Pathophysiology of brain injury
- One million patients attend A+E each year in UK with head injury
- 80% are minor (GCS 13-15)
- 10% are moderate (GCS 9-12)
- 10% are severe (GCS <8)
- Severe head injuries account for 50% of trauma related deaths
Primary brain injury
- Damage caused at time of impact
- Can be focal or diffuse
- Diffuse axonal injury is due to deceleration and shearing forces
- Dependent on extent of initial injury
- Difficult to treat
Secondary brain injury
- Insult imposed after initial injury
- Due to:
- Hypoxaemia
- Hypercapnia
- Systemic hypotension
- Intracranial haematoma
- Intracranial hypertension
- Early treatment is aimed at the prevention of secondary injury
- Autoregulation of cerebral blood flow is lost after head injury
Management of head injuries
- Patients should be managed according to ATLS protocols to prevent
secondary brain injury
- 5-10% patients with severe head injury have cervical spine injury
- Full assessment requires
- Glasgow Coma Scale
- Pulse, blood pressure
- Assessment of pupil diameter and response
- Assessment of limb movement
- Patients with GCS less than 8 require early intubation
Glasgow coma scale
| Eye opening |
|
Motor response |
|
Verbal response |
|
| Spontaneous |
4 |
Obeys |
6 |
Orientated |
5 |
| To speech |
3 |
Localises |
5 |
Confused |
4 |
| To pain |
2 |
Withdraws |
4 |
Inappropriate |
3 |
| None |
1 |
Abnormal flexion |
3 |
Incomprehensible |
2 |
|
|
Extensor response |
2 |
None |
1 |
|
|
None |
1 |
|
|
Signs of basal skull fracture
- Blood or CSF from nose or ear
- Periorbital haematoma
- Mastoid haematoma (Battle's sign)
- Haemotympanum
- Radiological evidence of intra-cranial air
- Radiological evidence of fluid levels in sinuses
Criteria for admission after head injury
- Altered level of consciousness
- Skull fracture
- Neurological symptom of sign
- Difficult assessment - drugs, alcohol
- No responsible carer
Indications for head CT scan
- Confusion (GCS <14) persisting after initial assessment and
resuscitation
- Skull fracture with neurological signs
- Skull fracture with epileptic fit
- Indications for transfer without preliminary head CT scan
Indications for transfer to neurosurgical centre without CT scan
- Deterioration in level of consciousness
- Progressive neurological deficit
- Tense fontanelle in child
- Penetrating injury
- Depressed skull fracture
NICE Guidelines (2003)
- CT is the primary investigation of choice for clinically important
brain injury
- MRI is not currently indicated as the primary investigation
- Skull x-rays have a role in the detection of non-accidental injuries
in children
- CT should be available within one hour of being requested
Indications for CT
- GCS less than 13 at any point since the injury
- GCS equal to 13 or 14 at 2 hours after the injury
- Suspected open or depressed skull fracture
- Any sign of basal skull fracture
- Post-traumatic seizure
- Focal neurological deficit
- More than one episode of vomiting
- Amnesia for greater than 30 minutes of events before impact
- If LOC in patients older then 65 years, coagulopathy or dangerous
mechanism of injury
Investigation of cervical spine
- The current investigation of choice is three-view plane radiographs
- CT is indicated if satisfactory plain radiographs can not be
obtained
- MRI is indicated in the presence of neurological signs and symptoms
Indications for imaging of cervical spine
- GCS less than 15 at the time of assessment
- Paraesthesia in the extremities
- Focal neurological deficit
- Not possible to test range of movement in neck
Indications for referral to neurosurgeon
- Persistent coma (GCS<8) after initial resuscitation
- Unexplained confusion persisting for more than 4 hours
- Deterioration in GCS after admission
- A seizure without full recovery
- Progressive focal neurological signs
- Definite or suspected penetrating injury
- CSF leak
Indications for admission to hospital
- Patients with new, clinically significant abnormalities on imaging
- Patients who have not returned to GCS equal to 15
- Patients fulfilling criteria for CT scanning
- Continuing worrying signs of concern to the clinician
Indications for intubation and ventilation
- GCS less than or equal to 8
- Loss of protective laryngeal reflexes
- Ventilatory insufficiency as judged by blood gases
- PaO2 less than 9kPa
- PaCO2 greater than 6kPa
- Spontaneous hyperventilation
- Respiratory arrhythmia
- Bilateral fractured mandible
- Copious bleeding into mouth
- Seizures
Methods of monitoring neurological function
- Methods of monitoring intracranial pressure
- Intraventricular catheter
- Fibreoptic devices
- Strain gauge microtransducer systems
- Methods of monitoring cerebral blood flow
- Methods of monitoring cerebral oxygenation
- Jugular venous oxygen saturation
- Near-infrared spectroscopy
- Brain oxygen tension
- Methods of monitoring function
- Clinical neurological assessment
- Glasgow coma scale
- Electroencephalogram (EEG)
- Electromyography
Bibliography
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547-542.
Flannery T, Buxton N. Modern management of head injuries.
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