2. Objectives
ā¢ Introduction to SUDI, SIDS, Ascertained/ Not
Ascertained Deaths
ā¢ Epidemiology
ā¢ Classification of SIDU
ā¢ Current theories on causation of SIDS
ā¢ Forensic Aspects
ā¢ Summary
3. Introduction to Sudden Unexpected Death in
Infancy (SUDI)
ā¢ Sudden unexpected death of an infant < 1 year of age who
ā was healthy.
ā not thought to have any life-threatening disease prior to death.
ā¢ The definite cause of death is not identified.
ā¢ Majority of deaths of young infants occurs between 1 week and 6 months
of age.
ā¢ SUDI should be investigated by a multidisciplinary team following a
standard protocol.
ā¢ Team should include
ā Police/ Social Services.
ā Specialist Pediatrician.
ā Pathologist/ forensic pathologist.
4. Sudden Death Infant Syndrome (SIDS)
ā¢ Sudden unexpected death of an infant < 1 year of age which
remained unexplained even after a thorough case investigation
which includes ā
ā Complete Autopsy.
ā Examination of a death scene.
ā Review of clinical history.
ā¢ SUDI is often confused for SIDS.
ā¢ Infant usually dies while asleep, mostly in the prone or side position
(pseudonyms of crib death or cot death).
ā¢ Some pathologists consider infants co-sleeping with a parent as a
exclusion criteria, whereas others donāt.
5. Ascertained/ Not Ascertained Deaths
ā¢ Cause of death when death is not explained after full investigation with
consideration of the following factors :
ā Child is older/younger than age acceptable for SIDS.
ā Atypical clinical features in the history.
ā Atypical/Unexplained pathological features.
ā¢ Some authors suggest that these could be classified as SUDI.
6. Objectives
ā¢ Introduction to SUDI, SIDS, Ascertained/ Not
Ascertained Deaths
ā¢ Epidemiology
ā¢ Classification of SIDU
ā¢ Current theories on causation of SIDS
ā¢ Forensic Aspects
ā¢ Summary
7. Epidemiology
ā¢ The rate of SIDS/ascertained deaths is about
0.5 per 1000 live births.
ā¢ Rates of SUDI are also broadly similar across
the world.
ā¢ It has been observed 600 infants per year still
die suddenly and unexpectedly in UK of causes
unexplained.
8. Objectives
ā¢ Introduction to SUDI, SIDS, Ascertained/ Not
Ascertained Deaths
ā¢ Epidemiology
ā¢ Classification
ā¢ Current theories on causation of SIDS
ā¢ Forensic Aspects
ā¢ Summary
9. Classification of Natural Infant Deaths
ā¢ According to Presentation
Expected
Unexpected
Observed Unobserved
Well Unwell Well Unwell
10. Classification of Natural Infant Deaths
ā¢ According to Cause
Commonest causes are
ļInfections.
ļCardiac Diseases.
ļRespiratory Tract Diseases.
ļMetabolic Diseases.
ļMiscellaneous.
11. Infections
ā¢ Bacterial infections causing pneumonia, septicaemia and
meningitis is a common cause of death in infancy.
ā¢ Bacterial pneumonia preceded by minor respiratory
symptoms causes unobserved death in apparently well
babies.
ā¢ The inflammation may not be histologically prominent in early
stages
12. Infections
ā¢ Epiglottis due to Hemophilus Influenza is a fairly
common illness
ā rare these days due to advent of Hib immunization
programme.
ā¢ Babies with meningitis shows some vague and non-
specific symptoms.
ā¢ Babies with acute encephalitis may lead to sudden
collapse through invovement of vital structures in the
brain stem.
ā¢ Peritonitis may also cause sudden death in infants
with vague symptoms. Pathology includes volvulus ,
Hirschsprungās disease , meconium ileus,
intussusception,congenital bands etc.
Primary peritonitis typically due to pneumococcus
ā¢ Gastroenteritis could cause death as a result of
dehydration which may not be assessed by the family.
13. Infections
ā¢ Viral infections are prevalent and fatal, but are less
frequently identified as a cause.
ā¢ Viral myocarditis caused by Type B Coxsackie virus
could be fatal.
ā Baby may appear non-specifically unwell prior to
collapse in the first few weeks of life.
ā¢ Viral encephalitis is usually symptomatic, babies die
before reaching the hospital, having being non-
specifically unwell.
ā Enterovirus predominate in first 3 months of life
followed by Herpes simplex after 6 months of life.
ā Others - adenoviruses,measles,mumps,rubella
ā¢ Viral pneumonitis caused by RSV
is generally symptomatic.
ā can lead to apnea in very young/premature infants.
14. Infections
ā¢ Babies with asplenia are particular prone to
infections especially pneumococcus.
