Head injury - Intracerebral, Subdural and Extradural Haemorrhage, and diffuse axonal injury Flashcards
What is an extradural haemorrhage?
A collection of blood that forms between the inner surface of the skull and outer layer of the dura, which is called the endosteal layer. EDH typically follows a linear skull vault fracture tearing a branch of the middle meningeal artery. Extradural blood accumulates rapidly over minutes or hours.
Which artery is most commonly implicated in an extradural haemorrhage?
Middle meningeal artery
When might you suspect an extradural haemorrhage?
After any skull fracture - especially temporal/parietal bone. Typically after trauma to the eye
Where does blood accumulate in an extradural haemorrhage?
Between bone and Dura
What are symptoms of an extradural haemorrhage?
- Lucid interval following trauma, then progressively decreasing GCS
- Increasingly severe headache
- Vomiting
- Confusion
- Seizures
What are signs of an extradural haemorrhage?
Raised ICP signs (in sequence)
- Lucid progressing to Decreased GCS
- Ipsilateral myadriasis (hutchison’s pupil), with Contralateral Hemiparesis + Brisk reflexes + Upgoing plantars
- Tetraplegia + Bilateral fixed dilated pupils
- Late signs - Bradycardia, Increased BP, Respiratory depression (cushings triad)
What is the general progression of extradural haemorrhage from initial insult?
Lucid period -> decreased GCS, signs of rasied ICP -> hemiparesis, brisk reflexes, hutchison’s pupil, coma, bilateral limb weakness, resp depression
What would differentials be for someone who you suspected might have an extradural haemorrhage?
- Epilepsy
- Carotid dissection
- Carbon monoxide poisoning
Why do individuals with an extradural haemorrhage get a hutchison’s pupil?
Caused by herniation of the uncus impinging on the occulomotor nerve
Why do individuals with extradural haemorrhage develop bradycardia as a late sign?
As part of Cushing’s Triad/Reflex:
- Increase in systolic and pulse pressure
- Bradycardia
- Irregular respiration
Baroreceptors in the aortic arch detect the initial increase in blood pressure and trigger a parasympathetic response - induces bradycardia, which signifies the second stage of the reflex
Why do those with extradural haemorrhage develop Hypertension as a late sign?
As part of Cushing’s Reflex
- Disturbed repiratory pattern
- Bradycardia
- Hypertension
In response to raised ICP, the body attempt to restore adequate perfusion to the ischaemic brain, as raised ICP reduces flow of blood into the brain
Why can those with an extradural haemorrhage develop irregular/depressed breathing?
As part of Cushing’s Reflex
- Disturbed repiratory pattern
- Bradycardia
- Hypertension
Distortion and/or increased pressure on the brainstem causes an irregular respiratory pattern and/or apnea
How would you investigate a suspected extradural haemorrhage?
- Imaging - CT Scan
- Skull X-ray - shows fracture line
- DON’T DO AN LP!!!
What is the following diagnosis?
Extradural haemorrhage
Why do extradural haemorrhage show up as a biconcave hyperattenuated area on CT?
Due to the insertion points of the dura to the suture lines of the skull
How would you manage someone with an extradural haemorrhage?
- Stabilise and transfer to neurosurgery
- Surgery - clot evacuation and ligation
- May require intubation/ventilation
What is a subdural haematoma?
A type of hematoma, usually associated with traumatic brain injury. Blood gathers between the inner layer of the dura mater and the arachnoid mater.
What layers of the meninges does a subdural haemorrhage occur between?
Dura and arachnoid mater
What is the cause of a subdural haemorrhage?
Rupture of bridging veins, caused by:
- Trauma (most commonly)
- Decreased ICP
- Dural metastases
What are risk factors for subdural haemorrhage?
- Falls - elderly, alcoholics
- Anticogulation
What are symptoms of a subdural haemorrhage?
- Fluctuating level of conscioussness
- Physical/intellectual slowing
- Sleepiness
- Headache
- Personality change
- Unsteadiness
What are signs of a subdural haemorrhage?
- Signs of raised ICP
- Focal deficits - hemiparesis, sensory loss
- Seizures
- Stupor
- Decreased GCS
- Late features - Hypertension, Bradycardia, Depressed resp rate
What investigations would you do in someone with suspected subdural haemorrhage?
Imaging - CT/MRI
What might you see on CT/MRI in someone with a subdural haemorrhage?
- Clot +/- midline shift
- Crescent-shaped collection of blood oer 1 hemisphere
How would you manage a subdural haemorrhage?
Refer to neurosurgery
- Reverse clotting abnormalities
- Surgery - if >10mm haemorrhage or >5mm midline shift
- Address cause of trauma - falls, abuse
What head injuries can cause focal neurological signs or seizures?
- Diffuse axonal injury
- Contusion
- Intracerebral haematoma
- Extra-cerebral haematoma - Extra-dural haematoma, Sub-dural haematoma
What GCS score would you consider intrubating someone?
GCS < 8 - unable to maintain own airway
Why are those who are elderly, drink alcohol or who have dementia more at risk of subdural haemorrhage?
Due to cerebral atrophy - stretches venous bridges, making them more prone to rupture
How would you manage raised ICP?
