Shaken baby syndrome (SBS) is a violent act of one form of child abuse, a non-accidental traumatic brain injury, which can cause neurologic, cognitive and other functional deficits. Retinal findings may be the only manifestation of SBS and then an eye specialist may initially recognise it. Cases should be thoroughly reviewed and prevention strategies developed to prevent further incidents. SBS has important medico-legal implications since the safety of child may be at stake.
Maltreatment of children, including non-accidental trauma, is problematic for children, families and care providers. Death may result in most serious cases due to maltreatment. SBS victims can present with wide range of symptoms, from generalised flu- like symptoms to unresponsiveness with risk of imminent death.
Signs of maltreatment may not be obvious. Detecting maltreatment requires careful attention of health care providers to ensure safety and care of victim, appropriate counselling of family, reporting of incidents to law enforcing agencies and prevention of repeat occurrences.
In 1946, Caffey described ‘whiplash shaken-baby syndrome’, a cluster of infantile subdural and subarachnoid haemorrhage, traction-type metaphyseal (wide portion or growth plate between epiphysis and narrow diaphysis) fracture, and retinal haemorrhage. This cluster of injuries was noted in many infants despite the lack of any external surface injury. Injuries were attributed to the developmental differences in infants head as compared with adults. Head comprises 25% of the total body weight in infants as compared to about 10% of total body weight in adults. In addition, infants have weak neck muscles, higher water content in brain matter and poor motor control rendering them more susceptible to injury through violent shaking.
Caffey J. On the theory and practice of shaking infants: its potential residual effects of permanent brain damage and mental retardation Am J Dis Child 1972; 124: 161-169.
Fulton, D.R. (2000). Shaken baby syndrome Critical care Nursing Quarterly, 23(2), 43-50.
American Academy of Paediatrics Committee on Child Abuse and Neglect (2001).Shaken baby syndrome: rotational cranial injuries-technical report. Paediatrics, 108(1), 206-210.
SBS victims may present with a wide variety of symptoms ranging from very mild to most critical of states.
Less severe cases:
Infant may present with parents or caretaker giving history of:-
- Poor feeding.
- Hypothermia or chills.
- Generalised failure to thrive.
- Increased sleeping.
- Failure to smile.
Symptoms may persist for days to weeks and are apparent to parent or caretaker as problematic and abnormal. However, care may or may not be sought. These fairly nonspecific features may be attributed to other causes of origin such as viral illness or colic and may resolve without the root-cause being even discovered.
More severe cases:
Infant may exhibit more life-threatening signs and symptoms of neurologic impairment. Following a violent shaking, immediate medical attention may or may not be sought. Parent or caretaker may put infant to bed anticipating that the child will recover. This may lead to missed opportunity for an early intervention.
Infant on presentation may show:-
- Difficulty in breathing including apnoea.
- Decreased level of consciousness.
- Bulging fontanelles (space where two sutures join to form a membrane covered soft spot in incompletely ossified skull) suggestive of raised intracranial pressure.
- Possible complete cardiovascular collapse requiring cardiopulmonary resuscitation (CPR).
Head injuries are the chief cause of traumatic death and leading cause of fatalities due to child abuse. Serious injuries in infants, notably those causing death, are rarely accidental unless there is a clear cause for the injuries, such as road traffic accident due to motor vehicle.
The majority of all cases of SBS are limited to children under three years of age. Shaking is generally attributed to the perpetrators level of tension and frustration, often generated by infants crying or irritability.
Risk factors for non-accidental injuries include:
- Young parents.
- Unstable family environment.
- Low socioeconomic status.
- Unrealistic child-rearing expectations.
- Infant prematurity or disability.
- Rigid attitudes and impulsivity.
- Feelings of inadequacy, isolation or depression.
- Negative childhood experiences including neglect or abuse.
- Crying of the infant or child may also play a role.
Additionally, parents or caretakers who have been involved in substance abuse and/or domestic violence may be at a higher risk for inflicting SBS. General demonstration of violence on television, radio and video games may also have a strong correlation with child abuse.
Parents may not be aware of the basic needs and normal development of their infant. Parents may have unrealistic expectations of the infant and a poor understanding of infant’s developmental level and abilities. According to Fulton, infants can spend up to 20% of their waking time crying. To the parents and caretakers, infant may seem inconsolable, and frustration can quickly build up. This may lead to physical shaking of infant in an attempt to calm the baby. Episodes of shaking are directly proportional to the degree of frustration felt by the parent or caretaker, and they become the perpetrators of abuse resulting in child fatality.
