7. CSF & Hydrocephalus Flashcards
What are the fxns of CSF
- provide homeostasis & mechanical protection/buoyancy
- removes brain metabolites (prevent bacterial spread; let ABs thru)
- hormone transport (endocrine fxn)
Where is CSF made
primarily by choroid plexus, ependymal cells (60-80%)
-found in lateral ventricle (65%), 3rd & 4th ventricles
What is the structure of choroid plexus
- villous folds lined by epithelium w/ central core of highly vascularized CT
- contains specialized layer of ependymal cells = choroidal epithelium overlies the villi (this dicates what goes in and out)
Compare/contrast CSF and plasma
CSF = clear/colorless w few cells and low protein
-doesnt differ from plasma qualitatively, but it does QUANTITATIVELY
CSF in bacterial meningitis
increased pressure (lumbar punture pressure)
increased PMNs (fighting bacteria) & protein (bacteria in cell & made of protein –> increase protein)
decreased glucose (bacteria eats glucose to stay alive)
CSF in fungal/TB meningitis
increased pressure (lumbar punture pressure)
increased lymphocytes (fighting foreign particles) and protein (fungi made of protein –> increase protein levels when in cell)
decreased glucose (eat glucose to stay alive)
CSF in viral meningitis
normal/increased pressure (lumbar punture pressure)
increased lymphocyte (fighting foreign particles)
normal/increased proteins (virus = very small; may not see increase)
normal glucose (virus is NOT living - depends on host to stay alive)
What is the flow of CSF in the ventricular system
lateral ventricles –> 3rd ventricle by right/left interventricular foramina of monro –> 4th ventricle via cerebral aqueduct of sylvius –> subarachnoid space via foramina of Luschka (lateral) & foramen of Magendie (medial)
-then reabsorbed by arachnoid granulations and then drains into dural vnous sinuses
label
define hydrocephalus
increased intracranial pressure (ICP) and ventricular dilation due to excess amount of CSF build up in ventricles &/or subarachnoid spaces
What are the causes of hydrocephalus
Congenital or Acquired
- Communicating (non-obstructive): overproduction of CSF OR under-absorption of CSF
- Non-communicating (obstructive): obstruction of outflow
What is aqueductal stenoisis
Non-communicating (obstructive)
• Accumulation of CSF in lateral & third ventricles due to obstruction
What are the causes of aqueductal stenosis
- Congenital (most common ; x-linked)
- Tumor (pineal)
- Previous/current case of meningitis leading to scarring or other infection
- Inflammation from intrauterine infection
treat: resolve meningitis or place shunt
What type of hydrocephalus occurs in adults bc CSF doesnt drain properly and causes enlarged lateral ventricles and cortical atrophy
normal pressure hydrocephalus
= communicating hydrocephalus
-may resolve w/ lumbar puncture, b/c taking CSF out
What are the causes of normal pressure hydrocephalus
- increased CSF viscosity
- altered elasticity of ventricular walls
- impaired CSF absorption
What is “wacky, wobbly and wet?”
the TRIAD that presents with normal pressure hydrocephalus
Wacky = cognitive impairment/confusion
Wobbly = unsteady/magnetic gait
Wet = urinary incontinence
What is Dandy-Walker Malformation
Congenital: 4th ventricle outlet obstruction (enlarged- press on cerebellum))
Causes –> Cerebellar hypoplasia => partial or complete agenesis of vermis
fluid accumulates above 4th ventricle
=non-communicating
What is Chiari II
- Downward displaced inferior cerebellar vermis & tonsils thru the foramen magnum
- Associated with lumbosacral myelomeningocele
- = non communicating
- build up above 4th ventricle
What is the treatment for Chiari II
Most common = Shunt - placed so fluid can drain to another part of the body
shunt contains valves that keep the fluid flowing in the right direction and correct speed
usually need it for the rest of their life
Areas proximal to the obstruction/problem—-
will enlarge
If all ventricles are ______ (generally unless a past 4th ventricle obstruction), you should think __________
If all ventricles are enlarged, (generally unless a post 4th ventricle obstruction) think about an absorption issue
lumbar punture is for….
=testing CSF via lumbar puncture (L4-L5)
-you know there is problem when CSF is yellow or has RBCs (after first tube)
how do you know you’re at the level of the telencehpalon/cerebral cortex from a slide
see the lateral ventricle
what structure will you see on the slide at the level of the thalami
see 3rd ventricle
when you see the 4th ventricle you know youre at which level…
level of pons
how are dandy-walker malformation and chiari II similar and diff
similar: fluid build up in 4th ventricle
dandy walker: cerebellum is not developed (problem in embryo)
chiari II: cerebellum is developed but pushed down
