Fig 92.1 CT scan demonstrating Extradural Haematoma (EDH)
92
Brain injury and coma
The uncertainty that exists about potential prognosis following traumatic brain injury (TBI) is encapsulated in the Hippocratic aphorism: ‘No head injury is so serious that it should be despaired of nor so trivial that it can be ignored.’
Most paediatric head injury is mild; however, head injury remains the most common cause of disability and mortality during childhood, with a mortality rate of 19 per 100 000 in children under 18 years old (Ragheb 2008). Head injury accounts for 5% of all paediatric hospital admissions, with an estimated 3000 children acquiring significant new neurological or cognitive disability annually in the United Kingdom (Sharples 1998).
The age groups most at risk from traumatic brain injury are newborn infants through to age 4, and teens from 15 to 19 years old. The most common cause is road traffic accidents (motor vehicle, bicycle, pedestrian) followed by falls. The best treatment is prevention. Advances in critical care management and reduction of secondary injuries offers the greatest potential to limit the consequences of TBI.
Classification can be mild (based on a Glasgow coma score (GCS) of 13–15), moderate (GCS 9–12) or severe (GCS 3–8).
Physiology
The infant skull is relatively large in comparison to the body and the cervical spine is highly mobile, therefore all children with a history of head trauma must have the neck stabilized at the scene of the accident and maintained until a cervical injury has been ruled out.
Incomplete myelination and less water content in the infant brain means that the young brain is more susceptible to acceleration and deceleration injuries, diffuse axonal injury (DAI) and extraparenchymal haemorrhage. Autoregulation is poor in infants and management must be provided accordingly.
Primary brain injury
This occurs at the time of injury and includes DAI, brainstem injury, cortical contusions and lacerations.
Secondary brain injury
This can occur as a consequence or independent from the primary injury, minutes to days following the injury as a result of adverse physiology, including cerebral oedema, ischaemia, raised intracranial pressure, hypoxia, hypertension, seizures, pyrexia, hyper- and hypoglycaemia and seizures.
Immediate management: this must be prompt and systematic, following paediatric life support principles. Cervical spine injury may occur with paediatric head injury and the cervical spine must be immobilized as a priority:
- A Check and maintain airway
- B Ensure good oxygenation levels; intubation and ventilation if required
- C Circulation must be maintained and blood pressure and pulse kept within normal ranges
- D Disability – neurological examination, assessment and treatment; use of paediatric GCS chartand/or AVPU; management of seizure, electrolytes and glucose.
Evaluation and management of other injuries: the key priorities are to stabilize the child and reduce secondary injury. NICE (2007) published evidence-based guidelines for the management of children with head injury, including pre-hospital management, inpatient management and discharge.
Coma
Coma is the most severe impairment of arousal and is defined as an inability to speak, open the eyes to pain or obey commands. It occurs with head injury, secondary to diffuse changes in the cerebral hemispheres and/or dysfunction of the brainstem, electrolyte imbalance and/or seizure activity. Treatment is by management of the underlying cause (e.g. raised intracranial pressure, cerebral oedema) and supportive care (e.g. elective mechanical ventilation).
Pharmacologically induced coma may be required for management of children with severe TBI.
Rehabilitation
Rehabilitation may be appropriate in the home setting with community input, but occasionally prolonged inpatient stay is required. Placement at a specialized paediatric rehabilitation centra may be available or appropriate for some children.
Prognosis
The effects of brain injury in the young child may not become obvious until affected skills are called upon, for example during early school years or during the move to senior school. During these early years the immature brain begins to process more complex information including sensory information.
Long-term deficits may be physical and neurocognitive, the latter including changes in behaviour, mood, speech, memory, learning, attention and executive functions.
Full access? Get Clinical Tree
