Sudden infant death syndrome
SUDDEN INFANT DEATH SYNDROME (SIDS)
SUDDEN INFANT DEATH SYNDROME (SIDS) DEFINITION
Sudden Infant Death Syndrome (SIDS) is the sudden and unexpected death of an infant less than 1 year of age from an unknown cause. SIDS remains unpredictable with an unknown cause despite years of research. Certain factors such as sleeping position and maternal smoking are associated with SIDS.
SUDDEN INFANT DEATH SYNDROME (SIDS) CAUSES
A combination of physical and sleep environmental factors can make an infant more vulnerable to SIDS. These factors may vary from child to child.
Physical factors associated with SIDS include:
- Brain abnormalities. Some infants are born with problems that make them more likely to die of SIDS. In many of these babies, the portion of the brain that controls breathing and arousal from sleep doesn’t work properly.
- Low birth weight. Premature birth or being part of a multiple birth increases the likelihood that a baby’s brain hasn’t matured completely, so he or she has less control over such automatic processes as breathing and heart rate.
- Respiratory infection. Many infants who died of SIDS had recently had a cold, which may contribute to breathing problems.
Sleep environmental factors
The items in a baby’s crib and his or her sleeping position can combine with a baby’s physical problems to increase the risk of SIDS. Examples include:
- Sleeping on the stomach or side. Babies who are placed on their stomachs or sides to sleep may have more difficulty breathing than those placed on their backs.
- Sleeping on a soft surface. Lying face down on a fluffy comforter or a waterbed can block an infant’s airway. Draping a blanket over a baby’s head also is risky.
- Sleeping with parents. While the risk of SIDS is lowered if an infant sleeps in the same room as his or her parents, the risk increases if the baby sleeps in the same bed — partly because there are more soft surfaces to impair breathing.
SUDDEN INFANT DEATH SYNDROME (SIDS) PATHOPHYSIOLOGY
Although multiple hypotheses have been proposed as the pathophysiologic mechanisms responsible for SIDS, none have been proven. The triple-risk model, proposed by Filiano and Kinney, suggests that SIDS represents an intersection of factors, including the following :
- A vulnerable infant possessing intrinsic abnormalities in cardiorespiratory control
- A critical period in the development of homeostatic control mechanisms
- Exogenous extrinsic stressors (triggering factors)
SIDS rarely occurs in infants who are risk free or those who have only one risk factor. Ostfeld et al (2010) report that in one study, 96.3% of decedents had 1 to 7 risk factors, with 78.3% having 2 to 7. In another report, 57% of SIDS infants had one intrinsic risk factor and 2 extrinsic factors.
Death occurs when vulnerable infants are subjected to stressors at times when normal defense mechanisms may be structurally, functionally, or developmentally deficient.
The triple-risk model allows for the possibility of multiple stressors and for heterogeneous underlying vulnerabilities that manifest as SUID. Epidemiologic data suggest that genetic factors play a role, and many studies have attempted to identify SIDS-associated genes. A copious literature implicates various genes, encoded proteins, and signaling pathways in the pathogenesis of SIDS, including central nervous system (CNS) pathways, cardiac channelopathies, immune dysfunction, metabolic pathways, and nicotine responses.
SUDDEN INFANT DEATH SYNDROME (SIDS) SYMPTOMS
Although sudden infant death syndrome can strike any infant, researchers have identified several factors that may increase a baby’s risk. They include:
- Sex. Boys are more likely to die of SIDS.
- Age. Infants are most vulnerable during the second and third months of life.
- Race. For reasons that aren’t well-understood, black, American Indian or Eskimo infants are more likely to develop SIDS.
- Family history. Babies who’ve had siblings or cousins die of SIDS are at higher risk of SIDS.
- Secondhand smoke. Babies who live with smokers have a higher risk of SIDS.
- Being premature. Both being born early and having low birth weight increase your baby’s chances of SIDS.
Maternal risk factors
During pregnancy, the risk of SIDS is also affected by the mother, especially if she:
- Is younger than 20
- Smokes cigarettes
- Uses drugs or alcohol
- Has inadequate prenatal care
SUDDEN INFANT DEATH SYNDROME (SIDS) DIAGNOSIS
Sudden infant death remains an unpredictable, unpreventable, and largely inexplicable tragedy. The baby is seemingly healthy without any sign of distress or significant illness prior to the incident.
- Death occurs rapidly while the infant is sleeping.
