Brief Resolved Unexplained Events and Other Acute Events in Infants

Background

Infants commonly experience acute, self-resolving changes in their breathing, tone, mental status, and skin color. Usually these events are normal manifestations of developmental immaturity. Nonetheless, caregivers may worry that the acute event could have been life-threatening or is a sign of an undiagnosed medical problem and seek medical attention. In most cases, after a comprehensive history and physical examination, a clinician will determine the event to have been a benign or normal process, such as gastroesophageal reflux (GER) or periodic breathing of the newborn. At times, however, the event defies a simple explanation and drives uncertainty about risk from a serious underlying cause or a future event. This situation poses a diagnostic and management challenge for both the family and the clinician.

Historically, these events were feared as precursors to sudden infant death syndrome (SIDS) and were referred to as near-miss SIDS , aborted crib deaths , or apparent life-threatening events (ALTEs) . These terms have been replaced because we now know that these events are not associated with SIDS and are rarely life-threatening. Clinical use of ALTE as a diagnostic term is additionally problematic because it relies on the subjective interpretation of the caregiver and includes a nonspecific constellation of symptoms. It also does not distinguish well-appearing patients from those with symptoms.

Most of these acute events in infants are best described as brief resolved unexplained events (BRUEs). A BRUE is a diagnosis of exclusion and should be used only when the event is transient and remains unexplained after an appropriate medical evaluation.

Definition

A BRUE (pronounced brew ) is an event that occurs in an infant younger than 1 yr that typically lasts less than 30 sec and is described by the observer as a sudden, brief, and now-resolved episode that involved at least one of the following:

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  cyanosis or pallor

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  absent, decreased, or irregular breathing

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  marked change in tone, either hyper- or hypotonia

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  altered level of responsiveness

The diagnosis of BRUE applies only to infants who were asymptomatic prior to the event and during evaluation, and when no explanation for the event is found through appropriate history and physical examination.

Infants who experience a BRUE are categorized as either lower or higher risk for a subsequent event or a serious underlying disorder based on patient factors, characterization of the event, additional historical factors, and the physical examination.

A lower-risk infant is defined as

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  age >60 days

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  gestational age ≥32 wk and postconceptional age ≥45 wk

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  occurrence of only 1 BRUE (no prior BRUE ever and not occurring in a cluster)

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  duration of event <1 min

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  no cardiopulmonary resuscitation (CPR) by trained medical provider required

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  no concerning historical features

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  no concerning physical examination finding