CSF, intracranial pressure and neuroradiology

Question 1

What structure is CSF created by?

Answer 1

Choroid plexus, main production is in the lateral ventricles

Question 2

Where does CSF travel from the lateral ventricles?

Answer 2

1. Drains into the inter-ventricular foramina to the 3rd ventricle
2. Then into the cerebral aqueduct to the 4th ventricle

Question 3

What are the 4 routes CSF can take from the 4th ventricle to the sub-arachnoid space?

Answer 3

1 x central canal
1 x median aperture (foramen of magendie)
2 x lateral apertures (foramen of luschka)

Question 4

How does CFS get reabsorbed into the dural venous sinuses?

Answer 4

Via arachnoid granulations

Question 5

What are the functions of CSF?

Answer 5

-Buoyancy
-Protection from physical injury/ ‘shock absorber’
-Clearing waste
Homeostasis of neurotransmitters and endocrine molecules
-Maintenance of brain perfusion

Question 6

How can the CSF help perfusion to the brain?

Answer 6

In the brain there are 3 elements needed to maintain intracranial pressure; blood, brain and CSF
Brain can reduce CSF volume and to maintain CSF more blood needs to be perfused to the brain

Question 7

How is CFS measured?

Answer 7

Measured by a lumbar puncture, which is attached to a manometer (pressure measurer)

Question 8

What is the composition of CSF?

Answer 8

No red blood cells
WBC should be < 5 per micrometer (very low)
Proteins and glucose present

Question 9

What are the normal pressures of CSF?

Answer 9

10-20cm H2O lying on side
20-30cm H2O sitting up

Question 10

What are the features of high intracranial pressure?

Answer 10

Headache; worse when lying down, coughing, sneezing or stooping
Also can see visual obscurations (greying/blacking out of vision)

Question 11

What are the features of low intracranial pressure?

Answer 11

Headache that is worse when sitting or standing
Blurred vision and dizziness

Question 12

What are the causes of low intracranial pressure?

Answer 12

Lack of production of CSF due to dehydration or drugs
CSF leak

Question 13

What are the causes of low intracranial pressure?

Answer 13

Lack of production of CSF due to dehydration or drugs
CSF leak

Question 14

What are the causes of high intracranial pressure?

Answer 14

CSF overproduction
Blocked CSF circulation or drainage
An increase in blood or brain tissue within the skull

Question 15

What is idiopathic intracranial hypertension?

Answer 15

CSF overproduction

Question 16

What can cause blocked CSF circulation?

Answer 16

Obstruction by mass or intracerebral bleeding

Question 17

What can cause blocked CFS drainage?

Answer 17

Very high protein content (makes CFS viscous)
Cerebral venous sinus thrombosis (CVST)

Question 18

What can cause an increase in blood or brain tissue within the skull?

Answer 18

Intracerebral haemorrhage, cerebral oedema, intracerebral mass e.g. a tumour

Question 19

What are the differences between MRI and CT brain scan?

Answer 19

CT is used when speed is important, as in trauma and stroke.Also good at detecting haemorrhage. MRI is best when the images need to be very detailed, looking for cancer, causes of dementia or neurological diseases