Risk factors of caretakers including babysitters, contributing to SBS, include their immaturity, young age and lack of life experience.
Situations suggesting possibility of abuse are:
- Infant presenting with a history that is not plausible or consistent.
- Presence of new adult partner in home.
- Delay in seeking medical attention.
- Absence of primary caretaker at the onset of injury or illness.
- Previous history or suspicion of abuse.
- Unexplained changes in neurological status.
- Unexplained shock and/ or cardiovascular collapse.
- Physical evidence of multiple injuries at varying stages of healing.
During shaking episode, rotational forces and differential movement of the brain in relation to surrounding tissues can tear the bridging vessels resulting in subdural haematoma. In addition, rotational forces lead to strains on the nerve axons in brain resulting in diffuse axonal injury. Head trauma seems to trigger a chain of events that result in cerebral hypoxia, cerebral oedema, raised intracranial pressure and vaso-occlusion. Displacing effect of subdural haematoma may lead to further ischaemia. In general, intracranial injury in absence of any significant accidental trauma is a significant indicator of inflicted injury.
Cervical spine epidural haematoma may take place in a significant proportion of abused infants, in addition to focal axonal injury of lower brainstem, superior spinal cord and spinal nerve roots. It is also thought that the effect of stretching at cranio-cervical junction during violent shaking may lead to apnoea, which causes diffuse hypoxia.
Mechanism of injury resulting in retinal haemorrhage is not conclusively known. Several mechanisms for retinal haemorrhages have been postulated such as acceleration-deceleration forces which cause damage via vitreo-macular traction. Other possible mechanisms include blunt head trauma, increased intracranial pressure due to trauma, sudden rise in intraocular pressure, hypoxia, extravasation of subarachnoid blood or coagulopathies.
The number, location, size and character of retinal haemorrhages varies from case to case, however, more severe haemorrhage may be associated with more serious brain injury.
The onset of symptoms is useful both in understanding prognosis as well as determining a cause. Timing can best be established by the history, clinical course and results of diagnostic imaging studies. When accurate, the clinical history is the most precise means for establishing a timeline. Elapsed time from the onset of injury can be estimated through the breakdown of intracranial haemoglobin as seen on diagnostic radiological studies.
The basis for the diagnosis of inflicted injury is a physical examination that conflicts with the history provided.
Three categories are identified for parent or caretaker explanations of infant injuries:-
- First category: First category include explanations of the child not being well including general malaise, fever, nausea, vomiting, having a fall or being dropped.
- Second category: Second category include explanations such as dangerous use of household objects, including appliances and toys, rough play, or no explanation of the events leading to injury. Over the time, parent or caretaker may or may not offer an explanation and may have used the time to construct a fictitious reason.
- Third category: Third category admits of shaking the infant. Very few caretakers do admit shaking, however, when they do, they often cite a history of attempting to console the child or prevent from choking on an object. Two to three explanations or stories are not uncommon.
One of the hallmark presentations of SBS is lack of external injuries. This may lead to a missed diagnosis even in most severe of the cases. Lack of obvious trauma may falsely minimise healthcare provider suspicion of possible maltreatment. In the event, any external injury is noted, it should be fully documented.
Repeated physical examinations may reveal further signs of trauma.
Evidence of other injuries including non-specific bruises, rib fractures, fractures of long bones, abdominal injuries and retinal haemorrhages should be assessed and documented. Forensic photography can aid in clear and accurate documentation of injuries.
An accurate diagnosis of retinal haemorrhage is crucial for appropriate medical care and for legal reasons.
- Ocular (eye) manifestations: A child with classic features of physical abuse should have detailed examination of eyes by an eye-specialist. A child may have signs such as:-
Periorbital trauma: Periorbital trauma like ecchymosis, lid oedema or orbital fractures.
Anterior segment trauma: Anterior segment trauma may show hyphaema (blood in anterior chamber of eye), iris prolapse, corneal laceration or cataract.
Posterior segment trauma: Posterior segment trauma may show vitreous haemorrhage, retinal haemorrhage, retinal detachment or avulsion of optic nerve. Macular retinoschisis (splitting of retina) may also occur.
It is somewhat controversial whether retinal haemorrhage in a child is a definitive sign of SBS. It is seen that large retinal haemorrhages are unusual in other forms of head injuries and are found in about 1% of cases with serious head trauma.
Retinal haemorrhages can be seen as early as 48 hours before any intracranial lesions can be found on CT scan or MRI of the brain.
Retinal haemorrhages are the cardinal manifestations of SBS which may be seen in 75-90% of cases. Classically, children have multilayered retinal haemorrhages i.e. pre-retinal, intra-retinal and sub-retinal. Retinal haemorrhages are too numerous to count and extend from posterior pole to the retinal periphery.
