Sudden infant death syndrome is an unexpected sudden death of an infant which remains unexplained after a thorough postmortem examination, investigation of the death scene and review of the medical history. SIDS is the most common cause of post neonatal infant mortality between one month to one year of age. The incidence of SIDS peaks between the two and four months after birth.
Sudden Infant Death Syndrome Risk Factors:
- Maternal and Antenatal risk factors:
- Young maternal age
- Maternal drug abuse
- Maternal smoking
- Nutritional deficiency
- Lower socioeconomic status
- Poor prenatal care
- Single marital status
- Higher parity
- Multiple Gestation
- Intrauterine hypoxia
- Fetal growth retardation
- Infant Risk factors:
- Age (peak 2-4 months)
- Low birth weight
- Male gender
- Prone and side sleeping position
- Recent febrile illness
- Thermal stress
- Winter months
- Smoking exposure (prenatal and postnatal)
- Bottle fed babies
- Genetic or biological risk factors:
- Ventilatory responsiveness
- Heart rate
- Vagal tone
- Blood Pressure
- Respiratory pattern
- Family History of SIDS in a sibling
- Abnormal inflammatory immune response to any infection
- Idiopathic apparent life threatening event
Pathophysiology of SIDS:
There is no autopsy finding pathognomonic of SIDS. There are some common observations, petechial hemorrhages are found in more than 90% of cases and may be more extensive than in other causes of infant mortality. Pulmonary odema is often present and may be substantial.
There are tissue markers indicative of pre-existing chronic low-grade asphyxia in nearly 2/3 of SIDS subjects, including persistence of adrenal brown fat, hepatic erythropoiesis, brainstem gliosis and other structural abnormalities.
Postmortem molecular analysis in SIDS cases has identified mutations on the cardiac sodium channel genetic abnormality.
Guidelines to reduce the risk of SIDS:
SIDS cannot be prevented in individual infants because it is not possible currently to prospectively identify future SIDS victims or effectively intervene. If obstructed breaths, central apnoea, bradycardia or Oxygen desaturation occurring as a part of the terminal event could be reliably detected sufficiently earlier so as to be amenable to intervention. Although prolonged QT interval of an infant may be treated if diagnosed.
- Full term and premature infants should be placed for sleep in the supine position. Side sleeping is not recommended.
- Infants should not be put to sleep on waterbeds, sofas, soft mattresses or other soft surfaces.
- Adults (other than parents) and children or other Siblings should not share a bed with an infant. The parent should not share a bed with their infant if they smoke or use substances such as drugs or alcohol that impair parental arousal.
- Overheating should be strictly avoided.
- The infant should be lightly clothed for sleep.
- Devices advertised to maintain the sleep position or to reduce the risk of rebreathing are not safe and should not be used.
Alternating the placement of the infant’s head as well as his or her orientation in the crib can also minimize the risk of head flattening.