Neurology

Question 1

Where is CSF made?

Answer 1

The choroid plexus, which is found in the lateral, third and fourth ventricles. Some CSF also arises due to interstitial fluid movement and some is secreted by the lining of the subarachnoid space

Question 2

What colour should CSF be?

Answer 2

Clear

Question 3

What would cause turbid or cloudy CSF?

Answer 3

Inflammatory cells, presence of micro organisms or raised protein

Question 4

What colour might CSF be if there is blood in it?

Answer 4

Yellow, pink or straw coloured

Question 5

What two things are most important to measure in CSF?

Answer 5

Protein and glucose

Question 6

What do high CSF protein levels suggest?

Answer 6

Inflammation of infection

Question 7

How much glucose should be in the CSF?

Answer 7

At least 2/3rds that of the blood glucose. A ration of CSF to blood glucose less than 0.5 is considered pathological.

Question 8

How many red blood cells should normal CSF contain?

Answer 8

None

Question 9

Where is the best place to gain access for a lumbar puncture? Describe how you would do this?

Answer 9

Palpate the iliac crests. (The lines connecting the iliac crests should correspond to the L4 spinous process.
Move 1 or 2 interspaces above this to access subarachnoid space

Question 10

At what level does the spinal cord terminate in an adult? Is it the same in a child?

Answer 10

L1

It is slightly lower in a child

Question 11

List all the structures that are penetrated, from superficial to deep with a spinal needle to take a lumbar puncture.

Answer 11

Skin
Subcutaneous connective tissue
Supraspinous ligament
Interspinous ligament
Ligamentum flavum
Epidural space
Dura mater
Subarachnoid space (This is where the CSF is)

Question 12

Give three indication fro a lumbar puncture?

Answer 12

Suspected CNS infection
Suspected subarachnoid haemorrhage
Theraputic reduction of CSF fluid

Question 13

Give three absolute contraindication to doing a lumbar puncture

Answer 13

1. Raised ICP
2. Suspected spinal cord mass or intracranial mass lesion
3. Uncontrolled bleeding diathesis
   (Local infections over proposed site)
   (Spinal column deformities may require fluroscopic assistance)

Question 14

What does pathological expanson of the head usually indicate in an infant? Why?

Answer 14

Raised ICP

Fontanelles are still soft and will widen to try and reduce the pressure.

Question 15

What is the calculation to work out cerebral perfusion pressure?

Answer 15

Mean arterial blood pressure - intracranial pressure

Question 16

What is hydrocephalus?

Answer 16

A disturbance of CSF productin, flow or reabsorption which results in an excessive amount of CSF in the skull vault.

Question 17

What are the most important tests to do in hydrocephalus?

Answer 17

Imaging - US, CT and MRI of brain