BRUE (Brief Resolved Unexplained Event)
🔹 Definition
A BRUE is defined as a sudden, brief (<1 minute), and now resolved episode in an infant <1 year of age, characterised by ≥1 of the following:
- Cyanosis or pallor
- Absent, decreased, or irregular breathing
- Marked change in tone (hypertonia or hypotonia)
- Altered responsiveness
AND:
- Infant returns to baseline state of health
- No explanation for the event is found after history and physical examination
- Not consistent with another condition (e.g., infection, seizure, reflux, trauma)
🔸 Previous term: ALTE (Apparent Life-Threatening Event) — replaced to reduce anxiety and avoid over-investigation.
🔹 Diagnostic Criteria
| Criteria | Requirement |
|---|---|
| Age | < 12 months |
| Event duration | < 1 minute |
| Resolution | Back to baseline, normal physical exam |
| Features | ≥1 of: cyanosis/pallor, irregular breathing, altered tone, altered responsiveness |
| No cause found | Thorough Hx & exam does not identify a cause |
| No signs of illness | No fever, cough, trauma, etc. |
🔹 Clinical Presentation
- Sudden and alarming to caregivers
- May include:
- Gasping or apnea
- Colour change (blue/pale)
- Floppy or stiff body
- Lack of responsiveness
- Infant is well-appearing post-event
🔹 Differential Diagnosis
BRUE is a diagnosis of exclusion. Consider and rule out:
More Common Causes:
- Gastrointestinal: GERD, aspiration
- Neurological:
- Seizures
- Breath-holding spells
- CNS malformations
- Respiratory:
- Bronchiolitis (RSV)
- Pertussis
- Apnoea of prematurity
- Infectious:
- Sepsis
- Meningitis
- Feeding issues: Swallowing incoordination, laryngospasm
Less Common:
- Cardiac:
- Arrhythmias (e.g., long QT)
- Congenital heart defects
- Metabolic:
- Inborn errors (e.g., urea cycle defect)
- Hypoglycaemia
- Airway: Laryngomalacia, OSA
- Toxicologic: Accidental ingestion
- Non-Accidental Injury (NAI):
- Recurrent or unusual episodes
- Mismatch between history and findings
- Retinal haemorrhages, bruises
🔹 Evaluation
History
- Description of event (breathing, colour, tone, responsiveness)
- Duration, recovery, preceding symptoms
- Caregiver interventions (stimulation, CPR)
- Feeding difficulties, vomiting, weight gain
- Developmental milestones
- Recent illness or trauma
- Family history (e.g., SIDS, seizures, arrhythmias)
- Environmental exposures (e.g., smoke, drugs)
- Social assessment (caregiver stress, home safety)
- Screening for NAI if red flags present
Physical Exam
- General appearance
- Vital signs: Temp, HR, RR, SpO₂, BP
- Respiratory: Wheeze, work of breathing
- Neurological: Tone, reflexes, eye movements, head lag
- Cardiac: Murmurs, perfusion
- Skin: Bruises, petechiae, signs of trauma
- Fundoscopy: Retinal haemorrhages (NAI)
🔹 Risk Stratification
| Category | Criteria |
|---|---|
| ✅ Low Risk | – Age > 60 days – Gestational age ≥32 weeks, corrected GA ≥45 weeks – First episode only – No CPR required by trained medical provider – No concerning features in history – Normal examination |
| ⚠️ High Risk | Any of the following: – Age < 60 days – Prematurity (GA <32 weeks) – Recurrent or clustered episodes – CPR required – Abnormal exam or history suggestive of underlying pathology |
🔹 Investigations
Low-Risk BRUE
- No routine bloods or imaging
- May consider:
- 12-lead ECG (to rule out cardiac arrhythmia)
- Pertussis PCR
- Observation for 1–4 hours ± pulse oximetry
- No hospitalisation unless:
- Inadequate follow-up
- Parental anxiety
High-Risk BRUE
Tests guided by clinical suspicion:
| System | Tests |
|---|---|
| Infectious | CBC, CRP, blood cultures, LP (if febrile or altered) |
| Neurologic | EEG, neuroimaging (if seizures suspected) |
| Cardiac | ECG, 24-hr Holter, echocardiogram |
| Metabolic | Glucose, ammonia, lactate, electrolytes, urine organic acids |
| Respiratory | CXR, pertussis PCR |
| Toxicology | Drug screen (if suspicious context) |
| Child abuse | Skeletal survey, fundoscopy, social work assessment |
🔹 Management
Low-Risk Infants
- Reassurance and education
- CPR training for caregivers
- Safe sleep counselling
- No home monitoring (not protective against SIDS)
- Review with GP in 24 hours
High-Risk Infants
- Admit for cardiorespiratory monitoring
- Treat identified cause
- Multidisciplinary care if suspected abuse or chronic illness
- Consider genetic/metabolic referral if indicated
🔹 Follow-Up
| Action | Timing |
|---|---|
| GP review | Within 24 hours (low-risk) |
| Specialist referral | If high-risk, recurrent, or underlying condition suspected |
| Social services | If risk of abuse/neglect |
🔹 Prognosis
| Factor | Prognostic Implication |
|---|---|
| Low-risk BRUE | Excellent, self-limited, no impact on development |
| High-risk BRUE | Depends on underlying etiology |
| Risk of SIDS | Not directly increased by BRUE, but may co-exist |
| Recurrent events | Investigate for pathology or possible abuse |
SIDS Link:
- Most BRUE infants do NOT go on to die of SIDS.
- 4–10% of SIDS cases have prior similar events.
- No evidence that home monitors reduce SIDS risk (AAP 2022).
🔹 Parent Education Summary
- BRUE is common and usually benign.
- The baby has returned to normal and is not at increased risk of death.
- CPR training is recommended.
- No need for home monitors unless instructed.
- Adhere strictly to safe sleep guidelines (supine position, no loose bedding, smoke-free environment).