Neuro Capsules Flashcards
What is the monro-kellie doctrine?
The idea that the cranium is made from brain, blood and CSF
What is the name and optimum pressure that allows oxygen and glucose to leave blood into the brain? Why does brain injury affect this?
Cerebral perfusion pressure = 60-70mmHg
Requires low ICP
MAP-ICP= perfusion pressure (CPP)
Ideal ICP
ICP should be less than 10mmHg
On a CT, what does white mean?
White = calcium or blood
Bifrontal contusions
What do you do if someone has dropped their GCS to less than 8? A-J
A - if GCS <8, call ICU or anaesthetist
B - think pCO2 as well as O2
C - circulation - think brain perfusion and metabolism
D - GCS, pupils, focal neurology, seizures
E - Blood sugar, temperature
F - fluids - HYPERtonic saline if raised ICP, or normal saline if normal
G and H - Get Help!!
I - imaging, urgent CT head
J - jerking - need for anti-epileptics (nystagmus of pupils in those who are paralysed)
What happens to the blood flow as carbon dioxide levels?
As it increases, the blood flow to the brain increases, which actually worsens the ICP
Where do you measure the mean arterial pressure?
Measure using arterial line - put the transducer at the level of the brain, at the level of the tragus of the ear
Difference between systolic in heart and brain
Systolic - 10 = brain systolic
Which can you not give hypotonic fluids like dextrose for neurosurgery patients?
If the fluid is hypotonic in comparison to the blood, it causes the fluid to seep into third spaces, causing oedema.
Mannitol
Diuretic
Pupils
Document size, shape and reaction to light
If the patient is fully awake but there is no reaction to light, what do you do? What might you need to consider?
Check accomodation
Consider correlation to GCS Direct injury to globe Previous eye surgery or cataracts Opthalmoscopy CN3 palsy
Which palsy gives you a dilated pupil?
CN3
If someone is not obeying commands, what do you think about?
Is there spontaneous movement
Are these purposeful e.g. trying to pull out NG tubes - means there is higher cortical involvement
What things might cause false neurological signs?
CN 7 palsy
Kernohan’s notch -
What do you call paralysis after epilepsy?
Todd’s paresis - post ictal
What is Kernohan’s notch?
A MASSIVE subdural haematoma crushes contralateral brainstem, causing IPSILATERAL weakness to the haematoma
What do you do if someone has hydrocephalus? How do you avoid coning?
External ventricular drain - if you set it at a particular level, the CSF will only come out if it is at that level or higher. The EVD is from the skull so avoids coning.
What do you call a catheter in the brain?
Shunt - CSF form ventricle gets siphoned into peritoneum.
What do you do if someone has a shunt but the patient has low GCS suddenly? What investigations do you do?
If the valve setting is incorrect, if the shunt isn’t working properly
Shunt series x ray of head neck and abdomen
Why might someone have a shunt?
Intraventricular haemorrhage
What is status epilepticus?
Recurrent seizures over 1 hr with breaks, but never quite recover
OR
epilepsy for 5 minutes or more
What is Keppra?
Levetiracetam
If someone’s pregnant, which antiepileptic do you give?
Lamotrigine
Management for status epilepticus
See if it stops spontaneously after 5 minutes
IF not, give IV lorazepam
then phenytoin or levetiracetam
Why would you choose levetiracetam over phenytoin?
Pheny - cardiac SE and requires central line to administer therefore pt needs to be on cardiac monitor. Complicated.
Leve can be given peripherally through a venflon therefore easier.
Treatment for focal epilepsy
CBZ
le
Treatment for generalised epilepsy
Sodium val
CBZ
Post-op urinary retention - what do you do?
Take pt to toilet and turn tap on
Insert catheter
Types or urinary retention and causes
Painful urinary retention - due to bladder, prostate etc
Painless retention - neurogenic e.g. due to cauda equina syndrome or nerve problems
Post op urinary retention 3 days after neurofibroma spine surgery - what do you do? Why has this occured?
Insert catheter
Document residual volume
Full neurological examination
MRI scan
Escalate to seniors
The three days have allowed something to expand (haematoma, black on MRI due to haemosiderin)
FEATURES OF NEUROGENIC SHOCK
Spinal injury above T1, therefore no sympathetic chain, therefore autonomic dysfunction:
Bradycardia
Hypotension
Poikilothermia
Noradrenaline
Neurogenic vs spinal shock
Autonomic dysreflexia
Injury to spine T6 or below means you’ve lost your PNS but sympatheic chain intact means:
Any small stimulus will lead to uninhabited sympathetic activity - tachycardic, tachypnoea, sweating, distended neck veins
Neurogenic vs spinal shock
Autonomic dysreflexia
Injury to spine T6 or below means you’ve lost your PNS but sympathetic chain intact means:
Any small stimulus will lead to uninhabited sympathetic activity - tachycardic, tachypnoea, sweating, distended neck veins
