Diffuse axonal injury by assault

A case of diffuse axonal injury (DAI) by assault is reported. The majority of DAI cases documented have been due to traffic accidents and some due to falls from height. DAI is caused by angular or rotational acceleration of the victim's head. The condition is common and is the second most important head injury after subdural hematoma with regard to death. Its clinical picture is characterized by immediate and prolonged coma or demented state. Because of the subtle nature of histological changes in DAI, awareness and intentional search for the lesion is essential. The triad of DAI is as follows: focal lesions (hemorrhages and/or lacerations) in the corpus callosum and brain stem, and microscopic demonstration of axonal damage--retraction balls. The concept of DAI will elucidate and enhance the understanding of many head trauma cases.     

Diffuse axonal injury by simple fall.

Diffuse axonal injury (DAI) is the second most common lethal head trauma after subdural hematoma and probably the most frequent cause of traumatic coma in the absence of an expanding intracranial mass lesion. Though it occurs most often in traffic accidents, it may occasionally result from falls from a height. Previously, it has not been associated with a simple fall or a fall of a distance not more than the victim's own height. We report herein a case of DAI from a simple fall.     

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.     

Fatal pediatric head injuries caused by short-distance falls.

Physicians disagree on several issues regarding head injury in infants and children, including the potential lethality of a short-distance fall, a lucid interval in an ultimately fatal head injury, and the specificity of retinal hemorrhage for inflicted trauma. There is scant objective evidence to resolve these questions, and more information is needed. The objective of this study was to determine whether there are witnessed or investigated fatal short-distance falls that were concluded to be accidental. The author reviewed the January 1, 1988 through June 30, 1999 United States Consumer Product Safety Commission database for head injury associated with the use of playground equipment. The author obtained and reviewed the primary source data (hospital and emergency medical services' records, law enforcement reports, and coroner or medical examiner records) for all fatalities involving a fall. The results revealed 18 fall-related head injury fatalities in the database. The youngest child was 12 months old, the oldest 13 years. The falls were from 0.6 to 3 meters (2-10 feet). A noncaretaker witnessed 12 of the 18, and 12 had a lucid interval. Four of the six children in whom funduscopic examination was documented in the medical record had bilateral retinal hemorrhage. The author concludes that an infant or child may suffer a fatal head injury from a fall of less than 3 meters (10 feet). The injury may be associated with a lucid interval and bilateral retinal hemorrhage.     

Skull Fracture with Brain Expulsion in a One-Level Jumping-Fall

Abstract:  Here presented is the case of a one-level jumping-fall with extensive skull fractures and brain expulsion. The body was found on the basement floor at the foot of the stairs. At the autopsy, the skull was extensively fractured, with about half of the brain expulsed several feet away from the body. The cause of death was established as a craniocerebral trauma with brain expulsion. The circumstances and manner of death were still unclear at that time. A low fall seemed very unlikely considering the severity of the skull and brain damage. The police investigation clearly revealed that the man, in a paranoid psychotic state, attacked his wife with a knife and then was witnessed by his children to have hit his head several times with a hammer. Afterwards, they saw him running to the top of the basement stairs and jumping to the bottom of the stairs head first.     

Case report of sudden death after a blow to the back of the neck.

A 13-year-old girl experienced a fall during gym class that caused immediate unresponsiveness and death. The lone witness reported that the decedent lost her balance as she approached a hurdle and fell, striking her head on a crossbar of the hurdle near the ground. Autopsy revealed no external injury. Internal injury that could be demonstrated anatomically was confined to a contusion within the right semicapitis muscle at the base of the skull. In the absence of an anatomic cause of death, possible explanations of the death include a cardiac dysrhythmia, a vasovagal stimulus, and diffuse axonal injury caused by a concussive force to the junction of the medulla and spinal cord. Animal studies have shown that severe concussion can cause death via profound autonomic dysfunction without leaving anatomic evidence of injury, and that the essential component of concussion is an element of rotational injury to the brain. The authors believe that the blow to the neck caused this death by the transmission of a concussive force through the reticular activating system. The prompt work of police in distinguishing the lone witness from several people in the area who thought they knew what had happened was essential for diagnosis. On reaching our conclusions, the authors notified first the family, then the superintendent of the school system, and finally the news media. The authors told each party in turn that they would be contacting the others.     

