Courtesy of Godoy Medical Forensics
What is SIDS?
The sudden, unexpected, and unexplained death of a seemingly healthy infant under one year of age is known as sudden infant death syndrome (SIDS). The age at peak incidence is 2 to 4 months, with 90 percent of cases being less than seven months of age. SIDS is a diagnosis of exclusion—meaning it is only diagnosed after a thorough death scene investigation, interviews of caregivers, a complete review of clinical and social history, and a complete forensic autopsy. SIDS should not be used as an emergency department diagnosis. Instead, sudden unexpected infant death (SUID) is a more accurate diagnosis when there is no clear evidence to suggest another cause of death.
SIDS can be difficult to distinguish from other types of SUIDs—particularly unintentional suffocation in an adult bed. However, when SIDS is identified as the cause of death, modifiable environmental factors may have been noted to contribute to the death. Some of these factors include sleeping on the stomach, bed-sharing with an adult, or maternal smoking.
The typical presentation begins with an infant being put to bed after feeding and subsequently found dead, usually in the same position in which he or she had been placed. Most infants are apparently healthy; however, there have been reports that babies had diarrhea, vomiting, and listlessness within the two weeks prior to death.
Causes and Risk Factors
Sudden Infant Death Syndrome is typically associated with a period of sleep, and in most cases no signs of distress are apparent.
Some of the causes of SIDS include low birth weight, recent respiratory infection, side or stomach sleeping, sleeping on a soft surface, hyperthermia, and sleeping with parents. Research examination of the brain stems of babies who died of SIDS showed a delay in the development of serotonin-binding nerve cell pathways in the brain. Delayed development of these pathways could prevent the infant from arousing from sleep if the mouth and nose became obstructed during sleep.
Some risk factors include infants in the second and third months of life; being male; being African American, American Indian, or Eskimo; babies who have had siblings or cousins die of SIDS; secondhand smoke; and being premature. Mothers also have risk factors that increase risk, including age younger than 20, cigarette smoking, drug and/or alcohol use, and inadequate prenatal care.
Three common autopsy findings in the pathophysiology of Sudden Infant Death Syndrome are unclotted blood in the heart, intrathoracic petechiae (small red spots inside the thoracic cavity caused by bleeding), and fluid-filled heavier organs.
Other findings that are consistent with SIDS include the following:
- Serosanguineous watery, frothy, or mucous-like drainage from the mouth or nose;
- Reddish-blue mottling of the fact and dependent portions of the body;
- Marks on pressure points of the body;
- Well cared-for appearance with no significant skin trauma;
- No environmental contribution, like an unsafe sleeping environment.
Considering Abuse in SIDS
Findings that raise suspicion for abuse include malnutrition or neglect and injuries to the skin, such as bruising, traumatic lesions, and abnormalities of the head and/or body. In the American Academy of Pediatrics’ Policy on Distinguishing SIDS from Child Abuse Fatalities, it is stated that the death of an infant may be attributed to SIDS when all of the following are true:
- A complete autopsy is done, including cranium and cranial contents, and autopsy findings are compatible with SIDS;
- There is no gross or microscopic evidence of trauma or significant disease process;
- There is no evidence of trauma on skeletal survey;
- Other causes of death are adequately ruled out, including meningitis, sepsis, aspiration, pneumonia, myocarditis, abdominal trauma, dehydration, fluid and electrolyte imbalance, significant congenital lesions, inborn metabolic disorders, carbon monoxide asphyxia, drowning, or burns;
- There is no evidence of current alcohol, drug, or toxic exposure; and
- Thorough death scene investigation and review of the clinical history are negative.