head injury Flashcards
what is a primary brain injury
occurs at the moment of impact
target prevention, not treatable
what is secondary brain injury
effects of trauma on the brain that occur later, e.g. lack of cerebral perfusion, blood glucose, CO2, temp
secondary processes which occur at the cells and molecular level to exacerbate neurological damage
what processes can cause secondary brain injury
glutamate release free radical generation calcium mediated damage inflammatory response mitochondrial dysfunction early gene activation oedema opening of BBB increased interstitial fluid pressure neuronal death cascades
describe a graph of intracranial volume against intracranial pressure
as intercranial pressure rises pressure slowly increases too until the critical volume where pressure rises exponentially
how do you manage head injury
assessment of pt
investigations -CT head
who should be sent to hospital
extremes of age amnesia LoC high energy injury vomiting seizure bleeding/clotting disorder
describe the eye component of GCS
1 eyes do not open
2 open to pain
3 open to speech
4 open spontaneously
what is the verbal component of GCS
1 no response 2 incomprehensible sounds 3 innapropriate words 4 confused 5 oriented
what is the motor component of GCS
1 no response 2 extension to pain 3 abnormal flexion to pain 4 normal flexion to pain 5 localizes pain 6 obeys command
what GCS constitutes a mild head injury
13-15
what GCS constitutes a moderate head injury
9-12
what GCS constitutes a severe head injury
8 or less
when should you request a ct head
GCS is less than 13 on initial assessment
gcs is less than 15 2 hours after injury
suspected open or depressed skull
basal skull fracture
vomiting
amnesia for events more than 30 mins before impact
what are red flags`
LoC painful headache vomiting visual disturbance clear fluid from ear or nose bleeding from ears deafness difficulty understanding loss of balance weakness difficulty walking
how do you treat convulsions in head injury
phenytoin
treat pyrexia
what PaCO2 is ideal
4.5-5 kPa
what is CPP
cerebral perfusion pressure
what is MAP
mean arterial pressure
diastolic pressure + 1/3 pulse pressure
what is ICP
intra cranial pressure
how do you calculate CPP
MAP - ICP
what is cerebral autoregulation
maintains constant blood flow to brain between various MAP
this may be compromised in trauma/ ischaemia
what parameters should be maintained after head injury
CPP above 60-70mmHg
systolic should be above 90mmHg
ICP less than 20 mmHg
what should you do if the patient is hypotensive
not due to head injury
could be chest trauma
pelvic fracture
stop bleeding and give fluids
what features suggest a risk of intracranial mass
high impact injury
retrograde amnesia
coagulopathy
seizure
gcs <12
signs of skull fracture
