CSF & Hydrocephalus

Question 1

CSF is produced primarily by?

Answer 1

Choroid Plexus

Question 2

Choroid plexus is found in?

Answer 2

• Lateral ventricle (majority- 65%) *
• Third ventricle
• Fourth ventricle

Question 3

– Consists of villous folds lined by epithelium with a central core of highly vascularized connective tissue

– Specialized layer of ? cells = choroidal epithelium overlies these
villi

Answer 3

Choroid Plexus

• ependymal

Question 4

BBB
1. Continuous ? junctions

2. ? provides structural support
3. ? necessary for BBB development
4. Transport carriers for ? and essential amino acids
5. ? ion transporters
6. Metabolic processes within the ? cells control entry of neurotransmitters

Answer 4

1. Tight **
2. Basement membrane
3. Astrocytic foot processes
4. Glucose
5. Sodium
6. Endothelial

Question 5

Blood-CSF Barrier

• Separates the CSF and blood
• Restricts the passage of substances
• More or less permeable than the blood-brain barrier?
• Impairment in the blood-CSF barrier leads
  to an increase in ? concentration in
  the CSF

Answer 5

• More

- Protein

Question 6

Blood-CSF Barrier

• ? cells are interconnected by tight junctions

Answer 6

Choroid cells **

Question 7

CSF takes 2 steps to form

Answer 7

Filtration and active transport

Question 8

How do plasma and CSF compare?

Answer 8

It differs in quantity not quality

Ex. Plasma protein is 7000 and CSF is 20

Question 9

Test for CSF composition by lumbar puncture between ? and ?

Answer 9

L4 and L5

Question 10

Functions of CSF

Answer 10

1. Protection: “shock absorber”
   – Protects brain from damage by “buffering”
   the brain

– Protects from sudden pressure or
temperature changes

2. Buoyancy
   – Brain is immersed in fluid, the net weight is reduced from 1,400 gm to about 50 gm
   – Pressure at the base of the brain is reduced ***
3. Metabolic
   – One-way flow of CSF to the blood takes
   potentially harmful metabolites, drugs, and
   other substances away from the brain
4. Endocrine Medium for the Brain
   – CSF serves to transport hormones to other
   areas of the brain

Question 11

What are the cavities inside the brain?

Answer 11

• Paired lateral ventricles
• 3rd ventricle
• Cerebral aqueduct
• 4th ventricle

Question 12

What leaves the 4th ventricle?

Answer 12

• 2 lateral foramina (Luschka)

- 1 medial foramen (Magendie)

Question 13

Flow of CSF

Answer 13

1. Lateral Ventricle
2. Through interventricular foramen of Monroe
3. Third ventricle
4. Cerebral aqueduct
5. Down to the Fourth Ventricle between pons and cerebellum
6. Goes to subarachnoid space via the 2 lateral and 1 medial aperture besides going to the central canal
7. Through the arachnoid villi, absorbed from subarachnoid space to sagittal sinus

Question 14

When ? is higher than ?, it will flow to the sagittal sinus

Answer 14

• CSF
• Venous pressure

(it will never flow backwards!)

Question 15

Disorder in which an excessive amount of cerebrospinal fluid (CSF) accumulates
within the cerebral ventricles and/or subarachnoid spaces, resulting in ventricular
dilation and increased intracranial pressure (ICP)
- can be congenital or aquired

Answer 15

Hydrocephalus

Question 16

Hydrocephalus:

- May be due to: ?

Answer 16

■ Overproduction of CSF (rare)

■ Under-absorption of CSF (at the level of the arachnoid villi)

■ Obstruction of the outflow of CSF from the ventricles

Question 17

2 types of Hydrocephalus

Answer 17

1. Communicating (or non-obstructive)

2. Non-communicating (or obstructive)

Question 18

Communicating Hydrocephalus:
- Flow of CSF is blocked (before or after?) it exits the ventricles

• Due to abnormalities that inhibit the resorption of CSF, most often at the level of the ?
• Typically associated with (increased or decreased?) ICP

Answer 18

• AFTER
• arachnoid villi
• increased

Question 19

• Condition of pathologically enlarged ventricular size
• Characterized by: enlarged cerebral ventricles with intermittent elevated CSF pressure on lumbar puncture
• Most common in adults over 60

Answer 19

Normal Pressure Hydrocephalus

- Chronic Communicating Hydrocephalus

Question 20

Normal Pressure Hydrocephalus
(Chronic Communicating Hydrocephalus) :

• Triad of symptoms?

Answer 20

• Dementia (memory loss)
• Apraxic gait
• Urinary incontinence

Question 21

Normal Pressure Hydrocephalus
(Chronic Communicating Hydrocephalus) :

• Could be due to?

Answer 21

– Increased viscosity of CSF

– Altered elasticity of ventricular walls

– Impaired absorption due to prior meningitis or subarachnoid hemorrhage

Question 22

• Compensatory enlargement of cerebral ventricles and subarachnoid spaces
• Not accompanied by increased ICP

Answer 22

Communicating Hydrocephalus:

Hydrocephalus Ex-Vacuo

Question 23

Hydrocephalus Ex-Vacuo

- Due to?

