CSF Interpretation

Question 1

Where is CSF produced?

Answer 1

Subarachnoid space and choroid plexuses

Question 2

How many choroid plexuses are there?

Answer 2

4

Question 3

What drains CSF?

Answer 3

Arachnoid villi

Question 4

How does CSF get to the subarachnoid space?

Answer 4

Via lateral apertures of 4th ventricle

Question 5

What does CSF surroung?

Answer 5

All aspects of central nervous tissue

Question 6

What are CSF functions?

Answer 6

Physical support, pressure regulation, nutrients, transmitters

Question 7

In general, CSF contains _____ K, Ca, glucose, and protein than serum

Answer 7

Less

Question 8

In general, CSF contains _____ Cl, Na, and Mg than serum

Answer 8

More

Question 9

Where can you obtain CSF?

Answer 9

Cisterna magna or lumbar

Question 10

Which direction does CSF predominantly flow?

Answer 10

Caudally (collect CSF caudal to lesion)

Question 11

What are contraindications to CSF collection?

Answer 11

ICP, coagulopathy, malformations

Question 12

What is the sensitivity and specificity of a CSF tap?

Answer 12

Usually very sensitive but non-specific

Question 13

How soon after collection should CSF be analyzed?

Answer 13

Within an hour; purple top tube + serum + hetastarch or refrigerate thereafter

Question 14

How will using a purple top tube affect CSF analysis?

Answer 14

Falsely elevates protein

Question 15

What color is caused by old hemorrhage and accumulation of blood pigments?

Answer 15

Xanthochromic (straw yellow)

Question 16

How much glucose is in CSF?

Answer 16

80% of what is in serum

Question 17

How much protein is in CSF?

Answer 17

Significantly less (reported as mg/dL in CSF and g/dL in serum)

Question 18

What is normal protein for a cisterna CSF tap?

Answer 18

<25mg/dL

Question 19

What is normal protein for a lumbar CSF tap?

Answer 19

<35mg/dL

Question 20

What is a normal WBC count for CSF?

Answer 20

<5/microliter

Question 21

Should RBC be in a CSF analysis?

Answer 21

Not unless there is disease or poor collection technique

Question 22

What is the most helpful aspect of CSF evaluation due to its high specificity?

Answer 22

Cytology

Question 23

How does Listeria monocytogens affects CSF?

Answer 23

Mononuclear pleocytosis

Question 24

How does thromboembolic meningoencephalitis (Histophilus somnus) affect CSF?

Answer 24

Neutrophilic pleocytosis, xanthrochromic/cloudy

Question 25

Indicates prior hemorrhage

Answer 25

Xanthrochromic (yellow discoloration)