Ocular hemorrhages in neonatal porcine eyes from single, rapid rotational events

Shaking Up Our Approach: The Need for Characterization and Optimization of Pre-clinical Models of Infant Abusive Head Trauma

Traumatic brain injuries (TBIs) are a large societal and individual burden. In the first year of life, the vast majority of these injuries are the result of inflicted abusive events by a trusted caregiver. Abusive head trauma (AHT) in infants, formerly known as shaken baby syndrome, is the leading cause of inflicted mortality and morbidity in this population. In this review we address clinical diagnosis, symptoms, prognosis, and neuropathology of AHT, emphasizing the burden of repetitive AHT. Next, we consider existing animal models of AHT, and we evaluate key features of an ideal model, highlighting important developmental milestones in children most vulnerable to AHT. We draw on insights from other injury models, such as repetitive, mild TBIs (RmTBIs), post-traumatic epilepsy (PTE), hypoxic-ischemic injuries, and maternal neglect, to speculate on key knowledge gaps and underline important new opportunities in pre-clinical AHT research. Finally, potential treatment options to facilitate healthy development in children following an AHT are considered. Together, this review aims to drive the field toward optimized, well-characterized animal models of AHT, which will allow for greater insight into the underlying neuropathological and neurobehavioral consequences of AHT.

Retinal hemorrhage variation in inertial versus contact head injuries

BACKGROUND

Abusive head trauma (AHT) is frequently accompanied by dense/extensive retinal hemorrhages to the periphery with or without retinoschisis (complex retinal hemorrhages, cRH). cRH are uncommon without AHT or major trauma.

OBJECTIVE

The study objectives were to determine whether cRH are associated with inertial vs. contact mechanisms and are primary vs. secondary injuries.

PARTICIPANTS AND SETTING

This retrospective study utilized a de-identified PediBIRN database of 701 children <3-years-old presenting to intensive care for head trauma. Children with motor vehicle related trauma and preexisting brain abnormalities were excluded. All had imaging showing head injury and a dedicated ophthalmology examination.

METHODS

Contact injuries included craniofacial soft tissue injuries, skull fractures and epidural hematoma. Inertial injuries included acute impairment or loss of consciousness and/or bilateral and/or interhemispheric subdural hemorrhage. Abuse was defined in two ways, by 1) predetermined criteria and 2) caretaking physicians/multidisciplinary team's diagnostic consensus.

RESULTS

PediBIRN subjects with cRH frequently experienced inertial injury (99.4 % (308/310, OR = 53.74 (16.91-170.77)) but infrequently isolated contact trauma (0.6 % (2/310), OR = 0.02 (0.0004-0.06)). Inertial injuries predominated over contact trauma among children with cRH sorted AHT by predetermined criteria (99.1 % (237/239), OR = 20.20 (6.09-67.01) vs 0.5 % (2/339), OR = 0.04 (0.01-0.17)). Fifty-nine percent of patients with cRH, <24 h altered consciousness, and inertial injuries lacked imaging evidence of brain hypoxia, ischemia, or swelling.

CONCLUSIONS

cRH are significantly associated with inertial angular acceleration forces. They can occur without brain hypoxia, ischemia or swelling suggesting they are not secondary injuries.

Modeling of inflicted head injury by shaking trauma in children: what can we learn? : Update to parts I&II: A systematic review of animal, mathematical and physical models

Inflicted shaking trauma can cause injury in infants, but exact injury mechanisms remain unclear. Controversy exists, particularly in courts, whether additional causes such as impact are required to produce injuries found in cases of (suspected) shaking. Publication rates of studies on animal and biomechanical models of inflicted head injury by shaking trauma (IHI-ST) in infants continue rising. Dissention on the topic, combined with its legal relevance, makes maintaining an up-to-date, clear and accessible overview of the current knowledge-base on IHI-ST essential. The current work reviews recent (2017-2023) studies using models of IHI-ST, serving as an update to two previously published reviews. A systematic review was conducted in Scopus and PubMed for articles using animal, physical and mathematical models for IHI-ST. Using the PRISMA methodology, two researchers independently screened the publications. Two, five, and ten publications were included on animal, physical, and mathematical models of IHI-ST, respectively. Both animal model studies used rodents. It is unknown to what degree these can accurately represent IHI-ST. Physical models were used mostly to investigate gross head-kinematics during shaking. Most mathematical models were used to study local effects on the eye and the head's internal structures. All injury thresholds and material properties used were based on scaled adult or animal data. Shaking motions used as inputs for animal, physical and mathematical models were mostly greatly simplified. Future research should focus on using more accurate shaking inputs for models, and on developing or and validating accurate injury thresholds applicable for shaking.

