Abusive head trauma: experience improves diagnosis

Age effects on the mechanical behavior of human cerebral bridging veins

BACKGROUND

It is well established that the probability of occurrence of acute subdural hematomas in traumatic situations increases with age, since the main cause of such hematomas is the mechanical failure of cerebral blood vessels known as bridging veins. This research aims to determine whether there is an effect of age on the mechanical properties of these cerebral vessels, because previous reported studies were conflicting.

METHODS

This study used mechanical tests blue of cerebral bridging veins from post-mortem human subjects. In particular, a series of in vitro tensile tests were performed on a balanced sample of bridging veins from different human subjects.

FINDINGS

The mechanical parameters measured from the tests were analyzed by means of regression analysis looking for age related effects. The results show that there is a significant effect on both the ultimate strength, maximum stress and strain that the specimens can withstand. The quantitative analysis shows reductions of nearly 50% in ultimate stress, and almost 35% in ultimate strain.

INTERPRETATION

Mechanical deterioration of the mechanical strength of cerebral blood vessels seems to be a major factor involved in the increase of frequency of acute subdural hematoma in elderly people in a wide range of life-threatening traumatic situations.

Abusive head trauma, protocols, and legal concerns in a South American Country

The abusive head trauma (AHT) is a form of child abuse and is a frequent entity all over de world. It is particularly unique among medical diagnoses because of the legal implications imposed by the diagnosis. Therefore, it has been the subject of much legal controversy over the decades. Knowledge of the clinical signs and imaging findings of abusive head trauma is vitally important for early diagnosis. An oriented anamnesis, as well as a complete physical examination and obtaining adequate images of the central nervous system, play a significant role in confirming the presumptive diagnosis. The interdisciplinary approach (pediatricians, neurosurgeons, neuroradiologists, social workers, and other specialists) is the key in the management of these patients. The purpose of this article is to familiarize the pediatric neurosurgeon with some of the more common medicolegal issues surrounding AHT as well as to discuss legal commitments and ethical obligations of the neurosurgeon in Argentina (South America) based on 2 clinical cases.

Neonatal Abusive Head Trauma without External Injuries: Suspicion Improves Diagnosis

The term “shaken baby syndrome” has been replaced by “abusive head trauma (AHT)” based on the mechanism of injury. The reported mortality rate of AHT ranges from 10% to 30%. Up to two-thirds of survivors suffer from serious long-term disabilities. Thus, an expeditious and accurate diagnosis is crucial to prevent further abuse that might result in death or serious disabilities. It remains a challenge for physicians to diagnose AHT when parents do not give a history of trauma in preverbal infants without any external signs. Here, we report a case of a 14-day-old boy who presented with a febrile convulsion without evident external injuries nor history of trauma according to his parents. He was diagnosed with AHT based on MRI findings of subacute subdural hemorrhage, multiple cortical hemorrhages, cerebral edema, and diffuse axonal injury. In conclusion, health care providers should keep in mind that the history of trauma provided by the parents or caregivers might not always be true and that reasonable suspicion of abuse is the most important in the diagnosis of AHT, although neuroimaging plays a pivotal role. Reasonable suspicion of AHT in combination with a thorough physical examination, neuroimaging, and skilled neuroradiologist can improve diagnosis and help victims in a timely manner.

Imaging of Abusive Head Trauma : A Radiologists' Perspective

Abusive head trauma (AHT) is the most common and serious form of child abuse and a leading cause of traumatic death in infants and young children. The biomechanics of head injuries include violent shaking, blunt impact, or a combination of both. Neuroimaging plays an important role in recognizing and distinguishing abusive injuries from lesions from accidental trauma or other causes, because clinical presentation and medical history are often nonspecific and ambiguous in this age group. Understanding common imaging features of AHT can increase recognition with high specificity for AHT. In this review, we discuss the biomechanics of AHT, imaging features of AHT, and other conditions that mimic AHT.

Mild abusive head injury: diagnosis and pitfalls

Clinicians often miss making the diagnosis of abusive head injury in infants and toddlers who present with mild, non-specific symptoms such as vomiting, fussiness, irritability, trouble sleeping and eating, and seizure. If abusive head injury is missed, the child is likely to go on to experience more severe injury. An extensive review of the medical literature was done to summarize what is known about missed abusive head injury and about how these injuries can be recognized and appropriately evaluated. The following issues will be addressed: the definition of mild head injury, problems encountered when clinicians evaluated mildly ill young children with non-specific symptoms, the risk of missing the diagnosis of mild abusive head trauma, the risks involved in subjecting infants and young children to radiation and/or sedation required for neuroimaging studies, imaging options for suspected neurotrauma in children, clinical prediction rules for evaluating mild head injury in children, laboratory tests than can be helpful in diagnosing mild abusive head injury, history and physical examination when diagnosing or ruling out mild abusive head injury, social and family factors that could be associated with abusive injuries, and interventions that could improve our recognition of mild abusive head injuries. Relevant literature is described and evaluated. The conclusion is that abusive head trauma remains a difficult diagnosis to identify in mildly symptomatic young children.

Mechanical Behavior of Blood Vessels: Elastic and Viscoelastic Contributions

The mechanical properties of the cerebral bridging veins (CBVs) were studied using advanced microtensile equipment. Detailed high-quality curves were obtained at different strain rates, showing a clearly nonlinear stress-strain response. In addition, the tissue of the CBVs exhibits stress relaxation and a preconditioning effect under cyclic loading, unequivocal indications of viscoelastic behavior. Interestingly, most previous literature that conducts uniaxial tensile tests had not found significant viscoelastic effects in CBVs, but the use of more sensitive tests allowed to observe the viscoelastic effects. For that reason, a careful mathematical analysis is presented, clarifying why in uniaxial tests with moderate strain rates, it is difficult to observe any viscoelastic effect. The analysis provides a theoretical explanation as to why many recent studies that investigated mechanical properties did not find a significant viscoelastic effect, even though in other circumstances, the CBV tissue would clearly exhibit viscoelastic behavior. Finally, this study provides reference values for the usual mechanical properties, as well as calculations of constitutive parameters for nonlinear elastic and viscoelastic models that would allow more accurate numerical simulation of CBVs in Finite Element-based computational models in future works.