Brief Resolved Unexplained Events (BRUE)
Comprehensive emergency evaluation and risk stratification of Brief Resolved Unexplained Events (BRUE) in infants under 12 months: retirement of the ambiguous Apparent Life-Threatening Event (ALTE) terminology, American Academy of Pediatrics (AAP) diagnostic criteria (cyanosis/pallor, absent/irregular breathing, marked tone alterations, altered responsiveness), strict low-risk stratification criteria, guideline-directed limitation of unnecessary lab/imaging workups, and high-risk presentation admission triggers.
Resuscitation Quick Actions • First 2 Minutes
BRUE Four Components
Event characterized by >= 1 of: 1) Cyanosis or pallor, 2) Absent, decreased, or irregular breathing, 3) Marked tone change (hyper/hypotonia), 4) Altered responsiveness
AAP Low-Risk Age Cutoff
Age > 60 days (2 months) AND born >= 32 weeks gestation (current post-conceptional age >= 45 weeks)
No Prior Events
Must be the FIRST and ONLY event; multiple or clustering events immediately disqualify from low risk
No CPR by Trained Medic
No CPR administered by trained healthcare provider (basic parental stimulation/tapping does not disqualify)
Low-Risk ED Workup
DO NOT routinely obtain: CBC, blood cultures, CMP, ABG/VBG, chest X-ray, head CT/MRI, EEG, or lumbar puncture; check pertussis if exposed
High-Risk Red Flags
Age < 60 days, prematurity, repeat events, non-accidental trauma bruising, fever, heart murmur, hepatosplenomegaly -> ADMIT
Bottom-Line Clinical Pearl
BRUE is an event in an infant < 12 months of age that is brief (< 1 min, typically 20–30 sec), has completely resolved, and has NO EXPLANATION after a thorough history and physical exam. It replaces the outdated term ALTE. An infant qualifies as LOW RISK only if: age > 60 days, gestational age >= 32 weeks (>= 45 weeks post-conceptional), first-ever event, duration < 1 minute, NO CPR performed by trained provider, and completely normal physical exam. Low-risk infants require NO extensive lab workup, neuroimaging, or hospitalization; observe with continuous pulse oximetry for 1–4 hours, provide infant CPR education to parents, and arrange primary care follow-up.
In 2016, the American Academy of Pediatrics (AAP) retired the clinical term Apparent Life-Threatening Event (ALTE) because it created unwarranted parental panic, lacked objective diagnostic criteria, and resulted in excessive, painful, and non-evidence-based inpatient workups. The AAP defined Brief Resolved Unexplained Event (BRUE) as an event occurring in an infant younger than 1 year of age when the observer reports a sudden, brief ($< 1\text{ minute}$, typically $20\text{ to }30\text{ seconds}$), now completely resolved episode that includes one or more of the following four features:
| BRUE Component | Clinical Description | Excluded Normal Variations |
|---|---|---|
| Cyanosis or Pallor | Central blue discoloration of perioral region/face or sudden extreme blanching | Isolated acrocyanosis (normal in healthy newborns) or flushing/erythema |
| Absent, Decreased, or Irregular Breathing | True central apnea, breath-holding, or severe choking | Periodic breathing of infancy (brief 5–10 sec pauses followed by rapid breathing without cyanosis) |
| Marked Change in Muscle Tone | Sudden marked hypotonia (flaccidity/'ragdoll') or rigid hypertonia | Normal newborn startle reflexes or shivering without gaze deviation |
| Altered Level of Responsiveness | Transient loss of consciousness, lethargy, stupor, or blank staring | Normal infant sleep states or brief drowsy transitions |
An infant can be categorized as LOW RISK if and only if ALL of the following objective criteria are fulfilled on history and physical examination:
| Low-Risk Criteria Category | Mandatory Threshold Requirements | Clinical Rationale |
|---|---|---|
| Age Threshold | Age > 60 days (2 months) | Infants < 60 days have immature respiratory drive and higher vulnerability to severe bacterial infections (SBIs). |
| Gestational Age Threshold | Gestational age $\ge 32\text{ weeks}$ AND post-conceptional age $\ge 45\text{ weeks}$ | Premature infants have a high prevalence of central apnea of prematurity and occult sepsis. |
| Event Characteristics | Duration $< 1\text{ minute}$ (typically 20–30 sec) AND first-ever episode | Recurrent or clustering events suggest occult epilepsy, metabolic disease, or child abuse. |
| Resuscitation Effort | No CPR administered by a trained healthcare provider | Chest compressions or bag-valve-mask by paramedics indicates true severe circulatory or respiratory collapse. |
| Physical Examination | Completely normal physical exam (normal vitals, alert, active, baseline muscle tone, no bruising) | Excludes occult head trauma, congenital heart disease murmurs, abdominal pathology, or infection. |
Clinical Caution
AAP RECOMMENDATIONS FOR LOW-RISK BRUE: Do NOT perform routine blood testing (CBC, electrolytes, blood gas, blood cultures), lumbar puncture, urinalysis, chest radiography, echocardiography, head CT/MRI, or routine continuous video EEG in infants meeting low-risk BRUE criteria. These tests have an extremely low diagnostic yield (< 1%) and generate false positives. You MAY perform: a 12-lead ECG (to screen for prolonged QTc, Brugada, or pre-excitation), pertussis testing if symptomatic, and continuous pulse oximetry for 1 to 4 hours in the ED before discharge.
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