D-03 - Controversies in Abusive Head Trauma and Physical Abuse AdvancedMedical Law Enforcement Legal Child Abuse (Physical/Sexual)
This presentation will discuss three of the major issues that are frequently utilized by defense expert witnesses to account for the pathological findings at autopsy in cases of abusive head trauma in young children, rebleeding of subdural hematomas, cortical vein thrombosis, and hypoxia. The suggestion is that these alternative causations are more likely sources of the pathological findings than is trauma in a given case.
The question of whether rebleeding has occurred in a chronic subdural hematoma needs to be considered in respect to experience which has evolved over the last 30 years from head CT scanning. We now appreciate that the development of a chronic subdural membrane at risk for rebleeding is a circumstance which occurs only in select patients, i.e. those who have a low intracranial pressure secondary to brain atrophy as in the elderly or alcoholic patient, or to foci of encephalomalacia from old brain damage, or to an intraventricular shunt placed for hydrocephalus. The “rebleeding” phenomenon proposes that a thin old subdural membrane which is several cell layers thick rebled to account for the appearance of acute subdural blood and a precipitous neurologic decline in a patient with a previously normal brain. There is no credible evidence to support that proposition. This presentation will also review the normal microscopic appearance of the young child’s dura. The latter is a unique structure which is the periosteum of the inner table of the skull and contains very active pigmented osteoblasts which may be incorrectly interpreted as macrophages containing hemosiderin and other changes indicative of a chronic membrane.
The claim that the common pathological findings seen in abusive head injuries, subdural and subarachnoid hemorrhages, are caused by thrombosis of the cerebral cortical vessels and sinuses will be discussed and critiqued. Venous thrombosis is a relatively rare problem that occurs in young infants who are quite clinically ill with sepsis or cases of malnutrition, hematological disorders, or leukemia. The pathological findings in such cases of venous thrombosis are not the subdural and subarachnoid hemorrhages common to abusive injury but are venous infarcts of the white matter of the brain. Many children with abusive head trauma who are on ventilators and eventually become brain dead demonstrate sluggish circulation in the brain which can be imaged on CT scans and at autopsy the cerebral vessels will be prominent with postmortem clot. These vessels should not be mistaken for antemortem venous thrombosis.
In 2003, Geddes and her colleagues proposed the “unified hypothesis” to explain the subdural hemorrhages and retinal hemorrhages commonly found in children with abusive head trauma. They had previously studied brains from young children and infants dying from abusive head trauma and found that these brains had hypoxic damage. These authors found that the duras of many young children dying from a variety of causes have intradural hemorrhage. They proposed that rather than axonal injury as the basis of the neurotrauma of abusive head injury, stretching at the craniocervical junction caused hypoxia and that the hypoxia then caused leakage of blood from the duras causing the subdural and retinal hemorrhages of abusive head trauma. This theory was discredited by the Supreme Court of Judicature in 2005 in the UK but is still utilized by some to explain the findings in abusive head trauma.