8: Sudden Infant Death Syndrome and Apparent Life-Threatening Events

OVERVIEW OF CLINICAL CONDITIONS

Sudden infant death syndrome (SIDS), apparent life-threatening event (ATLE), and infantile apnea are three clinical conditions that have specific definitions. The first, ALTE is defined as a collection of symptoms that is frightening to the observer which may include color change, apnea, change in muscle tone, and/or choking or gagging. The second, SIDS is a diagnosis rather than a collection of symptoms and is defined as a sudden unexpected infant death for which there is no explanation. In order to make the diagnosis of SIDS, there must be a complete autopsy, review of the medical and family history, and death scene investigation that excludes predisposing environmental factors and does not result in a clear explanation for the infant’s death. The third, infantile apnea is defined by the American Academy of Pediatrics (AAP) as “an unexplained episode of cessation of breathing for 20 seconds or longer, or a shorter respiratory pause associated with bradycardia, cyanosis, pallor, and/or marked hypotonia.”

ALTE should not be considered as a “near-miss SIDS.” There is insufficient evidence to suggest that ALTE precedes SIDS. Current literature indicates that ALTE, SIDS, and apnea are unrelated; instead, ALTE is a multifaceted all-encompassing term with the inclusion of apnea as one of the symptoms which may be perceived as life threatening by an observer. The literature has not reached consensus on components of the standard workup for an ALTE. This is in contrast to SIDS where a consensus has been reached that in order to make the diagnosis, a complete autopsy, review of the medical and family history, and death scene investigation that excludes predisposing environmental factors should be performed. Both ATLE and SIDS are similar in that the differential for the cause of each is vast and a definitive cause may never be found in each case.

SUDDEN INFANT DEATH SYNDROME

Evaluation

General Considerations

The definition of SIDS has evolved as our understanding of the syndrome has changed due to research and clinical experience. The National Institute of Health (NIH) originally defined SIDS as “sudden death of an infant or young child, which is unexpected by history, and in which a thorough postmortem examination fails to demonstrate an adequate cause.” Further research indicated that environmental conditions can play a role in SIDS such as trauma, hyper/hypothermia, and asphyxia. The definition of SIDS has been updated to include review of the medical and family history and a death scene investigation in addition to an autopsy. It is only after a complete review of the patient’s and family’s medical records, ...