Emergency Neurotrauma

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Emergency Neurotrauma

• Head Injuries
• in Emergency Medicine
• Dr Brett Gerrard
• Emergency Medicine Specialist
• Middlemore Hospital

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Overview

• What is neurotrauma?
• How do we classify injuries
• What goes wrong?
• Pathogenesis of brain injury
• How bad is it?
• Assessment of Head Injuries
• How do we fix it?
• Resuscitation in neurotrauma

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Definition

• Approx 700 per 100 000 NZ population
• Responsible for the majority of trauma deaths
• Occurs on a continuum
• Classification can guide approach to
  investigation and therapy
• Minimal
• Mild
• Moderate-Severe

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Minimal Head Injuries

• No loss of consciousness
• Normal alertness and memory
• No neurological deficit
• GCS 15
• No signs of skull fracture

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Mild Head Injuries

• Brief (lt5min) loss of consciousness
• Amnesia (retrograde vs anterograde)
• GCS 14-15
• Impaired alertness
• No signs of skull fracture

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Moderate or severe Head injury

• Prolonged (gt5min) loss of consciousness
• Persistant GCS lt14
• Focal neurological deficit
• Seizure
• Signs of skull fracture

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Pathogenesis of Brain Injury

• Primary (Immediate)
• Forces and disruptive mechanisms of original
  incident
• Secondary (2-24 hours post injury)
• Multiple factors
• Cerebral hypoxia due to impaired blood flow
  complicated by
• Vasospasm
• Oedema
• Cellular dysfunction
• This is the injury that we can potentially
  prevent!

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Classification of Neurotrauma Injuries

• 1 Skull fractures
• 2 Concussion
• 3 Contusion
• 4 Diffuse axonal injury
• 5 Intracranial haematoma
• 6 Penetrating injury

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Skull Fracture

• Increased risk of associated neurotrauma.
• Location of fracture important
• Base of skull
• Cribiform plate
• Depressed fractures

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Concussion

• Transient alteration in cerebral function,
  usually associated with LOC and often followed by
  rapid or complete resolution
• Disturbance in RAS
• Symptoms include
• Headache
• Altered cognition
• Nausea
• Second Impact Syndrome

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Contusion

• Bruising of the brain substance
• Usually due to blunt trauma
• Fractures are uncommon
• May lead to haematoma and oedema formation
• Most common in frontal and temporal lobes

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Diffuse Axonal Injury

• Predominant mechanism of injury in neurotrauma
• Physical forces (shearing and rotational) disturb
  the axonal network at a miscroscopic level
• Minimal changes may be evident on CT
• Clinical sequelae can range
• subtle neuropsychiatric changes
• Severe cognitive impairment
• Psychomotor retardation

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Intracranial Haemorrhage

• Defined anatomically
• Subdural
• Extradural
• Intracerebral
• Subarachnoid

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Extradural

• Uncommon
• Usually associated with temporal bone fracture
• Expanding haematoma strips dural away from bone
• Increasing intracranial pressure and uncal
  herniation
• Lenticular shape on CT

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Subdural

• May be acute, subacute or chronic
• Much higher risk in elderly
• Seen in non accidental shaking in children
• Acute subdural high mortality rate approx 50

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Intracerebral

• Most commonly frontal and parietal lobes
• Clinical sequelae dependent on site
• May be primary or secondary due to underlying
  contusion
• Symptoms and complicationsmay be delayed

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Subarachnoid

• Relatively common in severe head trauma.
• May co-exist with other bleeding sources
• Extention into the interventricular spaces may
  lead to raised ICP.
• Subarachnoid blood can lead to cerebral vasospasm
  and secondary ischaemic brain injury

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Penetrating Trauma

• Very high levels of morbidity and mortality
• High velocity
• Gunshot
• Impalement
• Low velocity
• Knife
• Crush
• Generally very dismal outlook although

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Assessment of Neurotrauma

• History
• Examination
• Investigations

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History

• Detailed history can help attribute degree of
  risk
• High Risk mechanisms are utilised by several
  clinical rules
• Pedestrian/cyclist struck by car
• Fall from height of gt1m or 5 stairs
• Ejected from vehicle
• Penetrating injury/blow to head with weapon
• Suspicion of NAI

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• Patient factors
• Risk factors for bleeding
• Co-morbidities
• Drugs
• Extremes of age
• Difficulties in patient evaluation

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• Was there loss of consciousness?
• How long?
• Any seizures?
• Can you remember what happened?
• Before? (Retrograde)
• After? (Anterograde)
• Any vomiting?
• How many times?
• Do you have a headache?
• Does it improve with medication?

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Examination

• Integral part of primary and secondary survery
• ABC evaluation still remains priority
• Remember risk of cervical spine injuries
• Facial injuries
• Assessment of neurological disturbance
• AVPU (Paediatric scoring system)
• GCS (Glasgow Coma Score)
• Focal neurological signs
• Early signs of raised intracranial pressure

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• GCS slide

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Signs of Skull Fracture

• Rhinorrhoea
• Haemotympanum
• Battles Sign
• Racoon Eyes

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InvestigationsTo CT or not to CT?

• Minimal Head Injuries
• No imaging required
• Moderate-Severe Head Injuries
• Prolonged (gt5min) loss of consciousness
• Persistant GCS lt14
• Focal neurological deficit
• Seizure
• Signs of skull fracture
• CT Investigation of choice

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• Mild Head Injuries?
• Several clinically derived decision rules have
  been developed
• New Orleans
• CHIP
• Canadian CT Head Rule
• CATCH
• Why not just scan EVERYBODY??

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Risks of CT

• Sedation/compliance
• Time
• Costs
• Ionizing radiation

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Indications for Head CT in Trauma

• A CT scan is indicated for an adult patient with
  a head injury if they have one of the following
• A Dangerous Mechanism
• Pedestrian hit by a car
• Fall from gt1 metre (or 5 stairs)
• Blow to head with weapon
• Ejected from vehicle

Based on Canadian CT Head Rules Stiel et al.
Lancet. 2001 May 5357(9266)1391-6 Initial Data
approx 3100 patients GCS 13-15.
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Indications for Head CT in Trauma

• 2. Patient History factors
• Age gt65
• On warfarin or dabigatran
• Vomited 2 or more times
• Knocked out for gt5 min
• Persistant retrograde amnesia gt30min or
  persistant anterograde amnesia

Based on Canadian CT Head Rules Stiel et al.
Lancet. 2001 May 5357(9266)1391-6 Initial Data
approx 3100 patients GCS 13-15.
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Indications for Head CT in Trauma

• 3. Patient Exam findings
• GCS 13 or less on arrival
• Persistant GCS lt15 after 2 hours
• Signs of a skull fracture

Based on Canadian CT Head Rules Stiel et al.
Lancet. 2001 May 5357(9266)1391-6 Initial Data
approx 3100 patients GCS 13-15.
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Paediatric Head InjuryIssues

• Differences in mechanism
• Differences in anatomy
• Signs may be subtle
• More prone to cerebral oedema
• Difficult in assessing GCS
• Potential for non accidental injury
• Radiation exposure