Diffuse axonal injury

Diffuse axonal injury is a distinct form of head injury, induced by direct external forces at the time of the trauma, and not produced by secondary changes due to a primary injury. This type of lesion may be without conspicuous findings on gross brain examination, or may be found with coexisting conventional types of brain injuries. It is characterized by diffuse retraction balls (axonal swellings), hemorrhage or laceration of the corpus callosum, and hemorrhages in the brain stem. It is of utmost importance for forensic pathologists to be aware of this little-recognized entity. Five illustrative cases are presented.     

Fatal child abuse-maltreatment syndrome. A retrospective study in Ontario,Canada, 1990-1995

Child death due to repeated episodes of physical assault or neglect has been termed the child abuse-maltreatment syndrome (CAMS). We characterized the injuries in a series of fatally abused or maltreated child to delineate objective diagnostic criteria for the CAMS for use by clinicians and pathologists. All deaths (age <17 years) investigated by the Office of the Chief Coroner for Ontario, Canada during the time period 1990-1995 were reviewed. Cases of CAMS were defined as death due to lethal recent injury or malnutrition in the presence of significant old (healing or healed) injuries indicative of repeated episode of inflicted trauma. The nature and frequency of the various injuries was determined. The frequency of the shaken baby syndrome, and the types and frequency of ano-genital injuries were also studied. Twenty-one cases of fatal CAMS were found in the study period. Most cases had significant recent head injury with intra-cranial hemorrhage (71%). Other significant recent injuries commonly observed included blunt injuries of the skin and soft tissues (67%), blunt abdominal trauma with visceral injuries (14%), and fractures (18%). Eight cases (38%) fulfilled accepted criteria for the shaken baby syndrome. Many children with fatal head injuries had evidence of older head trauma (38% of all cases). A significant minority of cases had evidence of malnutrition due to neglect (10%) or ongoing ano-genital injuries (10%). Most cases of child homicides due to repeated episodes of abuse or maltreatment involve head trauma including shaken baby syndrome. Fractures of long bone and ribs, the classical markers of child abuse, were relatively infrequent compared with head injury. A proportion of cases had ano-genital injuries due to repeated sexual abuse or punitive maltreatment. All clinicians and pathologists must recognize the wide spectrum of injuries in child abuse to ultimate protect the victim or other children in an at-risk situation.     

A clinico-morphological analysis of the traumatic substrates to cerebral injuries in different inertial loads on the brain]

The relationships between the inert tension of the head and the morphologic substrates of brain injuries were under study. A comparative clinical and morphologic analysis of lethal contusion and axonal injuries underlie this investigation. Differences in the neurologic semeiotics and CT data in such injuries are presented. The authors discuss the mechanisms of the physical processes in the skull, resulting in focal and diffuse injuries of the brain. Quantitative assessment of the traumatic cerebral substrates is given and relations of these parameters to the conditions of the head trauma (the direction of the external injurious factor action) and the clinical picture are shown. The results of this study may be useful in establishing some circumstances of craniocerebral injuries.     

Modification of the Marmarou and Foda model of diffuse axonal injury (DAI) improves percentage survival of rats at 24 h and increases the amount of DAI identified

More than two decades ago, Marmarou published a valid model for producing diffuse axonal injury (DAI) in rats. Since then, both mild and severe injuries have been obtained by researchers using the original method and a weight of 450 g. However, the diffuse brain injuries produced in rats were only similar to those seen in humans when the rats sustained severe brain injuries. In these cases, rat mortality in the original article was around 50%, and the cause of death was prolonged apnea post-impact. Rat survival after impact is critical for studying the progression of DAI. In order to explain the cause of death in human victims with cranial trauma who do not show gross brain injury, testing for the presence of DAI is essential. Thus, in order to minimize local and cervical injuries to increase rat survival, attention should be paid to the following aspects: a wider head protector disc should be used, the head of the rat should be elevated at the time of impact, and the foam bed should be soft enough to allow the movement caused by acceleration. With our modified method, rat survival increased by 30% compared to the original model (80% versus 50%). Moreover, 85.7% of rats demonstrated DAI after 24 h of survival. With these modifications, injuries appear in the same locations as in humans; thus, the method is suitable for the study of traumatic DAI in humans.     

