CSF and BBB

Question 1

What is the role of the BBB?

Answer 1

Controls compounds allowed into the brain or CSF

Question 2

Which molecules easily cross the BBB?

Answer 2

Small lipid-soluble molecules

Question 3

Active transport is generally required for which types of molecules to cross the BBB?

Answer 3

Larger lipid-soluble and more water-soluble molecules

Question 4

What does AE stand for in the context of the BBB structure?

Answer 4

Astrocyte Endfeet

Question 5

What does EC stand for in the context of the BBB structure?

Answer 5

Endothelial Cell

Question 6

What does TJ stand for in the context of the BBB structure?

Answer 6

Tight Junctions

Question 7

What does PC stand for in the context of the BBB structure?

Answer 7

Pericytes

Question 8

Name an example of a drug transport mechanism across the BBB.

Answer 8

Passive diffusion (lipid soluble drugs)

Question 9

Name an example of a transport mechanism for Amino acids across the BBB.

Answer 9

Carrier-mediated influx

Question 10

Name an example of a transport mechanism for Insulin across the BBB.

Answer 10

Receptor-mediated transocytosis

Question 11

What imaging highlights areas of BBB breakdown?

Answer 11

MRI gadolinium enhancement

Question 12

Give an example of a tumor that causes BBB breakdown.

Answer 12

Glioblastoma Multiform

Question 13

Give an example of an inflammatory disease that causes BBB breakdown.

Answer 13

Multiple Sclerosis

Question 14

Where is CSF produced?

Answer 14

By the Choroid Plexus in the lateral, 3rd, and 4th ventricles

Question 15

What are the two processes for CSF production?

Answer 15

Filtration and Active Transport

Question 16

What is the typical total CSF volume?

Answer 16

150 mL

Question 17

What is the approximate CSF production rate?

Answer 17

20mL/hr

Question 18

What must be equal regarding CSF to prevent pressure issues?

Answer 18

Production and reabsorption/loss

Question 19

What type of cells form the Choroid Plexus?

Answer 19

Epithelium (with microvilli/cilia)

Question 20

After the Lateral Ventricles, CSF flows to the Third Ventricle via which structure?

Answer 20

Interventricular Foramen (of Monro)

Question 21

What connects the Third Ventricle to the Forth Ventricle?

Answer 21

Cerebral Aqueduct

Question 22

Name the two apertures through which CSF exits the Fourth Ventricle.

Answer 22

Medial Aperture (of Magendie) and Lateral Aperture (of Luschka)

Question 23

Where does CSF flow after the Medial/Lateral Apertures?

Answer 23

Subarachnoid Space

Question 24

What structures reabsorb CSF into the bloodstream?

Answer 24

Arachnoid Vili

Question 25

The Arachnoid Villi reabsorb CSF into what part of the bloodstream?

Answer 25

Venous sinuses and cortical veins

Question 26

What connects the cells of the arachnoid villi?

Answer 26

Tight junctions

Question 27

What transport mechanisms drain CSF into the bloodstream at the arachnoid villi?

Answer 27

Passive diffusion and Active Transport

Question 28

What procedure involves inserting a needle into the lumbar cistern?

Answer 28

Lumbar Puncture (LP)

Question 29

What two pressures are measured during a Lumbar Puncture?

Answer 29

Opening and closing pressure

Question 30

In what position is the opening pressure measured during an LP?

Answer 30

Lateral recumbent position

Question 31

What is the normal LP opening pressure for adults?

Answer 31

≤25 cm H2​O

Question 32

What is the normal LP opening pressure for children?

Answer 32

≤28 cm H2​O

Question 33

What is the normal CSF finding for White Blood Cells (WBCs)?

Answer 33

0−5/HPF

Question 34

What are the three types of white blood cells that may be counted?

Answer 34

Neutrophils, lymphocytes, eosinophils (Differential)

Question 35

What is the normal CSF finding for Red Blood Cells (RBCs)?

Answer 35

No Red Blood Cells (RBCs)

Question 36

What is the normal CSF glucose level?

Answer 36

∼2/3 of serum glucose level

Question 37

What is the normal CSF color/fluidity?

Answer 37

Clear

Question 38

What does Visibly Bloody CSF indicate?

Answer 38

Either a traumatic lumbar puncture or subarachnoid hemorrhage

Question 39

What is Xanthochromia?

Answer 39

A color-tinged supernatant after centrifuging CSF

Question 40

What does Xanthochromia indicate?

Answer 40

RBCs in the CSF are hours old (consistent with Subarachnoid Hemorrhage)

Question 41

What causes the yellow color (Xanthochromia)?

Answer 41

Breakdown of RBCs releasing hemoglobin which is converted to bilirubin

Question 42

What are Oligoclonal Bands (OCBs)?

Answer 42

Proteins in CSF that are not found in serum

Question 43

What condition are OCBs seen in ∼90% of cases?

Answer 43

Multiple Sclerosis

Question 44

Name one specialized CSF test for Syphilis.

Answer 44

RPR

Question 45

What protein test is used for Creutzfeldt-Jakob disease?

Answer 45

14−3−3 protein

Question 46

What are the CSF findings for Herpes Encephalitis?

Answer 46

Elevated WBC count, Elevated Protein, and +HSV PCR

Question 47

Name an issue that can cause a High LP opening pressure (due to impaired CSF resorption).

Answer 47

Cerebral Venous Thrombosis (Venous outflow obstruction)

Question 48

What is the defining feature of Idiopathic Intracranial Hypertension (IIH) based on LP?

Answer 48

Elevated CSF opening pressure (with normal CSF composition/imaging)

Question 49

What are the CSF and imaging findings for Hydrocephalus?

Answer 49

Elevated opening pressure and enlarged ventricles

Question 50

What are the two types of Hydrocephalus?

Answer 50

Obstructive vs Communicating

Question 51

What can cause Obstructive Hydrocephalus?

Answer 51

Cerebral Aqueduct Stenosis

Question 52

Why is an LP contraindicated if a posterior fossa mass lesion is present?

Answer 52

Risk of downward herniation

Question 53

What types of conditions is CSF assessment useful for?

Answer 53

Meningitis (Bacterial, Viral, Fungal, noninfectious), Subarachnoid Hemorrhage, CNS/PNS Inflammatory Disease (MS, Sarcoidosis, Guillain Barre), and Neoplasm (Carcinomatous Meningitis)

Question 54

What conditions are associated with Low CSF pressure?

Answer 54

CSF leak (Low pressure headache)