Raised ICP and Nerve Palsies Flashcards
name the 2 kinds of hydrocephalus that exist
congenital
acquired
2 ways in which ICP can become raised?
increased pressure in the fluid surrounding the brain
increase in pressure within the brain
medical causes of raised icp
brain tumour head injury hydrocephalus meningitis stroke
is intracranial volume constant or variable? why is this relevant?
constant; if you add to it something will have to leave
name the 3 components that make up the intracranial volume
brain
blood
CSF
the cranial cavity is flexible T or F
F
what physical effect does raised icp have on the brain and its components?
damaged tissue
shift in tissue
herniation
contricted BVs and nerves
what could a raised icp at the very back of the brain cause?
herniation of the brainstem
visual symptoms associated with raised icp?
transient blurred vision double vision loss of vision papilloedema pupillary changes
what do the meninges cover?
optic nerve
name the 3 types of meninge
dura mater
arachnoid
pia
what 2 structures does the subarachnoid space lie between?
arachnoid
pia
what are meninges?
protective coverings of the brain and spinal cord
what meninge contains blood vessels?
subarachnoid space
sensory supply to the dura meninge?
CNV
what meninge encloses the dural venous sinus?
dura mater
what meninge is attached to the brain?
pia (encloses the entire brain)
main role of pia?
cushion and protect brain
how can the subarachnoid space be accessed non surgically?
lumbar puncture
what levels of the spinal cord should a lumbar puncture be performed at?
L3/4 or L4/5
why is the optic nerve at risk of damage from ICP?
is enclosed by meninges
icp will travel along subarachnoid space in the optic nerve sheath
cranial nerves to come off pons?
CN V only
what is a subdural haematoma?
vessels in subarachnoid space bursting and mixing with CSF
what meninge gives the brain ability to move?
subarachnoid space
what spinal level does the spinal cord end?
L2
name the most central of the all the ventricles of the brain
3rd
what ventricle does the central canal of the spinal cord follow on from?
4th
2 ways csf can go after release from the 4th ventricle?
subarachnoid space
central canal of spinal cord
what will optic nerve damage from raised icp look like on fundoscopy?
bulging/swollen optic disc -> papilloedema
what vessels will be affected by papilloedema?
central artery and vein of retina
symptoms of papilloedema?
blurred vision
constricted visual field
flickering
graying of vision
what kind of hernia could oculomotor nerve damage cause?
tentorial (of tentorium cerebelli)
what does cn3 come off?
midbrain
2 main fibres of the cn3 nerve
parasympathetic
somatomotor
presentation of cn3 palsy
eye looks down and out
slow light reflex
dilated pupil
ptosis
main fibres on cn4?
somatormotor
presentation of cn4 palsy
eye cannot move inferomedially
looks to the side and up
diplopia looking down
what muscle is affected by cn4 palsy?
superior oblique
what action cant be done if the superior oblique is affected?
intorsion
nerve with the longest course to the dura
cn6
presentation of cn6 palsy
medial deviation eye
cant move laterally
what muscle is affected by cn6 palsy
lateral rectus
what palsy presents with someone tilting their head to fix their vision?
cn4 palsy
