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Brief Resolved Unexplained Event (BRUE) is a clinical presentation in infants characterized by a sudden, brief, and now-resolved episode involving altered respiration, muscle tone, color, or responsiveness without an identifiable cause after thorough evaluation. The event often prompts significant concern due to its potential association with life-threatening disorders, although most cases represent benign and self-limited phenomena. Etiologic factors are diverse and may include underlying respiratory, neurologic, infectious, or gastrointestinal conditions, though many remain idiopathic. Risk factors for BRUE include younger age, prematurity, and prior similar episodes. The pathophysiologic mechanisms are incompletely understood but are believed to involve transient autonomic or cardiorespiratory instability. Clinical diagnosis is established when no alternative explanation is identified after detailed history, examination, and focused investigations. Management centers on risk stratification to differentiate lower- from higher-risk infants, guiding the extent of evaluation and need for observation or admission. Excessive or nontargeted testing is discouraged. Complications primarily arise from misdiagnosis and unnecessary interventions. Prognosis is excellent in low-risk infants, with recurrence or serious underlying pathology being uncommon when managed according to evidence-based protocols. This activity for healthcare professionals is designed to enhance learners' proficiency in evaluating and managing BRUE. Participants will deepen their understanding of the condition's etiology, risk factors, pathophysiology, clinical presentation, and evidence-based diagnostic and therapeutic approaches. Improved skills will empower clinicians to collaborate successfully with interprofessional teams caring for affected children. Objectives: Identify distinguishing clinical features that classify infants as low-risk or high-risk after a brief resolved unexplained event. Determine which infants require further evaluation after a brief resolved unexplained event based on the 2016 and 2019 American Academy of Pediatrics guidelines. Improve caregiver awareness of brief resolved unexplained events, emphasizing safe sleep, risk recognition, timely medical evaluation, and strategies to prevent unnecessary interventions and anxiety.

Determine which infants require further evaluation after a brief resolved unexplained event based on the 2016 and 2019 American Academy of Pediatrics guidelines. Improve caregiver awareness of brief resolved unexplained events, emphasizing safe sleep, risk recognition, timely medical evaluation, and strategies to prevent unnecessary interventions and anxiety. Apply effective strategies to improve care coordination among interprofessional team members to facilitate positive outcomes for children who experience brief resolved unexplained events. Access free multiple choice questions on this topic.

A brief resolved unexplained event (BRUE) is defined by the American Academy of Pediatrics (AAP) as a sudden, brief, and now-resolved episode in an infant younger than 1 year involving 1 or more of the following: Cyanosis or pallor Absent, decreased, or irregular breathing Marked change in tone Altered level of responsiveness By definition, no explanation is identified after an appropriate history and physical examination. The 2016 AAP clinical practice guideline replaced the former “apparent life-threatening event" (ALTE) terminology and introduced formal risk stratification with evidence-based recommendations for infants meeting lower-risk criteria, which include the following: Age greater than 60 days Gestational age of 32 through 37 weeks, with postconceptional age of at least 45 weeks A first and brief event lasting less than 1 minute Absence of cardiopulmonary resuscitation (CPR) by a trained provider No concerning historical or examination findings. In accordance with the guideline’s intent to minimize unnecessary interventions, clinicians are advised that avoiding low-value testing and monitoring provides clear benefits. When lower-risk criteria are satisfied, the small chance of missing a rare underlying condition is generally outweighed by these benefits. (Sources: Tieder et al, 2016; Tieder et al, 2019)

BRUE is a syndrome label rather than a diagnosis and is applied only when a targeted history and examination fail to identify a plausible cause for the index event. Potential underlying conditions span multiple organ systems and are particularly relevant in higher-risk infants. A structured 2019 framework prioritizes time-sensitive conditions, including child maltreatment, feeding problems such as aspiration, cardiac arrhythmias, infections, and congenital anomalies, followed by conditions less affected by delayed diagnosis, such as dysphagia, intermittent airway obstruction, and epilepsy. The framework further emphasizes that indiscriminate testing has low diagnostic yield and may initiate cascades of false-positive results. Etiologic investigation should therefore be hypothesis-driven, focused, and interprofessional. (Source: Merritt et al, 2019)

BRUEs occur in infants younger than 1 year, with a higher incidence during the 1st few months of life. Prematurity and very young age are consistently identified as higher-risk features. The 2016 guideline synthesized data from the ALTE era and, by consensus, defined a “brief” event as lasting less than 1 minute, recognized CPR by a trained provider as a risk factor, and noted that prematurity (less than 32 weeks’ gestation) confers risk that diminishes after the infant reaches a postconceptional age of approximately 45 weeks. The majority of infants (94%) evaluated after a BRUE do not meet all lower-risk criteria, for example, due to age, prematurity, longer event duration, or recurrent episodes. Therefore, these infants are classified as higher-risk, for whom no uniform, guideline-based diagnostic pathway exists.

