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BRUE and sudden infant death (SIDS) — safe sleep
A BRUE (brief resolved unexplained event) is a short, already-resolved episode in a baby younger than 12 months — cyanosis or pallor, a change in breathing, tone or responsiveness — that remains unexplained after history and examination; in a lower-risk infant no extensive work-up is done. The main protection against SIDS is back-sleeping on a firm mattress, in the parents' room yet never in the parents' bed.
Why it matters in the exam
The question describes a 3-month-old whom the parents saw "blue and floppy" for about 20 seconds, who looks excellent in the emergency department with a normal examination. The question is whether to admit and test. Per AAP 2016, a lower-risk infant — age above 60 days, birth at 32 weeks or later (postconceptional age at least 45 weeks), the first such episode, duration below one minute, no CPR needed from trained staff and no concerning findings — receives education, brief observation with pulse oximetry and possibly an ECG and pertussis testing, without routine blood tests, imaging or a home monitor.
An infant who is not lower-risk needs work-up according to the findings: abuse (especially eye examination and imaging when there are signs), seizures, infection (including pertussis), arrhythmias (long QT), reflux and metabolic disease. The old term ALTE was replaced, because "life-threatening" frightened families and led to unnecessary tests.
SIDS is most common at 2–4 months, and 90% occurs under 6 months. Risk factors are prone or side sleeping, soft bedding, bed-sharing, smoking in pregnancy and at home, overheating and prematurity. Protective factors: back to sleep for every sleep, a firm flat surface without pillows or blankets, room-sharing without bed-sharing (ideally for at least 6 months), breastfeeding, a pacifier at sleep and immunisations. A home breathing monitor does not prevent SIDS. To prevent a flat head — tummy time while awake and supervised.
Key points
- BRUE: a brief resolved event that remains unexplained in an infant under one year.
- Lower risk = age above 60 days, born at 32 weeks or later, a first episode shorter than one minute, and no CPR by staff.
- Lower risk — education and brief observation, no extensive work-up.
- SIDS: peak at 2–4 months.
- Safe sleep: back, firm bare surface, in the parents' room not their bed.
Summary table
| Topic | Definition or rule | Detail | Trap |
|---|---|---|---|
| BRUE | Under one year, brief resolved event, unexplained after history and examination | Cyanosis or pallor, change in breathing, tone or responsiveness | Fever or illness that explains the event — it is not a BRUE |
| Lower risk | Age above 60 days; born at 32 weeks or later; first episode; shorter than one minute; no CPR by staff | Brief observation, possibly ECG and pertussis test | No routine tests and no home monitor |
| Higher risk | Does not meet the criteria | Work-up: abuse, seizures, infection, heart, metabolic | Consider admission |
| SIDS — age | Peak at 2–4 months | 90% under 6 months | — |
| Safe sleep | On the back, firm surface, no soft objects, in the parents' room not their bed | Breastfeeding, pacifier, immunisations, smoke-free environment | A home monitor does not prevent SIDS |
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Sources
- AAP Clinical Practice Guideline: Brief Resolved Unexplained Events (Formerly Apparent Life-Threatening Events) and Evaluation of Lower-Risk Infants, 2016 — Definition, lower-risk criteria and recommendations
- AAP Policy Statement: Sleep-Related Infant Deaths — Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment, 2022 — Safe sleep recommendations
- Nelson Textbook of Pediatrics, 22nd edition (2024) — Sudden Infant Death Syndrome; Brief Resolved Unexplained Events
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.