- Surgery to relieve pressure - Heamatoma, ventricular shunt
- Osmotic agents - mannitol
- Nurse with head at 30-45o (Venous return)
- Reduce pain
- Maintain good PO2, reduce PCO2
- Reduce metabolism (reduce temperature, barbiturates)
What does the extent of retorgrade amnesia correlate with in a head injury?
Severity of injury - never occurs without anterograde amnesia
If someone had a head injury, when would you consider performing a CT within an hour of presentation?
- GCS <13, or < 15 at 2hrs
- Focal neurological deficit
- Suspected open/depressed skull fracture
- Signs of basal skull fracture
- Post-traumatic seizure
- Vomiting more than once
When would you consider doing a CT within 8 hrs of admission?
Any LOC/amnesia, and any of
- Age >/= 65
- Coagulopathy
- High-impact injury
- Retrograde amnesia >30 mins
When might you suspect a cervical spine injury in combination with a head injury?
- GCS <13 on inial assessment
-
Clinical suspicion, plus any of:
- 65 or older
- High-impact injury
- Focal neuro deficit
- Paraesthesia of upper/lower limbs
- Patient has to be intubated
- Multi-region trauma
What are early complications of head injuries?
- Subdural haemorrhage
- Extradural haemorrhage
- Seizures
- Uncal herniation
- CSF leak
- Hydrocephalus
- Cranial nerve palsies
What are late complications of head injury?
- Subdural haemorrhage
- Seizures
- Diabetes insipidus
- Parkinsonism
- Dementia
When is alcohol an unlikely cause of coma?
If blood alcohol levels <44 mmol/L
When would you consider admitting someone with a head injury?
- New, clinically significant abnormalities on CT
- GCS <15 after CT
- Other concerns - drugs/alcohol, other injuries, CSF leak, shock etc.
What are indicators of a bad prognosis in a head injury?
- Old age
- Decerebrate rigidity
- Extensor spasm
- Prlonged coma
- Hypertension
- Decreased PaO2
- To > 39
If someone presented with a head injury, what would you do as part of your initial assessment?
ABCDE
- Give oxygen if sats <92%
- Intubate and hyperventilate if necessary
- C-spine immobilisation
- Fluid resus/circulation support
- Treat seizures - lorazepam +/- phenytoin
- Assess GCS - if <8 -> manual airway
What initial blood investigations would you consider in someone presenting with a head injury?
- U+E’s
- Glucose
- FBC
- Blood alcohol
- Toxicology screen
- ABGs
- Clotting
What are signs of a CSF leak caused by a head injury?
- Rhinorrhoea
- Otorrhoea
- Blood behind ear drum
- Basal skull fracture signs
What is diffuse axonal injury?
Severe form of head injury that occurs as a result of shearing and tensile strains produced by rotational movements of the brain within the skull. It often occurs in the absence of a skull fracture and cerebral contusions. Two main components exist:
- Small haemorrhagic lesions in the white matter - corpus callosum and dorsolateral brainstem
- Diffuse damage to axons - eventually degenerate, resulting in a loss of fibres in the white matter.
What are mechanisms of brain damage form a head injury?
- Diffuse axonal injury
- Neuronal and axonal damage from direct trauma
- Brain oedema and raised ICP
- Brain hypoxia
- Brain ischaemia
What is an intracerebral haemorrhage?
Haemorrhage within the brain tissue itself
What are causes of intracerebral haemorrhage?
- Hypertension
- Trauma
- Aneurysm rupture
- Anticoagulation
- Thombolysis
How might you distinguish an intracerebral haemorrhage from a stroke?
Very difficult - may have a headache with stroke symptoms
What is the following?
Intracerebral haemorrhage
Which imaging modality is best for visualising intracranial haemorrhage?
CT is best and quickest option
What are features of anterior base of skull fracture?
Specific
- CSF rhinorrhoea
- Subcutaneous haematoma around orbit - racoon eyes
General
- Halo sign
- Headache
- Amnesia/confusion
- Focal neuro signs
- Seizures
What is halo sign?
Rapidly-expanding clear ring of fluid surrounding blood on discharge
What are features of posterior basal skull fracture?
Specific
- CSF otorrhoea: leakage of CSF from the external auditory meatus
- Subcutaneous hematoma behind the ear (Battle sign)
General
- Headache
- Amnesia; confusion, disorientation
- Impaired consciousness
- Dizziness, nausea, vomiting
- Focal neurologic symptoms (see stroke)
- Seizures
- Sensory disturbances
What is the following?
Racoon eyes - sign of anterior base of skull fracture
What GCS score would indicate a mild head injury?
13-15
What GCS score would indicate a moderate head injury?
9-12
What GCS score would indicate a severe head injury?
=8
How would you manage a mild TBI?
- Monitoring - 24 hrs
- Simple analgesia
-
Athletes
- Refrain from contact sports for a week - then reassess
- Monitor in A+E - 6 hours
What would you lookfor on CT in someone with a suspected traumatic brain injury?
- Midline shift
- Hemorrhage and hematomas (see “Differential diagnoses of intracranial hemorrhages” below)
- Diffuse axonal injury (DAI)