New Insights into the Diagnosis and Age Determination of Retinal Hemorrhages from Abusive Head Trauma: A Systematic Review

(1) Background: Head trauma represents the first cause of death in abused children, but diagnostic knowledge is still limited. The characteristic findings of abusive head trauma (AHT) are retinal hemorrhages (RH) and additional ocular findings, including optic nerve hemorrhages (ONH). However, etiological diagnosis must be cautious. (2) Methods: The Preferred Reporting Items for Systematic Review (PRISMA) standards were employed, and the research focus was the current gold standard in the diagnosis and timing of abusive RH. (3) Results: Sixteen articles were included for qualitative synthesis. The importance of an early instrumental ophthalmological assessment emerged in subjects with a high suspicion of AHT, with attention to the localization, laterality, and morphology of the findings. Sometimes it is possible to observe the fundus even in deceased subjects, but the current techniques of choice consist of Magnetic Resonance Imaging and Computed Tomography, also useful for the timing of the lesion, the autopsy, and the histological investigation, especially if performed with the use of immunohistochemical reactants against erythrocytes, leukocytes, and ischemic nerve cells. (4) Conclusions: The present review has made it possible to build an operational framework for the diagnosis and timing of cases of abusive retinal damage, but further research in the field is needed.

Abusive Head Trauma Animal Models: Focus on Biomarkers

Abusive head trauma (AHT) is a serious traumatic brain injury and the leading cause of death in children younger than 2 years. The development of experimental animal models to simulate clinical AHT cases is challenging. Several animal models have been designed to mimic the pathophysiological and behavioral changes in pediatric AHT, ranging from lissencephalic rodents to gyrencephalic piglets, lambs, and non-human primates. These models can provide helpful information for AHT, but many studies utilizing them lack consistent and rigorous characterization of brain changes and have low reproducibility of the inflicted trauma. Clinical translatability of animal models is also limited due to significant structural differences between developing infant human brains and the brains of animals, and an insufficient ability to mimic the effects of long-term degenerative diseases and to model how secondary injuries impact the development of the brain in children. Nevertheless, animal models can provide clues on biochemical effectors that mediate secondary brain injury after AHT including neuroinflammation, excitotoxicity, reactive oxygen toxicity, axonal damage, and neuronal death. They also allow for investigation of the interdependency of injured neurons and analysis of the cell types involved in neuronal degeneration and malfunction. This review first focuses on the clinical challenges in diagnosing AHT and describes various biomarkers in clinical AHT cases. Then typical preclinical biomarkers such as microglia and astrocytes, reactive oxygen species, and activated N-methyl-D-aspartate receptors in AHT are described, and the value and limitations of animal models in preclinical drug discovery for AHT are discussed.

Correlations of intracranial pathology and cause of head injury with retinal hemorrhage in infants and toddlers: A multicenter, retrospective study by the J-HITs (Japanese Head injury of Infants and Toddlers study) group

INTRODUCTION

In infants who have suffered head trauma there are two possible explanations for retinal hemorrhage (RH): direct vitreous shaking and occurrence in association with intracranial lesions. Which possibility is more plausible was examined.

MATERIAL AND METHODS

This multicenter, retrospective study reviewed the clinical records of children younger than four years with head trauma who had been diagnosed with any findings on head computed tomography (CT) and/or magnetic resonance imaging (MRI). Of 452 cases, 239 underwent an ophthalmological examination and were included in this study. The relationships of RH with intracranial findings and the cause of injury were examined.

