Traumatic brain injury Flashcards
What are 2 broad groups into which primary traumatic brain injury may be classed?
- Focal: contusion/haematoma
- Diffuse: diffuse axonal injury
What is the cause of diffuse axonal injury?
occurs as a result of mechanical shearing following deceleration, causing disruption and tearing of axons
What are 3 types of haematoma which represent a type of focal brain injury?
- Extradural
- Subdural
- Intracerebral
What are 2 types of contusions, which represent a form of focal primary brain injury?
- Adjacent to the side of impact (coup)
- Contralateral (contre-coup) to the side of impact
What is secondary brain injury?
occurs when cerebral oedema, ischaemia, infection, tonsillar or tentorial herniation exacerbate the original injury
What are 5 types of secondary brain injury which may exacerbate the original brain injury?
- Cerebral oeddema
- Ischaemia
- Infection
- Tonsillar herniation
- Tentorial herniation
Why is the brain susceptible to secondary brain injury following trauma?
the normal cerebral auto-regulatory processes are disrupted following trauma, rendering the brain more susceptible to blood flow changes and hypoxia
What is the Cushing’s reflex?
hypertension and bradycardia (+ Cheyne Stokes (irregular) breathing - triad)
When does the Cushings reflex typically occur following traumatic brain injury?
often occurs late - is usually a pre-terminal event
What type of traumatic brain injury can cause extradural (epidural) haematoma?
acceleration-deceleration trauma, or blow to the side of the head
Where do the majority of extradural haematomas occur?
temporal region where skull fractures cause a rupture of the middle meningeal artery
What are 2 key clinical features of EDH?
- Features of raised ICP (bradycardia, hypertension)
- Lucid interval
In which 2 lobes of the brain do subdural haemorrhages most commonly occur?
frontal and parietal lobes
What are 3 risk factors for subdural haematomas?
- Old age
- Alcoholism
- Anticoagulation
How does the presentation of symptoms of a subdural haematoma differ from extradural haematoma?
- Slower onset of symptoms with SDH than EDH
- May be fluctuating confusion/consciousness with SDH but not a lucid interval
What is the typical presentation of a subarachnoid haemorrhage?
classically causes a sudden occipital headache
What is more commonly the cause of a subarachnoid haemorrhage?
ruptured berry aneurysms
What is an intracerebral (or intraparenchymal) haemorrhage?
collection of blood within the substance of the brain
What are 6 risk factors for intracerebral haemorrhage?
- Hypertension
- Vascular lesion e.g. aneurysm or arteriovenous malformation
- Cerebral amyloid angiopathy
- Trauma
- Brain tumour
- Infarct (esp. stroke patient undergoing thrombolysis)
How will patients with an intracerebral haemorrhage typically present?
similarly to an ischaemic stroke - why crucial to obtain CT head in all stroke patients prior to thrombolysis
or decrease in consciousness
What will CT imaging show in intracerebral haemorrhage?
hyperdensity (bright lesion) within the substance of the brain
What is often the treatment of intracerebral haemorrhage?
often conservative under the care of stroke physicians
large clots in patients with impaired consciousness may warrant surgical evacuation
What is the management of large intracerebral haemorrahge with impaired consciousness?
may warrant surgical evacuation
What is the appearance of SAH on CT?
hyperdense (whiter) material seen filling the subarachnoid space - most commonly around circle of Willis (65% of berry aneurysms occur in this region) or in the Sylvian fissure (30%)
sometimes blood in interpeduncular fossa or within occipital horns of lateral ventricles