Shaking can lead to permanent vision impairment and may be even blindness in more severe cases.
There may be associated brain injury which may result in nystagmus (persistent, involuntary and repetitive to-and-fro movement of eyes), cortical (cortex of brain) blindness or cranial nerve palsies.
- Intracranial injury: The important diagnostic feature of SBS is the presence of intracranial injury in an infant. The most common injury is subdural haematoma. Other injuries may be epidural haematoma or subarachnoid haemorrhage.
- Traumatic brain injury (TBI): TBI occur when a sudden trauma, such as violent shaking, causes shearing injuries of the brain parenchyma. Clinical features of TBI can range from mild to severe, depending upon the extent of injury to the brain.
Mild signs are:-
-Changes in mood and memory.
Severe signs are:-
-Nausea and vomiting.
-Inability to arouse from sleep.
-Dilatation of one or both pupils.
-Loss of coordination.
-Refusal to nurse or eat.
- Bone fractures: Bone fractures can be found in half of all SBS cases, in spite of no apparent external injury. These fractures may take place anywhere in the body. Most common type of bony injury in SBS is the metaphyseal chip fracture. These fractures occur at the growth plate of bone due to uncontrolled swinging of extremities during shaking period. There may be rib fractures as well. In fatal cases, ribs are the most common site for fractures. In addition, whenever an infant presents with rib fractures, it is most often as a result of physical abuse. Posterior rib fractures are often due to antero-posterior thoracic compression such as that associated with a shaking episode.
- Radiological examination: Skeletal survey should include radiographs of hands, feet, long bones, skull, spine and ribs. This should be performed as soon as general condition of the child permits. Diagnostic yield of radiographs is further enhanced by follow-up skeletal survey conducted after two weeks.
- Scintigraphy: Scintigraphy is a nuclear medicine test which detects areas of increased or decreased bone metabolism, thus increase sensitivity of detecting rib fractures. Scintigraphy is of particular use if the child has to be discharged to a potentially unsafe environment, prior to two week follow up skeletal survey.
- Computed tomography (CT scan): CT scan has primary role in imaging evaluation of a child with TBI. CT scan can detect injuries requiring immediate attention. Initial CT scan should be performed without contrast and is the procedure of choice for demonstrating acute haemorrhage, including that involving subarachnoid space. CT scan should be repeated after a period of time or if there is rapid change in neurologic signs.
- Magnetic resonance imaging (MRI): MRI optimizes detection and assessment of intracranial injury including parenchymal haemorrhage, contusions, oedema and shearing injuries. MRI is also sensitive for detecting significant spinal injury and any parenchymal haemorrhage. A posterior, intra-hemispheric subdural haematoma, in the absence of significant accidental trauma, is indicative of inflicted injury.
Elapsed time from the onset of injury can be estimated through the breakdown of intracranial haemoglobin as seen on diagnostic radiological studies such as CT scan and MRI.
- Spinal tap: If a spinal tap yields bloody cerebrospinal fluid (CSF), a fluid which is xanthochromic (yellowish appearance of CSF) should arouse suspicion that the cerebral trauma may be several hours old and the blood in CSF is not from traumatic spinal tap.
Laboratory studies for SBS are nonspecific and are not diagnostic. Leukocytosis is seen in about 50% of cases. Serum chemistry findings are usually normal, but it may reveal evidence of acidosis.
SBS should be distinguished from conditions like:
- Accidental head trauma.
- Blunt ocular trauma.
- Purtscher’s retinopathy: Purtscher’s retinopathy is a haemorrhagic and vaso-occlusive vasculopathy which shows multiple white retinal patches and retinal haemorrhages associated with severe visual loss. It may be associated with traumatic injury, primarily blunt thoracic trauma and head trauma, and numerous non-traumatic diseases.
- Terson syndrome: Terson syndrome is the association of intra-retinal haemorrhage with subarachnoid haemorrhage.
- Normal birth of baby: After normal vaginal delivery, retinal haemorrhages are occasionally seen without any intracranial lesions. Haemorrhages appear to be related to obstetrical and perinatal changes. These can occur with any type of delivery but are more common with normal vaginal or vacuum assisted deliveries.
Management should be strictly under medical supervision.
The identification, investigation, management and prevention of SBS require a multidisciplinary approach. There is a need for united effort among healthcare, child welfare, law enforcement, social services, education professionals and community at large.
