Severe Retinal Hemorrhages with Retinoschisis in Infants are Not Pathognomonic for Abusive Head Trauma

Evidence for significant misdiagnosis of abusive head trauma in pediBIRN data

Independently witnessed events are used as a reference standard to robustly categorize accidental or non-abusive head trauma (non-AHT) cases in the pediBIRN data set of acutely symptomatic infants with closed head injuries. Findings in such independently witnessed non-AHT cases are compared to findings in cases that were diagnosed as AHT but were not independently witnessed. The data shows that 14% of independently witnessed non-AHT cases are misdiagnosed as AHT, and that risk factors for misdiagnosis include acute encephalopathy, bilateral or interhemispheric SDH, and/or severe retinal hemorrhages, findings that are commonly associated with AHT. The data also shows that "dense retinal hemorrhages extending to the periphery" are not highly suggestive of AHT, as they also occur in independently witnessed non-AHT cases.

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.

Exploring the Vitreoretinal Interface: a Key Instigator of Unique Retinal Hemorrhage Patterns in Pediatric Head Trauma

Purpose

Various types of trauma can cause retinal hemorrhages in children, including accidental and nonaccidental head trauma. We used animal eyes and a finite element model of the eye to examine stress patterns produced during purely linear and angular accelerations, along with stresses attained during simulated repetitive shaking of an infant.

Methods

Using sheep and primate eyes, sclerotomy windows were created by removing the sclera, choroid, and retinal pigment epithelium to expose the retina. A nanofiber square was glued to a 5 mm² area of retina. The square was pulled and separated from vitreous while force was measured. A finite element model of the pediatric eye was used to computationally measure tension stresses during shaking.

Results

In both sheep and primate eyes, tension stress required for separation of retina from vitreous range from 1 to 5 kPa. Tension stress generated at the vitreoretinal interface predicted by the computer simulation ranged from 3 to 16 kPa during a cycle of shaking. Linear acceleration generated lower tension stress than angular acceleration. Angular acceleration generated maximal tension stress along the retinal vasculature. Linear acceleration produced more diffuse force distribution centered at the poster pole.

Conclusions

The finite element model predicted that tension stress attained at the retina during forcible shaking of an eye can exceed the minimum threshold needed to produce vitreoretinal separation as measured in animal eyes. Furthermore, the results show that movements that involve significant angular acceleration produce strong stresses localized along the vasculature, whereas linear acceleration produces weaker, more diffuse stress centered towards the posterior pole of the eye.

The legal challenges to the diagnosis of shaken baby syndrome or how to counter 12 common fake news

BACKGROUND

The shaken baby syndrome (SBS) is a common cause of severe traumatic lesions in infants. Although well established for almost five decades, SBS and its diagnosis are becoming more and more aggressively challenged in courts. These challenges feed on the scientific debate and controversies regarding the pathophysiology and the differential diagnoses, scientific uncertainty being readily exploited by specialized barristers.

MATERIAL AND METHODS

In the present review, we analyze the most common challenges to the concept of SBS and its diagnosis, as well as the scientific evidence available to counter these challenges, the differential diagnoses, and how SBS can be diagnosed with confidence.

RESULTS

We found that the pathophysiology of SBS is well documented, with stereotyped descriptions by perpetrators, in good correlation with experimental studies and computer models. SBS is a well-defined clinico-pathological entity with a characteristic constellation of lesions; with a rigorous evaluation protocol, its diagnosis can be made rapidly and with excellent accuracy beyond a reasonable doubt.

CONCLUSION

It is important that medical experts master an extensive knowledge regarding the pathophysiology of the lesions of SBS, in particular infantile subdural hematomas, as well as other CSF-related conditions. This emphasizes the role that pediatric neurosurgeons should play in the clinical and medicolegal management of these patients.

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.

Ocular and Intracranial MR Imaging Findings in Abusive Head Trauma

Abusive head trauma (AHT) is a form of inflicted head injury. AHT is more frequent in 2-year-old or younger children. It is an important cause of neurological impairment and the major cause of death from head trauma in this age group. Brain magnetic resonance imaging allows the depiction of retinal hemorrhages, injured bridging veins, and identifying and localizing extra- and intra-axial bleeds, contusions, lacerations, and strokes. The diagnosis of AHT is a multidisciplinary team effort which includes a careful evaluation of social, clinical, laboratory, and radiological findings. Notwithstanding, the introduction in the current clinical practice of high-resolution techniques is adding forensic evidence to the recognition of AHT.