- Typically, it is a silent event. The baby does not cry.
- The infant usually appears to be well developed, well nourished, and is generally felt to be in good health prior to death. Minor upper respiratory or gastrointestinal symptoms due to viruses like respiratory (RSV) are not uncommon in the last two weeks preceding SIDS.
Sudden, unexpected infant death (SUID) is a general term used for the circumstance of an infant death which occurs suddenly and in an unexpected manner. SIDS is a diagnosis of exclusion, meaning that other causes of death must be ruled out. The cause of an infant’s death can be determined only through a process of collecting information and conducting, at times, complex forensic tests and procedures. All other recognizable causes of death are investigated prior to making the diagnosis of SIDS.
Four major avenues of investigation aid in the determination of a SIDS death: postmortem lab tests, autopsy, death-scene investigation, and the review of victim and family case history.
- Postmortem laboratory tests are done to rule out other causes of death (for example, electrolytes are checked to rule out dehydration and electrolyte imbalance; bacterial and viral cultures are obtained to evaluate whether an infection was present). In SIDS, these laboratory tests are generally not revealing.
- An autopsy provides clues as to the cause of death. In 15%-25% of sudden, unexpected infant deaths specific abnormalities of the brain or central nervous system, the heart or lungs, or infection may be identified as the cause of death. The autopsy findings in SIDS victims are typically subtle and yield only supportive, rather than conclusive, findings to explain SIDS.
- A thorough investigation of the death scene consists of interviewing the parents, other caregivers, and family members, collecting items from the death scene, and evaluating that information. A detailed scene investigation may reveal a recognizable and possibly preventable cause of death. Death scene investigations have helped to identify factors in the infant sleep environment that are potentially unsafe. These include soft, padded, or plushy objects that may obstruct an infant’s airway, posing a suffocation hazard.
o A parent or caregiver may be asked these questions:
Where was the baby discovered?
What position was the baby in?
Were there any objects within the sleep location that could have interfered with normal infant breathing?
When was the baby last checked? Last fed?
How was the baby sleeping?
Where there any recent signs of illness?
Was the infant taking any medication, either prescription or over the counter?
- You should let your doctor know about any family or infant medical history. Family history to note would include any previous history of unexplained infant death, sudden cardiac death, and metabolic or genetic disorders, for example.
SUDDEN INFANT DEATH SYNDROME (SIDS) TREATMENT
There’s no guaranteed way to prevent SIDS, but you can help your baby sleep more safely by following these tips:
- Back to sleep. Place your baby to sleep resting on his or her back, rather than on the stomach or side. This isn’t necessary when your baby’s awake or able to roll over both ways without help.
Don’t assume that others will place your baby to sleep in the correct position — insist on it. Advise sitters and child care personnel not to use the stomach position to calm an upset baby.
- Keep the crib as bare as possible. Use a firm mattress and avoid placing your baby on thick, fluffy padding, such as lambskin or a thick quilt. Don’t leave pillows, fluffy toys or stuffed animals in the crib. These may interfere with breathing if your baby’s face presses against them.
- Don’t overheat baby. To keep your baby warm, try a sleep sack or other sleep clothing that doesn’t require additional covers. If you use a blanket, make it lightweight.
Tuck the blanket securely into the foot of the mattress, with just enough length to cover your baby’s shoulders. Then place your baby in the crib, near the foot, covered loosely with the blanket. Don’t cover your baby’s head.
- Baby should sleep alone. Your baby’s sleeping in the same room with you is a great idea, but adult beds aren’t safe for infants. A baby can become trapped and suffocate between the headboard slats, the space between the mattress and the bed frame, or the space between the mattress and the wall.
A baby can also suffocate if a sleeping parent accidentally rolls over and covers the baby’s nose and mouth.
- Breast-feed your baby, if possible. Breast-feeding for at least six months lowers the risk of SIDS.
- Avoid baby monitors and other commercial devices that claim to reduce the risk of SIDS. The American Academy of Pediatrics discourages the use of monitors and other devices because of ineffectiveness and safety issues.
- Offer a pacifier. Sucking on a pacifier at naptime and bedtime may reduce the risk of SIDS. One caveat — if you’re breast-feeding, wait to offer a pacifier until your baby is 3 to 4 weeks old and you’ve settled into an effective nursing routine.
If your baby’s not interested in the pacifier, don’t force it. Try again another day. If the pacifier falls out of your baby’s mouth while he or she is sleeping, don’t pop it back in.