CSF And Hydrocephalus Flashcards
What and where is the CSF?
Fluid around brain and spinal cord
What is the function of the CSF?
helps provide homeostasis and mechanical protection/buoyancy
Remove brain metabolites
Endocrine mechanism in transporting hormones
What is the primary producer of CSF?
Choroid plexus by ependymal cells
Where is the choroid plexus found?
Lateral ventricle (65%)
Third ventricle
Fourth ventricle
What is the choroid plexus?
Villous folds lined by epithelium w/ a central core of highly vascularized connective tissue
What overlies the villi of the choroid plexus?
Specialized layer of ependymal cells - choroidal epithelium
What meningeal layer surrounds the ependymal cells?
Pia mater
What should the normal composition of CSF be?
Clear and colorless
Few cells and low protein
How does it differ from plasma?
Quantitatively
Same qualitatively
How do you test the CSF composition?
Lumbar puncture between L4 and L5
What is higher in CSF than in plasma?
Mg
CL
What is lower in CSF than in plasma?
K Ca HCO3 Protein Glucose
What is the flow of CSF thru the ventricles? I
Lateral —>
Interventricular foramina of Monroe—> 3
3rd -> cerebral aqueduct of Sylvius-> 4th
4th-> foramina of Luschka and foramen of magendie —> subarachnoid space
Subarachnoid-> granulations -> dural venous sinuses
Where are the foramina of luschka and the foramen of magendie
Luschka - 2 lateral apertures
Magendie - medial aperture
What is CSF re-absorbed by? Where does it drain to?
Re-absorbed by arachnoid granulation
Drains to dural venous sinuses
Where is the lateral ventricle at?
At what level will you see the lateral ventricle on a CT?
In telencephalon;
Cerebral cortex area
At what level, will you see the third ventricle?
Level of thalami
At what level will you see the fourth ventricle?
At the level of the PONS
What is hydrocephalus?
Increase amts. of ICP and ventricular dilation due to an excessive amt. of CSF accumulation in ventricles &/or subarachnoid spaces
What can hydrocephalus be due to?
Congenital or acquired things
What are examples of what can cause hydrocephalus? Non-comm. or comm.?
Overproduction of CSF - commun.
Under-absorption of CSF - commun.
Obstruction of outflow - non comm.
What is aqueductal stenosis?
Caused by?
Where will CSF accumulate?
Non-communicating hydrocephalus
Narrowing/obstruction of cerebral aqueduct
Fluid accumulates in 3rd and lateral ventricles
What are the causes of aqueductal stenosis?
Congenital (x-linked) (most common cause)
Pineal tumor
Previous meningitis that led to scarring (or other infection)
Inflammation from intrauterine infection
What is normal pressure hydrocephalus?
Failure of CSF to drain properly leading to enlarged ventricles and cortical atrophy
communicating hydrocephalus (no obstructions)
What can cause normal pressure hydrocephalus?
Increased CSF viscosity
Altered elasticity of ventricular walls
Impaired CSF absorption
What is the TRIAD assoc. w/ Normal Pressure Hydrocephalus?
Cognitive impairment/confusion
Unsteady, magnetic gait
Urinary in continence
Wacky, wobbly, wet
What ventricles are enlarged with normal pressure hydrocephalus?
All of them
What is Dandy-walker malformation?
Congenital brain malformation where the fourth ventricle outlet is obstructed and enlarged
Non-communicated hydrocephalus (obstructed)
What happens bc of the 4th ventricle enlargement in the Dandy Walker Malformation?
Hypoplasia of the cerebellum - specifically partial or complete agenesis of vermis
Cyst in the 4th ventricle causes cerebellum to not develop (no space for it)
When does the Dandy-Walker malformation occur in embryo?
Weeks 13-18
What is Chiari 2?
Non communicating hydrocephalus (obstructive)
Caused by downward displacement of inferior cerebellar veins and tonsil thru the foramen magnum closing off 4th ventricle.
What is Chiari 2 associated with?
Lumbosacral myelomeningocele
What is the difference between Chiari II and the Dandy-Walker malformation?
Chiari II - will have cerebellum
Dandy-Walker- agenesis of vermis and no cerebellum
Where does fluid accumulate in Chiari II?
Above the 4th ventricle
What are the treatments for hydrocephalus?
Most common = shunt to drain fluid to another part of body with valve keeping the fluid flowing in the right direction and at correct speed
Will need for the rest of life
Where will ventricles generally be enlarged for a non-communicating case of hydrocephalus
Proximal to obstruction