Cerebral traumatism with a playground rocking toy mimicking shaken baby syndrome

Shaken baby syndrome (SBS), one of the most deadly and devastating forms of child abuse, is caused by violent shaking. The combination of subdural hematoma, retinal hemorrhage, brain swelling, and diffuse axonal injury is highly typical of this syndrome and faced with these autopsy findings, induced traumatic lesions are strongly considered. However, it is known that motor-vehicle accidents and falls from great height can also produce this pattern of injury. Nevertheless, stories of arms fall, couch fall, or bumped head while the baby is being carried are generally considered incompatible with SBS. We here report a case of a 2-year-old boy presenting with all the classic autopsy findings of SBS from a playground rocking toy shaken by an older child.     

弥漫性轴索损伤的研究进展

弥漫性轴索损伤（diffuse axonal injury,DAI）以脑白质轴索弥漫性损伤为主要特征,迄今其形成机制尚未完全阐明,不同学科诊断标准迥异,是法医学和神经科学亟待解决的难题。磁共振弥散张量成像（diffusion tensor imaging,DTI）通过检测弥散参数及纤维束成像（fibre tracking,FT）可准确地反映轴索损伤部位及损伤程度,具有广泛的法医学应用前景。本文综述DAI发生机制及诊断方法的研究进展,尤其DTI技术在DAI诊断中的应用。     

Inadvertent clavicular fractures caused by "chiropractic" manipulations in an infant: an unusual form of pseudoabuse

A nine-month-old child was found unresponsive in his crib, five hours after his last feeding. At autopsy, there were no external or internal signs of abuse or neglect, and a few visceral pleural and epicardial petechiae were consistent with the sudden infant death syndrome (SIDS). However, postmortem total body radiographs revealed healing, symmetrical clavicular fractures and a healing left medial humeral epicondyle fracture. The parents had no explanation for these injuries and denied causing any harm to the child. The location and nature of the fractures strongly suggested abusive origin, and the case was reported to the police and the district attorney's office as child abuse. During the investigation, information from the parents indicated that the child had undergone "chiropractic" manipulations by an unlicensed therapist, between three and four weeks prior to death, to correct supposed "shoulder dislocations." This time interval correlated with the histologic age of the injuries, and the history explained their unusual bilateral location and appearance. The parents were exonerated of abuse charges, and the death was ascribed to SIDS.     

Diffuse vascular injury in fatal road traffic accident victims: its relationship to diffuse axonal injury

The authors have reported a macro- and microscopic study of brain lesions in 120 victims of fatal road traffic accidents, independent of the survival time. Diffuse vascular injury (DVI) was found in 14 patients (11.7%). All patients with DVI died within 24 h after the accident. The 14 patients with DVI also showed severe (Grade 2 or 3) diffuse axonal injury (DAI). Since DVI is restricted to road traffic accidents and incompatible with life, the high frequency observed in our series could be explained by the fact that all 120 patients were victims of road traffic accidents, and 69.2% had died within 24 h after the accident. The association between DVI and severe DAI (Grades 2 and 3) suggests that both lesions depend on the same mechanism, with the degree of axonal and vascular damage being determined by the intensity of the head acceleration. Our results show a relationship between DVI and DAI that suggest there may be a spectrum or at least a continuum between these entities as distinct from DVI being a separate entity.     

