Anatomy - Hydrocephalus Flashcards
where is choroid plexus found in the brain
lateral ventricle (majority)
third ventricle
fourth ventricle
describe the structure of the BBB
endothelial cells connected with tight junctions
then a basement membrane
then astrocyte foot processes
what transporters are in the BBB
transport carriers for glucose and essential amino acids
sodium ion transporters
what controls entry of NT in the BBB
metabolic processes within endothelial cells
describe the structure of the blood-CSF barrier
fenestrated epithelial (no tight junctions)
then a basement membrane
choroid cells connected by tight junctions
impairment of the blood-CSF barrier leads to what
increased protein concentration in the CSF
compare CSF and plasma content
CSF: low glucose, low protein
plasma: higher glucose, higher protein, amount the same Na+
how does CSF protect the brain from harmful toxins
it has a one-way flow wihch takes harmful metabolites, drugs, and other substances away from the brain
how does CSF work with the endocrine system
it serves to transport hormones to other areas of the brain
where is the interventricular foramen of monroe
between the lateral and 3rd ventricle
how does CSF leave the fourth ventricle
through either 2 of the lateral foramina (Luschka) or the 1 medial foramen (Magendie)
describe the pathway of flow of CSF
lateral ventricle –> interventricular foramen –> third ventricle –> cerebral aqueduct –> fourth ventricle –> lateral aperature, median aperature, or central canal –> subarachnoid space –> arachnoid villi of dural venous sinuses –> heart and lungs –> arterial blood –> back to brain
if CSF pressure is greater than venous pressure, how does CSF flow
if venous pressure is greater than CSF pressure, how does CSF flow
CSF > venous: flows into venous sagittal sinus
venous > CSF: one way valve; will not flow backwards
describe communicating/non-obstructive hydrocephalus
- where is the problem normally located
flow of CSF is blocked after it has exited the ventricles
- inhibition of resorption of CSF at the level of the arachnoid villi
what does this image show
communicating hydrocephalus
(enlarged lateral ventricle)
what is normal pressure hydrocephalus
- what can cause it
a type of chronic communicating hydrocephalus
- increased viscosity of CSF
- altered elasticity of ventricular walls
- impaired absorption due to prior meningitis or subarachnoid hemorrhage
normal pressure hydrocephalus normally presents in what types of patients
adults over 60
- dementia
- apraxis gait
- urinary incontinence
what is this
hydrocephalus ex-vacuo
what is hydrocephalus ex-vacuo and what causes it
a type of communicating hydrocephalus where there is compensatory enlargement of cerebral ventricles and subarachnoid spaces (making up for atrophy)
- brain atrophy
- post-traumatic brain injuries
- schizophrenia
compare LP results between normal pressure hydrocephalus and hydrocephalus ex vacuo (two types of communicating hydrocephalus)
normal pressure: intermittent elevated ICP pressure
ex vacuo: no increased ICP
what is non-communicating/obstructive hydrocephalus
excess accumulation of CSF due to structural blockage of CSF flow within the ventricular system
what dis
aqueductal stenosis
(non-communicating hydrocephalus)
signs and sx of aqueductal stenosis
“thunderclap” headache
papilledema
enlarged head (infants)
cognitive/developmental delays
upward gaze palsy
decrease level of consciousness
tremors
what is this
Dandy-Walker Malformation
what is this
Dandy-Walker Malformation
what is Dandy-Walker malformation
obstruction at outlet of 4th venticle + cerebellar hypoplasia
- enlargement at the base of the skull in infants
complete or partial agenesis of the cerebellar vermis is associated with what disease process
Dandy-Walker
what is this
Chiari type II
what is a chiari II malformation
downward displacement of inferior cerebellar vermis, cerebellar tonsils, and medulla through foramen magnum
causes of Chiari type II
structural defects in the brain and SC
genetics
lack of vertain vitamins in maternal diet
what two sx are often associated with chiari type II
myelomeningocele
hydrocephalus
what is this
aquired hydrocephalus from tumor
what is aquired hydrocephalus and what causes it
development of hydrocephalus from something preventing CSF drainage in the brain
- brain tumor/cyst
- blocked CSF flow
- subarachnoid hemorrhage
- head trauma
- infection (meningitis)
