CSF and Hydrocephalus

Question 1

Where is the majority (65%) of CSF formed?

Answer 1

Lateral ventricles

Question 2

BBB overview

Answer 2

Continuous tight junctions between endothelium on blood side.
Basement membrane for support.
Astrocyte foot processes on brain side.

Question 3

What kind of transporters exist in the BBB?

Answer 3

Glucose transporters
Essential AA transporters
Na+ transporters

Question 4

Blood-CSF barrier overview

Answer 4

Fenestrations between endothelium.
Basement membrane for support.
Choroid cells w/ tight junctions on CSF side.

Question 5

What is a big difference between the BBB and the B-CSF-B?

Answer 5

In the BBB, the tight junctions are between the endothelium of the blood vessels.
In the B-CSF-B, the tight junctions are between choroid cells on CSF side.

Question 6

Which barrier is more permeable?

Answer 6

B-CSF-B

Question 7

What can increase in conc. when there is an impairment in the B-CSF-B?

Answer 7

Increase is protein conc. in CSF

Question 8

Cavities in the brain (4)

Answer 8

Lateral ventricles
3rd ventricle
Cerebral aqueduct
4th ventricle

Question 9

Flow of CSF (6)

Answer 9

Lateral ventricles –> 3rd ventricle –> 4th ventricle –> subarachnoid space –> arachnoid villi of DVS –> venous blood

Question 10

What exists between the lateral ventricles and 3rd ventricle?

Answer 10

Interventricular foramina

Question 11

What exists between the 3rd ventricle and 4th ventricle?

Answer 11

Cerebral aqueduct

Question 12

What exists between 4th ventricle and subarachnoid space?

Answer 12

2 lateral foramina (Luschka)

1 medial foramen (Magendie)

Question 13

Non-obstructive hydrocephalus is:

Answer 13

Communicating hydrocephalus

Question 14

Obstructive hydrocephalus is:

Answer 14

Non-communicating hydrocephalus

Question 15

Where is CSF blocked in communicating hydrocephalus?
At what level does it usually occur?
Associated with?

Answer 15

Blocked after it exits the ventricles.
Abnormalities that inhibit the resorption of CSF, most often at arachnoid villi.
Associated w/ increased ICP.

Question 16

Normal pressure hydrocephalus (NPH) and SX

Answer 16

Chronic communicating hydrocephalus.

Sx: dementia, poor gait, urinary incontinuence.

Question 17

Causes of NPH

Answer 17

Increased viscosity of CSF
Altered elasticity of ventricular walls
Impaired absorption due to prior meningitis/hemorrhage.

Question 18

Hydrocephalus Ex-Vacuo

Answer 18

Communicating.
Compensatory enlargement of ventricles and subarachnoid spaces.
No increase in ICP.

Question 19

Causes of Hydrocephalus Ex-Vacuo

Answer 19

Brain atrophy
Post-trauma brain injuries
Psych disorders.

Question 20

Aqueductal stenosis

Answer 20

Narrowing of cerebral aqueduct blocking flow of CSF.

Question 21

SX of aqueductal stenosis

Answer 21

Severe headache
Papilledema
Enlarged head in infants
Developmental delay
Upward gaze palsy (trouble looking up)

Question 22

Causes of Aqueductal stenosis

Answer 22

Tumor compression
Narrow aqueduct
Gliosis (changes in glia, secondary to CNS problem)

Question 23

Dandy-Walker Malformation

Answer 23

Obstruction at outlet of 4th ventricle (4th ventricle enlarged) and cerebellar hypoplasia.
Congenital.

Question 24

Chiari II malformation

Answer 24

Downward displacement of cerebellar tonsils and medulla into upper cervical canal.

Question 25

Chiari II is associated with:

Answer 25

Lumbosacral myelomeningocele

Question 26

Causes of Chiari II

Answer 26

Genetic defects

Lack of vitamins/minerals in utero

Question 27

How does hydrocephalus occur in Chiari II?

Answer 27

Parts of hindbrain herniates through the foramen magnum and pinches off the cerebral aqueduct

Question 28

Acquired hydrocephalus

Answer 28

Develops later in life.

CSF does not drain properly.

Question 29

Causes of acquired hydrocephalus

Answer 29

Things that CAN BE acquired:

Tumors, cysts, bleeding, trauma, infection, etc.