Head Trauma in Infants. Overview and New Findings Shaken Baby Syndrome. Easy formula for disaster. Legal and Medical Fallout 8/4/2013

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1 Overview and New Findings Shaken Baby Syndrome Mary Ann Sens, MD, PhD Professor and Chair of Pathology; University of North Dakota Criminal Justice Institute St Paul, MN August 27, 2013 Head Trauma in Infants Shaken Baby : Colloquial term Infants (generally) Die unexpectedly Survive with varying degree of neurologic defects Triad of physical findings hemorrhage Retinal hemorrhage Encephalopathy Easy formula for disaster Crying, fussy infant Young parents / single or multiple caregivers External stressors (job, personal, financial) Sub optimal parenting skill Legal and Medical Fallout Canada Australia Great Britain United States 1

2 Concepts Puny neck muscles Large head Immature brain Triad: 1) Clinical Encephalopathy 2) hemorrhage 3) Retinal hemorrhage AFP, Matshes et al. Robert Finkbeiner 2

3 Clinical Encephalopathy Irritability, lethargy, vomiting, breathing irregularities, seizures, unresponsiveness, apnea Time course: Immediate or with lucid interval (uncommon, debated) Long term sequelae for survivors Hemorrhage Small Not space occupying Often bilateral Component of intradural hemorrhage Retinal Hemorrhage Present in 65 95% Unilateral or bilateral Flame shape common in superficial nerve layer Macula and perimacular regions most common May have retinal folds or detachments Less common: Pre retinal subhyaloid less common Intraretinal (dot blot) Vitreous No correlation with type of cerebral injury but total cerebral injury correlates with total retinal injury Current and Continuing Controversy Evolving Knowledge Triad accepted as definitive; injustices occurred Imperfect science and many expert witnesses Impact vs. No Impact How does the triad and each respective component produce clinical findings? Other explanations of findings? Does this exist? 3

4 Biomechanical Models Biomechanical Considerations First doubts of model with primate studies Subsequent studies by multiple authors Technical area: Disagreement amongst scientists with model types Strong background with injury mechanisms True model of infant head not currently perfect Mechanism of injury(ies) likely varies What is the cause of each component of triad hemorrhage Retinal hemorrhage Encephalopathy Clinical Encephalopathy Findings Controversy Cerebral edema (swelling) Mechanism of and neurologic deterioration encephalopathy Irritability, lethargy, Neuropathology findings vomiting, breathing Diffuse axonal damage irregularities, seizures, Local axonal damage unresponsiveness, apnea Role of ischemic changes, Death may result brain swelling / edema Long term sequelae for Time course for changes survivors and symptoms Origin of Encephalopathy Diffuse Axonal Injury Localized axonal injury Global ischemia Apnea Cerebral edema Classic Primary Apnea Causes of Triad Alternate Injury INJURY Contusion, Primary Apnea Fracture Scalp contusion / Retinal / fracture Consequence Hypoxia Consequence Hypoxia Shaken baby syndrome: re examination of diffuse axonal injury as cause of death. Oehmichen et. al., Acta Neuropathol (2008) 116: Secondary Brain Swelling Secondary (ICP, CVP, SAP) Brain Swilling Retinal Tertiary Hemorrhage hemorrhage Neither proven; not mutually exclusive Β Amyloid Precursor Protein (BAPP) 4

5 Hemorrhage Findings Small Not space occupying Often bilateral Component of intradural hemorrhage Controversies How subdural occurs Tearing of bridging veins Other mechanisms? Component to injury / death Origin of Hemorrhage Waney Squier Acta Neuropathol (2011) 122: Hematoma Origin of Retinal Hemorrhage Tearing of retinal vessels from acceleration deceleration forces Vitro retinal traction Venous obstruction / compression of optic nerve Known to occur in variety of clinical settings True incidence not known Difficult examination in infants Differentials: Triad and each component may be seen any other conditions Accidental craniocerebraltrauma Perinatal events: SDH (8%) and RH (34%) Natural, structural Arachnoid cyst; Benign Enlargement of Subarachnoid Space (BESS); Infections Aneurysm, AVM Cancer (variety of rare pediatric CNS tumors) Coagulopathy and thrombosis Genetic and metabolic: Glutaraciduria, OI, Menkeys, Terson syndrome, Galatosemia, others Complications of resuscitation, therapy Fig. 15 Cortical vein and sinus thrombosis. Male infant aged 4 weeks who collapsed and became floppy in a public park. bleeding was diagnosed on CT scan. a The autopsy showed dural sinus thrombosis. There is patchy bleeding over the surface of the brain related to thrombosed cortical veins. b Fixed brain: the right superficial middle (anastomotic) cerebral vein is thrombosed. This baby also had retinal haemorrhage which was due to central retinal vein thrombosis. c Haemorrhage at all levels of the retina (H&E 49). d There is thrombus in the central retinal vein in the optic nerve head (arrow). ON optic nerve (Masson s trichrome). e CD31 staining shows organization and early recanalisation of the central retinal vein (d, e 29) 5

