Dr. Perlstein received his Medical Degree from the University of Cincinnati and then completed his internship and residency in pediatrics at The New York Hospital, Cornell medical Center in New York City. After serving an additional year as Chief Pediatric Resident, he worked as a private practitioner and then was appointed Director of Ambulatory Pediatrics at St. Barnabas Hospital in the Bronx.
The cause (or causes) of SIDS is still unknown. Despite the dramatic decrease
in the occurrence of SIDS in the United States and worldwide in recent years,
SIDS remains one of the leading causes of death during infancy beyond the first
30 days following birth. It is generally accepted that SIDS may be the result of
multiple interacting factors.
Infant development: A leading hypothesis is that SIDS may reflect a delay
or abnormality in the development of nerve cells within the brain that are
critical to normal heart and lung function. Research examinations of the
brainstems of infants who died with a diagnosis of SIDS have revealed a
developmental delay in the formation and function of several serotonin-binding nerve
cell pathways within the brain. These pathways are thought to be crucial to
regulating breathing, heart rate, and blood pressure responses during awakening
The hypothesis is that certain infants, for reasons yet to be
determined, may experience abnormal or delayed development of specific critical
areas of their brain. This could negatively affect the function and connectivity
to regions regulating arousal during sleep.
Arousal, in this context, refers
to an infant's ability to awaken and/or respond to a variety of physiological
stimuli. For example, a child sleeping facedown (prone) may move his or her face
into such a position so that the nose and mouth are completely obstructed. This
may alter the levels of oxygen or carbon dioxide in the infant's blood.
Normally, these changes would trigger arousal responses, prompting the infant to
move his or her head to the side to relieve this obstruction.
responses to stressful stimuli may be defective in infants who are vulnerable
to SIDS. One such reflex is the laryngeal chemoreflex which arises from nerve
cell pathways located in the back of the throat (pharynx) and within the voice
box (larynx) and upper airway. This reflex regulates changes in breathing, heart
rate, and blood pressure when portions of the airway are stimulated by fluids
like saliva or regurgitated stomach contents. Having saliva in the airway may
activate this reflex, triggering swallowing responses which help to keep the
airway clear. When an infant is in the facedown position, the rate of swallowing
is decreased. Protective arousal responses to these laryngeal reflexes are also
diminished in active sleep when infants are in the facedown sleep position.
Rebreathing stresses: When a baby is facedown, air movement around the
mouth may be impaired. This can cause the baby to re-breathe carbon dioxide that
the baby has just exhaled. Soft bedding and gas-trapping objects, such as
blankets, comforters, waterbeds, and soft mattresses, as well as stuffed or
plush toys are other types of sleep surfaces that may impair normal air movement
around the baby's mouth and nose when positioned facedown.
Hyperthermia (increased temperature): Overdressing, using excessive
coverings, or increasing the air temperature may lead to an increased metabolic
rate in these infants and eventual loss of breathing control. However, it is
unclear whether the increased temperature is an independent factor or if it is
just a reflection of the use of more clothing or blankets that may act as
objects obstructing the airway.
Even though the specific cause (or causes) of SIDS remains unknown,
scientific efforts have eliminated several previously held theories. We now know
the following about SIDS:
Apnea is a term that describes the clinical situation in which a person's
breathing stops spontaneously. Apnea associated with prematurity and apnea which
occurs during infancy are felt to be clinical conditions that are distinct from
SIDS. Infants with apnea may, in some cases, be managed with electronic monitors
prescribed by doctors that track heart rate and respiratory activity. Apnea
monitors will not prevent SIDS.
SIDS is neither predictable nor preventable.
Infants may experience episodes termed apparent life-threatening events (ALTE).
These are clinical events in which young infants may experience abrupt changes
in breathing, color, or muscle tone. Common causes of ALTE include viral
respiratory infections (RSV), gastroesophageal reflux disease, and seizures;
however, no definite scientific evidence links ALTE as events that will lead to
SIDS is not caused by immunizations or bad parenting.
SIDS is not
contagious or hereditary.
SIDS is not anyone's fault.
Reviewed by David Perlstein, MD, MBA, FAAP on 8/12/2013