Hydrocephalus Flashcards
where the CSF is produced
choroid plexus that lines the lateral ventricles
where is CSF drained
through the arachnoid granulations into the superior sagittal sinus
how many times a day does CSF volume replace itseld
3/4
cerebral aqueduct connects what ventricles
3rd and 4th
what makes arachnoid granulations open to CSF
pressure becoming greater than dural venous sinus pressure and opening one-way valves
true/false CSF production uses ATP
true
true/false CSF production uses ATP
false - passive process driven by pressure gradient
two types of hydrocephalus
communicating and non-communicating
4 causes of a communicating hydrocephalus
infection, subarachnoid haemorrhage, post-operative and head trauma
infection can cause non/communicating hydrocephalus
both
how does a subarachnoid haemorrhage cause communicating hydrocephalus
increases ICP by increasing volume and also by the blood scarring the arachnoid granulations and obstructing reabsorption
pathophysiology of non-communicating hydrocephalus
obstruction of the normal CSF pathway
aquecuctal stenosis, tumours, cysts, infection, haemorrhage and congenital malformation may all cause what
non-communicating hydrocephalus
which nerve is damaged in raised ICP
the 6th (trochlea) because it has the longest intercranial course
3 Ws of normal pressure hydrocephalus
wet, wobbly and wacky
scan used to view ventricles in raised ICP
CT
two ratios of measuring ventricles on CT
Evan’s and ventricular index
urgent treatment of hydrocephalus
urgent external ventricular drain
long term treatment of hydrocephalus
a shunt –> can cause headache and infection
where do shunts drain from and to
ventricle or spine to atria or peritoneum
complication of an LP in raised ICP
herniation (coning)
what hydrocephalus is a rare and preventable cause of dementia
normal pressure hydrocephalus
what is contradictory about normal pressure hydrocephalus
LP in normal pressure but dilated ventricles on CT
what type is a 3rd ventriculostomy an option
in non-communicating - opens the ventricle space back up
brain receives how much of the cardiac output
15%
cerebral perfusion pressure =
mean arterial pressure - intracranial pressure
range of CPP that cerebral blood flow autoregulation can work
50-150mmHg
carbon dioxide is a vasoconstrictor/dilator
vasodilation
what cells make the blood brain barrier
astrocytes
what does the monro-kelly doctrine tell us
when a new intracranial mass in introduced there will be a compensatory change in volume through decrease of venous blood or CSF to maintain a constant intracranial volume
what do C waves correspond to
waves of blood pressure through systolic and diastolic
what do B waves correspond to
breathing
what do A waves correspond to
an abrupt elevation in ICP for 5-20 mins as high as 50/10mmHg
what is Cushing’s reflex
a nervous system response to reduce ICP by increasing BP, slowing heart rate and an irregular resp rate
what is Cushing’s triad
hypertension, bradycardia, irregular resp rate
when do you see cushing’s triad (i.e. in what condition)
coning
presentation of coning
cushing’s triad, altered mental status and cranial nerve defects
treating raised ICP
head elevated
fluids (mannitol or hypertonic saline)
surgical decompression
