Sudden infant death syndrome

Sudden infant death syndrome (SIDS) is the sudden, unexplained death of a child < 1 year of age, presumed to have occurred during sleep. SIDS is a diagnosis of exclusion and can only be made after a thorough postmortem examination has excluded other causes such as a cardiac abnormality or child maltreatment. The cause of SIDS is unknown but is likely due to a combination of intrinsic and extrinsic factors. Preventive measures include the avoidance of prenatal tobacco and alcohol exposure, exclusive feeding of breast milk for the first 6 months, and safe sleep practices. Parents should receive education on SIDS prevention during routine prenatal care and well-child visits.

• Sudden infant death syndrome (SIDS) ^[1]
  • The sudden, unexpected death of a child < 1 year of age
  • Cause of death remains unexplained after a complete postmortem examination.
  • Death is usually presumed to have occurred during sleep.
• Sudden unexpected infant death (SUID) ^[2]
  • An umbrella term for any sudden, unexpected death of a child < 1 year of age
  • Cause of death may be unexplained (e.g., SIDS) or explained (e.g., trauma, poisoning, metabolic disorder).
• Sudden unexplained death in children (SUDC) ^[2]
  • The sudden, unexpected death of a child ≥ 1 year of age
  • Cause of death remains unexplained after a complete postmortem examination.

SIDS is a diagnosis of exclusion and cannot be made until a thorough postmortem examination has been completed. ^[3][4]

• Peak incidence: 2–4 months ^[5]
• Sex: ♂ > ♀

Epidemiological data refers to the US, unless otherwise specified.

The etiology of SIDS remains unclear. Evidence suggests that it is caused by a combination of both extrinsic and intrinsic factors, which ultimately lead to acute or chronic hypoxia. ^[6][7]

Extrinsic factors ^[7][8]

• Sleeping in the prone position
• Exposure to nicotine during pregnancy and after birth (including 2nd-hand smoking)
• Young maternal age (especially < 20 years)
• Overheating
• Unsafe sleeping environment or CO₂ rebreathing, e.g., a shared blanket, stuffed animals in the crib, soft bedding

Intrinsic factors ^[6]

• Male sex
• Prematurity
• Prenatal and/or postnatal exposure to smoking, alcohol, and/or drugs
• Polymorphisms in the serotoninergic pathway
• Brainstem abnormality that affects serotoninergic modulation of cardiorespiratory control and impairs protective responses to external stressors

• Infectious
  • Pneumonia
  • Meningitis
  • Sepsis
• Cardiac
  • Myocarditis
  • Congenital heart defects
  • Arrhythmias
• Traumatic and environmental
  • Child maltreatment, e.g., shaken baby syndrome, intentional suffocation
  • Accidental or intentional poisoning
  • Aspiration, asphyxiation
  • Hyperthermia or hypothermia
• Congenital
  • Major congenital abnormalities
  • Inborn errors of metabolism
• Other
  • Dehydration or electrolyte abnormalities
  • Seizure ^[10]

The differential diagnoses listed here are not exhaustive.

There is no treatment for SIDS. Management focuses on providing compassionate support to caregivers and ensuring that all legal requirements are met. Follow local protocols. ^[2]

• Continue any resuscitation attempts until the criteria for diagnosing death are met.
• Inform caregivers of the infant's death.
• Always use compassionate, empathetic, nonaccusatory language.
• Allow caregivers to view the body; follow local protocols regarding the removal of medical devices (e.g., endotracheal tubes, IV catheters). ^[4]
• Offer emotional support (e.g., from a social worker or chaplain).
• Contact the medical examiner to arrange an autopsy.
• Provide additional services as indicated, e.g.: ^[2][3][4]
  • Educational material about SUID and SIDS
  • Bereavement and grief counseling
  • Genetic counseling ^[11][12][13]

Include education on SIDS prevention during prenatal care and well-child visits.

Prenatal interventions ^[14][15]

• Avoid nicotine and tobacco smoke exposure.
• Avoid alcohol, marijuana, opioids, and other substance use during pregnancy. ^[16]
• Obtain routine prenatal care.

Postnatal interventions ^[14][15]

General measures

• Maintain a smoke-free environment (including second-hand smoke exposure).
• Avoid maternal use of all nicotine products.
• Avoid maternal use of alcohol, marijuana, opioids, and other substances.
• Recommend exclusive feeding of breast milk for the first 6 months.
• Promote neck and shoulder muscle development with supervised awake prone positioning (i.e., tummy time).
• Follow the ACIP immunization schedule.

Safe sleep practices

• Avoid overheating the room and infant.
• Ensure infants sleep in the caregiver's room for the first 6 months.
• Avoid bed-sharing.
• Place the infant in the supine position for sleep until 1 year of age.
• Use a firm, flat, noninclined sleep surface.
• Keep soft objects (e.g., quilts, pillows, soft toys) away from the sleeping area.
• Offer a pacifier when putting the infant to sleep. ^[13]