The following statement is from the National Institutes of Health
“An apparent life-threatening event (ALTE) is defined as an episode that is frightening to the observer and is characterized by some combination of apnea (central or obstructive), color change (cyanotic, pallid, erythematous or plethoric) change in muscle tone (usually diminished), and choking or gagging. In some cases, the observer fears that the infant has died. Previously used terminology such as near-miss sudden infant death syndrome (SIDS) or aborted crib death should be abandoned because their use implies a possibly misleading close association between this type of spell and SIDS.” This original description was established by expert consensus in 1986.
In 2016, the American Academy of Pediatrics (AAP) released a new clinical practice guideline that recommended the replacement of the term ALTE with a new term, brief resolved unexplained event (BRUE). The authors define BRUE as an event observed in infants younger than 1 year during which an observer reports a sudden, brief (less than one minute), but then resolved episode including at least one of the following: cyanosis or pallor; absent, decreased, or irregular breathing; marked change in muscle tone (hyper- or hypotonia); or altered responsiveness. The guidelines also add that a BRUE is diagnosed only when there is no explanation for a qualifying event after completion of a thorough history and physical examination. Infants younger than 1 year who present with a BRUE are categorized either as (1) a lower-risk patient on the basis of history and physical examination for whom evidence-based recommendations for evaluation and management are offered or, (2) a higher-risk patient whose history and physical examination suggest the need for further investigation and treatment but for whom recommendations are not offered. This clinical practice guideline is structured to promote a patient- and family-centered approach to care, reduce unnecessary and potentially costly medical interventions, improve patient outcomes, and enhance efforts at future research.