Apparent Life-Threatening Event/Brief Resolved Unexplained Event

History

The most important diagnostic tool in the evaluation of a BRUE is a thorough history elicited from the caretaker who observed the episode. History taking should start with open-ended questions to obtain the story from the caretaker, followed by specific questions geared at characterizing certain key aspects of the episode. The history should focus on the activities and behaviors preceding the event, characteristics of the episode itself, interventions performed and their effect, and postepisode events and behavior. A comprehensive past medical history, social history, and family history should also be obtained for identifying clues that may aid in narrowing the focus of the investigation. Information essential to a complete history is outlined in Table 6.3 . Key historical findings by system can be useful in narrowing the differential (see Table 6.2 ).

The patient’s activities and behaviors immediately preceding the episode are important to consider and may provide clues to the diagnosis. Key associations include those with sleep, feeding, crying, cough, and emesis. The location and position of the child prior to the event should also be noted, such as placement in a car seat, on a soft or firm surface, prone or supine, and with or without surrounding blankets or pillows.

Key characteristics of the actual event include color change, respiratory effort, change in tone or movements, and level of alertness at onset and during the episode. Careful review of these signs and symptoms aids in the identification and classification of a BRUE, and they are important clues to potential alternative diagnoses.

Color: The specifics of any change in color should be clearly noted, and the hue of the change is significant. Unlike in the term ALTE where any change of color was considered, BRUE more precisely defines concerning color change as episodes of cyanosis or pallor. Episodes of rubor are not consistent with a BRUE, because they are common in healthy infants. The location of the change should also be noted, such as central cyanosis versus peripheral acrocyanosis, as the latter may be consistent with normal changes in perfusion.

Change in breathing: The term BRUE expands the respiratory criteria for ALTE beyond apnea to include absent breathing, diminished breathing, and other breathing irregularities. If apnea is noted, the duration of respiratory cessation aids in the determination of true pathologic apnea. Apnea is defined as cessation in breathing that is prolonged (>20 seconds) or associated with cyanosis, marked pallor or hypotonia, or bradycardia. The degree of respiratory effort noted assists in differentiating central versus obstructive processes. Central apnea with no respiratory effort may suggest underlying neurologic, cardiac, metabolic, or infectious causes, while obstructive processes include GER, respiratory tract infections, foreign body, suffocation, or airway anatomic anomalies.

Tone: It is important to determine if tone was increased or decreased during or after the event. If abnormal movements were identified, it should be noted if the movements were generalized or localized to a certain part of the body and the timing. The ability to suppress any abnormal movements should be documented, as this makes conditions such as seizure less likely.

Altered level of responsiveness: Specific note of the level of responsiveness is another criterion under the BRUE definition and is significant to note as it can be associated with episodic but serious cardiac, respiratory, metabolic, or neurologic events.

Of note, if the event was noted to consist primarily of choking or gagging without any of the other features listed earlier, unlike in the former ALTE definition, this would not be included within the current definition of BRUE. Choking and gagging usually indicate easily identifiable common diagnoses such as GER or respiratory infections and therefore are not considered a BRUE.

Additional history should include any interventions performed, by whom, and the effects of the interventions. The need for resuscitation, especially when performed by health care providers, has been associated with more severe and significant underlying etiologies and classifies the event as a higher-risk BRUE. Obtaining a direct history from any emergency personnel who may have been involved with the case is important.

Postepisode behavior should be carefully documented. Level of alertness following the event and time until return to normal behavior are also of particular importance.

Regarding past medical history , it is essential to note the birth history including gestational age, any prior similar episodes, preceding illnesses, and known medical conditions. Family history should also be obtained with a focus on the presence of BRUEs, ALTEs, sudden infant death syndrome (SIDS), early deaths, and metabolic or neurologic disorders in first- or second-degree family members. Social factors to consider include a full list of caregivers, siblings, and other children in the home; illness exposures; medications in the home; exposure to smoke; or prior Child Protective Services involvement.

