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Flashcards in CSF Deck (51):
1

Where does CSF originate?

Choroid plexus of the intracranial ventricles

2

What spaces does the fluid occupy?

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

3

The composition of CSF is derived from these 3 things...

-Filtration
-Differential absorption
-Active secretion

4

What are the functions of CSF?

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

5

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

Plasma

6

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

Equal or lower

7

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

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

8

Are proteins and lipids found in CSF?

Nope

9

Are RBC and WBC in the CSF?

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

10

Is bilirubin in CSF

No- seen in intracranial hemorrhage (xanthochromia)

11

What color should the CSF be?

Clear

12

How is normal pressure maintained in the brain

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

13

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

-Determine the diagnostic objective

14

When is a lumbar puncture normally used

-Suspected meningitis
-Subarachnoid hemorrhage
-Other intracranial bleed

15

What are 2 tests that replaced some need for lumbar punctures

-CT
-MRI

16

Do you have to consider the possibility of intracranial pressure?

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

17

When is a fundoscopy used?

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

18

What can be given to decrease the cranial pressures

Solute diuretic

19

What are 2 things to do before a lumbar puncture

-explain procedure
-provide reassurance

20

When is the pop sound heard?

When the needle punctures the dura

21

What are 2 things that can occur after a LP?

-Temporary parasthesias
-Post puncture headache

22

Describe the post puncture headache

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

23

How should the patient be positioned?

-Knees to chest with the chin flexed towards the knees
-Breath slowly and naturally

24

Where should the needle be inserted?

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

25

Should the opening pressure be recorded?

Yes

26

What does turbitity signify

Leukocytes

27

What does yellow discoloration mean?

Previous bleeding

28

What is the pH of CSF compared to blood?

CSF= 7.31
Blood= 7.41

29

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

The tube will get lighter by the 3rd tube

30

What does brown CSF mean?

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

31

When can spontaneous clotting occur?

-Whenever protein content is high

32

What is the mean CSF pressure

120 mmHg

33

What happens when a patient holds their breath or tenses muscles

Increase in CSF pressure

34

What causes a person to have decrease in CSF pressure

Dehydration

35

These three things cause increase in CSF

-Intracranial tumors
-Purulent meningitis
-Encephalitis
-Neurosyphillis

36

What is the average drop in CSF pressure

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

37

What kind of bloody tap does not clot

-subarachnoid hemorrhage

38

What is the correction factor?

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

39

10-200 cells=

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

40

200-500 mixed cell type=

-TB meningitis
-Herpes infection of CSF

41

Over 500 granulocytes

-Acute bacterial meningitis

42

Immature cells=

Meningeal leukemia

43

Normal blood concentrations of protein are less than __%

1%

44

What 2 things increase protein levels

-Purulent meningitis
-Multiple sclerosis

45

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

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

46

What are the levels of blood glucose in the CSF

50-80% of the normal blood glucose levels

47

How long is the lag period for glucose

30-40 minutes

48

In purulent meningitis, you get a ____ in CSF glucose

Drop

49

What do lactic acid levels reflect?

Local glycolysis

50

An isolated increase in CSF lactate indicates....

-Increased glucose metabolism

51

Are smears used?

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