PEDIATRICS Vol. 122 No. 1 July 2008, pp. 190-191 (doi:10.1542/peds.2008-1242)
COMMENTARY |
Apparent Life-Threatening Events: So What Happens Next?
Departments of Neurology and Pediatrics, University of Connecticut School of Medicine, Farmington, Connecticut; Division of Pediatric Neurology, Connecticut Children's Medical Center, Hartford, Connecticut
Abbreviations: ALTE, apparent life-threatening event
In this issue of Pediatrics, Bonkowsky et al1 review their experience and "long-term" outcomes of infants admitted to their tertiary care facility and health care system who had been evaluated for apparent life-threatening events (ALTEs). This is a difficult topic to analyze objectively, and the authors should be congratulated for their efforts. From the outset, difficulty emerges in that an accepted definition of the term ALTE is somewhat evanescent. The commonly used definition was provided by the National Institutes of Health Consensus Development Conference on infantile apnea and home monitoring from 1986,2 which defined an ALTE in a child less than 1 of year of age as an episode that is "frightening to the observer and that is characterized by some combination of apnea ..., color change ..., marked change in muscle tone ..., choking, or gagging. ... The observer fears that the infant has died."2 Explicit in this definition is the interpretation by the observer that the infant has died and manifests a significant alteration in appearance, activity, and signs of life (ie, breathing and color). There are a multitude of clinical phenomena exhibited by infants that may be frightening to an observer or at least recognized as abnormal infant behavior and trigger extreme anxiety, whereas the same event observed by another caretaker may not elicit the same response. Thus, our definition of an ALTE is centered on the perception of the observer when the event occurs. It should not be surprising that ALTEs encompass a heterogeneous collection of correlated etiologies and outcomes. The terminology, near–sudden infant death syndrome (SIDS), has been abandoned because previous studies have derived no data to garner support for a relationship between apnea and SIDS.3,4
The Bonkowsky et al study used a broad definition of ALTE to identify all potential subjects. As pointed out by the authors, ALTE is not a coded diagnostic term and, thus, serves only as a proxy terminology and introduces potential confounding diagnoses. The definition of ALTE used here was somewhat all-encompassing and consisted of 
1 of 5 specific clinical symptoms that concerned the caregiver. Subjects were excluded from the study if they had a known past medical history or an "apparent diagnosis" that could explain their current ALTE. However, hasn't that been the point of evaluating these infants? It would have been interesting to know what the outcome was of these excluded subjects (a control group?), many of whom had the same "apparent diagnoses" as the discharge diagnoses of those in the study cohort. Nonetheless, of the 1148 initially screened subjects, there was a cohort of 471 subjects (22% premature infants) evaluated.1
A decided strength of the Bonkowsky et al study was the comprehensive outpatient tracking ability used for outcomes. Many of the subjects were cared for within the same health care system via an electronic record format for ease of data recovery. Nonetheless, some outcome data may have been incomplete, which only served to underscore the main findings in that the actual outcomes may be underestimated. The 3 main outcomes characterized were deaths, child abuse, and adverse neurologic outcomes (chronic epilepsy and/or developmental delays). An average length of follow-up for the study cohort was 5.1 years (range: 2.6–7.6 years).1 The only 2 subjects who died had concurrent chronic epilepsy and static encephalopathy described as severe. Their deaths occurred at 18 months and 5.5 years after the initial ALTE evaluation.1 These 2 subjects both had deaths related to chronic respiratory and bulbar insufficiency.1 These risk factors themselves would predict a negative impact on long-term survival even in the absence of ALTEs.5
Adverse neurologic outcomes were identified in 23 (4.9%) of the children in the cohort, which included chronic epilepsy in 17 subjects.1 Was this outcome, in fact, a cause or result of the ALTE? It is important to note that each of these subjects shared in common a family history of epilepsy as an additional positive predictor. In fact, nearly three quarters of the cohort diagnosed with epilepsy returned for reevaluation at the time of a second event, all within 1 month of initial presentation. It was at this second event that a diagnosis of epilepsy was secured and antiepileptic drug therapy was used. This would not seem to be delayed in that, by definition, a diagnosis of epilepsy requires spontaneous recurrent events (ie, 2).6,7 Furthermore, the institution of therapy after the first epileptic event does not seem to alter the prognosis for long-term seizure remission and natural history of epilepsy.6,7 Thus, a diagnosis of epilepsy is neither imperative nor always possible at initial presentation.