ā¢ A congenital/acquired immune deficit in cases
of overwhelming infection should be
considered as investigation after death,
beyond histopathology could be problematic.
15. Cardiac Diseases
ā¢ Undiagnosed congenital heart malformations remain a
common cause of death in 1st week of life.
ā¢ Affected babies are poor feeders which may be observed by
their parents.
ā¢ Common cardiac disorders which cause sudden collapse are
ā Aortic stenosis/atresia
ā Hypoplastic left ventricle
ā Transposition of the great arteries.
ā Anomalous origin of coronary arteries.
16. Cardiac diseases
ā¢ Infantile Cardiomyopathy causes SUDI, usually an observed
collapse.
ā At autopsy, heart is severely hypertrophic than dilated.
ā Possibility of a metabolic /mitochondrial disease should be considered
with appropriate samples taken.
ā¢ Endocardial fibro-elastosis typically presents as fetal hydrops,
but occasionally leads to SUDI.
ā Possibilty of a metabolic disease should be considered.
ā There is an association with maternal autoimmune diorders (Anti-
Ro/Anti-La antibodies)
17. Cardiac diseases
ā¢ Cardiac tumors
ā may lead to arrhythmias and
severe cardiac enlargement.
ā Multiple rhabdomyomas alert the
possibility of tuberous sclerosis
ā¢ Disorders of the cardiac
conducting system may lead to
SUDI
ā Long QT Syndrome should be
considered if thereās positive
family history of sudden death.
ā Family members should be offered
ECG screening and storage of DNA
for genetic analysis.
18. Respiratory Tract Diseases
ā¢ Infections of the respiratory tract play a major role in causing SUDI.
ā¢ Structural malformations of the upper airways may be associated with respiratory
obstructions
ā Choanal Atresia
ā Laryngomalacia
ā Tracheomalacia
ļ Noisy breathing/stridor may be apparent
ļ Condition may be exacerbated by concurrent respiratory infection.
Respiratory failure due to neuromuscular disorders
ā Congenital myopathies
ā Polymyositis
ā Viral myositis
ā Anterior horn cell disease.
A careful examination of the respiratory tract is essential.
19. Metabolic Diseases
ā¢ Babies are at a risk of sudden cardiac collapse and seizures.
ā¢ An unwell infant usually collapses suddenly rather than ācot deathā.
ā¢ Onset is usually in early neonatal period.
ā¢ Follows an infectious disease, most often gatroenteritis.
ā¢ The babyā condition deteriorates ļ drowsy ļ collapses
ā¢ Typically seen in MCAD deficiency, other fatty acid oxidation defect and
mitochondrial disease.
ā¢ Fat stains of liver, kidney,muscle & hear should be routine to SUDI workup.
ā¢ Ideal biochemical screening of blood and bile by tandem mass
spectrometry should be carried out.
20. Miscellaneous
ā¢ Epileptic seizures in infants with known epilepsy may result in sudden
unobserved death.
ā Typical features may not be apparent at post-mortem examination.
ā Death is more likely in infants with underlying neurological disease than with idiopathic
epilepsy.
ā Samples to be taken for anticonvulsant levels.
ā¢ Pulmonary vascular disease is difficult to diagnose in early in infancy due
to ongoing vascular remodelling.
ā Typically associated with other syndromes
ā Smith Lemli Opitz Syndrome.
ā Williams Syndrome (Supraclavicular aortic stenosis & abnormal peripheral pulmonary
vessels)
21. Objectives
ā¢ Introduction to SUDI, SIDS, Ascertained/ Not
Ascertained Deaths
ā¢ Epidemiology
ā¢ Classification of SIDU
ā¢ Current theories on causation of SIDS
ā¢ Forensic Aspects
22. Current Theories on Causation of SIDS
Current favoured theories are : -
ā¢ Respiratory Arousal/Brainstem Development.
ā¢ Inflammatory mediators/Bacterial toxins.
ā¢ Cardiac Arrythmias.
23. Respiratory Arousal/Brainstem Development
Recent studies have shown evidence
of SIDS being a result of
ā¢ Failure of normal respiratory
arousal in response to adverse
sleeping environment.
ā¢ Failure of normal respiratory
arousal in response to hypoxia in
the first 6 months of life.
ā¢ Subtle abnormalities in
development of brainstem could
affect cardiorespiratory centres ā
present in at least 50% of SIDS.
24. Inflammatory mediators/Bacterial toxins
Recent studies have shown evidence of SIDS being a result of
ā¢ Immune activation
ā Increase of inflammatory cells in the lungs.
ā Thymic enlargement.
ā Raised levels of cytokines
ā¢ Abnormal Cytokine response to minor infection
ā Excess of high activator alleles of IL-10.
