1. Pediatric Pathology
Pediatric Pathology
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Dr. Krishna Tadepalli, MD, www.mletips.com

2. 6. Sudden Infant Death Syndrome
6. Sudden Infant Death Syndrome
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Dr. Krishna Tadepalli, MD, www.mletips.com

3. Sudden Infant Death Syndrome (SIDS)
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Definition = "the sudden death of an infant under 1 year of age which remains
unexplained after a thorough case investigation, including performance of a
complete autopsy, examination of the death scene, and review of the clinical
history”
Usually dies while asleep, mostly in the prone or side position (pseudonyms of crib
death or cot death)
Cause =unknown
Epidemiology
Leading cause of death between age 1 month and 1 year in USA
Third leading cause of infant deaths
90% of deaths occur during the first 6 months of life (peak- 2 and 4 months); this is
independent of risk factors & geographic locale
"apparent life-threatening event" (ALTE),= apnea + marked change in color or
muscle tone+ choking or gagging
Risk Factors: table in next slide
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Dr. Krishna Tadepalli, MD, www.mletips.com

4. Table 10-7. Risk Factors and Postmortem Findings Associated with SIDS
Table 10-7. Risk Factors and Postmortem Findings Associated with SIDS
PARENTAL
Young maternal age (age <20 years)
Maternal smoking during pregnancy
Drug abuse in either parent, specifically paternal marijuana and maternal opiate, cocaine use
Short intergestational intervals
Late or no prenatal care
Low socioeconomic group
African-American and American Indian ethnicity (? socioeconomic factors)
INFANT
Brain stem abnormalities, associated with delayed development of arousal and cardiorespiratory control
Prematurity and/or low birth weight
Male sex
Product of a multiple birth
SIDS in a prior sibling
Antecedent respiratory infections
Germline polymorphisms in autonomic nervous system genes
ENVIRONMENT
Prone or side sleep position
Sleeping on a soft surface
Hyperthermia
Co-sleeping in first 3 months of life
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Dr. Krishna Tadepalli, MD, www.mletips.com

5. Table 10-7. Risk Factors and Postmortem Findings Associated with SIDS
Table 10-7. Risk Factors and Postmortem Findings Associated with SIDS
POSTMORTEM ABNORMALITIES DETECTED IN CASES OF SUDDEN UNEXPECTED
INFANT DEATH*
Infections
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Viral myocarditis
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Bronchopneumonia
Unsuspected congenital anomaly
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Congenital aortic stenosis
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Anomalous origin of the left coronary artery from the pulmonary artery
Traumatic child abuse
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Intentional suffocation (filicide)
Genetic and metabolic defects
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Long QT syndrome (SCN5A and KCNQ1 mutations)
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Fatty acid oxidation disorders (MCAD, LCHAD, SCHAD mutations)
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Histiocytoid cardiomyopathy (MTCYB mutations)
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Abnormal inflammatory responsiveness (partial deletions in C4a and C4b)
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Dr. Krishna Tadepalli, MD, www.mletips.com

6. Sudden Infant Death Syndrome (SIDS)
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Morphology
Multiple petechiae =MC finding (seen in thymus, pleura, and epicardium)
Lungs =congested with vascular engorgement ± pulmonary edema
CNS = fails to provide a clear cause of death (hypoplasia of arcuate nucleus,
astrogliosis of the brain stem and cerebellum)
Hepatic extramedullary hematopoiesis and periadrenal brown fat
Pathogenesis (table 10.7)
Multifactorial
A "triple-risk" model
– vulnerable infant
– critical developmental period in homeostatic control
– exogenous stressor
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Most compelling hypothesis =delayed development of "arousal" and
cardiorespiratory control (which in turn under control of serotonergic (5-HT)
system of the medulla of brainstem
Traumatic child abuse must be carefully excluded under these circumstances
SIDS = Diagnosis of exclusion, requiring careful examination of the death scene
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and a complete postmortem examination.
Dr. Krishna Tadepalli, MD, www.mletips.com

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