What is Neuropathology and How Can It Be Of Use In Expert Witness Testimony?
Neuropathology encompasses a wide area of anatomic pathology, including neurodegenerative disorders, vascular disease, genetically determined developmental disorders of the central nervous system & skeletal muscle and finally; a variety of injuries caused by environmental factors as varied as toxins to trauma caused by a variety of circumstances.
The neuropathologist has expertise in the pathophysiology of these various disorders and injuries caused by toxins & trauma. Anotherwords, what circumstances precipitate or lead to these conditions which afflict the nervous system. More explicitly, the amount of exposure, the duration of exposure and whether other underlying health conditions place an individual at greater risk for injury. Age and sex sometimes are important factors. Insults can occur in utero during a pregnancy, in early stages of childhood that may have sweeping long term consequences.
The clinical neuropathologist works closely with neuroradiologists, neurologist and neurosurgeons in both diagnosis and treatment of neurological disease. Therefore, the treatment options, their likelihood of success, their risks are well known to the neuropathologist.
Neuropathologists have been closely involved in all efforts involving regeneration or repair of spinal cord, peripheral nerve & skeletal muscle. The Veterans Administration and the Armed Services Medical branches have made long term commitments in this area of applied research.
As our society extends the average lifespan, the neurodegenerative disorders have become much more commonplace and have impacted our society at many levels. The diagnosis and pathophysiology of these disorders is the domain of the neuropathologist. The bulk of current on-going research in this field is largely conducted by groups with integral neuropathologists to monitor the outcomes of their experiments testing various hypotheses of causality and possible modes of treatment.
If a post mortem examination has been performed or a biopsy of tissue hs been performed, the neuropathologist can examine the resultant glass microscopic slides and report and render a second opinion. In some instances, particularly specific neurodegenerative diseases associated with dementia cannot be definitively diagnosed without an actual tissue diagnosis. Similarly, with our aging population, a dual diagnosis of a multi-infarct dementia and Alzheimer’s disease or Luy body dementia are now commonplace.
Certainly the definitive diagnosis of the type of brain tumor requires a tissue diagnosis by biopsy, again the province of the neuropathologist. As treatment options increase and for prognosis alone this becomes a very important matter or the treating physician, the patient & the patient’s family.
The dating of a traumatic injury is of particular importance in many medical legal cases. A neuropathologist can provide a time estimate, based on the tissue changes visible either grossly or microscopically in brain tissue either obtained at post mortem or in brain tissue obtained from biopsy or removed in a surgical procedure-evacuation of a hematoma or removal of injured tissue. Similarly, dating of anoxic/ischemic injury resulting from an interruption of oxygen or blood supply to brain tissues can be crucial in either criminal trials or determining liability in a civil action.
There are delayed effects in neuropathophysiology which periodically come up in court cases. One example is the delayed vasospasm seen occasionally when clipping a saccular aneurysm or some other invasive vascular surgical procedure. Within the following few days, a vasospasm of the cerebral vasculature can precipitate devasting cerebrovascular accidents (CVA’s). As a neuropathologist, I have been instrumental in providing expert witness testimony in several such cases. Another example is the phenomenon of delayed cerebral edema. Following head trauma, a significant interval can elapse before the individual becomes symptomatic. At times this can be life threatening. It can occur in industrial accidents, motor vehicle accidents or accidents around the home which seemed at the time rather trivial. It is also seen in infancy in either accidental head injury or child abuse cases. Again, as a neuropathologist, I have been instrumental in providing expert witness testimony in such cases.
Finally, spinal cord trauma can be subtle or delayed in its manifestations due to a phenomenon called Wallerian degeneration, where there is a separation of the axon or out going nerve process from the body of a motor nerve cell secondary to trauma and subsequent anterograde degeneration. As much as thirty days have been reported between injury-either ishemic stroke or trauma- and the onset of weakness or paralysis. Again, a neuropathologist can be instrumental in explaining to a jury how the underlying pathophysiology explains this.
About the author
Thomas H. Gill, MD is a board certified neuropathologist of thirty-six years experience. He has had sixteen years of academic medical experience at the medical school of the Oregon Health Sciences University. He is also board certified in Anatomic pathology and Forensic Pathology. He has worked in the latter capacity at the Los Angeles County Coroner’s Department, the Jackson County Medical Examiner’s Office in Kansas City Missouri and in northern California for a private group of forensic pathologists. He has a total of approximately twenty years experience in forensic pathology.