Head injury lecture notes Flashcards
True or false: Half of TBIs are in under 16s
True
What is the definition of TBI (traumatic brain injury)?
TBI is defined as an alteration in brain function, or other evidence of brain pathology, caused by an external force
What are the common causes of TBI?
RTC (road traffic collision)
Falls (elderly)
Assaults
Sports and recreational
firearms
Contrecoup injury
Abrupt, accelerating/decelerating force can cause brain to shift. Damage to opposite end of impact as forces spread and opposite pole feels force
Secondary brain injury involves
altered cerebral blood flow - autoregulation
Hypotension - due to ICP
Release of neurotoxic susbstances
Hypoxia
Free radicals
Cerebral odedema
When is term ‘concussion’ used
Broad term. Not very helpful to describe an injury. People often use it for mild brain injury
What is a contusion?
Small pin-point haemorrhagic lesions, usually found superficially and associated with bony provinces. Causes bruising.
Often frontal and temporal lobes where bony provinces are.
Diffuse Axonal Injury (DAI)
white matter lesions
Very high forces involved
Often around brainstem and nuclei area at grey/white matter interface
Sometimes haemorrhage associated
Only 20% seen on CT scan
Better seen on MRI
poor prognostic indicator
Extradural bleeds
Signifies high force
Tend to occur quickly
Don’t cross suture lines, can self-limit so effects seem to resolve before further deterioration
Lemon-shaped on imaging as doesn’t cross suture lines)
Subdural haematomas
Often in elderly, shrunken brain so less movement needed to occur.
Generally occur with milder trauma eg fall
Can occur over a long time
Can show midline shift
Banana-shaped on imaging, can cross suture lines
Subarachnoid haematoma
Can bathe surface of brain, finger like extensions of blood
Intracerebral haematoma
Bleeding within the brain
affects drainage of CSF
Causes raised ICP
Acute management
ABCD
D for disability
Other injuries eg fracture
Oxygenate/intubate
IV fluids
Glucose
Seizures - Diazepam 10mg IV
CT scan once stable
What is Mild TBI?
Defined as GCS 13-15
Coma for under 30 mins
PTA (post traumatic amnesia) less than 1 hour
What is Moderate TBI?
GCS 9-12
Coma 30 mins - 6 hours
PTA 1-24 hours (lack of ability to form continuous new memories)
