Closed Head Injury in Pediatrics

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Background

Trauma is the leading cause of death in children over 1 year of age. 80% of deaths due to trauma are due to head injury. Head injury in the pediatric population is most often due to motor vehicle collisions. A large percentage of head injuries are due to child abuse, falls and recreational activities. Two things that must be considered in every pediatric patient with a head injury are the possibility of associated cervical spine injury and the possibility of abuse.

The pediatric brain is more susceptible to injury and complications of head injury than the adult brain. There is increased water content in infants and young children’s brains 88% versus 77% in adults. This makes them softer and more likely to be injured in acceleration-deceleration mechanisms. Also they have decreased myelination which increases the susceptibility to shear injury. The compliant infants skull is also easily deformed leading to underlying brain parenchymal injury. This also can be pretective in that very young children with open sutures can better tolerate increased intracranial pressure.

Diagnosis

Types of closed head injuries

Concussion

transient loss of consciousness
vomiting, amnesia, pallor
waxing and waning mental status but no focal deficit
improve over time

Contusion

from coup or contre-coup mechanism
most often frontal or temporal lobes
see progressive deterioration secondary to cerebral edema, hematoma and infarct to area.
focal deficits depending on area involved
decreased LOC

Epidural Hematoma

bleeding between dura and skull
often due to middle meningeal artery laceration
reaches peak size in 6-8 hours
characteristic lucid interval seen in adults may not happen in pediatric patients
mass effect leading to herniation symdromes

Sudural hematoma

between dura and arachnoid
usually due to tearing of bridging veins
acceleration-deceleration injuries or shaken baby
often have associated parenchymal injury
if large see profound progressive deterioration

Subarachnoid Hemorrhage

due to damage to small vessels over cortex
headache, nausea and vomiting and neck stiffness

Diffuse Axonal Injury

rapid acceleration-deceleration injury
basal ganglia, thalamus, corpus callosum most often affected
altered mental status and prolonged vegetative state
minimal findings on imaging
poor prognosis for recovery

Questions to Ask

Was the injury witnessed
Mechanism of injury and forces involved ( speed of vehicles, seat belt?)
Loss of conciousness, lucid period
neurological deficits noticed: vision, balance, motor or sensory function
seizures
nausea or vomiting
amnesia, disorientation
medications, alcohol or drugs involved
history of coagulation disorders and other medical problems

***Note: In the situation of acute head injury history may become secondary to initial resuscitation efforts

Physical examination

Often head injury occurs in the setting of the multi-trauma patient. So the head injury has to be assessed along with other injuries

Primary survey

Airway
Breathing
- Head injury patients often have apneic spells and hypoventilation
Circulation
- Hypotension should not be attributed to head injury alone until other causes have been ruled out
- Cushing’s Triad (↓HR; ↑BP; irregular respiration): seen with increased ICP (link to signs of inc_ICP)
Neurological Assessment
- Pediatric GCS (link pediatric GCS)
- AVPU (alert, verbal, pain, unresponsive)
- Pupils (Unilateral, dilated, unreactive pupil suggests actual or imminent uncal herniation and is a neurosurgical emergency. Bilateral dilated unreactive pupils is even more ominous)
Cervical spine stability

Secondary Survey

Examine head to toes, paying special attention to the following:

Cervical spine
Head: deformities, lacerations, Battle’s sign, Raccoon eyes, hemotympanum, otorrhea, rhinorrhea, bulging fontanelle
Neurological: Pupils, eye deviation, retinal hemorrhage, papilledema, decreased venous pulsations, reflexes (motor, corneal, gag and oculovestibular), motor and sensory function.

Investigations

Laboratory Investigations

CBC
PTT/INR
Blood type and cross
Arterial blood gases
Toxicology screen if history of head injury is unclear

ECG

Head injury can lead to cardiac dysrhythmias

Imaging studies

CT is the gold standard for initial assessment of head injury, and is indicated in the following circumstances:
- LOC >5 min
- Deterioration of mental status
- Focal deficit
- Seizure
- Vomiting > 6 hours
- Bulging fontanelle
- Suspicion of skull fracture
- Other injury requiring general anaesthetic
Ultrasound may be used in infants with open fontanelle

Management

Airway
- Intubate if GCS <8 (link to pediatric GCS)
Breathing
- Maintain normal ventilation
- PaO2 >90
Circulation
- Normotensive, euvolemic is the goal
- CPP=MAP-ICP
- Cardiac monitoring
Increased ICP (link to signs of inc_ICP)
- Elevate head of bed 30 degrees
- Mannitol or Furosemide
- Sedate and paralyze if needed
- Hyperventilation to PaCO2 35
- Barbituates and hypothermia as last resort
- Extraventricular drain for CSF
Seizure management
Bleeding management: one third head injury patients develop DIC
Neurosurgical definitive treatment
- Burr holes
- Craniotomy
- Drains

Disposition criteria

Minor injury
Responsible adult caregiver
Awake every 2 hours
No focal deficit
No LOC or normal CT
No signs or symptoms after 2 hours observation
Return to ED if increasingly sleepy, unarousable, unequal pupils, decreased motor function, seizure, protracted vomiting, severe head ache, change in mental status

Complications of Head Injury

Seizures
Cortical blindness (transient)
Hydrocephalus
Neurogenic pulmonary edema
DIC- permanent
Neurological defect

References

Acknowledgements

Written by: Carolyn Kelly-Smith

Edited by: Jeff Bishop