RESULT

Odds ratios for RH were significant for subdural hematoma (OR 23.41, p = 0.0004), brain edema (OR 5.46, p = 0.0095), nonaccidental (OR 11.26, p<0.0001), and self-inflicted falls (OR 6.22, p = 0.0041).

CONCLUSION

Although nonaccidental, brain edema and self-inflicted falls were associated with RH, subdural hematoma was most strongly associated with RH.

The Eyes Have It: How Critical are Ophthalmic Findings to the Diagnosis of Pediatric Abusive Head Trauma?

Pediatric abusive head trauma (AHT), still colloquially known as shaken baby syndrome, is a leading cause of morbidity and mortality among infants. Controversy has grown surrounding this diagnosis, and the specificity of the clinical findings-subdural hemorrhage, cerebral edema, and retinal hemorrhages-has been challenged. A literature search of peer reviewed publications on PubMed pertaining to the history, clinical, and pathologic features of AHT was conducted using the terms "shaken baby syndrome," "non-accidental trauma," "abusive head trauma," "inflicted traumatic brain injury," "shaken impact syndrome," and "whiplash shaken infant syndrome." Focus was placed on articles discussing ophthalmic findings in AHT. Retinal hemorrhages-particularly those that are too numerous to count, occurring in all layers of the retina (preretinal, intraretinal, subretinal), covering the peripheral pole and extending to the ora serrata, and accompanied by retinoschisis and other ocular/periocular hemorrhages-are highly suggestive of AHT, particularly in the absence of otherwise explained massive accidental trauma. Although the diagnosis has grown in controversy in recent years, AHT has well-documented clinical and pathologic findings across a large number of studies.

Animal models of pediatric abusive head trauma

BACKGROUND

Abusive head trauma (AHT), previously known as the shaken baby syndrome, is a severe and potentially fatal form of traumatic brain injury in infant children who have been shaken, and sometimes also sustained an additional head impact. The clinical and autopsy findings in AHT are not pathognomonic and, due to frequent obfuscation by perpetrators, the circumstances surrounding the alleged abuse are often unclear. The concept has evolved that the finding of the combination of subdural hemorrhage, brain injury, and retinal hemorrhages ("the triad") is the result of shaking of an infant ("shaken baby syndrome") and has led to the ongoing controversy whether shaking alone is able to generate sufficient force to produce these lesions.

OBJECTIVE

In an attempt to investigate whether shaking can engender this lesion triad, animal models have been developed in laboratory rodents and domestic animal species. This review assesses the utility of these animal models to reliably reproduce human AHT pathology and evaluate the effects of shaking on the immature brain.

RESULTS

Due largely to irreconcilable anatomic species differences between these animal brains and human infants, and a lack of resemblance of the experimental head shaking induced by mechanical devices to real-world human neurotrauma, no animal model has been able to reliably reproduce the full range of neuropathologic AHT changes.

CONCLUSION

Some animal models can simulate specific brain and ophthalmic lesions found in human AHT cases and provide useful information on their pathogenesis. Moreover, one animal model demonstrated that shaking of a freely mobile head, without an additional head impact, could be lethal, and produce significant brain pathology.

Reproducibility and Characterization of Head Kinematics During a Large Animal Acceleration Model of Traumatic Brain Injury

