Sudden Infant Death Syndrome

Basics

Description

  • Sudden unexpected infant death (infant <1 yr old) (SUID) who was typically well before being placed down to sleep
  • SUID includes sudden infant death syndrome (SIDS) as well as accidental suffocation and strangulation in bed (ASSB) and unknown cause of death in infants <1 yr of age
    • ∼3500 infants die of sleep-related infant deaths including SIDS, ASSB, and ill-defined deaths, annually in the US
  • SIDS deaths remain unexplained after being thoroughly investigated by autopsy, evaluation of the death scene, investigation of the circumstances, and review of the family and infant medical histories
  • SIDS is distinct from ASSB, which occurs when something limits a baby’s breathing such as a blanket against the face or the baby being trapped between two objects (eg, mattress and wall), which has increased since 1995
  • If nonfatal, event is a brief resolved unexplained event (BRUE), previously described as an apparent life-threatening event (ALTE)
  • Leading cause of death in infants 1 mo–1 yr of age; the incidence has declined markedly since the initiation of the “Back to Sleep” program in 1994:
    • 1992: 120 deaths/100,000 live births (US)
    • 2001: 56 deaths/100,000 live births (US)
    • No change from 2001–2008
    • 2009: 54 deaths/100,000 live births (US)
    • 2013: 40 deaths/100,000 live births (US)
    • 2015: 39 deaths/100,000 live births (US)
  • Peak occurrence of SIDS is 1–4 mo of age:
    • 90% occur <6 mo of age
    • 2% occur >10 mo of age
  • Ethnic differences: Using 2010–2013 data, SIDS rates for non-Latino/a/e Black and American Indian/Alaska Native populations were much higher than non-Hispanic White populations, while SIDS rates for Asian/Pacific Islander and Latino/a/e populations were much lower than non-Latino/a/e White populations
  • Sleeping on back (supine) reduces incidence significantly (“Back to Sleep”), a practice that began initially in Europe and then in the US

Etiology

  • Pathophysiology is complex and multifactorial. The triple risk model is the most widely accepted: SIDS occurs when an infant with intrinsic vulnerability (impaired arousal, cardiorespiratory and/or autonomic responses) undergoes an endogenous trigger event (such as exposure to an unsafe sleep environment) during a critical developmental period
  • SIDS infants likely have predisposing conditions that make them more vulnerable to both internal and external stressors
  • Potential stressors include anemia, congenital diseases, dysrhythmias, electrolyte abnormalities, genetic defects, infection, metabolic disorders, neurologic events, suffocation, trauma, and upper airway obstruction
  • Maternal and antenatal risk factors:
    • Alcohol and illicit drug use
    • Intrauterine growth restriction
    • Lower socioeconomic status
    • Poor prenatal care
    • Prior sibling death secondary to SIDS
    • Shorter interval between pregnancies
    • Smoking
    • Younger age
  • Infant risk factors:
    • Bed sharing:
      • Increases the baseline risk >10 times if sharing with someone whose alertness or ability to arouse is impaired (fatigue, medication, drug or alcohol use, a current smoker) or on a soft surface (couch, old mattress, armchair, waterbed)
      • Increases the baseline risk 5–10 times for term, normal weight infants <4 months (even if parents are nonsmokers and infant is breastfed) or if bed sharing with anyone who is not the parent including nonparent caregivers and/or other children
    • Increases the baseline risk 2–5 times if infant is preterm or low birth weight (even if neither parent smokes) or if pillows or blankets are present on bed. Exposure to environmental smoking
    • Gastroesophageal reflux (GER)
    • Hyperthermia
    • Low birth weight, prematurity
    • Male gender
    • Soft bedding, soft sleeping surface
    • Recent febrile illness
  • Current recommendations to decrease the risk of sleep-related death:
    • Back to sleep with every sleep
    • Sleeping on a firm, flat, noninclined sleep surface without blankets, pillows, or other soft items
    • Feeding human milk
    • Offer pacifier at naptime and bedtime
    • Room sharing without bed sharing (especially in the first 6 mo)
    • Avoid smoke, nicotine, alcohol, and drug use during pregnancy and after birth
    • Avoid overheating and head covering
    • Follow American Academy of Pediatrics (AAP)/Centers for Disease Control and Prevention CDC) immunization guidelines
    • Avoid use of commercial devices inconsistent with safe sleep recommendations
  • Home monitoring has not been shown to prevent SIDS
  • Swaddling has not been shown to prevent SIDS. Weighted swaddles should never be used. When an infant shows signs of attempting to roll, swaddling should be discontinued to decrease risk of suffocation

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