus High-Risk Events
Risk stratification is used following a BRUE to determine the infant’s likelihood of having a serious underlying disorder or a recurrent event. The assigned risk category dictates the extent of the medical evaluation and whether hospitalization is required. An infant is classified as “low-risk” only if they meet all specific criteria defined by the AAP guidelines.
Low-Risk Criteria
Low-risk criteria require the infant to meet all of the following:
- Older than 60 days of age.
- Born at 32 weeks gestation or later, with a post-conceptional age of at least 45 weeks.
- The first event the infant has experienced.
- Lasted less than one minute.
- Did not require cardiopulmonary resuscitation (CPR) by a trained medical professional.
If the infant fails to meet even one of these criteria, or if the history or physical exam reveals concerning findings, they are automatically categorized as “high-risk.”
The Clinical Assessment and Testing Process
The clinical assessment starts with a detailed history of the event, focusing on the caregiver’s observations, such as color change, duration, and actions that resolved the episode. A complete physical examination is performed to look for signs of an underlying infection, neurological issue, or cardiac problem. The risk stratification then determines the subsequent testing strategy.
For low-risk infants, the evaluation is minimal, often consisting only of a brief observation period (typically one to four hours) with continuous pulse oximetry monitoring. A 12-lead electrocardiogram (EKG) is often performed to screen for potential cardiac rhythm abnormalities. Extensive laboratory work or imaging studies are not recommended for this group, as the yield is low. High-risk infants require a more comprehensive diagnostic workup tailored to the suspected problem, which may include tests like electroencephalograms (EEG), metabolic screening, or advanced cardiac studies.
Follow-Up Care and Parental Education
Management of a BRUE emphasizes parental education and close follow-up, especially for low-risk infants discharged quickly. Caregivers are educated about the benign nature of the event and are reassured that a BRUE does not increase the risk of Sudden Infant Death Syndrome (SIDS). A follow-up appointment with the primary care provider is scheduled within the first few days after discharge to ensure the infant continues to thrive.
A primary recommendation for all caregivers is to complete a certified infant cardiopulmonary resuscitation (CPR) course. This training empowers parents to respond effectively should a similar event occur. Clinicians also reinforce safe sleep practices, such as placing the infant on their back for sleep. Parents are advised to seek immediate medical attention if a repeat event occurs or if the infant develops new concerning symptoms:
- Fever.
- Poor feeding.
- Lethargy.