"BRUE" is a descriptive label. Pathophysiologic mechanisms reflect any underlying diagnosis if subsequently identified. In higher-risk infants, aspiration due to oropharyngeal dysphagia can produce color change, altered breathing, and tone abnormalities. Dysphagia and intermittent airway obstruction are specifically highlighted in the 2019 framework’s secondary tier. Conversely, attributing BRUE to gastroesophageal reflux disease based solely on nonspecific symptoms is problematic. A 2024 multicenter analysis of BRUE evaluations demonstrated that commonly elicited symptoms lacked predictive value for videofluoroscopic swallow study (VFSS) abnormalities or reflux studies, reinforcing that observed symptoms do not establish causation and cautioning against reflexive acid-suppression therapy.[1] Rarely, serious neurologic hypoxic injuries can mimic BRUE. One report describes infantile hypoxic encephalopathy presenting with ALTE or BRUE characteristics, emphasizing that transient events do not exclude occult injury.[2]

Evaluation begins with confirmation that the event fulfills BRUE criteria and identification of any features that may explain the episode. The AAP provides a detailed, structured history template encompassing antecedents, precise event phenomenology, duration, interventions, recovery characteristics, and context, in addition to a thorough physical examination to detect concerning findings. Particular attention should be directed toward age, gestational history, infant position, feeding patterns, respiratory sounds, color changes, tone, and family history of arrhythmia or sudden death. For infants meeting all lower-risk criteria, brief observation, for example, by short-term continuous pulse oximetry with serial examinations, may be considered, incorporating shared decision-making with caregivers regarding the limited benefits versus potential harms, including false-positive results and anxiety.

The AAP guideline strongly recommends against routine diagnostic testing in lower-risk infants, including complete blood count, electrolytes, cerebrospinal fluid analysis, chest radiography, upper gastrointestinal series, pH probe, neuroimaging, or electroencephalography. Hospitalization and empiric acid-suppression therapy are also strongly discouraged. The guideline provides a weak recommendation to consider electrocardiography and pertussis testing. An erratum clarifies that “laboratory evaluation for anemia” belongs in the "Should Not" category rather than “Need Not,” reinforcing that indiscriminate hematologic testing represents low-value care in lower-risk BRUE. (Source: Tieder et al, 2016) For higher-risk infants, a tiered evaluation approach is recommended. Initial-tier actions, often feasible without hospital admission, prioritize conditions for which diagnostic delay could cause harm. These measures include continuous pulse oximetry for 4 or more hours, social work assessment when maltreatment is suspected, careful bedside feeding evaluation, electrocardiography interpreted by pediatric cardiology, rapid testing for respiratory viruses and pertussis when indicated, targeted laboratory studies (eg, hematocrit, glucose and bicarbonate or venous blood gas, lactate), and child abuse imaging when suspicion exists. Secondary-tier evaluations address residual concerns, such as VFSS for dysphagia or aspiration and neurologic studies when seizures are suspected, rather than being performed reflexively. Contemporary data underscore the low diagnostic yield of indiscriminate testing. In a 2025 multicenter observational study involving 1,042 infants across 11 hospitals, 82.1% underwent diagnostic evaluation, with only 8.4% yielding results that supported a causative diagnosis. Subspecialty consultations were obtained in 42.2% of infants and identified an underlying cause in 27.4%. (Source: Nama et al, 2025)

Caregiver education, including CPR training, as well as shared decision-making and safe discharge with prompt follow-up, are central to managing lower-risk BRUE. Hospitalization and pharmacologic interventions, particularly acid suppression, are discouraged. Higher-risk infants benefit from a family-centered, interprofessional plan tailored to identified risks, often coordinating outpatient services to minimize unnecessary inpatient care. Management is etiology-specific when a treatable cause, such as feeding dysfunction, is identified and may include feeding therapy, thickening strategies, or modified feeding plans when aspiration is documented on VFSS. In the absence of a unifying diagnosis, clinicians should avoid empiric therapies lacking evidence of benefit in BRUE, such as proton pump inhibitors, and instead emphasize anticipatory guidance and structured follow-up.

