Nervous system: Head trauma Flashcards
What is cerebral contusion?
‘Bruising’ of the brain where blood mixes with cortical tissue due to microhaemorrhages. Occurs as a result of direct trauma, and the areas affected are where the brain can hit a bony prominence
What is coup contrecoup injury?
Coup is when the brain is injured at the site of impact, contrecoup is the injury that occurs at the opposite side, from where the brain is pushed back onto the skull
What is the definition of concussion?
Head injury with temporary loss of brain function, it is a milder from of diffuse axonal injury
What is the pathophysiology of concussion?
Trauma occurs which stretches and injures the axons, causing impaired neurotransmission, loss of ion regulation and reduction in cerebral blood flow. As a result there is temporary brain dysfunction.
What is the definition of diffuse axonal injury?
Shearing of the interface between grey and white matter following trauma acceleration/deceleration or rotational injury damaging the intra-cerebral axons and dendritic connections
What is the pathophysiology of diffuse axonal injury?
There is trauma which shears the grey and white matter interface causing axonal cell death. There is cerebral oedema which raises ICP. Commonly fatal
What are the clinical signs of a basilar skull fracture?
- Racoon eyes from venous sinus bleeds
- CSF rhinorrhoea
- CSF otorrhoea from perforated ear drum
- Battle sign
- Haemotympanum
How is a basilar skull fracture managed?
- Need to look for other injuries as it takes significant force to break the base of the skull
- depressed fractures may need to be elevated
- persistant CSF leak may need surgery
How are head injuries classified into mild, moderate and severe?
Mild: GCS 13-15, post-traumatic amnesia <1 day, LOC 0-30 minutes
Moderate: GCS 9-12, post-traumatic amnesia 1-7 days, LOC 30m-24hrs
Severe: GCS 3-8, post-traumatic amnesia more than 7 days, LOC >24 hours
What are the urgent CT head criteria?
Urgent CT is within 1-3 hours.
- GCS <13 at any point, <14 2 hours after injury
- suspected skull fracture
- 2 discrete episodes of vomiting
- seizure
- LOC with any of:
65 and over, coagulopathy, dangerous mechanism of injury, amnesia >30 minutes
What is the site of an extradural haemorrhage?
Between the inner surface of the skull and the periosteal dura mata.
What is the cause of an extradural haemorrhage?
Which patient groups are most common?
90% cases is a severed artery, commonly the middle meningeal artery.
50% of cases happen in young patients under the age of 20, this is because the dura are firmer in older patients, and younger patients tend to do more risky activities.
What is a supratentorial extradural haemorrhage?
The haemorrhage occurs above the tentorium cerebelli (95% of cases)
Describe how the conscious level of patient with an extradural haemorrhage will change with time
The patient will initially present with LOC as a result of the impact of initial injury
40% then experience a ‘lucid interval’ where they have transient recovery with an ongoing headache
As the haematoma enlarged ICP will raise causing a rapidly deteriorating level of consciousness.
This can all happen in a few hours so need urgent CT and pressure relieved
What is the management of an extradural haemorrhage?
What is the prognosis?
Small EDH can be observed and managed conservatively
Large EDH need referral to neurosurgery for craniotomy and clot evacuation
Prognosis is very good with early diagnosis and intervention.