Lecture 7: Ventricles and CSF

Question 1

Where is the majority of the CSF produced?

Answer 1

Lateral Ventricle (65%)

Question 2

What layer of the BBB controls entry of neurotransmitters?

Answer 2

Endothelium

Question 3

What layer of the Blood-CSF barrier controls passage of substances?

Answer 3

Choroid cells

Question 4

What is the flow of CSF?

Be Specific

Answer 4

• Step 1: Lateral Ventricle –> 3^rd Ventricle
  
  • via Foramen of Monro
• Step 2: 3^rd Ventricle –> 4^th Ventricle
  
  • via Cerebral Aqueduct
• Step 3: 4^th 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

Question 5

When viewing a CT, what can the three differnet ventricles tell you about what level of the brain you are looking at?

Answer 5

• Lateral Ventricle: Telencephalon Structures
  
  • Cerebral Cortex
• Third Ventricle: Level of Thalami
• Fourth Ventricle: Pons

Question 6

What is hydrocephalus?

Answer 6

Increased amounts of intracranial pressure and ventricular dilation due to an excessive amount of CSF in ventricles and/or subaracnoid spaces

Question 7

What is the difference between communicating vs non-communicating hydrocephalus?

Answer 7

• 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

Question 8

What is this?

Answer 8

Aqueductal Stenosis

Question 9

What ventricles would be enlarged in Aqueductal stenosis?

Answer 9

Lateral and 3^rd Ventricles due to obstruction of cerebral aqueduct

Question 10

What are some causes of aqueductal stenosis?

Answer 10

• Congenital (x-linked)
• Pineal Tumor
• Meningitis Infection
• Inflammation from inrauterine infection

Can treat with shunt or cure infection

Question 11

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?

Answer 11

Aqueductal stenosis

Non-communicating (obstructive)

Question 12

What is this?

Answer 12

Communicating Hydrocephalus at the level of lateral ventricle

Question 13

Where is the problem in a normal pressure hydrocephalus?

Answer 13

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)

Question 14

What are some symptoms of Normal Pressure Hydrocephalus?

Answer 14

Triad

• Cognitive impairment (wacky)
• Unsteady, magnetic gait (wobbly)
• Urinary incontinence (wet)

Question 15

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?

Answer 15

Chronic Communicating Hydrocephalus

Normal Pressure Hydrocephalus

Question 16

What is this?

Is this communicatinng or non-communicating?

Answer 16

Dandy Walker Malformation

Non-communicating (Obstructive)

Question 17

What are symptoms of a Dandy Walker Malformation?

Answer 17

Congenital Brain Malformation

• Enlarged 4^th ventricle
  
  • fluid accumulates above this ventricle
• Cerebellar hypoplasia: agenesis of vermis of cerebellum
• Enlargement at the base of the skull in the posterior fossa

Question 18

Why is Dandy Walker Malformation considered a congenital problem?

Answer 18

• Problems start between 13^th-18^th week of development
• Cyst forms in 4th ventricle, disrupting development of cerebellum

Question 19

What is happening in this image?

Is this communicative or non-communicative

Answer 19

Chiari II Malformation

Non-communicating (Obstructive)

Question 20

What occurs in a Chiari II malformation?

Answer 20

• Displacement of inferior cerebellar vermis and tonsils through the foramen magnum
• Lumbosacral myelomeningocele
• Fluid accumulates above 4^th ventricle

Question 21

What is a big difference between Dandy Walker and Chiari Type II malformations?

Answer 21

• Dandy Walker: cerebellum not fully formed
• Chiari Type II: cerebellum formed

Question 22

If all the ventricles are enlarged, what type of issue should we think about?

Answer 22

Problem with Absorption of CSF