实验性大鼠弥漫性轴索损伤的傅里叶红外光谱检测

目的探讨利用傅里叶红外光谱技术诊断弥漫性轴索损伤的可行性。方法利用HE染色、银染和β-APP免疫组化染色确认大鼠弥漫性轴索损伤模型,利用傅里叶变换显微红外光谱面扫描成像技术检测弥漫性轴索损伤区域酰胺Ⅱ带的光谱分布情况,得到弥漫性轴索损伤的红外光谱数据,绘制红外光谱病理图像。结果实验组与对照组的酰胺Ⅱ带红外光谱吸收度之间存在明显差异,红外光谱病理图像中酰胺Ⅱ带的高吸收区与弥漫性轴索损伤区符合。结论傅里叶红外光谱技术可对弥漫性轴索损伤进行病理形态学诊断。     

大鼠弥散性轴索损伤后β-APP的表达

目的观察大鼠DAI损伤后β-APP表达和Gless神经纤维轴索染色在诊断DAI损伤及判断损伤时间的价值。方法按Marmarou法复制大鼠DAI损伤模型,脑组织常规取材后进行β-APP及Gless氏神经纤维轴索染色观察。结果β-APP及Gless氏染色法在大鼠DAI损伤后0.5h即可见神经轴索断裂、扭曲变形、增粗膨大,12h以后可见到轴索收缩球。二种方法均显示DAI损伤的病理形态学变化,伤后12h明显,1d达到高峰,3d后开始修复,10d后基本恢复正常。β-APP表达强度在实验组不同时间存在着明显的差异,即3h呈明显阳性表达,1d达到高峰,3d后逐渐减弱,10d基本恢复正常。结论β-APP免疫组织化学染色法及Gless氏神经纤维轴索染色法,对DAI的早期诊断具有重要应用价值,并能从病理形态学上反映DAI损伤的时序性。β-APP表达强度变化是推断早期DAI损伤时间的重要参考指标。     

Fatal acute intracranial injury, subdural hematoma, and retinal hemorrhages caused by stairway fall

We describe an infant with an acute subdural hematoma, a fatal head injury, and severe hemorrhagic retinopathy caused by a stairway fall. His cerebral and ocular findings are considered diagnostic of abusive head trauma by many authors. Our literature search of serious injuries or fatalities from stairway or low-height falls involving young children yielded 19 articles of primary data. These articles are discrepant, making the classification of a young child's death following a reported short fall problematic. This case report contradicts the prevalent belief of many physicians dealing with suspected child abuse that low-height falls by young children are without exception benign occurrences and cannot cause fatal intracranial injuries and severe retinal hemorrhages. The irreparable harm to a caregiver facing an erroneous allegation of child abuse requires physicians to thoroughly investigate and correctly classify pediatric accidental head injuries.     

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.     

Traumatic dissection of the vertebral artery in a toddler following a short fall

Spontaneous subarachnoid haemorrhage (SAH) in children is uncommon, but is sometimes seen after rupture of aneurysms, and in different disorders. Traumatic SAH is common after serious accidental head injury, but is also reported after child abuse with vigorous shaking. To avoid unnecessary accusations of innocent care givers, it is important not to misinterpret the findings as abusive head trauma in small children with SAH. In the presented case, a nearly two-year-old girl was brought to the hospital after a fall witnessed by her father. The girl was unconscious, with elevated intracranial pressure, SAH and bilateral retinal haemorrhage (RH). She was pronounced dead after 9h. Premortem angiography revealed a dissection of the right vertebral artery, and postmortem examination revealed a traumatic lesion deep in the neck, at the base of the skull. Cerebral edema, in combination with SAH and RH, is highly suggestive of abusive head trauma. However, no external lesions, no skeletal lesions, especially no long bone metaphyseal lesions, or subdural haematomas occurring at the same time as SAH, were found. There was no report of previous child abuse in the family. Based on the radiological and postmortem findings, we believe that an accidental fall caused a blunt force trauma with a subsequent dissection of the right vertebral artery. To our knowledge, accidental tear of one of the vertebral arteries, leading to SAH in a toddler, has previously not been described. Child abuse is an important exclusion diagnosis with serious legal implications.     

