Stephanie S. Erlich

Dating/aging of common lesionsin neuropathology

This chapter summarizes the present understanding of dating/aging issues that may be encountered by the forensic neuropathology consultant, and to do this in a format that also highlights areas in which data are not sufficient to answer some frequently asked questions. Issues of timing of tissue responses receive more emphasis in forensic pathology than general pathology because timing conclusions based on histological studies may help to confirm or refute certain witness and advocate statements. In general pathology, etiologic and mechanistic issues understandably often take precedence over detailed timing of the earliest appearance, maximum expression, or longest duration of a given histological finding. For the consulting neuropathologist involved in forensic work, the question so often is usually not about “time of death” as it is about “time interval between central nervous system (CNS) insult and death.” This question is perhaps most often asked in the context of child abuse cases in an attempt by counsel to include or exclude involvement by a given caretaker. It can also occur in a variety of other scenarios. In this chapter, the dating/aging data are selected with criteria that reflect ones understanding of conceptual filters, or gradually evolving working hypotheses. These “timetables” continue to be revised as indicated, as additional data are collected and examined, and by reviewing pertinent publications that become available. More data must be gathered before a general consensus is likely to be reached in many of these parameters.

Blunt force head injury

Head injuries can be broadly divided into blunt force and penetrating, or closed and open injuries, simple in concept, but infinitely variable in individual cases. The types of injuries are limited in number, but extremely complex in each case. In this chapter, types of head injuries are listed and reviewed in turn with illustrated case examples. The scalp provides an ideal anatomic arrangement for development of abrasions, contusions, and lacerations because of scalp soft tissue overlying the hard, rounded bony prominences of the cranium. Traumatic subcutaneous hemorrhage of the scalp may be broadly localizing, but when it underlies an abrasion, contusion, or laceration, it would be an indicator of the impact point. The biomechanics of the mechanisms at play in skull fractures are relevant in assessing types and directions of forces occurring in any injury. Head injury potentially results in a wide variety of consequences that interact in complex ways. A common method of categorizing these consequences is to divide them into primary and secondary effects. Primary effects result from direct injury to central nervous system (CNS) parenchymal and supporting structures. Secondary vascular effects may include events, such as external compression due to brain parenchymal swelling or hematoma, hydrocephalus, an increase in intracranial pressure, impaired reactivity to physiologic stimuli, vascular dilatation; vascular spasm, thrombosis or embolism, infarction, abnormal vascular permeability with tendency for edema and/or hemorrhage, and traumatic aneurysms or arteriovenous fistulae. The role of immediate post-head injury apnea as a contributory factor in subsequent events, leading to hypoxic-ischemic CNS injury, has been increasingly appreciated.

The forensic neuropathology autopsy: II: Developmental considerations

This chapter discusses a few selected aspects of central nervous system (CNS) development that may be useful in the examination of immature brain and spinal cord tissue. Forensic cases involving CNS malformations frequently include questions of whether some incident during pregnancy or delivery is responsible for the present abnormality. For this reason, neuropathology problems encountered in pregnant women, the fetus and in early childhood, including malformations, are also discussed. The primary forensic interest in this chapter, probably best viewed as a syndrome with varied etiologies, is some preliminary evidence raising the question of whether children with external hydrocephalus may have a greater than average tendency to develop subdural hematomas. A brief introduction to developmental topics is included in several general neuropathology and pediatric autopsy texts, although it should be noted that some sources clearly specify that they extrapolate to humans to some extent from animal experimental material. In the chapter, a few sources representative of the more extensive literature in each category are discussed.

Responses of the central nervous system to acute hypoxic-ischemic injury and related conditions

The cerebro vascular diseases reported to date can injure the central nervous system (CNS) via mechanisms such as an altered cerebrospinal fluid (CSF) chemical milieu in intra ventricular hemorrhage, mass effect in intracerebral hemorrhage, or obstruction of blood supply to a given area. However, a feature shared by all these conditions is some component of hypoxicischemic injury. This injury mechanism leads to numerous questions in forensic cases, and this chapter addresses several of those most frequently encountered in this office. The varying vulnerabilities with increasing age are to be regarded as estimates based on isolated cases, or as generalizations. No large single study specifically addressing this issue in a wide age range of subjects exists. Under this general heading of unusual distributions of presumed hypoxic-ischemic injury, may also be included such combinations as pallido-reticular preferential injury, preponderant combined involvement of the globus pallidus with the substantia nigra, and the basal ganglia and brainstem tegmental pattern. Available data indicate that examination of the CNS alone, without supporting data, provides no findings diagnostic of hyperthermia, but a disproportionate degree of cerebellar involvement compared with other areas of the brain, as described earlier, might warrant further exploration of the possibility of hyperthermia in difficult cases in which this possibility was not previously considered. Also, primary CNS lesions situated in locations from the upper pons to the hypothalamus, as well as hydrocephalus, may cause hyperthermia as a secondary effect.