A more compelling finding of the study is that 54 (11%) of the subjects were ultimately found to be victims of child abuse either by direct physical or sexual abuse or by exposure to abuse within the confines of their environments.1 Indeed, 2 were diagnosed as victims of physical abuse during their initial evaluation, and 17 were identified within 1 year.1 These chilling facts suggest that there may still be value in central nervous system imaging, although it is a low-yield procedure. Brand et al8 previously identified a similar frequency of abusive head injury in a study of 243 infants after ALTEs. They found 6 instances of abusive head injury identified with neuroimaging during initial evaluation. Long-term outcome data from their cohort were not available. The Bonkowsky et al study offers us this new perspective, because the true incidence of child abuse in this population is not known. A consideration for Munchausen by proxy abuse is an additional important consideration in this context.9 It should be more seriously pursued if previous siblings have suffered a similar presentation, especially if there was an undetermined cause of death.10 When there is a high index of suspicion for potential child abuse, protective measures augmented by the use of diagnostic testing are warranted.
Another point that deserves comment is the high frequency with which a diagnosis of gastroesophageal reflux disease (GERD) was made. A full 40% (190 of 471 subjects) who presented with an ALTE were ultimately diagnosed with GERD.1 Although it is true that GERD is a fairly common finding among infants, it has not been demonstrated clearly as an important cause of ALTEs or even apnea. In a study regarding the effects of gastroesophageal acid reflux on the duration of apnea in premature infants, there was no specific temporal relationship found between the 2 of them.11 It was demonstrated that of 119 infants studied with concurrent oxygen saturation and esophageal pH probe and cardiorespiratory monitoring of >6250 recorded episodes of gastroesophageal acid reflux, only 1% of these episodes were associated with apnea that lasted >15 seconds.11 These new data do not imply causality of ALTEs but, rather, concurrency.
Perhaps the most self-evident finding reported by the authors concerns the utility of a neurologic consultation. Despite the fact that many infants identified with an ALTE underwent inpatient neurologic evaluation, few of them were prospectively identified as having either chronic epilepsy or an identifiable neurologic cause for their presentation. Important as always, however, is the nature of the consultation request. If the cause of an ALTE is the indicated query, then an answer may not be readily forthcoming. However, should important elements of family history be abstracted (ie, positive family history of epilepsy not otherwise identified), subtle neurodevelopmental abnormalities not previously appreciated, or to interpret a previously obtained abnormal neurodiagnostic examination not clearly recognized as relevant, then the value of a neurologic consultation may be enhanced. Nonetheless, the typical low yield of multiple evaluations, consultations, and laboratory investigations has been clearly documented previously. In a previous study, Brand et al8 reviewed >3776 tests ordered on 243 patients with ALTEs and found that 17.7% returned positive results. However, only 5.9% (224 tests) contributed to diagnosis, and even in a majority of these cases one could further question their true utility.8
Thus, the clinician is faced with a bewildering array of potentially contributing causes and concurrent entities to what caretakers perceive as an ALTE. In reality, there are 2 fundamental questions that face the clinician: What best explains the cause of the actual event, and is it truly life-threatening or only apparently so? This long-term outcome study would suggest that special attention should be paid to historical features that potentially contribute to the development of chronic epilepsy; static encephalopathy/neurodevelopmental disorders; and maintaining a high index of suspicion for potential child abuse. Special efforts to uncover elements in support of these 3 diagnostic conditions in particular should be used. Initial neurologic consultation may have only select and limited added value.
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FOOTNOTES |
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Accepted Apr 30, 2008.
Address correspondence to Francis J. DiMario, Jr, MD, Connecticut Children's Medical Center, Division of Pediatric Neurology, 282 Washington St, Suite 2A, Hartford, CT 06106. E-mail: fdimari{at}ccmckids.org
The author has indicated he has no financial relationships relevant to this article to disclose.
Opinions expressed in these commentaries are those of the author and not necessarily those of the American Academy of Pediatrics or its Committees.
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PEDIATRICS (ISSN 1098-4275). ©2008 by the American Academy of Pediatrics
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