DESCRIPTION

• A brief, resolved, unexplained event (BRUE) is an episode in an infant <1 year of age that has concluded and was sudden, brief, and characterized by any of the following:
  • Absent, decreased, or irregular breathing
  • Cyanosis or pallor
  • Marked change in muscle tone (hypertonia or hypotonia)
  • Altered responsiveness
• BRUE is diagnosed when the infant appears to have returned to the previous healthy state and no other condition can adequately describe the event after a thorough history and physical exam.
• It is a term originally described in a 2016 American Academy of Pediatrics (AAP) clinical practice guideline to replace the term apparent life-threatening event (ALTE). The change was made with the intent of standardizing care in order to minimize extraneous medical interventions, guide further research, and improve outcomes.
• BRUE is further classified as low risk and high risk based on the likelihood of recurrence or a serious underlying disorder.
  • Low-risk criteria are based on:
    • Age >60 days
    • Born ≥32 weeks’ gestation and corrected age ≥45 weeks
    • No cardiopulmonary resuscitation (CPR) performed by a trained medical provider
    • Event lasting <1 minute
    • First event
• Low- and high-risk criteria are also determined by history and physical examination findings.
• A diagnostic and management approach have been suggested for each risk category.

EPIDEMIOLOGY

• 43% of healthy term infants have at least one 20-second apneic episode over a 3-month period.
• 5.3% of parents recall seeing apnea.
• 87% of BRUE presentations to the emergency department qualify as high-risk BRUE.
• 4% of infants who present with BRUE are ultimately diagnosed with a serious underlying condition.

RISK FACTORS

There are no clear risk factors for BRUE given that BRUE is an unexplained event.

PATHOPHYSIOLOGY

• There is no unifying pathophysiology because of the numerous potential presentations and the unexplained nature of the event. The role of swallowing dysfunction, laryngospasm, gastroesophageal reflux (GER), and autonomic dysfunction in BRUE still need to be explored.
• Additional pathophysiologic explanations are grouped by the patient’s presentation and illustrative diagnoses in the differential of BRUE:
  • Central apnea: disrupted propagation of respiratory signals from the brainstem along the descending neuromuscular pathways; example diagnoses with similar presentations include:
    • Apnea of prematurity
    • Congenital central hypoventilation syndrome (CCHS)
  • Obstructive apnea: neuromuscular respiratory effort disrupted by an occluded airway; example diagnoses with similar presentations include:
    • Obstructive sleep apnea
    • Pierre Robin
  • Mixed apnea: combination of central and obstructive apnea; example diagnoses with similar presentations include:
    • Laryngomalacia with a sedating medication
    • Prematurity with superimposed upper respiratory viral infection
  • Color change from decreased oxygenation or differential blood flow; example diagnoses with similar presentations include:
    • Cyanotic heart disease
    • Acrocyanosis
  • Altered muscle tone from central or autonomic nervous system disruption; examples include:
    • Seizure
    • Breath-holding spell
  • Altered responsiveness from effects on the cerebral hemispheres and/or reticular activating system; example diagnoses with similar presentations include:
    • Toxic ingestion
    • Traumatic brain injury