Major factors suggestive of risk for future adverse events and/or a serious underlying diagnosis include age, prematurity, multiple events, and the need for CPR by trained medical providers. Prematurity is a frequently noted risk factor for a BRUE/ALTE, perhaps due in part to the preterm infants’ immature respiratory centers, arousal mechanisms, and airway reflexes. The risk is increased for infants born at <32 weeks’ gestation, and the risk decreases once they reach 45 weeks’ postconception age. A history of multiple events raises the concern for serious underlying pathology and progression of future events. With a history of multiple events over days to months, the concern for child maltreatment, seizures, intracranial pathology, and inborn errors of metabolism increases. Multiple events occurring over the course of the day of presentation escalate concern for serious infections and child maltreatment.

Physical Examination

One of the diagnostic challenges of the evaluation of a child with a BRUE is that the patient has returned to their baseline state of health after the event and has a reassuring physical examination and vital signs when evaluated by a trained medical provider. Infants should undergo a complete head-to-toe examination fully unclothed, including vital signs with pulse oximetry, growth parameters with head circumference, and complete ear, nose, throat, cardiac, respiratory, abdominal, neurologic, musculoskeletal, and skin examinations to note any abnormalities or clues to suggest an alternative diagnosis.

Abnormalities noted on the presenting examination may indicate various possible diagnoses and should prompt additional evaluation for the suggested etiology (see Table 6.2 ). Particular attention should be paid to the child’s general appearance for dysmorphic features that might suggest an underlying genetic or metabolic syndrome. Abnormal growth parameters may identify failure to thrive, which can be suggestive of pathologic reflux, cardiac disease, or metabolic disorders. Signs of trauma, including retinal hemorrhages, unexplained bruising, or evidence of oral pharyngeal trauma (torn frenulum), suggestive of child maltreatment should also be noted. A full neurologic examination may raise concern for an intracranial bleed or mass requiring prompt attention.

Diagnostic Evaluation

A comprehensive history is essential both in performing a risk stratification to determine if the event would be classified as higher or lower risk and in identifying indications of potential alternative diagnoses.

For patients identified as lower risk , laboratory studies, imaging studies, and other diagnostic procedures are unlikely to be useful or necessary (see Fig. 6.1 ). Low-risk patients should not be admitted to the hospital solely for cardiorespiratory monitoring or undergo extensive evaluations. Two evaluations that are recommended for consideration in the lower-risk population include an ECG and pertussis in conjunction with brief monitoring on a continuous pulse oximeter with serial exams. ECGs may be useful in identifying channelopathies, ventricular pre-excitation, cardiomyopathy, or other heart disease. Although the incidence of these is low, the benefit of identifying a patient at risk of sudden cardiac death may outweigh the cost and risk of potential false positives leading to additional evaluation. Pertussis and respiratory syncytial virus (RSV) have been reported to cause BRUE-like events with gasping, color change, and apnea and may not have associated fever or respiratory symptoms particularly when present in young infants.

When evaluating patients presenting with a higher-risk BRUE, it is often difficult to determine the degree to which diagnostic work-up is indicated, especially in well-appearing infants with a nonspecific history and physical examination. A potential framework for the approach to evaluation of a higher-risk BRUE suggests consideration of the following: continuous pulse oximetry monitoring for at least 4 hours; consultation with a social worker; a bedside feeding evaluation; ECG; laboratory studies including consideration of a rapid viral respiratory panel and pertussis testing, hematocrit, blood glucose, bicarbonate or venous blood gas, and lactate; consultation with a child abuse expert; head imaging with CT or MRI, and skeletal survey if concerned for child maltreatment; and then additional consultation and evaluation as indicated based on the clinical context. The level of evidence varies for each of these recommendations and the clinical context should be carefully considered when approaching the evaluation of a BRUE. Prior data from the ALTE literature suggests that in approximately 20% of patients the history and physical examination alone yield the cause; in about 50% of patients, a likely diagnosis is suspected from the history and physical examination and is subsequently confirmed by diagnostic testing. Diagnostic testing alone yields an etiology in approximately 15% of patients. When testing is performed, it is most successful when done in a focused and targeted manner geared toward diagnoses suggested by the history and physical examination, specifically addressing concerning features identified.