para>Occurs only in infants
ETIOLOGY AND PATHOPHYSIOLOGY
Strong evidence for a respiratory pathway that includes the following stages:
- A life-threatening event causes severe asphyxia and/or brain hypoperfusion. This can include rebreathing exhaled carbon dioxide in a facedown position.
- The vulnerable infant does not wake up or turn his or her head in response to asphyxia, resulting in further rebreathing and inability to recover from apnea.
- Progressive apnea leads to hypoxic coma.
- Bradycardia and hypoxic apnea occur.
- Autoresuscitation fails, resulting in prolonged apnea and death (2).
- There are many theories. There may be subtle developmental abnormalities resulting from pre- and/or perinatal brain injury, which make the infant vulnerable to SIDS.
- Possible causes
- Abnormalities in respiratory control and arousal responsiveness
- Central and peripheral nervous system abnormalities
- Cardiac arrhythmias
- Rebreathing in facedown position on soft surface, leading to hypoxia and hypercarbia
- SIDS may occur when ≥1 environmental risk factors interact with ≥1 genetic risk factors.
Genetics
Emerging evidence for genetic risk factors, especially related to impaired brainstem regulation of breathing or other autonomic control, impaired immune responses, and cardiac ion channelopathies associated with long QT syndrome and fatal arrhythmia
RISK FACTORS
- Although some infants may die from SIDS who have no apparent risk factors, most have ≥1 of the following risk factors associated with SIDS:
- Race: African Americans and Native Americans have highest incidence.
- Season: late fall and winter months
- Time of day: between midnight and 6 am
- Activity: during sleep
- Low birth weight; intrauterine growth retardation
- Poverty
- Maternal factors
- Younger age
- Decreased education
- Maternal use of cigarettes/drugs (e.g., cocaine, opiates) during pregnancy
- Higher parity
- Inadequate prenatal care
- Respiratory/GI infection in recent past
- Sleep practices
- Prone and side sleep positions
- Overheating from heavy clothing and bedding and/or elevated room temperature
- Soft bedding
- Bed sharing, independent of other factors (3)[B]
- Parental smoking, alcohol, and drug use greatly increase the risk associated with bed sharing (3)[B].
- No room sharing
- Passive cigarette smoke exposure after birth
- Not using pacifier; not breastfeeding
GENERAL PREVENTION
Because a SIDS death is sudden and the cause is unknown, SIDS cannot be "treated. " However, some measures may be effective in reducing the risk of SIDS (4)[B].
- Maternal avoidance of cigarette smoking and illicit drug use during pregnancy
- Avoidance of passive cigarette smoke exposure
- Avoidance of the prone (facedown) and side sleep positions, excessive bed clothing, and soft bedding such as pillows, comforters, and bumper pads or a soft mattress. Bumper pads of any kind are not recommended.
- Avoidance of overheating
- A crib, bassinet, or cradle conforming to federal safety standards is the recommended sleeping location.
- Avoidance of bed sharing with the infant, particularly by adults other than the parent(s) or by other children. Bed sharing should be avoided if the mother/father has used cigarettes, drugs, or alcohol. Bed sharing on couches is very dangerous and should never be done.
- Infants who sleep in the same room, as their parents (without bed sharing), have a lower risk of SIDS. It is recommended that infants sleep in a crib/bassinet in their parents ' bedroom, which when placed close to their bed will allow for more convenient breastfeeding and contact.
- Breastfeeding is associated with a decreased risk of SIDS and is recommended for all infants (5)[B].
- Pacifier use is associated with a reduced risk of SIDS.
- Consider offering a pacifier at bedtime and nap time (6)[B].
- Delay the introduction of the pacifier among breastfed infants until 3 to 4 weeks of age.
- Pacifier use has not been found to be detrimental to breastfeeding if it is introduced after the baby is 3 to 4 weeks of age, when breastfeeding is well established (7)[A].
- Avoid commercial devices marketed to reduce the risk of SIDS.
- It is critical that all people caring for infants, including daycare providers, be instructed in these risk-reduction measures.
- Newborn nurseries should implement these recommendations well before discharge, so parents see appropriate practices modeled.
- The guidelines related to safe infant sleep environment are also effective in reducing the risk of other sleep-related infant deaths (4).
COMMONLY ASSOCIATED CONDITIONS
Infants are generally well or may have had a mild febrile illness (i.e., gastroenteritis or an upper respiratory infection) prior to death.
DIAGNOSIS
The diagnosis of SIDS is made by trained medical examiners/coroners when the death is believed to be from natural causes and after thorough reviews of the medical history, death scene investigation, and postmortem examination do not produce an explanation of the death.
HISTORY
Infant usually found unresponsive by parent/other caregiver without any warning
PHYSICAL EXAM
- These babies generally appear healthy or may have had a minor upper respiratory/GI infection in the last 2 weeks before death.
- Complete postmortem exam to look for signs of possible trauma/child abuse or other cause of death
DIFFERENTIAL DIAGNOSIS
- Accidental suffocation/asphyxia
- Abnormalities of fatty acid metabolism (e.g., deficiency of medium-chain acyl-coenzyme A dehydrogenase or of carnitine)
- Dehydration/electrolyte disturbance
- Homicide
DIAGNOSTIC TESTS & INTERPRETATION
Standardized postmortem protocols have been proposed. Although testing varies across sites, common diagnostic tests include electrolytes, toxicology, and microbiology.
- Postmortem laboratory tests are performed to rule out other causes of death (e.g., electrolytes to rule out dehydration and electrolyte imbalance). No consistently abnormal laboratory tests are found.
- Pneumocardiograms have been abandoned in the workup.