171例脑干颅神经损伤

目的　观察头部受力致脑干颅神经损伤的形态学改变 ,探讨脑干颅神经损伤形成机制及其与头受力部位和方式的关系。方法　 171例脑干标本 ,于双侧第 3～ 12对颅神经的根部水平横切取组织块 ,常规固定、脱水、包埋、切片、HE染色 ,光镜检查。结果　所有标本均见颅神经损伤。有动眼神经损伤 ( 12 0例 ,70 2 % ) ,面听神经损伤( 92例 ,5 3 8% ) ,三叉神经损伤 ( 85例 ,49 7% ) ,外展神经损伤 ( 4 5例 ,2 6 3 % ) ,舌下神经损伤 ( 3 1例 ,18 1% ) ,迷走神经损伤 ( 2 7例 15 8% ) ,舌咽神经损伤 ( 2 4例 ,14 0 % )及滑车神经和副神经损伤 (各 10例 ,5 8% )。损伤可为单侧或双侧 ,累及单条或多条。病理形态学改变有出血 ( 4 2例 ,2 4 6% ) ,水肿 ( 2 6例 ,15 2 % ) ,神经根部组织结构变形 ( 71例 ,41 5 % ) ,根部撕裂 ( 3 2例 ,18 7% )等。结论　脑干颅神经损伤是脑干损伤的并存病变 ;位脑干高位的颅神经损伤比位低位的多 ,粗的神经损伤比细的多而严重 ;动眼、面、听神经损伤的发生率较高。     

The forensic-medical expertise in craniofacial trauma

Archive materials of the recent 6 years, including 14720 death cases of victims, were analyzed for the purpose of detecting the general regularities of injuries within the craniofacial trauma (CFT). The diversity of CFT with injuries to skull bones and medullary substance was found not to interfere with establishing an actual type and mechanism of trauma provided all injuries are thoroughly and comprehensively examined. The trauma specificity must be evaluated with respect to a location and direction of traumatic force in order to define an actual impact that caused death. CFT is special variation of craniocerebral trauma, whose onset mechanism needs more research. The efficiency of forensic-medical examination of CFT cadavers directly depends on the coordination and logic of measure undertaken by expert as well as on his technical outfit and knowledge of such trauma. The diversity of variations of damage to anatomic head structures requires an interdisciplinary approach with the need to isolate a predominant chain that affects the course and outcome of trauma.     

Fall from height--surprising autopsy diagnosis in primarily unclear initial situations

External post-mortem examination and first police assessments are often not consistent with subsequent autopsy results. This is all the more surprising the more serious the injuries found at autopsy are. Such discrepancies result especially from an absence of gross external injuries, as demonstrated by four examples. A 42-year-old, externally uninjured male was found at night time in a helpless condition in the street and died in spite of resuscitation. Autopsy showed severe polytrauma with traumatic brain injury and lesions of the thoracic and abdominal organs. A jump from the third floor was identified as the cause. At dawn, a twenty-year-old male was found dead on the grounds of the adjacent house. Because of the blood-covered head the police assumed a traumatic head injury by strike impact. The external examination revealed only abrasions on the forehead and to a minor extent on the back. At autopsy a midfacial fracture, a trauma of the thorax and abdomen and fractures of the spine and pelvis were detected. Afterwards investigations showed that the man, intoxicated by alcohol, had fallen from the flat roof of a multistoried house. A 77-year-old man was found unconscious on his terrace at day time; a cerebral seizure was assumed. He was transferred to emergency care where he died. The corpse was externally inconspicuous. Autopsy revealed serious traumatic injuries of the brain, thorax, abdomen and pelvis, which could be explained by a fall from the balcony. A 47-year-old homeless person without any external injuries was found dead in a barn. An alcohol intoxication was assumed. At autopsy severe injuries of the brain and cervical spine were found which were the result of a fall from a height of 5 m. Conclusion: On the basis of an external post-mortem examination alone gross blunt force trauma cannot be reliably excluded.     

