Brief Resolved Unexplained Event (BRUE)

Introduction

For Canadian medical students and international medical graduates preparing for the MCCQE1, understanding the evolution from Apparent Life-Threatening Event (ALTE) to Brief Resolved Unexplained Event (BRUE) is crucial. This topic falls under General Pediatrics and frequently appears in the context of emergency medicine or general pediatric clinic scenarios.

The terminology shift reflects a move away from the subjective, frightening label of “life-threatening” toward a more objective, clinical description that emphasizes the transient nature of the event and the lack of an obvious cause after history and physical examination.

Definition and Criteria

BRUE is a diagnosis of exclusion. It is defined as an event occurring in an infant <1 year of age when the observer reports a sudden, brief, and now resolved episode of one or more of the following:

1. Cyanosis or pallor (rubor/redness does not count)
2. Absent, decreased, or irregular breathing
3. Marked change in tone (hyper- or hypotonia)
4. Altered level of responsiveness

If there is an explanation (e.g., reflux with aspiration, seizure, choking on milk), it is not a BRUE; it is a specific diagnosis.

Acronym Code Block

BRUE Criteria:
B - Brief (< 1 min)
R - Resolved (back to baseline)
U - Unexplained (after Hx and Px)
E - Event (Cyanosis/Pallor, Breathing, Tone, Responsiveness)

Risk Stratification

The most critical skill for the MCCQE1 is distinguishing between Low-Risk and High-Risk BRUE. This determines the management plan (discharge vs. admission).

Differential Diagnosis

When an event is not unexplained (i.e., not a BRUE), consider the following differential diagnoses. In the MCCQE1, you may be given a vignette that sounds like a BRUE but has a specific clue pointing to one of these:

Management and Approach

Follow this step-by-step approach for MCCQE1 clinical reasoning scenarios.

Key Points to Remember for MCCQE1

• Terminology: BRUE replaces ALTE. It implies a lower acuity and emphasizes the “unexplained” nature.
• Age Cutoff: Low-risk criteria strictly require age > 60 days.
• Prematurity: Gestational age must be $\ge$ 32 weeks and corrected age $\ge$ 45 weeks for low risk.
• Intervention: If the infant required CPR by a trained provider, it is High Risk. Rubbing the back or blowing in the face by a parent does not count as “CPR” for risk stratification.
• GERD: Gastroesophageal reflux is a common mimic but usually presents with spitting up; silent reflux causing apnea is rare.
• Guideline: Refer to the AAP 2016 Clinical Practice Guideline, which is widely adopted in Canada.

Sample Question

Case Scenario: A 3-month-old female is brought to the Emergency Department by her parents. They report that 2 hours ago, while the infant was awake in her crib, she appeared to stop breathing for about 10 seconds and her face turned pale. Her father picked her up and rubbed her back, and she immediately returned to her normal state. She has been behaving normally since. She was born at 39 weeks gestation via uncomplicated vaginal delivery. She has no past medical history. Physical examination is completely unremarkable. Vital signs are stable.

Which one of the following is the most appropriate management plan?

• A. Admit for 24-hour cardiorespiratory monitoring
• B. Order a stat electroencephalogram (EEG)
• C. Discharge with reassurance and follow-up
• D. Prescribe ranitidine for presumed gastroesophageal reflux
• E. Order a skeletal survey to rule out non-accidental trauma

Explanation

The correct answer is:

• C. Discharge with reassurance and follow-up

Detailed Explanation:

This infant presents with a classic Low-Risk BRUE.

1. Event: Brief, resolved, unexplained (after normal exam), involving pallor and apnea.
2. Risk Stratification:
   • Age: 3 months (> 60 days) - Pass
   • Gestational Age: 39 weeks (> 32 weeks) - Pass
   • First event - Pass
   • Duration: ~10 seconds (< 1 min) - Pass
   • CPR: Only stimulation (rubbing back) was required, not CPR by a trained provider - Pass
   • History/Physical: Normal - Pass

According to current guidelines (AAP/CPS), infants meeting Low-Risk BRUE criteria should not be subjected to unnecessary admission or extensive workup, as the risk of a subsequent serious event is extremely low. The most appropriate plan is reassurance, education (perhaps CPR training), and ensuring follow-up with a primary care provider.

• Option A (Admit): Unnecessary for a low-risk BRUE; increases cost and potential for iatrogenic harm.
• Option B (EEG): Not indicated unless there are specific features suggestive of seizure (e.g., tonic-clonic movements, nystagmus).
• Option D (Ranitidine): Empiric treatment for GERD is not recommended for BRUE without specific symptoms of pathologic reflux.
• Option E (Skeletal Survey): Not indicated unless there are red flags for abuse in the history or physical exam (e.g., discordant history, bruising).

Canadian Guidelines & Resources

1. Choosing Wisely Canada (Paediatrics): “Don’t routinely admit or investigate infants with a Brief Resolved Unexplained Event (BRUE) who meet low-risk criteria.”
2. Canadian Paediatric Society (CPS): While the CPS often references AAP guidelines, they emphasize the importance of social history and ensuring follow-up in the Canadian public health system.

References

1. Tieder JS, Bonkowsky JL, Etzel RA, et al. Brief Resolved Unexplained Events (Formerly Apparent Life-Threatening Events) and Evaluation of Lower-Risk Infants. Pediatrics. 2016;137(5):e20160590.
2. Canadian Paediatric Society. Acute Care Committee. Assessment and management of brief resolved unexplained events (BRUE) in infants. [CPS Position Statement].
3. UpToDate. Acute events in infancy including brief resolved unexplained event (BRUE). Accessed for MCCQE1 preparation context.
4. Medical Council of Canada. MCCQE Part I Objectives: Pediatrics.