CSF and hydrocephalus Flashcards
what makes CSF? where is most CSF made?
- choriod plexus ependymal cells (choroidal epithelium) inside of the ventricles
- mainly in the lateral ventricle
where are the tight junctions of the BBB and the Blood-CSF barrier
BBB- continous with endothelial lining (facing the blood side) [ non fenestrated capillary lining]
BCB - continous with choroid cells (on the CSF side)
[fenestrated capillary endothelial lining]
what is the function of the astrocyte foot cells in the BBB
needed for BBB development
(type of glial cell)
-regulate water intake inside the brain
what is more permeable, BBB? blood-csf barrier ?
blood csf barrier
Blood CSF barrier impairment leads to an increase in ___ concentration of the CSF
protein
what are the steps of CSF production?
- filtration- filtered blood passes capillary fenestrations and enters choroidal cells in the ventricles due to pressure gradient between the CSF and blood
- active transport of fluid into the ventricles
how to test for composition and pressure of CSF
lumbar puncture between L3/L4 or L4/L5
blood and CSf differ ___ not _____
differ quantitatively not qualitatively
t/f
you have 2 lateral ventricles
true
how does CSF leave the 4th ventricle
- continuous with central canal down into spinal cord
- foramen of luschka- 2 lateral apertures moves CSF back to subarachnoid space in brain then to superior sagitall sinus to drain in venous circulation via subarachnoid villi
- foramen of magendie - 1 medial aperture moves CSF back to subarachnoid space brain then to superior sagitall sinus to drain in venous circulation
what happens if CSF pressure > venous pressure ? venous pressure > CSF pressure?
CSF pressure > - flow of CSF into venous sinuses
Venous pressure> - no flow of CSF **no retrograde flow possible
how is CSF replenished once the CSF has left the brain via the venous sagitall sinuses
goes to heart, gets filtered back to arterial blood, enters the brain again and replenishes CSF via choroid plexuses in each ventricle
disorder of excessive CSF accumulation in the cerebral ventricles or subarachnoid space that causes ventricular dilation and increased inter cranial pressure
hydrocephalus
*expansion of ventricular system
causes of hydrocephalus
- CSF overproduction
- CSF under -reabsorption at level of arachnoid villi
- obstruction
1-2 = communicating (flow of CSF blocked after leaving ventricles, or too much made) 3 = non-communicating
t/f
communicating hydrocephalus is typically associated with increased ICP
true
*except hydrocephalus ex-vacuo
what are the triad of symptoms associated with normal pressure hydrocephalus {NPH) ? what type of hydrocephalus is it? possible causes ?
*chronic communicating hydrocephalus - [underabsorption]
dementia
apraxic gait
urinary incontinence
casuses: increased CSF viscosity, change of ventricle elasticity, impaired absorption
- apraxic gait = frontal lobe disorder in which patient can not initiate walking but has the motor function to walk still intact
- common in the elderly
how is the CSF pressure affected in Normal pressure communicating hydrocephalus ?
intermittently elevated
what type of hydrocephalus is hydrocephalus ex-vacuo? possible causes? common symptoms ? associated ICP?
- communicating [ overproduction ]
- brain atrophy, post traumatic brain injury, psychiatric disorders
- no increased ICP (bc increases CSF production tries to keep weight of brain constant with loss of brain tissue)
- symptoms : blurred vision, headaches, n/v, drowsiness
what is aqueductal stenosis ? common signs/symptoms ? common causes ?
- narrowing of the cerebral aqueduct between 3rd and 4th ventricle leading to obstruction of CSF flow and non-communicating hydrocephalus
- sx: thunderclap headaches, papilledema, cognitive delays, difficulty looking up, tremors, (infant) enlarged head
-causes: tumor compression, narrow duct, gliosis (hypertrophy of glial cells due to CNS damage)
what is dandy-walker malformation ?
-congenital brain malformation in which agenesis/hypoplasia of the cerebellar vermis causes the 4th ventricle to be open to the posterior fossa, this leads to CSF accumulation in the posterior fossa and a “dandy walker cyst” which enlarges after birth and causes compression of the central canal which leads to 4th ventricle obstruction
[cerebellar hyoplasia + CSF cyst + 4th ventricle obstruction]
-noncommunicating hydrocephalus
-symptpms slow motor development, enlarged skull (present at birth)
what is arnold Chiari type 2 malformation ?
- displacement of the cerebellar tonsils, medulla, and 4th ventricle down passed the foramen magnum into cervical canal possibly (90%) causing aquaductal stenosis and non-communicating hydrocephalus
- associated with myelomeningocele
- causes: embryo malformation
- *presents at birth