- X-rays to rule out possible child abuse
Diagnostic Procedures/Other
Because the diagnosis of SIDS is often one of "exclusion, " it is crucial to do a thorough death scene investigation and case review in addition to the autopsy and laboratory tests.
Test Interpretation
Characteristic findings on postmortem examination
- Frothy discharge, sometimes blood tinged, from nostrils and mouth
- Petechiae on surface of lungs, heart, and thymus gland in 50 " 85% (but not unique to SIDS)
- Pulmonary congestion and edema often present
- Morphologic markers of hypoxia: increased gliosis in brain stem, retention of periadrenal brown fat, and hematopoiesis in the liver
- Present to varying degrees; not confirmed by all studies
ONGOING CARE
General recommendations for positioning infants
- Infants frequently should be placed on their bellies when awake and observed by responsible adults to prevent head flattening (plagiocephaly) that can result from infants sleeping supine.
- Avoid placing infants for extended periods in car seat carriers or "bouncers. "
- Upright "cuddle time " should be encouraged.
- Alter the side to which the infant places his or her head during sleep.
- Swaddling infants may aid in sleeping more comfortably in the supine position. Infants should never be swaddled if sleeping in the prone or side position. Swaddling should be discontinued when the infant starts to roll over or when the infant reaches the age of 3 to 4 months.
FOLLOW-UP RECOMMENDATIONS
- Safe sleep and SIDS risk-reduction messages should be delivered at all well-child checks and by all health professionals in a consistent manner.
- Parents often change from the recommended practices as the baby gets older, often during the peak SIDS incidence period. Thus, it is important to ask about infant care practices at each well-child check.
Patient Monitoring
Although some authorities recommend cardiopulmonary monitoring in siblings of prior SIDS victims, no evidence indicates that the use of monitors prevents SIDS, and they should not be prescribed for that purpose (8)[B].
PATIENT EDUCATION
- Family counseling (see "Prognosis " )
- Safe to Sleep: InformationLine (800) 505-CRIB (2742); Web site: http://www.nichd.nih.gov/sts/Pages/default.aspx
- Centers for Disease Control and Prevention: Web site: http://www.cdc.gov/SIDS/
- First Candle, Bel Air, MD (800) 221-SIDS (7437); Web site: http://www.firstcandle.org/
- CJ Foundation for SIDS, Hackensack, NJ (888) 8CJ-SIDS (825-7437); Web site: http://www.cjsids.org/
- Cribs for Kids, Pittsburgh, PA (888) 721-CRIB (2742); Web site: http://www.cribsforkids.org/
PROGNOSIS
- SIDS deaths have a powerful impact on families and their functioning. Physicians play an important role in providing immediate information about SIDS and sensitive counseling to limit parents ' misinformation and feelings of guilt.
- Counseling needs of families vary from the short term to long term.
- Support groups are helpful to many couples.
- Physicians need to be familiar with resources available in their communities to help families mourning a SIDS death.
- Follow-up counseling, including review of the autopsy report with the family after some time has passed, is important to help with understanding this condition and to alleviate the tremendous guilt these families experience.
- Parents need to be counseled about subsequent pregnancies.
- Genetic testing and counseling may be indicated to rule out a metabolic/other genetically acquired disorder.
- Parents need to be advised of the most current recommendations regarding sleep position and other infant care practices during subsequent pregnancies.
REFERENCES
11 Shapiro-Mendoza CK, Camperlengo L, Ludvigsen R, et al. Classification system for the Sudden Unexpected Infant Death Case Registry and its application. Pediatrics. 2014;134(1):e210 " e219.22 Kinney HC, Thach BT. The sudden infant death syndrome. N Engl J Med. 2009;361(8):795 " 805.33 Carpenter R, McGarvey C, Mitchell E, et al. Bed sharing when parents do not smoke: Is there a risk of SIDS? An individual level analysis of five major case-control studies. BMJ Open. 2013;3(5):e002299. doi:10.1136/bmjopen/2012/002299.44 Task Force on Sudden Infant Death Syndrome, Moon RY. SIDS and other sleep-related infant deaths: expansion of recommendations for a safe infant sleeping environment. Pediatrics. 2011;128(5):1030 " 1039.55 Hauck FR, Thompson JM, Tanabe KO, et al. Breastfeeding and reduced risk of sudden infant death syndrome: a meta-analysis. Pediatrics. 2011;128(1):103 " 110.66 Hauck FR, Omojokun OO, Siadaty MS. Do pacifiers reduce the risk of sudden infant death syndrome? A meta-analysis. Pediatrics. 2005;116(5):e716 " e723.77 O 'Connor NR, Tanabe KO, Siadaty MS, et al. Pacifiers and breastfeeding: a systematic review. Arch Pediatr Adolesc Med. 2009;163(4):378 " 382.88 Committee on Fetus and Newborn; American Academy of Pediatrics. Apnea, sudden infant death syndrome, and home monitoring. Pediatrics. 2003;111(4 Pt 1):914 " 917.
ADDITIONAL READING
Task Force on Sudden Infant Death Syndrome, Moon RY. SIDS and other sleep-related infant deaths: Expansion of recommendations for a safe infant sleeping environment. Pediatrics. 2011;128(5):e1341 " e1367.
CODES
ICD10
R99 Ill-defined and unknown cause of mortality
ICD9
798.0 Sudden infant death syndrome
SNOMED
Sudden infant death syndrome (finding)
CLINICAL PEARLS
- Although the exact cause of SIDS is unknown, several risk-reduction measures will significantly reduce an infant 's chance of dying from SIDS.
- SIDS incidence has decreased by >50% just by placing infants in a supine position to sleep.
- Breastfeeding is recommended for all infants.
- Safe sleeping arrangements and pacifier use are other ways to reduce the risk of SIDS.