Acceleration parameters have been utilized for the last six decades to investigate pathology in both human and animal models of traumatic brain injury (TBI), design safety equipment, and develop injury thresholds. Previous large animal models have quantified acceleration from impulsive loading forces (i.e., machine/object kinematics) rather than directly measuring head kinematics. No study has evaluated the reproducibility of head kinematics in large animal models. Nine (five males) sexually mature Yucatan swine were exposed to head rotation at a targeted peak angular velocity of 250 rad/s in the coronal plane. The results indicated that the measured peak angular velocity of the skull was 51% of the impulsive load, was experienced over 91% longer duration, and was multi- rather than uni-planar. These findings were replicated in a second experiment with a smaller cohort (N = 4). The reproducibility of skull kinematics data was mostly within acceptable ranges based on published industry standards, although the coefficients of variation (8.9% for peak angular velocity or 12.3% for duration) were higher than the impulsive loading parameters produced by the machine (1.1 vs. 2.5%, respectively). Immunohistochemical markers of diffuse axonal injury and blood-brain barrier breach were not associated with variation in either skull or machine kinematics, suggesting that the observed levels of variance in skull kinematics may not be biologically meaningful with the current sample sizes. The findings highlight the reproducibility of a large animal acceleration model of TBI and the importance of direct measurements of skull kinematics to determine the magnitude of angular velocity, refine injury criteria, and determine critical thresholds.

Charting the Globe: How Technologies Have Affected Our Understanding of Retinal Findings in Abusive Head Trauma/Shaken Baby Syndrome

Purpose: Ocular findings such as retinal hemorrhages are common in abusive head trauma (AHT). Binocular indirect ophthalmoscopy has been the standard for assessing the eyes of children who are victims of AHT. However, technological advances have changed our understanding of retinal findings in AHT.Methods: Literature review on AHT - retinal findings, imaging technologies, models of representation, and telemedicine applications.Results: Many studies suggest vitreoretinal traction from repetitive acceleration-deceleration shearing forces during shaking plays an important role in the development of retinal findings in AHT. This is further supported by different imaging modalities [optical coherence tomography (OCT); magnetic resonance imaging (MRI); fluorescein angiography (FA)] and models of representation (animal and mechanical models; finite element analysis).Conclusion: Emerging technologies have augmented our diagnostic abilities, enhanced our understanding regarding the pathophysiology of retinal findings, and strengthened the link between vitreoretinal traction and ocular pathology in AHT. Telemedicine is also starting to play an important role in AHT.

Determining the Tractional Forces on Vitreoretinal Interface Using a Computer Simulation Model in Abusive Head Trauma

PURPOSE

Abusive head trauma (AHT) is the leading cause of infant death and long-term morbidity from injury. The ocular consequences of AHT are controversial, and the pathophysiology of retinal research findings is still not clearly understood. It has been postulated that vitreoretinal traction plays a major role in the retinal findings. A computer simulation model was developed to evaluate the vitreoretinal traction and determine whether the distribution of forces in different layers and locations of the retina can explain the patterns of retinal hemorrhage (RH) seen in AHT.

DESIGN

Computer simulation model study.

METHODS

A computer simulation model of the pediatric eye was developed to evaluate preretinal, intraretinal, and subretinal stresses during repetitive shaking. This model was also used to examine the forces applied to various segments along blood vessels.

RESULTS

Calculated stress values from the computer simulation ranged from 3-16 kPa at the vitreoretinal interface through a cycle of shaking. Maximal stress was observed at the periphery of the retina, corresponding to areas of multiple vessel bifurcations, followed by the posterior pole of the retina. Stress values were similar throughout all 3 layers of the retina (preretinal, intraretinal, and subretinal layers).

CONCLUSIONS

Ocular manifestations from AHT revealed unique retinal characteristics. The model predicted stress patterns consistent with the diffuse retinal hemorrhages (RH) typically found in the posterior pole and around the peripheral retina in AHT. This computer model demonstrated that similar stress forces were produced in different layers of the retina, consistent with the finding that retinal hemorrhages are often found in multiple layers of the retina. These data can help explain the RH patterns commonly found in AHT.

