Sudden infant death syndrome is the sudden and unexpected death of an infant or young child between 2 wk and 1 yr of age in which a thorough postmortem examination fails to show cause.

Sudden infant death syndrome (SIDS) is the most common cause of death between 2 wk and 1 yr of age, accounting for 35 to 55% of all deaths in this age group. Distribution is worldwide, occurring in 1.5/1000 births in the US. Peak incidence is between the 2nd and 4th mo of life. Many risk factors for SIDS (see Table 4: Miscellaneous Disorders in Infants and Children: Risk Factors for Sudden Infant Death Syndrome) apply to non-SIDS infant deaths as well. Almost all SIDS deaths occur when the infant is thought to be sleeping.

Etiology

The cause is unknown, although it is most likely due to dysfunction of neural cardiorespiratory control mechanisms. The dysfunction may be intermittent or transient, and multiple mechanisms are probably involved. Fewer than 5% of SIDS victims have been noted to have episodes of prolonged apnea before their death, so the overlap between the SIDS population and infants with recurrent prolonged apnea is very small. Many studies link a prone (on stomach) sleeping position with increased risk of SIDS. Other risk factors include soft bedding (eg, lamb's wool), waterbed mattresses, smoking in the home, and an overheated environment.

Diagnosis

The diagnosis, while largely one of exclusion, cannot be made without an adequate autopsy to rule out other causes of sudden, unexpected death (eg, intracranial hemorrhage, meningitis, myocarditis).

Management

Parents who have lost a child to SIDS are grief-stricken and unprepared for the tragedy. Because no definitive cause can be found for their child's death, they usually have excessive guilt feelings, which may be aggravated by investigations conducted by police, social workers, or others. Family members require support not only during the days immediately after the infant's death, but for at least several months to help them with their grief and dispel guilt feelings. Such support includes, whenever possible, an immediate home visit to observe the circumstances in which SIDS occurred and to inform and counsel the parents concerning the cause of death.

Autopsy should be performed quickly. As soon as the preliminary results are known (usually within 12 h), they should be communicated to the parents. Some clinicians advise a series of home or office visits over the 1st month to continue the earlier discussions, answer questions, and give the family the final (microscopic) autopsy results. At the last meeting, it is appropriate to discuss the parents' adjustment to their loss, especially their attitude toward having other children. Much of the counseling and support can be complemented by specially trained nurses or by lay people who have themselves experienced the tragedy of and adjustment to SIDS (eg, members of a local chapter of the National Foundation for Sudden Infant Death Syndrome or of the International Guild for Infant Survival).

Prevention

The American Academy of Pediatrics recommends that infants be placed supine (on back) for sleep unless other medical conditions prevent this. The incidence of SIDS increases with overheating (clothing, blankets, hot room) and in cold weather. Thus, every effort should be made to avoid an overheated or an overly cold environment, to avoid overwrapping the infant, and to remove soft bedding, such as sheepskin, pillows, stuffed toys/animals, and comforters, from the crib. Mothers should avoid smoking during pregnancy, and infants should not be exposed to smoke. Parents should not have the infant in the parents' bed.

Courtesy: The Merck Manuals