Transcript Slide 1
Emergency Neurotrauma
Head Injuries in Emergency Medicine
Dr Brett Gerrard Emergency Medicine Specialist Middlemore Hospital
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
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
Minimal Head Injuries
No loss of consciousness Normal alertness and memory No neurological deficit GCS 15 No signs of skull fracture
Mild Head Injuries
Brief (<5min) loss of consciousness Amnesia (retrograde vs anterograde) GCS 14-15 Impaired alertness No signs of skull fracture
Moderate or severe Head injury
Prolonged (>5min) loss of consciousness Persistant GCS <14 Focal neurological deficit Seizure Signs of skull fracture
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!
Classification of Neurotrauma Injuries
1 Skull fractures 2 Concussion 3 Contusion 4 Diffuse axonal injury 5 Intracranial haematoma 6 Penetrating injury
Skull Fracture
Increased risk of associated neurotrauma.
Location of fracture important Base of skull Cribiform plate Depressed fractures
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
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
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
Intracranial Haemorrhage
Defined anatomically Subdural Extradural Intracerebral Subarachnoid
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
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%
Subdural
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
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
Penetrating Trauma
Very high levels of morbidity and mortality High velocity Gunshot Impalement Low velocity Knife Crush Generally very dismal outlook although…
Assessment of Neurotrauma
History
Examination
Investigations
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 >1m or 5 stairs Ejected from vehicle Penetrating injury/blow to head with weapon Suspicion of NAI
Patient factors Risk factors for bleeding Co-morbidities Drugs Extremes of age Difficulties in patient evaluation
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?
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
GCS slide
Signs of Skull Fracture
Rhinorrhoea Haemotympanum Battles Sign Racoon Eyes
Investigations “To CT or not to CT?”
Minimal Head Injuries No imaging required Moderate-Severe Head Injuries Prolonged (>5min) loss of consciousness Persistant GCS <14 Focal neurological deficit Seizure Signs of skull fracture CT =Investigation of choice
Mild Head Injuries……?
Several clinically derived decision rules have been developed New Orleans CHIP Canadian CT Head Rule CATCH Why not just scan EVERYBODY??
Risks of CT
Sedation/compliance Time Costs Ionizing radiation
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:
1. A Dangerous Mechanism
Pedestrian hit by a car Fall from >1 metre (or 5 stairs) Blow to head with weapon Ejected from vehicle Based on Canadian CT Head Rules Stiel et al. Lancet. 2001 May 5;357(9266):1391-6 Initial Data approx 3100 patients GCS 13-15.
Indications for Head CT in Trauma
2. Patient History factors
Age >65 On warfarin or dabigatran Vomited 2 or more times Knocked out for >5 min Persistant retrograde amnesia >30min or persistant anterograde amnesia Based on Canadian CT Head Rules Stiel et al. Lancet. 2001 May 5;357(9266):1391-6 Initial Data approx 3100 patients GCS 13-15.
Indications for Head CT in Trauma
3. Patient Exam findings
GCS 13 or less on arrival Persistant GCS <15 after 2 hours Signs of a skull fracture Based on Canadian CT Head Rules Stiel et al. Lancet. 2001 May 5;357(9266):1391-6 Initial Data approx 3100 patients GCS 13-15.
Paediatric Head Injury Issues
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