Modeling Hypertension as a Contributor to Retinal Hemorrhaging from Abusive Head Trauma

Retinal hemorrhaging (RH) is indicative and prevalent in abusive head trauma (AHT)—yet the direct cause of the RH from AHT is unknown. Our hypothesis is that RH in AHT is the combination of shaking forces and hypertension. This combination of effects explains why RH is not normally observed in common childhood accidents but is nearly exclusively observed in AHT. An experimental model using porcine eyes was designed to ascertain the required pressure change for sudden RH and, via a computer model, the subsequent stress increase in blood vessels. The porcine eyes were cannulated via the maxillary artery and pressurized until perfusion and RH were observed. Fluid was injected into the head with a computer-controlled continuous flow syringe pump; video of the fundus was recorded during perfusion; and the pressure of the fluid entering the eye was recorded as well. A computer model was created in COMSOL to simulate loading from hypertension, shaking, and the combination of the forces. This model was validated via experimental data collected from the porcine model. It was found that hypertension or shaking alone did not cause an increase in stress required to cause RH. But when the loading of shaking and hypertension was combined, as would occur in AHT, the stress increases were greater than those extrapolated from the porcine model and would cause RH.

Modeling of inflicted head injury by shaking trauma in children: what can we learn? : Part I: A systematic review of animal models

Inflicted blunt force trauma and/or repetitive acceleration-deceleration trauma in infants can cause brain injury. Yet, the exact pathophysiologic mechanism with its associated thresholds remains unclear. In this systematic review an overview of animal models for shaking trauma and their findings on tissue damage will be provided. A systematic review was performed in MEDLINE and Scopus for articles on the simulation of inflicted head injury in animals. After collection, the studies were independently screened by two researchers for title, abstract, and finally full text and on methodological quality. A total of 12 articles were included after full-text screening. Three articles were based on a single study population of 13 lambs, by one research group. The other 9 articles were separate studies in piglets, all by a single second research group. The lamb articles give some information on tissue damage after inflicted head injury. The piglet studies only provide information on consequences of a single plane rotational movement. Generally, with increasing age and weight, there was a decrease of axonal injury and death. Future studies should focus on every single step in the process of a free movement in all directions, resembling human infant shaking. In part II of this systematic review biomechanical models will be evaluated.

Biomechanical Studies on Patterns of Cranial Bone Fracture Using the Immature Porcine Model

This review was prepared for the American Society of Mechanical Engineers Lissner Medal. It specifically discusses research performed in the Orthopaedic Biomechanics Laboratories on pediatric cranial bone mechanics and patterns of fracture in collaboration with the Forensic Anthropology Laboratory at Michigan State University. Cranial fractures are often an important element seen by forensic anthropologists during the investigation of pediatric trauma cases litigated in courts. While forensic anthropologists and forensic biomechanists are often called on to testify in these cases, there is little basic science developed in support of their testimony. The following is a review of studies conducted in the above laboratories and supported by the National Institute of Justice to begin an understanding of the mechanics and patterns of pediatric cranial bone fracture. With the lack of human pediatric specimens, the studies utilize an immature porcine model. Because much case evidence involves cranial bone fracture, the studies described below focus on determining input loading based on the resultant bone fracture pattern. The studies involve impact to the parietal bone, the most often fractured cranial bone, and begin with experiments on entrapped heads, progressing to those involving free-falling heads. The studies involve head drops onto different types and shapes of interfaces with variations of impact energy. The studies show linear fractures initiating from sutural boundaries, away from the impact site, for flat surface impacts, in contrast to depressed fractures for more focal impacts. The results have been incorporated into a “Fracture Printing Interface (FPI),” using machine learning and pattern recognition algorithms. The interface has been used to help interpret mechanisms of injury in pediatric death cases collected from medical examiner offices. The ultimate aim of this program of study is to develop a “Human Fracture Printing Interface” that can be used by forensic investigators in determining mechanisms of pediatric cranial bone fracture.