All individuals and groups involved with detection, management and prevention should be provided knowledge of SBS. Creative preventive interventions, education regarding hazards of shaking and the development of appropriate coping skills can be disseminated to the community. The future well-being of children who have been victim to, or have the potential to become a victim of SBS, rests with the ability to work collectively.
Final outcome from inflicted injury is generally worse than accidental injury. Therefore, one must have a heightened index of suspicion for recognising patterns of injury of SBS. Although cause of injury may vary greatly, there are no differences in actual management of non-accidental versus accidental cases.
In suspected SBS, health providers should notify child protective services and law enforcement officials. Prompt notification facilitates a thorough investigation before the medical history becomes blurred by time. Early involvement of child protective services is also important for protection of other children under the custody of same caretakers.
In addition to diagnostic team having specialists from various disciplines, treatment team should have health care practitioners who can resuscitate and stabilise the victim immediately. Follow-up examination should also be carried out by the same treatment team.
Supportive medical care is the mainstay of management in SBS:
- Blood pressure and vital signs should be maintained.
- Resuscitate the child, if required.
- Manage raised intracranial pressure, if present.
- Some children require treatment for amblyopia or strabismus due to visual defect developing after SBS.
- Antiepileptic medication may be indicated for seizures.
- Physiotherapy and occupational therapy may be helpful after neurological injury.
- Speech therapy might be of use for patients in whom speech and/or language is affected.
- Surgical vitrectomy may be needed rarely for non resolving vitreous haemorrhage.
- Surgery may be needed for subdural haematoma or retinal detachment.
The morbidity and mortality of inflicted head injury is worse than accidental head injury. Vast majority of inflicted head injury possess some degree of neurologic or cognitive impairment.
Complications may be:-
- Cortical blindness: Occipital lobe impairment may lead to cortical blindness.
- Acquired microcephalus: Acquired microcephalus is common, with head circumference measurements reflecting a change in growth of brain, as early as two months following injury.
- Seizure disorders.
- Chronic subdural fluid collections.
- Enlargement of ventricles.
- Cerebral atrophy.
- Motor, cognitive or learning disabilities: Children injured early in their course of growth and development, are less likely to acquire appropriate skills than are children who are injured later in life. It is suggested that children who are severely brain injured before the age of six years, do not catch up with their peers and have a lower rate of gaining new skills.
- Long term impairment: Long term impairment may occur as:-
Alzheimer’s disease: Alzheimer’s disease is associated with a head injury early in life, with a more severe injury leading to even a greater risk of developing disease.
Parkinson’s disease: Parkinson’s disease and other movement disorders may develop years after an injury as a result of damage to basal ganglia.
Dementia pugilistica (Boxers’ dementia or Punch drunk syndrome): Dementia pugilistica is a variant of chronic traumatic encephalopathy which leads to dementia.
Post-traumatic dementia: Post-traumatic dementia patients have similar features as dementia pugilistica, however, they may have long term memory problems as well.
Factors strongly related to poor outcome include young age, duration of unconsciousness, and low score on Glasgow coma scale.
Primary prevention activities are directed at the general population with the goal of ending child abuse and maltreatment. This include:-
- Public service announcements and awareness campaigns.
- Family support and strengthening programs.
Secondary prevention activities are directed to population who possess one or more risk factors associated with abuse or maltreatment. This includes:-
- Parent education programs in targeted area: Primary goal of education is to teach parents and caregivers about the realities of parenting / childcare and how to cope up with crying babies. Education creates awareness about dangers of shaking and giving parents alternative when they feel as if crying cannot be tolerated for another moment. Fathers may be taught to the reality of infant crying and they also learn coping methods when the baby cries, as well as effective ways to understand and deal with their own feelings of frustration, when the baby would not stop crying.
- Home visit programs: Home visit program has become a strategy for service delivery. These services include education, maternal / child health and mental health services directed toward strengthening and supporting families. Antenatal visits help in parental coping, assessment of strengths and needs, as well as screening for postpartum depression.
- Family resource centers located in targeted communities.
Tertiary prevention activities focus on families with identified abuse or maltreatment. Programs for tertiary prevention include:-
- Parent mentoring programs.
- Intensive family preservation services.
- Mental health services to improve family.
Health care providers can also be instrumental in preventing child abuse and maltreatment, including SBS. Paediatricians frequently have insight into family dynamics and witness family interactions. Prevention practices such as screening for caretaker stress, discipline, substance abuse and response to child crying can aid in the identification of individuals and families at increased risk for abuse.
Formation of child death investigation and review teams can also become a key factor in developing prevention strategies. Information about the death of one child may generate knowledge leading to prevention strategies that will serve to protect the lives of other children.