A BRUE is “an event occurring in an infant younger than 1 year when the observer reports a sudden, brief, and now resolved episode of ≥1 of the following: (1) cyanosis or pallor; (2) absent, decreased or irregular breathing; (3) marked change in tone (hyper- or hypotonia); (4) altered level of responsiveness.”^1,2 It is diagnosed after a history and physical examination fails to find an explanation for the event. The term BRUE was recently proposed in a clinical practice guideline by an expert committee of the American Academy of Pediatrics.^1,2 In this guideline, the committee recommends that BRUE replace ALTE (apparent life-threatening event) which had been in use since being proposed at a National Institutes of Health consensus conference in 1986.³

ALTE as defined is a symptom rather than a diagnosis.⁴ It encompasses a heterogeneous group of conditions potentially involving any body system. Because of the variability and non-specificity of ALTE, the risk for a subsequent or underlying disorder cannot be quantified.¹ However, within the ALTE population is a benign, idiopathic group with negligible risk for recurrence. In these patients with no underlying cause of ALTE, in fact, the event was not “life-threatening.” The heterogeneity of potential conditions within ALTE undermined the quality of care and complicated the research of these infants. Therefore, a new term was needed to better describe these events. The BRUE practice guideline provides an approach to the evaluation and management of these infants and guides future research.

A thorough history and physical examination is the cornerstone of the evaluation of these infants. By definition, the event must be brief (typically <1 minute in duration), resolved prior to presentation for medical care, and without apparent explanation from history and physical examination. The patient must have normal vital signs and appearance. To qualify for the lower-risk category, the infant must be >60 days of age and have a gestational age ≥32 weeks and a post-conceptual age ≥45 weeks. The patient’s history cannot include any previous BRUEs, a need for CPR by a trained medical provider during the event, family history of sudden cardiac death, or any concerning social history, or any other concerning features which may indicate an underlying etiological condition. If the medical history, social history, and physical examination do not provide an explanation for the event, the diagnosis of BRUE can be made (Fig. 4-1).