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The assessment and management of infants who are described as having had a frightening, perhaps life-threatening, event is a challenging problem for clinicians. The fear that the infant may experience additional episodes, perhaps a fatal one, heightens the anxiety level of both families and medical professionals.

An apparent life-threatening event (ALTE) was defined in 1986 at a National Institutes of Health (NIH) Consensus Development Conference on Infantile Apnea and Home Monitoring as an “episode that is frightening to the observer and that is characterized by some combination of apnea (central or occasionally obstructive), color change (usually cyanotic or pallid but occasionally erythematous or plethoric), marked change in muscle tone (usually limpness), choking, or gagging.” In addition, it was recommended that previously used terminology such as “aborted crib death” or “near-miss sudden infant death syndrome (SIDS)” be abandoned to avoid implication of a causal association between this type of spell and SIDS.1

Apparent life-threatening events were described in the Consensus Development Conference statement as a “chief complaint that describes a general clinical syndrome.” This general clinical syndrome may be secondary to a specific diagnosis or may remain idiopathic despite a thorough evaluation. The definition of an apparent life-threatening event appears straightforward; however, in practice, the decision regarding whether or not an infant experienced an ALTE can be extraordinarily difficult for clinicians. Although more than 20 years have passed since the adoption of the ALTE definition, the published literature regarding the epidemiology, clinical course, and prognosis of ALTE remains limited, and there is no evidence that these events arise from any single mechanism. Nor is there evidence that the manifestations represent a consistent pattern. Factors that contribute to the difficulty in studying infants who experience ALTE episodes include the following:

  • Marked heterogeneity of clinical presentation
  • Lack of signs or symptoms during initial assessment by medical professionals
  • Parents or other caretakers who have been very frightened and have difficulty accurately describing signs or symptoms2-7
  • Possibility that some signs or symptoms are fabricated or inflicted

Data regarding incidence of ALTEs are limited. Their incidence is estimated to be 0.05% to 1% in population-based studies.8-11 Some perspective on the occurrence of idiopathic ALTE can be obtained from the Collaborative Home Infant Monitoring Evaluation (CHIME study), which was conducted at five medical centers (located in Cleveland, Toledo, Chicago, Los Angeles, and Honolulu) during the mid-1990s. This study included a systematic review of infants who presented with diagnoses consistent with ALTE and found that a typical urban medical center hospital provides care for about one case of possible ALTE each week and that approximately 20% of such cases will be considered an idiopathic ALTE.12

Asymptomatic Infants

Most commonly infants are no longer experiencing respiratory or circulatory dysfunction by the time they are first seen by medical professionals. Even in cases in which an emergency medical team has been called, the ...

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