The shaken infant syndromeBMJ 1995; 310 doi: https://doi.org/10.1136/bmj.310.6976.344 (Published 11 February 1995) Cite this as: BMJ 1995;310:344
- Helen Carty,
- Jane Ratcliffe
- Consultant radiologist Consultant in paediatric intensive care Alder Hey Children's Hospital, Liverpool L12 2AP
Parents and other carers need to know of its dangers
In children less than 1 year, non-accidental injury is the commonest cause of serious head injury1—much of it resulting from shaking and impact. Last week saw the launch of a leaflet, “Handle with Care,” produced by the National Society for the Prevention of Cruelty to Children and the Department of Health, in response to increasing professional concern over the dangers of shaking babies.
John Caffey first drew attention to the association of fractures of the long bones and subdural haematomas, and he implicated whiplash injury as the cause of the intracranial trauma.2 It is accepted that shaking alone can cause the brain damage,3 and it is now recognised that the infant's head also undergoes rotational forces as well as whiplashing during shaking.4 Injuries may result from single or multiple episodes of shaking.
The severity of the shaking force is such that shaking injuries cannot occur in any form of playful activity (as Caffey originally suggested2). A recent description of the act of shaking states that it is so violent that neutral observers would recognise it as dangerous.5
The clinical presentation of a shaking injury may not suggest abuse—signs include irritability, lethargy, vomiting, convulsions, apnoea, shock, and fluctuating consciousness. The history may be confusing if the adult bringing the child to medical attention has no knowledge that the child has been shaken or withholds information. Shaking injuries that produce subtle clinical changes may never be brought to medical attention. There may be a delay in seeking medical help because the perpetrator believes that the shaken child is asleep rather than unconscious. After a variable time, the infant will develop signs of cerebral irritation, cerebral oedema, or intracranial haemorrhage.4 Acute deterioration, convulsions, or respiratory or circulatory arrest may follow.
Although clinical examination of the infant may reveal bruising or other evidence of neglect in addition to the neurological signs, it often shows nothing unusual. Retinal haemorrhages are present in between 50% and 80% of patients,6 and when other causes have been excluded are virtually pathognomonic of child abuse. Ideally, the fundi should be examined by an ophthalmologist who frequently examines children. If the cerebrospinal fluid is examined frank haemorrhage or xanthochromia indicate acute or recent haemorrhage, but this investigation is not done when there are concerns about raised intracranial pressure. Where safe, a subdural tap should be done as the analysis of cerebrospinal fluid is helpful in the dating of injuries.
During the shaking episode the infant is often held by the thorax4 and the compression forces on the ribs may result in fractures. Alternatively, the child may be held by the shoulders and upper arms or feet.7 The squeezing and violent movement associated with the shaking may cause the typical fracture patterns of child abuse.8 Brain damage is often multifactorial with direct shaking injury to the brain being compounded by hypoxic and ischaemic injury, infarction, coning, and the pressure effects of subdural haematomas and impact trauma.7
Computed tomography in suspected cases of shaking injury is essential. Subdural haematomas, sometimes of different ages; subarachnoid blood; intracerebral and intraventricular bleeding; cerebral oedema; diffuse loss of differentiation between grey and white matter; and cerebral laceration and contusional tears may all be found in shaken infants.9 Skull radiology is essential as fractures may be missed on computed tomography.10 Magnetic resonance imaging supplements computed tomography by showing small subdural collections or identifying subdural haematomas of different ages and shaking injuries that are not visible on computed tomography.11 Owing to its availability computed tomography remains the primary imaging procedure. More recently, high resolution ultrasonography performed through a patent fontanelle has been shown to be very sensitive in showing shearing injuries and subdural and subarachnoid fluid.12 Late results of brain injury include multicystic encephalomalacia, obstructive or communicating hydrocephalus, cerebral atrophy, infarctions, and gliosis.
The most severe shaking injuries tend to occur in younger infants as the head is relatively large in relation to the body. As body weight increases and neck muscles strengthen the incidence of brain damage due to shaking falls and is rare after the second year of life.
The outcome depends on the severity of the shaking injury; morbidity and mortality are high when the infant is comatose on presentation.3 5 Long term sequelae include profound mental retardation, spasticity, motor dysfunction, blindness, convulsions, and hydrocephalus.5 In one series of children shaken to unconsciousness 60% died or had profound mental retardation, spastic quadriplegia, or severe motor dysfunction. Others who had convulsions, irritability, or lethargy but no lacerations, cerebral infarction, or severely raised intracranial pressure had subtle neurological sequelae or persistent convulsions.13
Who shakes their child? The shaking may represent a response to tension and frustration generated by the infant's incessant crying, which may be exacerbated by ignorance of appropriate infant care. People experiencing stress may be more prone to impulsive and aggressive behaviour.14
Until now social and medical effort has focused mainly on diagnosing and treating the shaken infant, with little emphasis on prevention. Studies in the United States have shown that although between a quarter and a half of the public did not know of the dangers of shaking infants, they retained information given in an awareness campaign.15
We do not know how many infants are shaken in Britain each year, but over 100 deaths occur from child abuse or neglect and in many of these children death is due to brain injury. Increased public awareness of the dangers of shaking should reduce this number and reduce the disabilities of survivors.
Drs Carty and Ratcliffe have been involved in the campaign to increase public awareness of the dangers of shaking babies.