Brief Resolved Unexplained Event

Etiology

Implicit in the definition of brief resolved unexplained event is the word unexplained, indicating that there is no underlying cause. Nevertheless, infants in the high-risk category may have an underlying cause similar to those previously described in the apparent life-threatening event literature. These include gastroesophageal reflux, seizures, bronchiolitis, pertussis, and child abuse[5]. Other less frequent causes are inborn errors of metabolism, cardiac arrhythmias, increased intracranial pressure, toxic ingestions, and syndromic conditions, especially those involving craniofacial anomalies.

Epidemiology

The brief resolved unexplained event was described only in 2016, and thus there are no reports describing the epidemiology. An apparent life-threatening event includes a subset of brief resolved unexplained events accounted for approximately 0.6% to 0.8% of all emergency department (ED) visits[3] and 0.6 to 2.6 per 1000 live births. One study in the Lombardy region, Italy[6] had a cumulative incidence of 4.1 cases per 1000 live births. 

Pathophysiology

As brief resolved unexplained event is an unexplained event, the pathophysiology of these events is unknown. However, the possible role of abnormalities in the swallowing mechanisms, laryngospasm, gastroesophageal reflux, and autonomic function, are yet to be elucidated.

History and Physical

History and physical exam are essential to categorize the event as brief resolved unexplained event or to assign an alternate diagnosis. It is useful to ascertain the history with a clear focus on the circumstances before, during, and after the event. Features to be clarified before the event include the location of the event (home/daycare), whether the infant was awake or asleep, infant position (supine/prone, other), and activity (feeding, the presence of anything in the mouth, vomit/spit up). A thorough description of the event including if the infant was active or quiet, responsive or unresponsive, breathing, not breathing, or struggling to breathe, choking or gagging, appeared limp, rigid, or seizing, seemed distressed or alarmed, and change in skin or lip color (red, pale, blue). After the event, determine the approximate duration of the event, abrupt or gradual termination, spontaneous termination, or any interventions used (picking up, rubbing, CPR), and behavior before returning to normal (quiet, startled, fussy, or crying). Other useful information about recent illness, associated symptoms, history of illnesses especially apparent life-threatening event/brief resolved unexplained event, antenatal/perinatal history including gestational age, developmental delays, family history of early deaths especially, SIDS/apparent life-threatening event or presence of cardiac arrhythmias. Social history should focus on identifying the availability of social support systems and access to resources.

Infants presenting with brief resolved unexplained events are well and appear to have normal vital signs and physical exam findings. However, a thorough physical exam is required to identify those with a high-risk brief resolved unexplained event or find the trigger to an alternate diagnosis.

Evaluation

Infants with a low-risk brief resolved unexplained event do not require any testing. A brief period of observation (one to four hours) with continuous pulse oximetry is adequate. The American Academy of Pediatrics does not offer any guidance for infants with high-risk brief resolved unexplained events; the common sense approach is to perform relevant tests based on specific areas of concern identified in the history or physical exam. Performing a 12-lead EKG can be considered as the benefit of identifying channelopathies that lead to sudden death and outweigh any harm. Testing for pertussis may be useful in the at-risk populations (suggestive symptoms, unimmunized patients). Other tests such as complete blood count, electrolytes, blood glucose, lactic acid, bicarbonate levels, blood gas, blood cultures, urine analysis, imaging, electroencephalogram (EEG), pH probe, and polysomnography[7] are not routinely recommended.

Treatment / Management

The key component of management is to educate caregivers about the condition, ensure close follow-up after discharge, and provide resources for training in cardiopulmonary resuscitation. Admission for cardiorespiratory monitoring is not routinely indicated. There is no role for medications, tests, specialist consultations, or home cardiorespiratory monitoring. Infants that are not low-risk should be managed based on the physiological status and abnormalities identified in history and physical exam. Admission criteria[8] recommended for patients that were previously described as ALTE included patients that required CPR and had another clear reason for hospitalization, had more than one ALTE event within a 24-hour period, and if there was associated significant underlying disease associated. AAP guideline does not make any recommendations for the management of high-risk BRUE.

Differential Diagnosis

Several conditions can present with a brief apneic event, but would not be categorized as BRUE if they fit into another definable diagnosis. Both upper and lower respiratory infections (e.g. Bronchiolitis, pertussis, pneumonia) can cause apneic events. Other conditions to consider include sepsis, meningitis, gastroesophageal reflux, seizures, infant botulism, prolonged QT syndrome, metabolic disorders, and child abuse.

Prognosis

As BRUE is a new entity, there is a paucity of data regarding prognosis. Previously studies on prognosis for ALTE may offer some insight at least for patients with high-risk BRUE. One year mortality after ALTE in one study was less than 1%.[9] The readmission rate within 30 days for an ALTE visit was 2.5%[10]

Complications

There are no known complications