Ventricle, CSF, & Hydrocephalus Flashcards
This is the fluid around the brain and spinal cord that helps provide homeostasis and mechanical protection and buoyancy.
Cerebrospinal Fluid (CSF)
The CSF also helps remove brain __________ and contains an endocrine mechanism by helping with ________ transport.
Metabolites
Hormone
CSF is produced primarily by the ________ _______ (by ependymal cells) which is found in the lateral ventricle (65 percent produced here), third ventricle, and fourth ventricle.
Choroid Plexus
The Choroid Plexus consists of villous folds lined by epithelium with a central core of highly vascularized connective tissue. The specialized layer of _________ cells is the choroidal epithelium that overlies these villi.
Ependymal
Normal CSF is clear and colorless and has few cells and low ________.
Protein
CSF does not differ from ________ qualitatively, but does differ quantitatively.
Plasma
How do we test for CSF composition?
By lumbar puncture between L4 and L5
What drains the lateral ventricles into the 3rd ventricle?
Interventricular Foramina of Monro (right and left)
What drains the 3rd ventricle into the 4th ventricle?
Cerebral Aqueduct (of Sylvius)
What drains the 4th ventricle into the Subarachnoid Space?
Foramina of Luschka (Lateral Aperture)
Foramina of Magendie (Medial Aperture)
CSF made by choroid plexuses are located in the lateral and 4th ventricles. It then travels to the subarachnoid space via the medial and lateral apertures and is reabsorbed by ________ ________ and then drains into dural venous sinuses.
Arachnoid Granulations
In an axial CT, if you can see the lateral ventricles then you know you are at what level of the brain?
Telencephalon and Cerebral Cortex area
In an axial CT, if you can see the 3rd ventricle then you know you are at what level of the brain?
Level of Thalamus
In an axial CT, if you can see the 4th ventricle then you know you are at what level of the brain?
Level of Pons
This is the term for increased amounts of intracranial pressure and ventricular dilation due to an excessive amount of CSF accumulation in the ventricles and/or subarachnoid spaces.
Hydrocephalus
Hydrocephalus can be congenital OR acquired due to…
1) Overproduction of CSF (rare)
2) Under-absorption of CSF
3) Obstruction of outflow
Overproduction of CSF or under-absorption of CSF are both (NON-COMMUNICATING/COMMUNICATING) and (NON-OBSTRUCTIVE/OBSTRUCTIVE).
Communicating
Non-obstructive
Obstruction of outflow is (NON-COMMUNICATING/COMMUNICATING) and (NON-OBSTRUCTIVE/OBSTRUCTIVE).
Non-communicating
Obstructive
This is due to an accumulation of CSF in the lateral and 3rd ventricles due to an obstruction. It is non-communicating (obstructive).
Aqueductal Stenosis
***The Cerebral Aqueduct (drains 3rd ventricle into 4th ventricle) is being blocked!
What are the possible causes of Aqueductal Stenosis?
1) Congenital (most common cause)
2) Tumor (pineal)
3) Previous case of meningitis (or other infection) leading to scarring
4) Inflammation from intrauterine infection (current meningitis)
This is a form of communicating (non-obstructive) hydrocephalus that occurs when CSF fails to drain properly, leading to enlarged ventricles and cortical atrophy. Patients present with the triad of:
1) Cognitive impairment/confusion
2) Unsteady, magnetic gait
3) Urinary incontinence
Normal Pressure Hydrocephalus
***WET - WACKY - WOBBLY
What can cause Normal Pressure Hydrocpehalus?
- Increased CSF viscosity
- Altered elasticity of ventricular walls
- Impaired CSF absorption (i.e., arachnoid granulations)
What could possibly resolve Normal Pressure Hydrocephalus?
Lumbar puncture, because you take out fluid and release some of the pressure. If the patient goes too long though, the cortex can start to atrophy from the pressure and some of the effects could be irreversible.
This is a non-communicating (obstructive) congenital hydrocephalus brain malformation where the 4th ventricle outlet is obstructed, causing the 4th ventricle to be enlarged and fluid to accumulate above it. It causes cerebellar hypoplasia, specifically partial or complete agenesis of the vermis.
Dandy-Walker Malformation
This is a form of non-communicating (obstructive) hydrocephalus that causes the downward displacement of the inferior cerebellar vermis and tonsils through the foramen magnum. This causes the 4th ventricle outlet to be closed off, so fluid accumulates above it. It is closely associated with lumbosacral myelomeningocele.
Chiari II
How is a tonsillar herniation and Chiari II different?
Chiari II is congenital, while a tonsillar herniation is due to increased intracranial pressure.
What is the most common treatment for hydrocephalus?
Shunt
A _______ is placed so that the fluid can drain to another part of the body. It contains a valve that keeps the fluid flowing in the right direction and at the correct speed. Most people will need this for the rest of their lives.
Shunt
In hydrocephalus, the ventricles (PROXIMAL/DISTAL) to the obstruction/problem will enlarge.
Proximal
If all ventricles are enlarged (generally, unless a post 4th ventricle obstruction) think about there being an _________ issue.
Absorption