Cyclic Head Rotations Produce Modest Brain Injury in Infant Piglets

Repetitive back-and-forth head rotation from vigorous shaking is purported to be a central mechanism responsible for diffuse white matter injury, subdural hemorrhage, and retinal hemorrhage in some cases of abusive head trauma (AHT) in young children. Although animal studies have identified mechanisms of traumatic brain injury (TBI) associated with single rapid head acceleration-decelerations at levels experienced in a motor vehicle crash, few experimental studies have investigated TBI from repetitive head rotations. The objective of this study was to systematically investigate the post-injury pathological time-course after cyclic, low-velocity head rotations in the piglet and compare them with single head rotations. Injury metrics were the occurrence and extent of axonal injury (AI), extra-axial hemorrhage (EAH), red cell neuronal/axonal change (RCNAC), and ocular injury (OI). Hyperflexion/extension of the neck were purposefully avoided in the study, resulting in unscaled angular accelerations at the lower end of reported infant surrogate shaking kinematics. All findings were at the mild end of the injury spectrum, with no significant findings at 6 h post-injury. Cyclic head rotations, however, produced modest AI that significantly increased with time post-injury (p < 0.035) and had significantly greater amounts of RCNAC and EAH than noncyclic head rotations after 24 h post-injury (p < 0.05). No OI was observed. Future studies should investigate the contributions of additional physiological and mechanical features associated with AHT (e.g., hyperflexion/extension, increased intracranial pressure from crying or thoracic compression, and more than two cyclic episodes) to enhance our understanding of the causality between proposed mechanistic factors and AHT in infants.

A Porcine Model of Traumatic Brain Injury via Head Rotational Acceleration

Unique from other brain disorders, traumatic brain injury (TBI) generally results from a discrete biomechanical event that induces rapid head movement. The large size and high organization of the human brain makes it particularly vulnerable to traumatic injury from rotational accelerations that can cause dynamic deformation of the brain tissue. Therefore, replicating the injury biomechanics of human TBI in animal models presents a substantial challenge, particularly with regard to addressing brain size and injury parameters. Here we present the historical development and use of a porcine model of head rotational acceleration. By scaling up the rotational forces to account for difference in brain mass between swine and humans, this model has been shown to produce the same tissue deformations and identical neuropathologies found in human TBI. The parameters of scaled rapid angular accelerations applied for the model reproduce inertial forces generated when the human head suddenly accelerates or decelerates in falls, collisions, or blunt impacts. The model uses custom-built linkage assemblies and a powerful linear actuator designed to produce purely impulsive non-impact head rotation in different angular planes at controlled rotational acceleration levels. Through a range of head rotational kinematics, this model can produce functional and neuropathological changes across the spectrum from concussion to severe TBI. Notably, however, the model is very difficult to employ, requiring a highly skilled team for medical management, biomechanics, neurological recovery, and specialized outcome measures including neuromonitoring, neurophysiology, neuroimaging, and neuropathology. Nonetheless, while challenging, this clinically relevant model has proven valuable for identifying mechanisms of acute and progressive neuropathologies as well as for the evaluation of noninvasive diagnostic techniques and potential neuroprotective treatments following TBI.

The optic nerve sheath hemorrhage is a non-specific finding in cases of suspected child abuse

In young infants, the triad consisting of acute encephalopathy, retinal hemorrhages, and a subdural hematoma is a nonspecific finding. It has traumatic and non-traumatic etiologies. The triad may be found among a vast spectrum of natural diseases. Optic nerve sheath hemorrhage in infants is typically detected at autopsy. It is a nonspecific finding that can be found in traumatic and non-traumatic etiologies. Neither the triad nor the ONSH are pathognomonic for an abusive head injury. Opposite to the triad, the spectrum of non-traumatic etiologies of ONSH is limited. In infants ONSH rarely occurs in spontaneous subarachnoidal hemorrhage or in infectious conditions. Our results show that the clinical significance of the optic nerve sheath hemorrhage in the forensic work-up of fatal cases of alleged abusive head injury is its limited differential diagnosis. Only after careful differential diagnosis ONSH may contribute to the diagnosis of AHT. However, the main limitation of our study is the sampling bias, as the eyes are usually removed when abusive head trauma is suspected.