Punched with a fist: the etiology of a fatal depressed cranial fracture

We report a case in which a 33-year-old man was discovered unconscious following a fistfight with another man. Emergency neurosurgical efforts to repair a depressed temporoparietal skull fracture and associated brain injuries were unsuccessful. The forensic anthropologist and pathologist worked in tandem to sort out a complex combination of cranial evidence, including healed antemortem trauma, perimortem blunt force trauma, remote and recent neurosurgical intervention, and the craniotomy cut performed at autopsy. The victim had suffered head injuries and a right temporoparietal craniotomy ten years prior to death. The perimortem cranial fractures were centrally located within a surgically repaired roundel of bone involving portions of the right temporal and parietal bones. Reportedly, the victim was punched on the right side of his head as he was lying on the ground with the left side of his head against an asphalt surface. A primary question in the case was whether a blow with a fist could have produced the observed cranial injuries. To adequately answer that question, known data on the minimum amount of force required to fracture the temporoparietal region were compared to data on the amount of force generated by a blow with a fist. A biomechanics expert demonstrated that a single blow with a fist to the rigidly supported head of the victim could generate the required force to produce the observed fractures. The previous medical condition possibly predisposed the victim to the cranial fractures and contributed to the depressed nature of the fractures. Although depressed cranial fractures do not typically result from a blow with a fist, it was determined in this case that the fracture pattern was consistent with a punch to the head.     

The shaking trauma in infants - kinetic chains

The findings in three children who died as a consequence of shaking and those in another child who survived are presented. In the three fatal cases, a combination of anatomical lesions were identified at autopsy which appear to indicate the sites where kinetic energy related to the shaking episodes had been applied thus enabling the sequence of events resulting in the fatal head injury to be elucidated. Such patterns of injuries involved the upper limb, the shoulder, the brachial nerve plexus and the muscles close to the scapula; hemorrhages were present at the insertions of the sternocleidomastoid muscles due to hyperextension trauma (the so-called periosteal sign) and in the transition zone between the cervical and thoracic spine and extradural hematomas. Characteristic lesions due to traction were also found in the legs. All three children with lethal shaking trauma died from a subdural hematoma only a few hours after the event. The surviving child had persistant hypoxic damage of the brain following on massive cerebral edema. All the children showed a discrepancy between the lack of identifiable external lesions and severe internal ones.     

Death due to concussion and alcohol

We encountered 5 deaths following blunt trauma to the face and head in which the injuries were predominantly soft tissue in nature with absence of skull fractures, intracranial bleeding, or detectable injury to the brain. All individuals were intoxicated, with blood ethanol levels ranging from 0.22 to 0.33 g/dl. We feel that in these deaths, ethanol augmentation of the effects of concussive brain injury, with resultant posttraumatic apnea, was the mechanism of death.     

Peculiarities of combined blunt head injuries in children and adolescents

The objective of the present study was to evaluate the frequency and peculiar features of combined head injuries in children and adolescents who suffered the fatal blunt trauma. A total of 101 corpses and 188 archive records were available for the analysis. The control data group was comprised of 227 original observations of adult corpses. It was shown that head injuries prevail over injuries to other parts of the body in children with combined blunt traumas. The craniocerebral injuries are more frequent in children and adolescents than in adult subjects but their extent is smaller. Fractures of the facial bone skeleton in adults occur twice as frequently as in children. A peculiar feature of craniocerebral injuries in children and adolescents is incomplete splintered fractures and folded deformation of the bone plate. Subarachnoidal hemorrhage occurs equally frequently in children and adults with craniocerebral injuries. Other intracranial manifestations of the injury, such as ruptured brain tunics, epidural and subdural hemorrhage, cerebral contusion and ventricular hemorrhage in children occur less frequently than in adults.     

Unsuspected meningoencephalitis in a case of assault by blunt force trauma

Reported is a case of an assault causing extensive blunt force injuries in which the clinical, radiologic, and postmortem findings were all consistent with death resulting from brain damage arising from the assault. The assailant was charged with murder. Subsequent full neuropathologic (including histologic) examination revealed the unsuspected finding of a widespread meningoencephalitis but no evidence of significant traumatic brain damage. The contributions of the infective process and of the trauma to death were felt to be unclear and a guilty plea to attempted murder was accepted. This case highlights the importance of a full neuropathologic examination, including histology, in cases of trauma to the head, even when the cause of death may initially appear obvious.     

