Head injury Flashcards
What are the different types of head injury?
- Primary brain injury
- Focal
- Bleeds
- Extradural
- Subdural
- Subarachnoid
- Contusion
- Bleeds
- Diffuse
- Concussion
- Diffuse axonal injury
- Focal
- Secondary brain injury
- seizures, siADH, raised ICP (haemorrhage, oedema, ischaemia, infection)
How would you approach someone presenting with head injury?
Extradural haemorrhage - where is the bleed?
Extradural haematoma – bleed between dura mater and the skull (middle meningeal artery)
Subdural haemorrhage - where is the bleed?
Subdural haematoma – bleed between the dura and arachnoid (bridging veins from dural venous sinuses and brain most commonly around frontal and parietal lobes)
Traumatic subarachnoid haemorrhage and Spontaenous subarachnoid haemorrhage
Where is the bleed?
difficult to distinguish whether the trauma leads to SAH or spontaneous SAH leads to trauma (spontaneous SAH usually caused by berry aneurysms)
bleed is between arachnoid and pia and bleed is arterial within the circle of willis
List 5 differences between extradural, subdural haemorrhages and subarachnoid haemorrhages
Which bleed is associated with a lucid interval?
extradural haemorrhage
What is the most mild form of primary brain injury?
concussion
What is concussion?
Head injury with a temporary loss of brain function
trauma –> stretching and injury to axons –> impaired neurotransmission, loss of ion regulation and reduction in cerebral blood flow –> temporary brain dysfunction
How are patients with concussion managed?
Safe to be discharged with safety netting
Safety net to tell them to return if any of the signs appear
Advise them on post-concussion syndrome - headache, dizziness, anxiety, brain fog for 7-10 days
Ensure they are going home with someone so that any potential loss of consciousness is witnessed
Concussion is considered a relatively mild form of diffuse brain injury. What is the more serious and severe form of diffuse brain injury?
Diffuse axonal injury - disruption and tearing of axons
What happens in diffuse axonal injury?
trauma –> shearing of grey matter and white matter interface –> axonal death –> cerebral oedema –> raised ICP –> coma
What kind of injury is likely to cause diffuse axonal injury?
deceleration - this causes mechanical shearing
What is the name for focal brain injury?
Contusion
How do contusions occur?
trauma –> microhaemorrhages –> cerebral contusion –> cerebral oedema/intracranial haemorrhage –> raised ICP –> coma
Can occur coup (adjacent to) or contre-coup (contralateral) to the injury
What are the signs of a basilar skull fracture?
What are the symptoms of raised intracranial pressure?
- Headache - postural, worst in morning
- N&V
- visual disturbances - blurring, obscurations
- confusion
What are the signs of raised ICP?
- Papilloedema (optic nerve surrounded by meninges)
- Sixth nerve palsy (false localising sign - first nerve affected because close to skull and long route)
- Leg weakness (subfalcine herniation)
- Third nerve palsy (uncal herniation)
- Reduced GCS (tonsillar herniation)
- Cushings reflex - bradycardia, hypertension, bradypnoea (late sing due to brainstem compression)
What are the criteria for CT head within 1 hour of head injury?
GCS < 13 on initial assessment
GCS < 15 at 2 hours post-injury
suspected open or depressed skull fracture.
any sign of basal skull fracture (haemotympanum, ‘panda’ eyes, cerebrospinal fluid leakage from the ear or nose, Battle’s sign).
post-traumatic seizure.
focal neurological deficit.
more than 1 episode of vomiting
What are the criteria for CT head within 8 hours of head injury?
age 65 years or older
any history of bleeding or clotting disorders
dangerous mechanism of injury (a pedestrian or cyclist struck by a motor vehicle, an occupant ejected from a motor vehicle or a fall from a height of greater than 1 metre or 5 stairs)
more than 30 minutes’ retrograde amnesia of events immediately before the head injury
