Lecture 7: Ventricles and CSF Flashcards
What is a big difference between Dandy Walker and Chiari Type II malformations?
- Dandy Walker: cerebellum not fully formed
- Chiari Type II: cerebellum formed
What ventricles would be enlarged in Aqueductal stenosis?
Lateral and 3rd Ventricles due to obstruction of cerebral aqueduct
Where is the problem in a normal pressure hydrocephalus?
CSF fails to drain properly, leading to enlarged ventricles and cortical atrophy
- Increased CSF viscosity
- Alterted viscosity of ventricular walls
- Impaired CSF absorption by arachnoid villi
Communicating (Non-obstructive)
What occurs in a Chiari II malformation?
- Displacement of inferior cerebellar vermis and tonsils through the foramen magnum
- Lumbosacral myelomeningocele
- Fluid accumulates above 4th ventricle
What are some symptoms of Normal Pressure Hydrocephalus?
Triad
- Cognitive impairment (wacky)
- Unsteady, magnetic gait (wobbly)
- Urinary incontinence (wet)
What is the flow of CSF?
Be Specific
- Step 1: Lateral Ventricle –> 3rd Ventricle
- via Foramen of Monro
- Step 2: 3rd Ventricle –> 4th Ventricle
- via Cerebral Aqueduct
- Step 3: 4th Ventricle –> Subrachnoid Space
- Lateral: Foramen of Luschka (2)
- Medial: Foramen of Magendie (1)
- Step 4: Reabsorbed by arachnoid granulations
- Step 5: Drainage into dural venous sinuses
If all the ventricles are enlarged, what type of issue should we think about?
Problem with Absorption of CSF
What is happening in this image?
Is this communicative or non-communicative
Chiari II Malformation
Non-communicating (Obstructive)
What is this?
Aqueductal Stenosis
75 y/o male patient presents with progressive gait apraxia, memory loss, and urinary incontinence for the past few months. What kind of hydrocephalus does he most likely have?
Chronic Communicating Hydrocephalus
Normal Pressure Hydrocephalus
2 y/o male patient presents with enlarged head and decreasing consciousness. On exam, he has papilledema and difficulty looking up. What type of hydocephalus might this patient have?
Aqueductal stenosis
Non-communicating (obstructive)
When viewing a CT, what can the three differnet ventricles tell you about what level of the brain you are looking at?
-
Lateral Ventricle: Telencephalon Structures
- Cerebral Cortex
- Third Ventricle: Level of Thalami
- Fourth Ventricle: Pons
What layer of the BBB controls entry of neurotransmitters?
Endothelium
What is this?
Communicating Hydrocephalus at the level of lateral ventricle
What is hydrocephalus?
Increased amounts of intracranial pressure and ventricular dilation tue to an excessive amount of CSF in ventricles and/or subaracnoid spaces
What layer of the Blood-CSF barrier controls passage of substances?
Choroid cells
Why is Dandy Walker Malformation considered a congenital problem?
- Problems start between 13th-18th week of development
- Cyst forms in 4th ventricle, disrupting development of cerebellum
What is this?
Is this communicatinng or non-communicating?
Dandy Walker Malformation
Non-communicating (Obstructive)
What are some causes of aqueductal stenosis?
- Congenital (x-linked)
- Pineal Tumor
- Meningitis Infection
- Inflammation from inrauterine infection
Can treat with shunt or cure infection
Where is the majority of the CSF produced?
Lateral Ventricle (65%)
What are symptoms of a Dandy Walker Malformation?
Congenital Brain Malformation
- Enlarged 4th ventricle
- fluid accumulates above this ventricle
- Cerebellar hypoplasia: agenesis of vermis of cerebellum
- Enlargement at the base of the skull in the posterior fossa
What is the difference between communicating vs non-communicating hydrocephalus?
-
Communicating (Non-Obstructive) Hydrocephalus
- Due to overproduction (rare) or under-absorption of CSF (more common)
- Occurs when the flow of CSF is blocked after it exits the ventricles. (CSF can still flow between the ventricles, which remain open)
-
Non-Communicating (Obstructive) Hydrocephalus
- Obstruction of outflow
- CSF is blocked along one or more of the narrow passages connecting the ventricles