Answer 23

■ Brain atrophy (in dementias)

■ Post-traumatic brain injuries

■ Some psychiatric disorders (schizophrenia)

Question 24

■ Excess accumulation of cerebrospinal fluid
(CSF) due to structural blockage of CSF flow
within the ventricular system

■ Obstruction can be congenital or acquired

■ Depending on location of the obstruction
there is selective dilation of ventricles

• Lateral and third ventricle are enlarged and the 4th ventricle is normal
• So there is blockage at the cerebral aqueduct

Answer 24

Non-Communicating = Obstructive Hydrocephalus

• Can pinpoint where ventricles are dilated! ** (versus communicating)

Question 25

■ Narrowing of the cerebral aqueduct blocking the flow of CSF ■ Most likely place for blockage

Answer 25

Aqueductal Stenosis (obstructive)

Question 26

Signs/symptoms of Aqueductal Stenosis?

Answer 26

- “Thunderclap headache” - Papilledema (increased pressure causing optic nerve to swell so vision issues and headaches or vomitting) - Enlarged head (in infants) - Cognitive/developmental delays - Decreased level of consciousness - Upward gaze palsy—difficulty looking up - Tremors have been reported

Question 27

Causes of Aqueductal Stenosis ?

Answer 27

– Tumor compression – Narrow aqueduct – Gliosis (reactive change in glial cells)

Question 28

■ Obstruction at the outlet of the 4th ventricle + cerebellar hypoplasia ■ Congenital brain malformation (chromosomal abnormalities) ■ Involves a complete or partial agenesis of the cerebellar vermis

Answer 28

Dandy-Walker Malformation | obstructive

Question 29

Symptoms of Dandy-Walker Malformation?

Answer 29

Slow motor development, breathing difficulties, irritability, and vomitting

Question 30

Characteristic of Dandy-Walker Cysts?

Answer 30

Enlarged fourth ventricles

Question 31

What is key to know about Dandy-Walker Malformation?

Answer 31

* Can have underdevelopment or missing Vernis ** * Cystic enlargement of 4th ventricle ** * Can have enlarged base of skull (usually in infants) and posterior fossa **

Question 32

Characterized by: – Downward displacement of inferior cerebellar vermis and cerebellar tonsils and medulla through the foramen magnum into the upper cervical canal

Answer 32

Chiari II Malformation

Question 33

What is displaced through foramen magnum in Chiari II Malformation?

Answer 33

- Medulla - 4th ventricle - Cerebellar vermis

Question 34

Chiari II Malformation Causes?

Answer 34

– Structural defects in the brain and SC during fetal development – Result of genetic mutations – Lack of certain vitamins in maternal diet

Question 35

What disorder is usually accompanied by lumbosacral | myelomeningocele?

Answer 35

Chiari II Malformation

Question 36

What is seen in 90% of cases of Chiari II Malformation?

Answer 36

Hydrocephalus

Question 37

What is the cause of obstruction for Chiari II Malformation?

Answer 37

Narrowing of the cerebral aqueduct

Question 38

Symptoms of Chiari II Malformation in an infant?

Answer 38

– Swallowing problems – Slow and noisy breathing – Feeding problems : ■ Gagging ■ Drooling ■ Vomiting – Difficulty moving lower extremities – Poor bladder control – Clubfoot (from case study)

Question 39

What part of the brain is associated with clumsiness and ataxia?

Answer 39

Cerebellum

Question 40

``` What disease? ■ 3 year old male presents with: – Headaches – Morning N/V that gradually gets worse – Clumsiness or ataxia – Decreased activity ```

Answer 40

Acquired Hydrocephalus

Question 41

MRI for Acquired Hydrocephalus

Answer 41

- Lateral and third ventricle are enlarged | - Tumor compressing on cerebral aqueduct (ex. Medulla Blastoma)

Question 42

■ Develops later in life ■ Occurs when something happens to prevent the CSF in the brain from draining properly

Answer 42

Acquired Hydrocephalus

Question 43

Causes of Acquired Hydrocephalus

Answer 43

– Brain tumor or cyst – Blocked CSF flow – Bleeding inside the brain (subarachnoid hemorrhage) – Head trauma – Infection (such as meningitis)

Question 44

MRI for Chiari II Malformation

Answer 44

- Significance in lateral ventricle, Third ventricle, and a normal Fourth ventricle - Vermis, medulla, and part of the 4th ventricle protrude through the foramen magnum - Also in most cases see protrusion of lumbar-sacral spine (spina bifida)

Question 45

MRI of Dandy-Walker Malformation

Answer 45

- Large lateral ventricle - A big cyst on the back of the head - Cerebellar vermis being pushed up and the cerebellum being compressed

Question 46

MRI of Aqueductal Stenosis

Answer 46

- Lateral and third ventricle are enlarged - Fourth ventricle is enlarged - Blockage in cerebral aqueduct

Question 47

Hydrocephalus Ex-Vacuo CT (communicating)

Answer 47

- Ventricles are enlarged | - On the sides of the brain there is cortical atrophy (filled with CSF)

Question 48

Chronic Communicating Hydrocephalus CT

Answer 48

- enlarged lateral ventricles - Third and Fourth ventricles are enlarged - Black inside the brain = extra fluid in there - Ballooning of corpus callosum