Brief, resolved, unexplained event (BRUE): Clinical sciences

Brief Resolved Unexplained Events, or BRUEs, are witnessed episodes during infancy, lasting less than one minute, that are characterized by cyanosis or pallor; absent, decreased, or irregular breathing; a marked change in muscle tone; or altered responsiveness; followed by a return to the infant’s baseline state of health.
BRUE is diagnosed when no underlying cause for these symptoms can be identified after a thorough history and physical examination. Based on historical features and exam findings, infants who meet the criteria for BRUE can be classified into higher or lower-risk categories.

When a pediatric patient presents with a chief concern suggesting BRUE you should start by obtaining a focused history and physical exam.

These patients are under 1 year of age, and caregivers typically describe a witnessed episode lasting less than 1 minute, during which the infant’s skin appeared blue, dusky, or pale for no clear reason. They may also report that the infant had an irregular or shallow pattern of breathing during this episode, or that they stopped breathing altogether. Caregivers might also describe the infant’s tone as stiff or floppy, or report that the child was less responsive and excessively sleepy. Further history usually reveals no obvious symptoms suggesting an identifiable precipitant or an acute illness. As far as the exam goes, your patient will be well-appearing and afebrile, with normal vital signs.

Keep in mind that, by definition, patients with BRUE present after the resolution of the episode and have returned to their baseline level of functioning, so an unstable child will not have the diagnosis of BRUE.

Based on these findings, you should suspect a BRUE. Next, you’ll need to assess the event criteria to determine if the event was really a BRUE. The criteria include one or more of the following: cyanosis or pallor; absent, decreased, or irregular breathing; a marked change in muscle tone; and altered responsiveness. Additional criteria include a lack of history or exam findings that could provide a medical explanation for the event; and a return to the infant’s baseline state of health following the event.

If these criteria are not met, consider an alternative diagnosis.
For example, symptoms like nasal congestion or cough suggest a respiratory tract infection, while repetitive focal or generalized motor activity followed by unresponsiveness suggests a seizure.

Here’s a clinical pearl to keep in mind! Always consider the possibility of non-accidental trauma when an infant presents with a suspected BRUE.
Some clues to look for include changes or inconsistencies in the caregiver’s history, recurrence of similar episodes, or delays in seeking medical care. On exam, look for alarm signs that suggest abuse, such as oropharyngeal or frenulum damage, an unusual pattern of bruising, or retinal hemorrhages.

Now let’s see what to do once we diagnosed BRUE. Alright, if your patient meets event criteria, go ahead and diagnose BRUE. Then, assess your patient for the presence of higher-risk BRUE characteristics. These include an age of 60 days or less; a gestational age at birth of less than 32 weeks with a corrected chronological age of 45 weeks or less; the need for cardiopulmonary resuscitation during the event; and a history of recurrent events.

Now, if any of these characteristics are identified, your patient is higher-risk. A higher-risk classification suggests that the patient might have a higher likelihood of a recurrent event, an adverse outcome, or a serious underlying condition.

In this case, they require additional medical evaluation, even though the initial history and exam findings did not uncover a clear medical explanation for the episode.