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Content Update

January 16, 2017

Previous chapter 115, Suddent Infant Death Syndrome and Apparent Life-Threatening Event, has been rewritten as two separate chapters: 115A-Suddent Infant Death Syndrome, and 115B-Brief Resolved Unexplained Events and Apparent Life Threatening Events. New AAP clinical practice guidelines have been incorporated.6


It is quite common for infants to have events that are brief, self-resolved, and difficult to characterize. Sometimes these events appear respiratory, cardiovascular, or neurologic in origin and caregivers may seek medical attention for reassurance that the event is not a sign of a serious underlying condition. Through a comprehensive history and physical, clinicians can explain many of these events as a benign or normal process such as choking or gagging from feeding or gastroesophageal reflux (GER). Sometimes, however, the event remains poorly understood or unexplainable and this uncertainty poses a diagnostic and management challenge.


In 1986, before the risk factors for Sudden Infant Death Syndrome were well understood, an expert consensus group from the National Institute of Health coined the term Apparent Life Threatening Event, or ALTE. ALTE was defined as an episode that is frightening to a caregiver and involving some combination of apnea, color change (cyanosis, pallor, or plethora), change in muscle tone (limp or stiff), choking, or gagging.1 Unfortunately, the term ALTE described a constellation of presenting symptoms rather than a diagnosis and relied heavily on the subjective impression of nonmedical caregivers. No differentiation was made between the ~80% of ALTE patients who are well-appearing at the time of presentation2-5 from those with on-going symptoms such as respiratory difficulty or an ill appearance. To address these concerns, in 2016, the American Academy of Pediatrics more precisely defined these events as Brief Resolved Unexplained Events (BRUEs).


A BRUE specifically includes infants <1 year of age who have experienced a brief (<1 minute), unexplained event consisting of one or more of the following features: cyanosis or pallor; absent, decreased, or irregular breathing; marked change in tone (hyper- or hypotonia); and/or altered level of responsiveness. The infant must return to his or her baseline state of health after the brief event and have a reassuring history and physical exam after medical evaluation, including vital signs.6 The BRUE guideline provides risk-stratification criteria and management recommendations for lower-risk patients (Figure 115B-1).

FIGURE 115B-1.

Diagnosis, risk classification, and recommended management of a BRUE. [Reproduced with permission from Tieder JS, Bonkowsky JL, Etzel RA, et al: Brief Resolved Unexplained Events (Formerly Apparent Life-Threatening Events) and Evaluation of Lower-Risk Infants, Pediatrics. 2016 May;137(5). pii: e20160590]

*See Tables 3 and 4 of the original article for the determination of an appropriate and negative FH and PE. **See Fig 2 of the original article for the AAP method for rating of evidence and recommendations. CSF, cerebrospinal fluid; FH, family history; PE, physical examination; WBC, white blood cell.

BRUE patients considered lower-risk for subsequent events or serious underlying diagnosis include those >60 days age, gestational age ≥32 weeks and postconceptional age ≥45 weeks, only one event (no prior BRUE ever and not occurring in clusters), event duration <1 minute, no cardiopulmonary resuscitation (CPR) required by trained medical provider, no concerning historical features, and no concerning PE findings (see “Risk Stratification”).

This chapter does not address patients with on-going symptoms [e.g., ...

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