Neuropathology of pregnancy and delivery

Cerebral palsy can be used to illustrate a general approach to cases submitted for neuropathologic consultation that involve the pregnant woman, fetus, or young child. Cerebral palsy, a clinical term, has been defined as “a group of conditions that are characterized by chronic disorders of movement or posture; it is cerebral in origin, arises early in life, and is not the result of progressive disease.” The neuropathologic substrate of cerebral palsy is quite variable from case to case, because a number of lesions may result in this spectrum of clinical features. It follows that, from a neuropathologic standpoint, cerebral palsy is a syndrome rather than a disease entity and may well have a progressive underlying structural component when the brain is studied by special techniques, albeit not necessarily obvious clinically. A reasonable approach under such circumstances is to evaluate each case with the aid of guidelines such as those recommended in the consensus statement of the International Cerebral Palsy Task Force, keeping in mind that the legal professions approach to such issues may not be identical. In this chapter, conditions in mother and child, which are more likely to be encountered by the forensic neuropathologist, are emphasized. Thus, fatal conditions such as cerebrovascular catastrophes are considered, but other neurologic conditions simply potentially aggravated by pregnancy, which are less likely to present to a medical examiner than to a clinician (for example, multiple sclerosis), are generally omitted. Reviews of pregnancy-related deaths that include non-CNS causes have recently appeared in the forensic literature, and provided a useful perspective for the medical examiner.Publisher Summary Cerebral palsy can be used to illustrate a general approach to cases submitted for neuropathologic consultation that involve the pregnant woman, fetus, or young child. Cerebral palsy, a clinical term, has been defined as “a group of conditions that are characterized by chronic disorders of movement or posture; it is cerebral in origin, arises early in life, and is not the result of progressive disease.” The neuropathologic substrate of cerebral palsy is quite variable from case to case, because a number of lesions may result in this spectrum of clinical features. It follows that, from a neuropathologic standpoint, cerebral palsy is a syndrome rather than a disease entity and may well have a progressive underlying structural component when the brain is studied by special techniques, albeit not necessarily obvious clinically. A reasonable approach under such circumstances is to evaluate each case with the aid of guidelines such as those recommended in the consensus statement of the International Cerebral Palsy Task Force, keeping in mind that the legal professions approach to such issues may not be identical. In this chapter, conditions in mother and child, which are more likely to be encountered by the forensic neuropathologist, are emphasized. Thus, fatal conditions such as cerebrovascular catastrophes are considered, but other neurologic conditions simply potentially aggravated by pregnancy, which are less likely to present to a medical examiner than to a clinician (for example, multiple sclerosis), are generally omitted. Reviews of pregnancy-related deaths that include non-CNS causes have recently appeared in the forensic literature, and provided a useful perspective for the medical examiner.

Neuropathology of pregnancy and delivery: Mother and child

Cerebral palsy can be used to illustrate a general approach to cases submitted for neuropathologic consultation that involve the pregnant woman, fetus, or young child. Cerebral palsy, a clinical term, has been defined as “a group of conditions that are characterized by chronic disorders of movement or posture; it is cerebral in origin, arises early in life, and is not the result of progressive disease.” The neuropathologic substrate of cerebral palsy is quite variable from case to case, because a number of lesions may result in this spectrum of clinical features. It follows that, from a neuropathologic standpoint, cerebral palsy is a syndrome rather than a disease entity and may well have a progressive underlying structural component when the brain is studied by special techniques, albeit not necessarily obvious clinically. A reasonable approach under such circumstances is to evaluate each case with the aid of guidelines such as those recommended in the consensus statement of the International Cerebral Palsy Task Force, keeping in mind that the legal professions approach to such issues may not be identical. In this chapter, conditions in mother and child, which are more likely to be encountered by the forensic neuropathologist, are emphasized. Thus, fatal conditions such as cerebrovascular catastrophes are considered, but other neurologic conditions simply potentially aggravated by pregnancy, which are less likely to present to a medical examiner than to a clinician (for example, multiple sclerosis), are generally omitted. Reviews of pregnancy-related deaths that include non-CNS causes have recently appeared in the forensic literature, and provided a useful perspective for the medical examiner.Publisher Summary Cerebral palsy can be used to illustrate a general approach to cases submitted for neuropathologic consultation that involve the pregnant woman, fetus, or young child. Cerebral palsy, a clinical term, has been defined as “a group of conditions that are characterized by chronic disorders of movement or posture; it is cerebral in origin, arises early in life, and is not the result of progressive disease.” The neuropathologic substrate of cerebral palsy is quite variable from case to case, because a number of lesions may result in this spectrum of clinical features. It follows that, from a neuropathologic standpoint, cerebral palsy is a syndrome rather than a disease entity and may well have a progressive underlying structural component when the brain is studied by special techniques, albeit not necessarily obvious clinically. A reasonable approach under such circumstances is to evaluate each case with the aid of guidelines such as those recommended in the consensus statement of the International Cerebral Palsy Task Force, keeping in mind that the legal professions approach to such issues may not be identical. In this chapter, conditions in mother and child, which are more likely to be encountered by the forensic neuropathologist, are emphasized. Thus, fatal conditions such as cerebrovascular catastrophes are considered, but other neurologic conditions simply potentially aggravated by pregnancy, which are less likely to present to a medical examiner than to a clinician (for example, multiple sclerosis), are generally omitted. Reviews of pregnancy-related deaths that include non-CNS causes have recently appeared in the forensic literature, and provided a useful perspective for the medical examiner.

