Lumbar puncture

Question 1

What connects the spinous processes?

Answer 1

Supraspinal ligaments

Question 2

_______ _______ is an elastic membrane covering the intralaminar space in which you must go through.

Answer 2

Ligamentum flavum

Question 3

​ ______ _________ is composed of tough, fibrous, and elastic tissue
​Outermost covering membrane of spinal canal

Answer 3

Dura mater/dural sac

Question 4

​________ ________ is delicate, avascular membrane, Lines dural sac Encloses CSF filled subarachnoid space containing spinal cord and nerves.

Answer 4

Arachnoid mater

Question 5

Lumbar punctures are performed at what anatomic landmarks?

Answer 5

L3-L4 or L4-L5

Question 6

Angle the needle towards what ?

Answer 6

The umbilicus

Question 7

What to do if you hit bone :

Answer 7

Remove needle and try again this time more downward (caudally).

Question 8

If there are many neutrophils in the CSF analysis, the infection is most likely

Answer 8

Bacterial

Question 9

If there are many lymphocytes in the CSF then this could indicate :

Answer 9

VIRAL aseptic meningitis

Question 10

Normal RBC count in CSF analysis :

Answer 10

<10

Question 11

Traumatic Tap is ruled out by the appearance of :

Answer 11

Xanthochromia

Question 12

Normal glucose in CSF analysis :

Answer 12

50-80 mg/dL

Question 13

CSF glucose might be low in which conditions ?

Answer 13

Bacterial meningitis
Sarcoidosis
Syphilis
Subarachnoid hemorrhage

Question 14

Glucose levels are variable in :

Answer 14

Viral causes

Question 15

SERUM hyperglycemia may be masking what ?

Answer 15

It may be masking low CSF glucose. Check serum as well.

Question 16

Normal protein CSF? What if it’s elevated?

Answer 16

15-45 mg/dL. Elevated could mean infection from either bacterial or viral origin.

Question 17

Gram stain showing gram negative diplococci :

Answer 17

N. Meningitides

Question 18

Gram negative bacilli:

Answer 18

H. flu

Question 19

Gram positive cocci:

Answer 19

Step pneumoniae, strep, or staph

Question 20

How long do cultures take ?

Answer 20

24-48 hours

Question 21

__________ is a yellow / orange discoloration of CSF fluid, is a product of RBC lysis, and is a a result of subarachnoid hemorrhage.

Answer 21

Xanthochromia

Question 22

What is the normal opening pressure in LP?

Answer 22

18-20 mmH2O

Question 23

Bacterial infection if opening pressure is what?

Answer 23

> 30

Question 24

How to get opening pressure ?

Answer 24

Patient laying on side with the stop cock valve pointing up.

Question 25

This position is called what ?

Answer 25

Lateral recumbent position

Question 26

Clinical findings associated with pseudotumor cerebri ( intercranial hypertension) :

Answer 26

Headache, papilledema, diplopia, blurry vision.

Question 27

Diagnostic indications for LP:

Answer 27

CNS infection (meningitis), inflammatory processes, suspected spontaneous subarachnoid hemorrhage, unexplained seizure, malignancy

Question 28

Therapeutic indications for LP:

Answer 28

relieve intracranial pressure, deliver medication

Question 29

Indications for emergent CT before LP:

Answer 29

To rule out head bleed and meningitis. (Important not to delay antibiotics )

Question 30

What are the absolute contraindications for LP?

Answer 30

local skin infection, intracranial/spinal cord lesion, raised ICP w impending herniation, uncontrolled bleeding, Coumadin

Question 31

What are the relative contraindications for LP?

Answer 31

raised ICP, spinal cord deformity, body deformity, suspected lumbar epidural abscess, thrombocytopenia, elevated INR

Question 32

How many tubes are used to collect fluid ?

Answer 32

Four

Question 33

What is tube 1

Answer 33

Cell count, differential

Question 34

What is tube 2?

Answer 34

Glucose, protein

Question 35

What is tube 3?

Answer 35

Culture, gram stain.

Question 36

What is tube 4

Answer 36

Also cell count , differential

Question 37

Approximately how much fluid is collected?

Answer 37

4-8ml

Question 38

If RBC is higher in tube 4 than tube 1 this might indicate what ?

Answer 38

Traumatic tap

Question 39

The line connecting posterior iliac crests will intersect midline at approximately ____.

Answer 39

L4