Abusive head trauma or shaken baby syndrome

The shaken baby syndrome was on the rise during the COVID-19 pandemic lockdown. The Chair has therefore focused on this form of abuse.

The term “shaken baby syndrome” (SBS) has long been used to refer to head injuries inflicted on infants as a result of shaking or bumping. Since 2009, the scientific community has recommended using the term “abusive head trauma” (AHT), which is considered more appropriate because it does not limit the causes of the trauma to shaking alone.

The symptoms of AHT are variable in intensity and non-specific. These may include vomiting sometimes mistakenly attributed to gastroenteritis, anorexia, irritability or abnormal pallor, and even coma with cardiorespiratory arrest. This syndrome is characterized by the presence of a diffuse subdural hematoma, due to a tearing of the bridging veins connecting the cerebral cortex and the venous sinuses of young infants. These inflicted intracranial injuries may also be accompanied by spinal injuries. 

This type of head injury is caused by violent shaking of the child, whether or not associated with shocks. Often, this type of violence occurs when the perpetrator, exasperated by the child's crying, grabs the child by the chest and shakes him. AHT is the leading cause of fatal head injury in children under 2 years of age because of their fragile bodies.

There are many risk factors for AHT. Risk factors related to the child include male gender, prematurity or perinatal medical complications, mother-infant separation in the neonatal period, multiple or closely spaced pregnancies, unwanted pregnancy, inconsolable crying, sleep disorders, eating disorders, previous social service interventions. Perpetrators often have a significant lack of understanding of the child's needs, skills and normal behaviors. These violences can occur in any socio-economic environment, but precariousness and social or family isolation increase the risk.

Untreated and repeated abuse can result in the death of the child or severe neurocognitive damage. These sequelae may include motor or cognitive impairments, behavioral or attentional problems, visual impairment or epilepsy. These consequences may not be felt until years later, even into adulthood, impacting the child throughout their life. The repetition of shaking episodes is a key factor in the risk and severity of sequelae, and this repetition occurs most of the time (a shaken baby has been shaken on average 10 times). However, while repetition is an aggravating factor, a single episode of shaking may be sufficient to cause serious consequences. In all cases, early detection and diagnosis are very important to avoid recurrence, treat the child and protect him/her.

A multidisciplinary approach around the radiologist

To make this diagnosis, a multidisciplinary approach is necessary, especially a work in pair between the pediatrician and the radiologist. Depending on the lesions present in the child, other specialists also contribute with their expertise (visceral surgeon, orthopedist, ophthalmologist, etc.). AHT may be suspected, for example, if there is an inconsistent clinical history that varies among callers, if there is bruising, especially on the face, axillae, trunk, or neck of an infant who is not moving on his/her own, if macrocrania is evidenced by a head circumference curve showing abrupt alteration of growth velocity or if retinal hemorrhages are detected at the back of the eye.

Even without physical signs, the slightest suspicion of AHT should lead to a comprehensive medical imaging exploration. The radiologist then plays a central role in detecting evidence of potential abuse and in communicating the degree of certainty of this suspicion. Because the author never admits to violent shaking in the hospital, the radiologist is often the first specialist to make the diagnosis. In case of acute head trauma, a brain scan — or computed tomography (CT) scan — must necessarily be done. It is ideally completed by magnetic resonance imaging (MRI). This technique allows a complete evaluation of the neuraxis in case of suspicion or diagnosis of violent head trauma, especially in the presence of intracranial and cervical subdural hemorrhage and cervical ligament lesions. Finally, high-definition radiographs of the entire skeleton should also be performed, with all bone segments x-rayed separately. Each infant suspected of having AHT should be further evaluated for other conditions that may have similar findings (differential diagnosis).

This use of radiology raised some concerns about the potential danger of radiation on infants and the risk of cancer it could generate. Radiation exposure from CT scans may indeed present a small but potential cancer risk. The number of brain scans should therefore be limited to minimize this risk. However, until better evidence is available, a full skeletal survey of the child is necessary to diagnose AHT. While the use of magnetic resonance imaging may be preferred in cases of non-acute head trauma, a brain scan may be essential in the opposite case. The decision to proceed with a skeletal X-ray and/or a brain scan must be made after a thorough investigation, taking into account the child's examination history. It is therefore essential to have access to all the images taken since birth in order to be able to adapt and protect the child as best as possible. 

