CSF

Question 1

Where does CSF originate?

Answer 1

Choroid plexus of the intracranial ventricles

Question 2

What spaces does the fluid occupy?

Answer 2

-Ventricles
-Subarachnoid space
(around the brain and spinal cord)

Question 3

The composition of CSF is derived from these 3 things…

Answer 3

• Filtration
• Differential absorption
• Active secretion

Question 4

What are the functions of CSF?

Answer 4

• Enhance nutrition of the brain
• Remove metabolic biproducts
• Protect against mechanical injury

Question 5

The composition of electrolytes in CSF varies with the changes in _______ levels

Answer 5

Plasma

Question 6

Most constituents in CSF are present in ______ or ______ concentration than the plasma

Answer 6

Equal or lower

Question 7

Pathological conditions cause inflammation, this causes leaky vessels, this leads to…

Answer 7

Elements that are typically restrained entering the blood brain barrier getting into the CSF and causing high concentrations

Question 8

Are proteins and lipids found in CSF?

Answer 8

Nope

Question 9

Are RBC and WBC in the CSF?

Answer 9

Nope- only enter if there is a ruptured blood vessel of inflammation of the meninges

Question 10

Is bilirubin in CSF

Answer 10

No- seen in intracranial hemorrhage (xanthochromia)

Question 11

What color should the CSF be?

Answer 11

Clear

Question 12

How is normal pressure maintained in the brain

Answer 12

By absorption of CSF through the arachnoid villi in equal amounts to its production by the choroid plexus

Question 13

What are the steps for determining if you need a lumbar puncture

Answer 13

-Determine the diagnostic objective

Question 14

When is a lumbar puncture normally used

Answer 14

• Suspected meningitis
• Subarachnoid hemorrhage
• Other intracranial bleed

Question 15

What are 2 tests that replaced some need for lumbar punctures

Answer 15

• CT

- MRI

Question 16

Do you have to consider the possibility of intracranial pressure?

Answer 16

Yes- if there is a pressure difference and you release it in a lumbar puncture you can pull the brainstem through the foramen magnum

Question 17

When is a fundoscopy used?

Answer 17

To rule out the presence of papilledema (swelling of the optic disk)

Question 18

What can be given to decrease the cranial pressures

Answer 18

Solute diuretic

Question 19

What are 2 things to do before a lumbar puncture

Answer 19

• explain procedure

- provide reassurance

Question 20

When is the pop sound heard?

Answer 20

When the needle punctures the dura

Question 21

What are 2 things that can occur after a LP?

Answer 21

• Temporary parasthesias

- Post puncture headache

Question 22

Describe the post puncture headache

Answer 22

• occurs in 25% of patients
• bilateral occipital or frontal
• occurs only in the upright position
• lying suprine relieves the pain quickly

Question 23

How should the patient be positioned?

Answer 23

• Knees to chest with the chin flexed towards the knees

- Breath slowly and naturally

Question 24

Where should the needle be inserted?

Answer 24

Between the 3rd, 4th, or 5th lumbar intervertebral spaces

Question 25

Should the opening pressure be recorded?

Answer 25

Yes

Question 26

What does turbitity signify

Answer 26

Leukocytes

Question 27

What does yellow discoloration mean?

Answer 27

Previous bleeding

Question 28

What is the pH of CSF compared to blood?

Answer 28

``` CSF= 7.31 Blood= 7.41 ```

Question 29

How do you know if the blood is due to puncture of a vessel on the way into do the LP

Answer 29

The tube will get lighter by the 3rd tube

Question 30

What does brown CSF mean?

Answer 30

-Presence of methemalbumin (which is associated with subdural hematoma)

Question 31

When can spontaneous clotting occur?

Answer 31

-Whenever protein content is high

Question 32

What is the mean CSF pressure

Answer 32

120 mmHg

Question 33

What happens when a patient holds their breath or tenses muscles

Answer 33

Increase in CSF pressure

Question 34

What causes a person to have decrease in CSF pressure

Answer 34

Dehydration

Question 35

These three things cause increase in CSF

Answer 35

- Intracranial tumors - Purulent meningitis - Encephalitis - Neurosyphillis

Question 36

What is the average drop in CSF pressure

Answer 36

5-10 mm drop in pressure for every mL of fluid removed

Question 37

What kind of bloody tap does not clot

Answer 37

-subarachnoid hemorrhage

Question 38

What is the correction factor?

Answer 38

Allow 1-2 WBC for every 1000 RBC= anything greater is indicative of preexisting leukocytes

Question 39

10-200 cells=

Answer 39

Primarily lymphocytosis - viral meningitis - late neurosyphillis - MS - Tumor

Question 40

200-500 mixed cell type=

Answer 40

- TB meningitis | - Herpes infection of CSF

Question 41

Over 500 granulocytes

Answer 41

-Acute bacterial meningitis

Question 42

Immature cells=

Answer 42

Meningeal leukemia

Question 43

Normal blood concentrations of protein are less than __%

Answer 43

1%

Question 44

What 2 things increase protein levels

Answer 44

- Purulent meningitis | - Multiple sclerosis

Question 45

What do you suspect if you have elevated protein levels without cells

Answer 45

-Degenerative disease of CNS (MS, neurosyphillis) -Subarachnoid blockage

Question 46

What are the levels of blood glucose in the CSF

Answer 46

50-80% of the normal blood glucose levels

Question 47

How long is the lag period for glucose

Answer 47

30-40 minutes

Question 48

In purulent meningitis, you get a ____ in CSF glucose

Answer 48

Drop

Question 49

What do lactic acid levels reflect?

Answer 49

Local glycolysis

Question 50

An isolated increase in CSF lactate indicates....

Answer 50

-Increased glucose metabolism

Question 51

Are smears used?

Answer 51

Yes- if there is any question of meningitis or CNS infection - use a gram stain or acid fast stain