Age-specific peculiarities of manifestations of a craniocerebral injury in children and adolescents with a combined blunt trauma

This study was designed to estimate the frequency of head injuries and selected manifestations of craniocerebral traumas in children and adolescents with a fatal combined blunt trauma. It is included 289 cases of death from a combined blunt trauma (101 original observations and data of 188 archival documents). The victims were categorized into 3 age groups. One group was comprised of cases from 0 to 3 years of life, group 2 included children aged from 4 to 11 years, and group 3 those at the age from 12 to 18 years. The age was shown to significantly influence both the frequency of head injuries and their severity. The maximum values of the two variables were recorded in the youngest age group. The frequency of head injuries and the number of selected manifestations of the craniocerebral trauma decreased with age.     

The mechanism of injury of the abducens nerve in severe head trauma: a postmortem study

The aim of this study is to investigate the mechanism of injury of abducens nerve at petroclival region in severe head trauma. Twenty specimens provided from 10 autopsied cases due to severe head trauma were investigated macroscopically and histopathogically. The slices of the abducens nerve taken consecutively along its course at petroclival region were stained with Hematoxylline-Eosin and evaluated under light microscope. In addition, coexisting cervical injuries in these cases were assessed macroscopically. Edema and perineural hemorrhagia of abducens nerve were identified in all cases. Nerve injury was found more exaggerated at the sites of dural entry point and petrous apex than any other parts of the abducens nerve. Furthermore, microscopically, also remarkable perineural hemorrhage of the abducens nerve was observed at the site of its anastomoses with the sympathetic plexus on the lateral wall of the internal carotid artery (ICA). Abducens nerve is injured at the sites of dural entry point, petrous apex and lateral wall of the ICA, directly proportional with the severity of the trauma. This finding is also significant in verification of the severe head trauma.     

Myocardial lesions induced after trauma and treatment.

In order to clarify the effect of trauma and treatment as stresses on myocardia, we examined histological changes of myocardia in victims who received various kinds of traumata and treatments. We also undertook a histochemical study for calmodulin, which we found useful in the diagnosis of early ischemia. Those who died shortly after stab wounds, traffic accident or head injuries, showed mild cardiac lesions such as contraction bands or fragmentation and mild diffusion of calmodulin, a marker for necrosis. A case with hemorrhagic shock after a traffic accident, involving intense resuscitation for 2 h, showed severe cardiac lesions such as contraction bands, hydropic change and subendocardial hemorrhage along with severe diffusion of calmodulin. In most of the instant death cases after falls, severe contraction band necrosis and severe calmodulin diffusion were observed. Myocardia of victims, who died several days after head injuries or traffic accidents, generally demonstrated distinct diffusion of calmodulin as compared to the mild and non-specific lesions detected by hematoxylin-eosin (H&E) staining. In cases of long-term survival in a state of brain death, calmodulin staining was very low, which was not always associated with the severity of the lesions on H&E staining. In cases with intensive or extended treatment, it appeared to be difficult to determine the cause-effect relationship between trauma and cardiac lesions or to distinguish the lesions due to extrinsic factors from those of disease. In some cases, calmodulin intensely stained the areas with hydropic appearance or hypereosinophilia, which may be related to calcium overload.     

Position paper on fatal abusive head injuries in infants and young children

This article represents the work of the National Association of Medical Examiners Ad Hoc Committee on shaken baby syndrome. Abusive head injuries include injuries caused by shaking as well as impact to the head, either by directly striking the head or by causing the head to strike another object or surface. Because of anatomic and developmental differences in the brain and skull of the young child, the mechanisms and types of injuries that affect the head differ from those that affect the older child or adult. The mechanism of injury produced by inflicted head injuries in these children is most often rotational movement of the brain within the cranial cavity. Rotational movement of the brain damages the nervous system by creating shearing forces, which cause diffuse axonal injury with disruption of axons and tearing of bridging veins, which causes subdural and subarachnoid hemorrhages, and is very commonly associated with retinal schisis and hemorrhages. Recognition of this mechanism of injury may be helpful in severe acute rotational brain injuries because it facilitates understanding of such clinical features as the decrease in the level of consciousness and respiratory distress seen in these injured children. The pathologic findings of subdural hemorrhage, subarachnoid hemorrhage, and retinal hemorrhages are offered as "markers" to assist in the recognition of the presence of shearing brain injury in young children.     

