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Infants are often brought for urgent or emergent medical assessment owing to abnormal breathing patterns or worrisome respiratory episodes. Often the episode resolves before the patient arrives for initial evaluation and does not recur. However, some infants with respiratory episodes have significant underlying medical conditions or even life-threatening events. Many infants with both types of episodes are hospitalized for monitoring, diagnostic testing, and management despite a stable appearance at presentation, while others are able to be managed as outpatients. There is wide variation in the evaluation and management of these episodes. This chapter addresses presentations suggestive of apparent life-threatening events (ALTEs) and briefly discusses central apnea of neonates and young infants. It also examines pediatric obstructive sleep apnea.


Apparent life-threatening event (ALTE) refers to a complex set of symptoms that presents unexpectedly in an infant, are of concern to the observer, and cannot be easily characterized by the healthcare provider.1,2 Approximately 1% of infants have an ALTE which prompts admission. The most common age at presentation ranges from 6 to 10 weeks.3-7 Many other events may occur during infancy, yet not be appreciated or raise concern for the caregiver. For example, in one large longitudinal cohort study of infants on home cardiorespiratory monitors, 43% of healthy term infants had at least one 20-second apneic episode over a 3-month period.8 In a separate study, over 5% of parents recalled seeing an apnea of that duration.7 The pediatric hospitalist may be asked to clarify the features of the presentation, stabilize the infant, and reassure the caregivers. If admission is considered, the hospitalist must diagnose and treat the precipitating cause (if one is determined), educate the caregivers, and render a disposition.


In September 1986, the National Institutes of Health (NIH) convened an expert panel to review the literature and discuss the relationship of infantile apnea, ALTE, and sudden infant death syndrome (SIDS). These experts standardized the definition of ALTE by describing it 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 marked limpness), choking, or gagging.” NIH also proposed eliminating the terms “near miss SIDS” and “aborted crib death” because no causal link could be found between ALTE and SIDS.1 The relationship among ALTE, infant apnea, and SIDS is still unclear, and there is increasing evidence that these disorders are unrelated.3,8,9

Owing to the breadth of the definition, ALTE has been attributed to everything from normal physiologic events to life-threatening illnesses.5,10,11 Therefore, it must be stressed that the symptoms of ALTE may represent a normal physiologic occurrence and be of no clinical significance. Although most ALTEs ...

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