ā Polymorphisms in VEGF & IL-6.
ā¢ Bacterial infections
ā Bacterial toxins trigger SIDS by inappropriate cytokine response as a result
of genetic polymorphisms.
25. Cardiac Arrythmias
Recent studies have shown evidence of SIDS being a result of
ā¢ Mutations in genes coding for membrane ion channels.
ā LQTS predisposing to cardiac arrythmias ļ sudden death
ā LQTS attributes to 5% of cases classified as SIDS.
ā Gene SCN5A could lead to sudden death in sleep.
ā Polymorphisms in LQTS genes could result in SIDS.
ā Genetic testing of child or ECG screening of close family members is
necessary if there is positive family h/o sudden unexplained/cardiac
death.
26. Objectives
ā¢ Introduction to SUDI, SIDS, Ascertained/ Not
Ascertained Deaths
ā¢ Epidemiology
ā¢ Classification of SIDU
ā¢ Current theories on causation of SIDS
ā¢ Forensic Aspects
ā¢ Summary
27. Forensic Aspects
Suffocation
ā¢ Study by carpenter et al identified 87% in their series as
natural
ā¢ Pathological appearances of suffocation are commonly
identical to those in a true SIDS ā Negative biopsy.
ā¢ May be accidental ā suffocating with pillow, cushion, hands
ā¢ May be inflicted upon as in abuse ā a forensic + paediatric
pathologic should take the lead in investigation.
ā¢ Rarities include obstruction of airway by a foreign object.
ā¢ Careful history & detailed external examination of infants are
essential.
28. Forensic Aspects
Suffocation
External findings
ā¢ Facial and conjuctival petechiae - non-specific for upper airway obstruction.
ā¢ Facial bruising, pressure marks & abrasions - require an explanation.
ā¢ Frank bleeding from upper airways is unusual in the context of SIDS - h/o resuscitation
needs to be excluded.
ā¢ Frenulum injury may require careful assessment if intubation has been carried out.
ā¢ Natural causes (infection/vascular lesions) should also be excluded.
ā¢ H/o co-sleeping with parent should also be considered.
29. Forensic Aspects
Suffocation
Internal Findings
ā¢ Severe alveolar hemorrhages
ā May be an indicator of airway obstruction
(suffocation) or resuscitation.
ā Feature of co-sleeping deaths ā
mechanism unclear.
ā¢ Haemosiderin- laden
macrophages
- Suggested as a marker of previous upper
airway obstruction though there is no
literature to substantiate this fact.
- Natural causes like pulmonary
hemosiderosis, bleeding disorders &
cardiac disease needs to be excluded.
30. Forensic Aspects
Suffocation
Internal Findings
ā¢ The presence or absence of
petechiae ā whether thymic ,
cardiac or pleural ā has no
diagnostic significance .
ā¢ Epidural hemorrhage around
the spinal cord
ā May be a postmortem artefact.
ā Caused by congestion of epidural
fat network.
31. Forensic Aspects
Co-sleeping Deaths
ā¢ This group has increased
incidence with parental co-
sleeping & smoking.
ā¢ Legal issues arise if the
carer was under the
influence of alcohol/drugs
ā¢ Some infants are vulnerable
to transient airways
obstruction.
32. Forensic Aspects
Munchasen Syndrome by Proxy
ā¢ The carer (commonly the mother) causes harm
to the infant to bring it to the attention of the
medical authorities.
ā¢ Identification of such cases are extremely
difficult.
ā¢ Infants may present with apparent life-
threatening events ā poisonings.
ā¢ History of apnoeic episodes in infants before
sudden death.
ā¢ Attention should be given to any injuries
identified, external airway occlusion being the
commonest pathology.
ā¢ Toxicological analysis is essential ā should be
done as routine.
33. Summary
ā¢ Investigation of SUDI requires a multidisciplinary team.
ā¢ Case review by the team can be helpful in refining the diagnosis.
ā¢ A full postmortem should be undertaken to an agreed protocol including ancillary tests.
ā¢ Tissue should be stored in case DNA is required for genetic tests.
ā¢ A diagnosis of long QT Syndrome (LQTS) should be considered if there s a family h/o sudden death.
ā¢ Current theories highlight possible role of poor respiratory arousal, inflammatory response/infection/LTQS
for causes of SIDS.
ā¢ Suffocation (accidental/deliberate) is difficult to diagnose in this young age group.
ā¢ The significance of fresh alveolar hemorrhage & haemosiderin macrophages need to be judged in the light
of all findings & circumstances of death.
ā¢ Fresh spinal epidural hemorrhage may be a postmortem artefact.
ā¢ Toxicological testing should be routine part of the postmortem examination in SIDS.