Intracranial Pressure Flashcards
What causes raised ICP
increased pressure in the fluid surrounding the brain
increase in pressure in the brain itself
Give some examples of pathologis which result in raised intracranial pressure
brain tumour head injury hydrocephalus meningitis stroke
how does the intracranial volume remain constatn
monro kellie hypothosis
ie and increase in one of the cranial cavity compontens (brain, blood and CSF) will result in a decrease in the other components to try and maintain a stable intracranial volume
What visual problems occur with raised intracranial pressure
transient blurred vision double vision loss of vision papilloedmea pupillary changes
What is the outermost layer of the meniges
the dura mater
what is the sensory nerve supply to the dura mater
CNV
What is enclosed in the dural mater
dural venous sinuses
What is the menige that adheres to the brain
pia
Where is CSF and blood vessels contained
the subarachnoid space
where is csf produced
the choroid plexus of the ventricles
where is csf reabsorbed
the dural venous sinuses via the arachnoid granulations
How can csf be accessed
lumbar puncture at L3/4 or L4/5 IV discs
Where does the subarachnoid space end
inferiorly att the level of S2 of the sacrum
where is the choroid plexus situites
the lateral and third ventricles
Decribe the circulation of CSF
Choroid plexus - lateral venticles- third ventricle- via the cerebral aqueduct to 4th ventricle- subarachnoid space- reabsorbed into the dural venous sinus
What are the symptoms of papilloedema
transient visual obscurations transietn flickering blurring vision constriction of the visual fiels decreased colour perception
What will result if the oculomotor nerve is damaged
loss of pupillary light reflex (due to loss of parasympathetic innervation to the eye)
dilated pupil
ptosis
eye will turn inferiolaterally
What will result from damage to the trochlear nervw
superior oblique paralysis
eye will move inferomedially due to inferior oblique being unopposed
diplopia when looking down
what will result for damage to abducent nerve
paralysis of lateral rectus
eye cannot move laterall in horizontal plane – results in medial deviation of the eye
What is papilloedema
swollen optic discs secondary to raised ICP
what do all patients with a bilateral optic disc swelling have
raised ICP due to a space occupying lesion until proven otherwise
what happens if disc swelling due to any cause becomes chronic
disc swelling subsides but discs become atrophic and pale
loss of vision and blindness may occur
Name the parts of cranial nerve II examination
opthalmoscopy
visual acuity
pupil exam
visual field
Why is it important to check blood pressure
malignant hypertension or idiopathic intracranial hypertension are both causes of raised ICP and thus papilloedema
What usually causes a sixth nerve palsy
raised intracranial pressur
What usually causes a fourth nerve palsy
trauma
or congenital
What usually caused a third nerve palsy
aneurysm
MS also important
What usually caused a third nerve palsy
aneurysm
MS also important
What is the causes internuclear opthalmoplegia
MS
vascular