CSF and Hydrocephalus Flashcards
Where is CSF produced?
primarily by choroid plexus in lateral ventrical (65%)
also in 3rd and 4th ventricles
What makes up the BBB?
continuous tight jxns in endothelial cells
basement membrane
asctrocyte foot processes
transport carriers for glucose and AAs
sodium ion transporters
How does the Blood-CSF barrier compare to the BBB?
more permeable
fenestrations in the endothelium
basement membrain
*tight jxns btw choroid cells (not endo cells like in BBB)
What occurs if there is a problem in the blood-csf barrier?
will see an increase in protein concentration in the CSF
Where do you do a lumbar puncture and what are you looking for?
btw L4 and L5
looking for an increase in protein content in CSF
What are the 4 main functions of CSF?
protection: shock absorber
buoyancy: pressure at base of brain is reduced
metabolic: one-way flow of CSF to blood takes toxins away
endocrine medium
Where is the interventricular foramen of monroe?
in btw lateral and 3rd ventricles
Where is the cerebral aqueduct?
btw 3rd and 4th ventricles
How does CSF leave the 4th ventricle?
2 lateral foramina of Luschka
1 median aperture/foramen of magendie
What is the flow of CSF?
choroid plexus –> lateral ventricles –> interventricular foramen –> 3rd –> crebral aqueduct –> 4th –> median aperture and foramenia of luschka –> subarachnoid space –> villi –> bloodstream
What is hydrocephalus?
excessive amount of CSF accumulates w/in cerebral ventricles and/or subarachnoid spaces –> ventricular dilation –> increased ICP
What can cause hydrocephalus?
overproduction of CSF (rare)
under-absorption of CSF
obstruction of outflow of CSF from ventricles
What are the 2 types of hydrocephalus?
communicating = non-obstructive
non-communicating = obstructive
What are the hallmarks of communicating hydrocephalus?
flow of CSF is blocked AFTER it leaves the ventricles
due to abnormalities that inhibit the resorption of CSF - at level of arachnoid villi
typically assoc w/ increased ICP
What is normal pressure hydrocephalus?
chronic communicating hydrocephalus
intermittently elevated CSF pressure
most common in adults over 60
*triad of sx: dementia, apraxic gait, urinary incontinence
What can cause normal pressure hydrocephalus?
increased viscosity of CSF
altered elasticity of ventricular walls
impaired absorption due to prior menigitis or subarachnoid hemorrhage
What is hydrocephalus ex-vacuo?
compensatory enlargement of ventricles and subarachnoid spaces due to brain atrophy, post-traumatic, in some psych disorders
What is a non-communicating hydrocephalus?
excess accumulation of CSF due to structural blockage of CSF flow w/in ventricular sys
can be concenital or acquired
can figure out where block is based on which ventricles are enlarged
What is aqueductal stenosis?
narrowing of cerebral aqueduct blocking flow of csf –> non-communicated hydrocephalus
caused by tumor compression, gliosis (hypertrophy of glial cells, w/ hx of infection)
What are the signs/sx of aqueductal stenosis?
thunderclap headache
papilledema
enlarged head (in infants)
decreased level of consciousness
upward gaze palsy
What is the Dandy-Walker Malformation?
congenital bran malformation
obstruction at outlet of 4th ventricle + cerebellar hypoplasia
complete or partial agenesis of crebellar vermis
dandy-walker cysts: enlarged fourth ventricles
What are sx of dandy-walker malformation?
frequent vomiting
tense anterior fontanelle
hypotonia
rapid enlargement of head circumference
what is Chiari II malformation?
downward displacement of inferior cerebellar vermis, tonsils, and medulla through foramen magnum
usually w/ myelomeningocele
hydrocephalus in 90% of cases
What are sx of chiari II malformation?
swallowing and breathing problems
feeding problems
poor bladder control
difficulty moving lower extremities
What can cause acquired hydrocephalus?
brain tumor or cyst
blocked CSF flow
bleeding
trauma
infection