The eye in child abuse: key points on retinal hemorrhages and abusive head trauma

This review presents an up-to-date overview of ocular injuries resulting from child abuse, with a spotlight on abusive head trauma. Retinal hemorrhage is a principle finding of inflicted head trauma. The specific pattern of hemorrhages holds valuable diagnostic information, which can help to guide multidisciplinary assessments of the likelihood of abuse. Indirect ophthalmoscopy through dilated pupils by an ophthalmologist is necessary for adequate examination and documentation of retinal findings. Initial pediatrician evaluation of the eye and indications for ophthalmological consultation are reviewed. Focus is then placed upon understanding retinal hemorrhage patterns, their diagnostic significance and likely pathophysiological mechanisms. The differential diagnosis of retinal hemorrhage in young children is discussed, highlighting key distinctions among retinal hemorrhage patterns, severity and frequencies, as well as other ocular findings. The most common cause of retinal hemorrhage in an infant is trauma, and most other causes can be identified by considering the hemorrhage pattern, ocular or systemic signs and the results of laboratory and imaging tests, when indicated.

Negative g-Force Ocular Trauma Caused by a Rapidly Spinning Carousel

We present a case of a 10-year-old boy who presented with bilateral diffuse subconjunctival hemorrhages after spinning rapidly on a carousel attached to an electrical scooter. We present his clinical course and discuss the physics and pathophysiology of this unique mechanism of ocular trauma.

Patterns of retinal hemorrhage associated with increased intracranial pressure in children

OBJECTIVE

Raised intracranial pressure (ICP) has been proposed as an isolated cause of retinal hemorrhages (RHs) in children with suspected traumatic head injury. We examined the incidence and patterns of RHs associated with increased ICP in children without trauma, measured by lumbar puncture (LP).

METHODS

Children undergoing LP as part of their routine clinical care were studied prospectively at the Children's Hospital of Philadelphia and retrospectively at Nationwide Children's Hospital. Inclusion criteria were absence of trauma, LP opening pressure (OP) ≥ 20 cm of water (cm H2O), and a dilated fundus examination by an ophthalmologist or neuro-ophthalmologist.

RESULTS

One hundred children were studied (mean age: 12 years; range: 3-17 years). Mean OP was 35 cm H2O (range: 20-56 cm H2O); 68 (68%) children had OP >28 cm H2O. The most frequent etiology was idiopathic intracranial hypertension (70%). Seventy-four children had papilledema. Sixteen children had RH: 8 had superficial intraretinal peripapillary RH adjacent to a swollen optic disc, and 8 had only splinter hemorrhages directly on a swollen disc. All had significantly elevated OP (mean: 42 cm H2O).

CONCLUSIONS

Only a small proportion of children with nontraumatic elevated ICP have RHs. When present, RHs are associated with markedly elevated OP, intraretinal, and invariably located adjacent to a swollen optic disc. This peripapillary pattern is distinct from the multilayered, widespread pattern of RH in abusive head trauma. When RHs are numerous, multilayered, or not near a swollen optic disc (eg, elsewhere in the posterior pole or in the retinal periphery), increased ICP alone is unlikely to be the cause.

Educational paper : retinal haemorrhages in abusive head trauma in children

Retinal haemorrhages are an important component of the clinical effects of non-accidental head injuries which have significant visual morbidity. Their importance extends into the legal investigations of carers of children with subdural haemorrhages and encephalopathy who are suspected of having been non-accidentally injured. The vital precision in diagnosis relies not just on the presence of retinal haemorrhages but on the severity, extent, bilaterality and their location in the retina. Inadequate documentation of ophthalmological clinical findings and too short a follow-up to allow proper assessment of severity each give rise to difficulties for both expert witnesses and the courts.

Retinal hemorrhage in abusive head trauma

Retinal hemorrhage is a cardinal manifestation of abusive head trauma. Over the 30 years since the recognition of this association, multiple streams of research, including clinical, postmortem, animal, mechanical, and finite element studies, have created a robust understanding of the clinical features, diagnostic importance, differential diagnosis, and pathophysiology of this finding. The importance of describing the hemorrhages adequately is paramount in ensuring accurate and complete differential diagnosis. Challenges remain in developing models that adequately replicate the forces required to cause retinal hemorrhage in children. Although questions, such as the effect of increased intracranial pressure, hypoxia, and impact, are still raised (particularly in court), clinicians can confidently rely on a large and solid evidence base when assessing the implications of retinal hemorrhage in children with concern of possible child abuse.