Given the nonspecific presentation of BRUE, clinicians must consider a broad spectrum of possible causes. Key categories of underlying conditions include the following: Child maltreatment, including abusive head trauma and intentional suffocation Infections, such as pertussis and bronchiolitis Cardiac pathologies, including arrhythmias and channelopathies Neurological conditions, such as seizures and central apnea Gastrointestinal abnormalities, including dysphagia with aspiration and, less commonly, pathologies such as intussusception Pulmonary and sleep disorders, like intermittent airway obstruction The higher-risk framework provides a comprehensive table of potential causes and a structured pathway that prioritizes time-sensitive threats before proceeding to targeted secondary evaluations. Case literature indicates that some gastrointestinal and neurologic conditions may initially present with BRUE-like episodes, emphasizing the need for vigilance when red-flag features are present.[3]

Serious outcomes are uncommon among lower-risk infants, and brief observation combined with structured caregiver education is generally sufficient. The guideline emphasizes that the benefits of minimizing unnecessary testing and hospital exposure typically outweigh the small risk of missing a rare underlying disorder. Nonetheless, many families experience ongoing concern and heightened symptom vigilance. In a prospective BRUE cohort, caregivers frequently reported persistent symptoms and anxiety following the index event, underscoring the importance of clear education and timely follow-up.

Complications arising from BRUE primarily reflect either morbidity from missed diagnoses or harm resulting from overtesting and overtreatment. Reports describe serious conditions initially labeled as "BRUE" or "ALTE," including intussusception presenting with transient episodes resembling BRUE and infantile hypoxic encephalopathy manifesting as brief color or breathing changes prior to recognition. These cases underscore that recurrent events, persistent symptoms, or red-flag features warrant reassessment. According to AAP literature, higher-risk infants are more likely to have congenital, infectious, or maltreatment-related etiologies and should undergo vigilant, targeted diagnostic evaluation. Concurrently, indiscriminate testing carries its own risks. The 2016 guideline outlines potential harms, such as false-positive results, cascades of further testing, procedural complications, and caregiver anxiety, supporting a restrained approach in lower-risk patients. A 2025 multicenter study further quantifies the low diagnostic yield of untargeted evaluation, with only 8.4% of tests identifying a causative diagnosis, highlighting the dual risks of missed and misattributed conditions.

Caregivers should receive a concise, written management plan. The AAP’s “What Parents and Caregivers Need to Know” handout for BRUE highlights indications for urgent care, including apnea, color change, or sudden limpness or stiffness, and provides practical guidance on observation, safe sleep, and follow-up with the primary care clinician. Educational resources also promote caregiver training in infant CPR and advise against home cardiopulmonary monitoring unless specifically indicated by the clinical team. Clinicians should acknowledge caregivers’ concerns, explain the rationale for avoiding unnecessary testing, particularly in lower-risk infants, and provide a clear script for return precautions. (Source: AAP, 2022)

The 2016 BRUE guideline correction classifies “laboratory evaluation for anemia” in the "Should Not" category, rather than “Need Not,” for lower-risk infants, addressing the common inclination to add routine labs. A 2024 multicenter analysis demonstrated that symptoms frequently elicited during BRUE evaluations did not reliably predict abnormalities on VFSS or reflux studies, and acid-suppression therapy was often employed without evidence that symptoms indicated reflux disease. Even in higher-risk cohorts, specialty consultations and diagnostic testing exhibited low positive predictive value for identifying underlying diagnoses, emphasizing the importance of targeted evaluation and close follow-up over indiscriminate testing. Following implementation of the AAP BRUE clinical practice guideline, hospitals reported substantial reductions in diagnostic testing, admissions, costs, and length of stay without an increase in revisit rates, supporting the safety and value of conservative, criteria-based care. (Source: Patra et al, 2022)

BRUE care is optimized when clinical teams implement a shared, tiered plan and communicate transparently with families. For lower-risk infants, management may be standardized around brief observation, structured caregiver education, and timely follow-up rather than hospital admission or broad testing. For higher-risk infants, the 2019 framework advocates a family-centered, interprofessional approach, including pediatrics, feeding and occupational therapy, cardiology, neurology, and social work, prioritizing time-sensitive assessments and reserving secondary studies for persistent, hypothesis-driven concerns. Teams should avoid fragmented or parallel consultations that increase low-yield testing. Multicenter data in 2025 demonstrating low positive predictive values for both testing and consultations support coordinated pathways with audit and feedback to reduce unwarranted variation. Institutions can further enhance care by distributing the AAP caregiver handout, standardizing return-precaution instructions, and promoting caregiver CPR training, addressing the documented persistence of caregiver anxiety and ongoing symptom vigilance after discharge.