CSF and Hydrocephalus (Keim)

Question 1

CSF functions:

Answer 1

Provide homeostasis and protection/buoyancy to the brain
Remove brain metabolites
Hormone transport

Question 2

What produces CSF?

Answer 2

Choroid plexus (by ependymal cells). This is found in the lateral (65%), third and fourth ventricles

Question 3

Characteristics of the choroid plexus:

Answer 3

Villous folds lined with epithelium with central core of highly vascularized connective tissue
Choroidal epithelium overlies these villous folds

Question 4

Normal CSF features:

Answer 4

Clear and colorless

Few cells and low protein.

Question 5

Which test is used to assess CSF composition?

Answer 5

Lumbar puncture (between L4 and L5)

Question 6

Describe the flow of the CSF:

Answer 6

Lateral ventricle > interventricular foramina of Monro > 3rd ventricle > cerebral aqueduct of Sylvius > 4th ventricle > subarachnoid space via Foramina of Luschka (lateral) and Foramina of Magendie (Medial) > absorption of arachnoid granulations > dural venous sinuses

Question 7

What is hydrocephalus?

Answer 7

Increased ICP. Enlarged ventricles due to excessive CSF accumulation in ventricles or subarachnoid spaces

Question 8

Communicating Hydrocephalus:

Non-communicating Hydrocephalus:

Answer 8

• Under-absorption or overproduction (rare) = nonobstructive
• Obstruction of outflow = obstructive

Question 9

Aqueductal Stenosis

Answer 9

Non communicating (obstructive) 
Accumulation of CSF in the lateral and third ventricles. There is something wrong with the cerebral aqueduct

Question 10

Causes of Aqueductal stenosis

Answer 10

Congenital (most common cause)
Tumor (in the pineal gland)
Previous meningitis leading to scarring
Inflammation from intrauterine infection

Question 11

Normal pressure hydrocephalus:

Answer 11

CSF does not drain properly leading to enlarged ventricles and cortical atrophy. Usually due to arachnoid granulations problems. Resolves with lumbar puncture
Triad of symptoms: cognitive impairment/confusion, unsteady/magnetic gait (wobbly), urinary incontinence (wacky, wobbly, wet)
Communicating hydrocephalus

Question 12

Causes of normal pressure hydrocephalus:

Answer 12

Increased CSF viscosity, altered ventricular wall elasticity, impaired CSF absorption

Question 13

Dandy-Walker Malformation

Answer 13

4th ventricle outlet obstruction (appears enlarged). Fluid accumulation above the 4th ventricle. 
Cerebellar hypoplasia (really small cerebellum, agenesis of vermis)
Non-communicating hydrocephalus

Question 14

Chiari II

Answer 14

Downward displacement of the inferior cerebellar vermis and tonsils through the foramen magnum blocking the outlet to the fourth ventricle. Fluid accumulates above the 4th ventricle.
Associated with lumbosacral myelomeningocele
Non-communicating hydrocephalus

Question 15

Treating hydrocephalus

Answer 15

Shunt placed so fluid can drain to another part of the body.

Question 16

Hydrocephalus general concepts:

Answer 16

Areas proximal to the obstruction/problem will enlarge

If all ventricles are enlarged (unless a post 4th ventricle obstruction), think absorption problem