Animal models of pediatric abusive head trauma

Retinodural haemorrhage of infancy, abusive head trauma, shaken baby syndrome: The continuing quest for evidence

The shaken baby syndrome was originally proposed in the 1970s without any formal scientific basis. Once data generated by scientific research was available, the hypothesis became controversial. There developed essentially two sides in the debate. One side claimed that the clinical triad of subdural haemorrhage, retinal haemorrhage, and encephalopathy, or its components, is evidence that an infant has been shaken. The other side stated this is not a scientifically valid proposal and that alternative causes, such as low falls and natural diseases, should be considered. The controversy continues, but the contours have shifted. During the last 15 years, research has shown that the triad is not sufficient to infer shaking or abuse and the shaking hypothesis does not meet the standards of evidence-based medicine. This raises the issue of whether it is fit for either clinical practice or for the courtroom; evidence presented to the courts must be unassailable. WHAT THIS PAPER ADDS: There is insufficient scientific evidence to assume that an infant with the triad of subdural haemorrhage (SDH), retinal haemorrhage, and encephalopathy must have been shaken. Biomechanical and animal studies have failed to support the hypothesis that shaking can cause SDH and retinal haemorrhage. Patterns of retinal haemorrhage cannot distinguish abuse. Retinal haemorrhages are commonly associated with extracerebral fluid collections (including SDH) but not with shaking. Infants can develop SDH, retinal haemorrhage, and encephalopathy from natural diseases and falls as low as 1 foot. The shaking hypothesis and the literature on which it depends do not meet the standards of evidence-based medicine.

Clinical and Forensic Investigation Protocols for Diagnosing Abusive Head Trauma: A Literature Review

Abusive head trauma (AHT) represents a very serious global public health problem. Prevention of these episodes is essential to reduce the morbidity and mortality of this phenomenon. All healthcare professionals should be able to recognize the signs of abuse. However, diagnosis is very complex as the signs are often blurred and cannot be recognized with certainty without carrying out adequate instrumental investigations. It has been calculated that approximately one-third of AHT cases remain undetected and require more than one medical visit to be correctly interpreted and diagnosed. On the other hand, the literature has recently also emphasized the problems related to possible false diagnoses of abuse and the numerous family and personal repercussions that follow from this issue. For these reasons, correct and timely recognition is essential to avoid the risk of recurrence of AHT and to start proper forensic investigations, in order to identify the offender or exonerate a suspect. The present work explores the most recent evidence of recent years in the field of AHT diagnostics through a literature review. The purpose of this article is to provide forensic pathologists with clear tools for diagnosis based on the literature. To this end, the review suggests clinical and forensic protocols aimed at the timely diagnosis of AHT in order to prevent abuse from remaining undetected.

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.