Vascular diseases of the central nervous system

With the very high prevalence of strokes and other cerebro-vascular diseases (CVD) in the US population, it is inevitable that a significant percentage of cases referred for forensic investigation have CVD as the primary or contributory cause of death. However, cerebro-vascular disease is still by far the most common neurologically disabling and lethal disorder in the United States, with atherosclerosis and hypertension as the major predisposing causes of stroke. Strokes are the fourth leading cause of death in the United States. Nevertheless, depending on circumstances, only a relatively small fraction of strokes become the subject of forensic investigation. Hypertensive cerebral hemorrhages have their favored anatomic sites. Common sites are putamen and thalamus, lobar white matter, cerebellum, and pons. Clearly, the volume of hemorrhage is an important, but not the only, determinant of outcome, and those cases referred to the medical examiner usually have large hemorrhages. In this chapter, the emphasis is on the presence of severe bilateral thalamic lesions in some cases. Three major topographic patterns of cerebral injury, or some combination thereof, may result in a persistent vegetative state such as widespread and bilateral cerebral cortical damage; extensive bilateral involvement of intra- and subcortical connections of the cerebral hemispheric white matter and bilateral severe thalamic involvement.

Malformations and other congenital central nervous system lesions

The forensic neuropathology consultant may be called on to investigate central nervous system (CNS) developmental disorders from several sources. Sources of information helpful in the identification of the various types of CNS malformations can provide a starting point for further study. Older nomenclature for a particular abnormality may infer causation not supported by more recent studies. More than one type of simultaneous insult may act in concert to produce a particular abnormality. Alternatively, one must consider the possibility of adverse events occurring on more than one occasion during gestation, the resulting abnormality representing the aggregate result of a sequence of similar or dissimilar etiologies. The omission of specific etiologies in place of “period of insult” is purposeful, for reasons outlined earlier. Consideration of potential contributing factors, such as cardiovascular disease, other causes of hypoxic-ischemic events, hyper vitaminosis A, nutritional deficiency, chromosomal abnormalities, maternal metabolic disorders, infections, drugs, toxins, hormonal abnormalities, trauma, antigen antibody interactions, irradiation, placental, or umbilical cord abnormalities, may be necessary on a case-by-case basis.

Injuries due to firearms and other missile-launching devices

The consulting neuropathologist involved in the study of firearm and other missile injuries will find injuries caused because of firearms and other missile-launching devices, to be a complex and challenging area, and one in which some of the neuropathology questions posed are not presently answerable. The consultant interested in providing a more comprehensive service to his colleagues, however, requires a broader knowledge base in this subspecialty. In this chapter, the focus is on a few selected topics and cases viewed primarily from the vantage point of the neuropathology consultant, and suggest procedures that will aid the medical examiner in obtaining as much useful information as possible from such consultations. If certain points, which have been added later, appear redundant in several of the references listed previously, it is because their reiteration appears to require reinforcement based on the frequency of questions received or because such sources contradict one another on certain points. This chapter emphasizes handgun wounds, because they account for approximately 90% of firearms-related homicide cases and a slightly lower percentage of firearms-related suicide cases. It may be concluded that some findings on admission are more important than others in determining prognosis in gunshot wounds, and individual variations, which are difficult to predict, can occur. The prognostic issues of gunshot wounds in testimony are primarily within the sphere of expertise of experienced clinicians, who work with such cases, and are intimately familiar with standards of care in the community, rather than pathologists.

Sudden unexpected death

Publisher Summary A sudden death may be better characterized as a relatively sudden, unexpected death. In this chapter, most of the cases fall in the latter category. The neuropathologic processes falling in the categories of sudden unexpected death (SUD) usually lead to accurate determination of cause of death by gross examination alone, although the exact mechanism of death is not always clear. Vital to the determination of the mode in cases of SUD is the accurate recognition of several pathologic processes. Excluding drug overdose, intentional or otherwise, nondrug intoxications, and so-called reflex SUD, nervous system causes of SUD tend to group into limited categories of anatomically identifiable diseases. Postmortem molecular analysis also proves useful in providing a more definitive diagnosis in some of these cases by exposing predisposing factors that spontaneously (or in some instances by various environmental triggers) may result in SUD. This can be helpful diagnostically, and may also result in medical intervention and prevention of deaths in similarly affected relatives of the decedent. Study of gene mutations may also eventually provide a better understanding of how fever, sleep and awakening, fear, exercise, swimming, and other yet undefined factors can precipitate potentially fatal arrythmias.