Infants who are close (especially siblings) to those with suspected AHT are at increased risk for maltreatment compared to the general infant population. These "contact children" must therefore be evaluated with the same care and rigor as the index case. In these asymptomatic close children, MRI can be used in the first place.

When AHT is diagnosed, reporting is decided after a comprehensive, multidisciplinary medical evaluation. In most countries, the report is made to the appropriate authorities, who then initiate the appropriate procedures to protect the child and investigate the abuse. Doctors may subsequently be called upon to act as witnesses or experts in court to provide technical advice to the magistrates.

Improving the diagnosis

Although the diagnosis of AHT is clearly defined, it continues to be refined in some areas. First, if the validity of the diagnosis is proven, the datation method of the shaking is still subject to controversy. Indeed, no imaging method allows precise dating of the lesions observed. It is however possible to indicate dating ranges, distinguishing recent lesions from older ones. To assess the age of a subdural hemorrhage, the joint use of MRI and CT scan is currently recommended, as MRI alone is too difficult to interpret. In addition, the child's entire history of clinical and radiological data should be carefully reviewed to provide the most accurate information possible about the date and recurrence of the trauma.

Another challenge is the standardization of international recommendations. Worldwide, AHT is increasingly recognized as a serious and deadly form of child maltreatment. However, organizational models of pediatric care vary across countries. In addition, the need to improve early diagnosis and management, to organize and report on surveillance, and to build an evidence base for prevention is recognized internationally. Therefore, there is a need to develop evidence-based guidelines for all countries in the world. This could help to overcome organizational and cultural differences that may slow down or hinder an appropriate procedure for the protection of abused infants.

A controversy that hurts the real victims

In recent years, the diagnosis of AHT has also been the subject of fierce controversy in court cases, some of which have received media attention. Alternative theories to explain the physical signs and symptoms of AHT have been proposed in court several times by denialist experts, questioning the diagnosis while testifying for the defense. This challenge is based on a Swedish meta-analysis, dating from 2017, which was nevertheless taken into account in the diagnostic procedure and in the recommendations. This challenge accuses researchers of attributing AHT to abuse without taking into account the possibility of an accidental or natural cause, even though the use of differential diagnoses is well recommended. It is therefore not scientists who are opposed to each other but the scientific consensus which is faced with an opposition that questions the legitimacy of the institutions. It is therefore not a scientific controversy but a socio-cultural controversy.

It should also be remembered that these denial experts are not neutral in some countries — common law — where each party has its own expert. This poses a problem of conflict of interest. In some other countries like France, the judicial expert is free and only allows to enlighten the magistrate. The diagnosis of maltreatment by this independent expert is therefore imposed on both parties and leaves no other possibility than to debate on the identity of the author of the maltreatment. This could lead the defense to attack the institutions themselves in order to protect their client(s). It is therefore necessary to ensure the ethics and compliance of expert testimony presented in civil and criminal cases involving AHT, especially when those experts are not neutral.

Finally, denialists tend to view the medical diagnosis as an accusation of abuse when it is a scientific finding, to be dissociated from the court verdict. The lack of material evidence to directly identify the perpetrator of the abuse facilitates and contributes to the denial of the abuse, but it does not negate the diagnosis. A diagnosis of AHT is indeed a medical conclusion, which involves many experts, and whose methodological rigor attests to its quality and validity. If a diagnosis of AHT is made, it means that there has been an episode of abuse, and it is then up to the magistrate to consider this.

The diagnosis of AHT plays an essential role in the fight against maltreatment and is the result of a long work of many researchers and experts. The HAS (Haute Autorité de Santé, French National Authority of Health) says that "to challenge the recommendations is to take the wrong subject". The real subject of this controversy is the difference in institutional functioning between countries and the question of the attribution of experts. Having a neutral expert being unfavorable to the defense pushes the latter to look for a way to disqualify him/her to remove his/her legitimacy. This issue, coupled with the denial that abuse generates in its perpetrators, is at the root of the controversy. However, the issue of protection of abused children should take precedence over the legal issue.

Gauthier Pichevin