Brief Resolved Unexplained Event (BRUE): Definition and Clinical Significance
An isolated event in the medical context refers to a brief, sudden occurrence that resolves completely without explanation, such as a Brief Resolved Unexplained Event (BRUE) in infants, which is characterized by a sudden episode of cyanosis/pallor, breathing changes, tone alterations, or responsiveness changes that resolves completely and has no identifiable cause after appropriate evaluation. 1
Definition and Characteristics
A BRUE (formerly known as Apparent Life-Threatening Event or ALTE) is defined as an event occurring in an infant less than 1 year of age when an observer reports a sudden, brief (typically <1 minute), and now resolved episode of one or more of the following: cyanosis or pallor, absent/decreased/irregular breathing, marked change in muscle tone, or altered level of responsiveness 1
For an event to be classified as a BRUE, it must be unexplained, meaning there is no identifiable cause after conducting a thorough history and physical examination 1
The event must be completely resolved with the infant returning to their baseline state of health 1, 2
Distinction from Previous Terminology
In 2016, the American Academy of Pediatrics recommended replacing the term "Apparent Life-Threatening Event" (ALTE) with "Brief Resolved Unexplained Event" (BRUE) to improve clinical care and management 1
Unlike ALTE, the BRUE definition:
Clinical Significance and Risk Stratification
BRUE events are classified as either lower-risk or higher-risk based on patient age, corrected gestational age, event duration, number of events, and whether CPR was performed 1, 2
Most patients with BRUE will have a benign clinical course, but important underlying conditions must be considered, including airway, cardiac, gastrointestinal, genetic, infectious, neurologic, and traumatic conditions 2
Studies show that prior BRUE events are associated with serious diagnoses and episode recurrence, highlighting the importance of proper risk stratification 2
Isolated Events in Other Medical Contexts
In cardiovascular medicine, isolated events may refer to single occurrences of symptoms that don't meet the criteria for established diagnoses, such as a single episode of chest pain that doesn't qualify as unstable angina 1
In the context of patient safety, isolated events may refer to single occurrences of adverse events that happen during hospitalization but are not part of a pattern 3, 4
The concept of "isolated events" contrasts with recurrent events or patterns that might indicate a systemic issue or ongoing pathology 5
Clinical Approach
When evaluating an isolated event, clinicians should determine if it meets criteria for a specific diagnosis (like BRUE in infants) or represents a one-time occurrence without clinical significance 1, 2
For BRUE specifically, the American Academy of Pediatrics provides evidence-based guidelines for evaluation and management of lower-risk patients, advocating against routine admission, blood testing, and imaging 1, 2
Documentation of isolated events is crucial for monitoring potential recurrence and establishing patterns that might indicate underlying pathology 4, 5