6 Current Assessment Clinical reports: Compelling Spontaneous reports: Common if solicited Physical findings Cerebral edema, small SDH, retinal hemorrhage Neck findings Most *not all* with impact No smoking gun by any known modality Variety of disease and conditions contribute / cause findings Dr. Norman Guthkelch stated in 2011,"I don't think that the famous triad, however well some people think it's defined, can ever be so well defined that you can say that and nothing else cause it that meaning shaking." Shaking may cause NECK injury Neck Injury Component(s) Traditional anterior neck examination at autopsy negative Posterior neck dissection usually negative Cervical cord examination negative or subdural hemorrhage / ischemia Shaking may injure cervical ganglia: Delicate structures in fixed position in bone Phrenic nerve roots (c3,4,5; infants obligate diaphragm breathers) Cannot be examined with traditional dissections / clinical studies Three, Four, Five Keeps the Diaphragm Alive Matshes EM, Evans RM, Pinkard JK, Joseph JT, Lew EO. Shaken Infants die of neck trauma, not brain trauma. Academic Forensic Pathology 1: (1) 82 91, Study of neck structures in infants 35 infants, three ME jurisdictions, ages newborn to 36 months (3.2 months median) 12 documented hyper flexion injury (both abusive & MVA) 11 co sleeping/overlay 8 SIDS/SUID/Undetermined 2 blunt abdominal trauma (both abusive) 1 drowning 1 septic pneumonia (unsuspected; presented as potential abuse) Results Nerve root injury 12/12 with hyperflexion history 1/23 with no hyperflexion history (undetermined death) Location of nerve root injury Uni or bilateral C3, 4, 5: 100% C2, C6: 50% C7: 25% Matshes EM, Evans RM, Pinkard JK, Joseph JT, Lew EO. Shaken Infants die of neck trauma, not brain trauma. Academic Forensic Pathology 1: (1) 82 91,

7 Control History of Hyperextension 12/12 (10 with impact) 2/ 23 (one with suspicious history; other with sepsis) Encephalopathy 8/12 (all with survival > 4 hours) 5/23 (all but one with prolonged survival) Retinal Hemorrhage 9/ 12 examined; 8/9 RH 4/23 examined; ; 2/4 RH Matshes EM, Evans RM, Pinkard JK, Joseph JT, Lew EO. Shaken Infants die of neck trauma, not brain trauma. Academic Forensic Pathology 1: (1) 82 91, Conclusions Removal of neck and examination of cervical root ganglia beneficial Difficulty with clinical examination without specialized MRI equipment; current MRI resolution and probes at limit of detection / cannot detect Research area and capital expenditure for clinical evaluation of potential neck injury. Neuropathology Research Areas and Contributions to Understanding Immature brain: Huge difference in wounding pattern and response Trigeminal system Evolution of injury patterns within clinical practice Virtually all children are on life support for extended period findings from a few years ago do not fit Evolving Concepts Continued interface of law and medicine Continued public / political understanding and influences Medical Increased ability of life support systems Donation requests Biomarkers Imaging advances Forensic autopsy advances Unresponsive Infant Physical Findings Investigations WHAT HAPPENED When? Who? Child Family Society Health Team 7

8 Acute Trauma (inflicted, accidental) Disease Past injury, birth Findings Doctorial Level Expert Pool Forensic Pathologists (+/ Pediatric training) Neuropathologist(+/ Pediatric) Pediatric Pathologists (+/ Forensic training) Pediatricians (Child Abuse Pediatrics) Neurosurgeons (+/ Pediatric) Neurologists (+/ Pediatric) Ophthalmologists (+/ Pediatric) Intensivists / Hospitalists (+/ Pediatric, forensic training) Radiologists (+/ Forensic, pediatric training) Anthropologists (various specializations) Biomechanical Engineers (various specializations) The Future Case by Case Country by Country Evidence based Review 8