Pediatric PathologyPediatric Pathology

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Dr. Krishna Tadepalli, MD, www.mletips.com

6. Sudden Infant Death Syndrome6. Sudden Infant Death Syndrome

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Dr. Krishna Tadepalli, MD, www.mletips.com

Sudden Infant Death Syndrome (SIDS)• 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

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

Table 10-7. Risk Factors and Postmortem Findings Associated with SIDSTable 10-7. Risk Factors and Postmortem Findings Associated with SIDS

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Dr. Krishna Tadepalli, MD, www.mletips.com

POSTMORTEM ABNORMALITIES DETECTED IN CASES OF SUDDEN UNEXPECTED INFANT DEATH*

Infections

Viral myocarditis

Bronchopneumonia

Unsuspected congenital anomaly Congenital aortic stenosis

Anomalous origin of the left coronary artery from the pulmonary artery

Traumatic child abuse Intentional suffocation (filicide)

Genetic and metabolic defects Long QT syndrome (SCN5A and KCNQ1 mutations)

Fatty acid oxidation disorders (MCAD, LCHAD, SCHAD mutations)

Histiocytoid cardiomyopathy (MTCYB mutations)

Abnormal inflammatory responsiveness (partial deletions in C4a and C4b)

Table 10-7. Risk Factors and Postmortem Findings Associated with SIDSTable 10-7. Risk Factors and Postmortem Findings Associated with SIDS

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Dr. Krishna Tadepalli, MD, www.mletips.com

Sudden Infant Death Syndrome (SIDS)• 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

• 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 and a complete postmortem examination. 6

Dr. Krishna Tadepalli, MD, www.mletips.com

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