IL-1β和TNF-α在大鼠弥漫性轴索损伤中的作用

目的观察大鼠弥漫性轴索损伤后IL-1β和TNF-α蛋白表达的时序性变化,探讨其在大鼠弥漫性轴索损伤（diffuse axonal injury,DAI）中的作用。方法 55只健康雄性SD大鼠,随机分为正常对照组、手术对照组和DAI组,采用HE、Gless氏嗜银染色和免疫组织化学（SP法）观察不同时间（30min～7d）脑干组织病理学改变及IL-1β和TNF-α蛋白的表达情况。结果 HE染色显示DIA大鼠脑干组织结构疏松、水肿,Gless氏嗜银染色可见轴索肿胀、扭曲、收缩球形成等改变,证明弥漫性轴索损伤模型成功;IL-1β和TNF-α在正常对照组与假手术组大鼠脑干神经元内有低表达,而在DAI后30min～6h大鼠脑干神经元和小胶质细胞内表达迅速增加,于6h达高峰。结论大鼠弥漫性轴索损伤后IL-1β和TNF-α蛋白在脑干内表达的增加,与轴索继发性损伤有关。     

Preliminary Study on Diffuse Axonal Injury by Fourier Transform Infrared Spectroscopy Histopathology Imaging

The objective of this study was to evaluate the application of Fourier transform infrared (FTIR) spectroscopy for detecting diffuse axonal injury (DAI) in a mouse model. Brain tissues from DAI mouse model were prepared with H&E, silver, and β‐amyloid precursor protein (β–APP) immunohistochemistry stains and were also studied with FTIR. The infrared spectrum images showed high absorption of amide II in the subcortical white matter of the experimental mouse brain, while there was no obvious expression of amide II in the control mouse brain. The areas with high absorption of amide II were in the same distribution as the DAI region confirmed by the silver and β‐APP studies. The result suggests that high absorption of amide II correlates with axonal injury. The use of FTIR imaging allows the biochemical changes associated with DAI pathologies to be detected in the tissues, thus providing an important adjunct method to the current conventional pathological diagnostic techniques.     

Morphometrical analysis of retinal hemorrhages in the shaken baby syndrome

A morphometrical analysis of retinal hemorrhages was performed in cases of physical child abuse including the shaken baby syndrome and in controls (severe head injury, intravital brain death, non-traumatic intracranial hemorrhage, SIDS including cardiopulmonary resuscitation). The extent of the retinal hemorrhages was significantly different between both groups. In all cases of physical child abuse, massive retinal hemorrhages in at least one eye could be found ranging between a maximum value of 19.2 and 73.2% of the entire retinal area. In contrast, only two cases of the control group (severe head injury with skull fractures and intracranial bleeding following traffic accident or fall) showed slight hemorrhages of 3.33 or 1.18% of the retinal area but only in one eye. Therefore, the results provide evidence that massive intraretinal hemorrhages indicate violent shaking — in particular in association with other signs of physical child abuse.     

Crossbow suicide: mechanisms of injury and neuropathologic findings

Crossbow injuries are rarely reported events in modern times. Two cases of death due to self-inflicted crossbow injuries to the head are reported in 2 men aged 18 and 27 years, respectively. Despite relatively low velocity and concussive force, the sharpness and propulsion force of crossbow bolts may be sufficient to enable penetration of the skull at short range. Due to the relatively low concussive force of the crossbow bolt, however, death may not be instantaneous but may occur from intraparenchymal cerebral damage sometime thereafter. Detailed neuropathologic evaluation of such cases may therefore demonstrate "red cell" hypoxic injury, as well as axonal injury, not limited to the region of the missile tract, but widely distributed, even to the point of extensive brain stem involvement. These changes may result from primary mechanical deformation at the time of injury, from secondary hypoxic damage, or from a combination of both factors. Immunohistochemical staining of brains for amyloid precursor protein to delineate more clearly the pattern of axonal damage may assist in determining the extent of injury in such cases.