TV tip-over morbidity and mortality in children

Twenty-eight non-fatal cases of TV related injuries were noted in San Diego in the 2 years prior to September 2008. We reviewed the scene, witness reports, past history, and autopsy findings from three fatal cases and distinguished them from abusive head trauma. The recent literature was also reviewed. Our fatal cases resulted from TVs falling on small children and causing severe head injury. The literature review showed increasing injuries and deaths relating to TV tip-over, TV stands and dressers. Most of the fatalities were head injuries in small children. The reporting methods may not be complete or accurate. Some authors in the literature review suggested preventive measures so as to decrease these injuries. Forensic scientists should become familiar with these injuries and measures so that they may communicate effectively with their communities.     

Investigative and autopsy findings in sport aircraft-related deaths in southwest Florida

Aircraft designated for sport or recreational use only, including ultralights, experimental aircraft and light-sport aircraft, have become increasingly popular. Because of their relative safety and the rarity of fatalities resulting from crashes of these aircraft, the forensic literature contains little information concerning the pathologic findings in such deaths. We report 9 deaths resulting from 6 sport aircraft crashes in southwest Florida, 6 pilots and 3 passengers. The vehicles involved 3 experimental aircraft, 1 ultralight and 2 "ultralight-like" aircraft. The patterns of injuries included trauma predominantly to the chest (3 cases), abdomen (1) or head (1), as well as multiple blunt force injuries involving the chest and abdomen (1) or the head and torso (3). Extremity fractures were found in only 2 cases, whereas injuries to the symphysis pubis were found in six. No "control-type" injuries were identified. These cases illustrate the varied pathologies associated with deaths due to crashes of sport aircraft and reveal the lack of uniformity associated with the investigations of such deaths.     

Animal-related fatalities--part I: characteristic autopsy findings and variable causes of death associated with blunt and sharp trauma

Animals may be responsible for an array of potentially lethal injuries. Blunt force injuries characteristically involve larger animals such as cattle or horses that may kick, crush, or trample a victim causing head and facial injuries. Farm workers in particular are at high risk of lethal injuries involving the head and torso. Significant blunt trauma may be found in vehicle occupants after collisions with large animals such as camels or moose. Rarely, zookeepers may be crushed by particularly massive animals such as elephants. Sharp force injuries usually involve carnivore bites, most often from dogs with a "hole and tear" pattern of wounding. Injuries from animals such as alligators and sharks may have a significant component of crushing. Incised wounds may result in death from exsanguination and air embolism. On occasion, blunt or sharp trauma from animal activity may be confused with postmortem damage or with inflicted injury from an assault.     

Cardiopulmonary resuscitation-related injuries and homicidal blunt abdominal trauma in children

Defendants accused of inflicting fatal abdominal injuries to children occasionally raise the defense that the injuries were caused by cardiopulmonary resuscitation (CPR). The purpose of this study is to answer the question: Does closed chest CPR result in fatal blunt abdominal injuries that can be mistaken for homicidal assault? To that end, a retrospective study was conducted of all homicidal blunt abdominal injuries in children 10 years and younger from the Dade, Broward, and Palm Beach Medical Examiner's Offices from 1981 through 1997. These were compared to cases of children who died of natural causes during the same time period in Broward County who had CPR (control group 1) and to children who died of nonvehicular accidental blunt abdominal trauma (control group 2). Children with life-threatening head injuries were excluded. Medical examiner records, autopsy reports, documenting photographs, and clinical records were reviewed. The data analyzed included subject demographics, whether CPR was performed and by whom, and autopsy findings. Thirty-three child homicides with fatal abdominal injuries were reviewed. Twenty-four (73%) of the homicides received CPR. There was no difference in the nature and severity of injuries between the 24 children who received CPR and the 9 who did not. Three hundred and twenty-four cases of pediatric natural deaths were reviewed, all of which had CPR. No traumatic abdominal injuries were found in any of the children who died of natural causes. Only four children who died of natural causes had evidence of extraabdominal trauma related to CPR. No cases of nonvehicular accidental blunt abdominal trauma were identified during the 17-year period, although there were nonvehicular accidental fatalities due to extraabdominal injuries. The likelihood of CPR-related primary abdominal trauma in child homicides is very low.