8. Ventricle CSF and Hydrocephalus (Fellow)

Question 1

Diagnosis?

Answer 1

Aqueductal stenosis.

Notice that the lateral and third ventricles are enlarged, but the fourth is not.

Question 2

What are they signs and symptoms of normal pressure hydrocephalus?

Is this communicating or non-communicating hydrocephalus?

Answer 2

Triad of sx: Wacky, Wobbly, Wet

• Dementia
• Ataxic gait
• Urinary incontinence

Intermittent increase in CSF pressure, but not constant.

Imaging will show communicating hydrocephalus.

Question 3

What are the 4 functions of CSF?

Answer 3

The functions of CSF are as follows:

• Shock absorber
• Buoyancy
• Metabolic
  
  • Moves metabolites away from the brain due to one-way flow.
• Endocrine
  
  • CSF moves hormones around in the brain.

Question 4

Answer 4

Question 5

Diagnosis?

Answer 5

Chiari II, notice how the cerebellum is protruding through the foramen magnum.

Question 6

What are the causes of aqueductal stenosis?

Sx:

Answer 6

Tumor pressing on the aqueduct (pineal)

Congenitally narrow aqueduct (most common)

meningitis–>scarring

IU infection leading to inflammation

HA/vomiting, vision changes, gait changes

Question 7

What are the ventricles and foramen, in order of the flow of CSF?

Answer 7

Lateral ventricle -> Foramen of Monro -> Third Ventricle -> Cerebral aqueduct -> Fourth ventricle -> Lateral foramina of Luschka and Medial foramina of Magendie -> Subarachnoid space

(CSF also goes from the fourth ventricle into the central canal of the spinal cord)

Question 8

What are the typical findings in a Dandy-Walker malformation?

Answer 8

Cystic enlargement of the fourth ventricle.

Missing or underdeveloped vermis of the cerebellum.

Swelling of the base of the skull in infants.

Non-communicating Hydrocephalus

Question 9

What are the components of the blood–CSF barrier, and how does it differ from the blood brain barrier?

Answer 9

blood-CSF barrier

• more permeable
• , tight junctions between the choroid cells and basement membrane cells.
• endothelial cells are fenestrated

BBB

• endothelial cells have tight junctions

Question 10

What causes hydrocephalus ex-vacuo?

Is this obstructive or non-obstructive hydrocephalus?

Answer 10

Brain atrophy (schizophrenia, dementia, head trauma) causes CSF to expand into those spaces. (CSF pressure is normal).

Non-obstructive hydrocephalus.

Question 11

What are the expected findings in Chiari II malformation?

Answer 11

Meningomyelocele

Herniation of the medulla, cerebellum, and fourth ventricle through the foramen magnum.

Non-communicating Hydrocephalus

Fluid in the 4th ventricle

Cerebellum present

Question 12

What are the signs and symptoms of aqueductal stenosis?

Answer 12

Thunderclap headache

Papilledema

Upward gaze palsy

Tremors?

Enlarged head in infants

Cognitive or developmental delay

Question 13

Diagnosis?

Answer 13

Dandy-Walker

Notice the large cystic expansion of the fourth ventricle.

Also notice that this is a T2 MRI, which they did not show us. Don’t be confused if they use T2s on the test.

Question 14

Special Notes on the Formation/Composition of CSF

Choroid Plexus

CSF vs. Plasma

Answer 14

specialized ependymal cells with layer of choroidal epithelium overlying villi

same quality, different quantity

Question 15

Hydrocephalus

Non-obstructive vs. Obstructive

Answer 15

Non-Obstructive/communicating:

CSF overproduction (rare)

CSF under-absorption

Obstructive/non-communicating:

outflow blocked

Question 16

Take Home on Hydrocephalus

Answer 16

proximal to obstruction–> enlargement

If all ventricles are enlarged, think about absorption issue