The Eye & Raised Intracranial Pressure

Question 1

What is a raised ICP caused by and give examples.

Answer 1

Caused by an increased pressure in fluid surrounding the brain or an increase in pressure within the brain itself.

Examples:
Brain tumour
Head injury
Hydrocephalus
Meningitis
Stroke

Question 2

The intracranial volume is….

Answer 2

CONSTANT

Question 3

List 5 symptoms a patient with raised ICP can experience.

Answer 3

Transient blurred vision
Double vision
Loss of vision (increased pressure can compress the artery or the optic nerve)
Papilloedema (swelling of the optic disc)
Pupillary changes

Question 4

List the layers of the meninges.

Answer 4

Dura
Arachnoid
Pia

Question 5

The space between the arachnoid and the pia is known as? and contains what?

Answer 5

The subarachnoid space which contains cerebrospinal fluid (CSF).

Question 6

What are the meninges?

Answer 6

Protective coverings of the brain and spinal cord.

Question 7

Describe the dura mater.

Answer 7

Toughest layer
Sensory supply from CN V
Encloses dural venous sinuses

Question 8

Describe the arachnoid mater.

Answer 8

Arachnoid granulations

Question 9

Describe the subarachnoid space.

Answer 9

Contains circulating CSF and blood vessels
Completely surrounds the brain and spinal cord
Is continous
Cushions and protects

Question 10

If vessels in the subarachnoid space rupture, you can get a what?

Answer 10

Subdural haematoma

Question 11

Describe the pia

Answer 11

Adheres to brain (and vessels and nerves entering or leaving)

Question 12

Where is CSF produced?

Where is it reabsorbed?

Answer 12

In the choroid plexus of the ventricles.

Reabsorbed into the dural venous sinuses via the arachnoid granulations.

Question 13

Where is a lumbar puncture done?

Answer 13

L3/4 or L4/5

Question 14

Describe the circulation of CSF.

Answer 14

Secreted by the choroid plexus from the right and left lateral ventricles and some in the 3rd ventricle

It then moves via the cerebral aqueduct into the 4th ventricle

and then moves mainly into the subarachnoid space of the brain and spinal cord but some passes into the central canal

It is then reabsorbed from the subarachnoid space via the arachoid granulations

And moves into the dural venous sinuses

Question 15

What is papilloedema?

Answer 15

Bulging or swollen optic discs

Question 16

Where does the oculomotor nerve come off of?

Answer 16

The Midbrain

Question 17

In what 4 ways is the oculomotor nerve susceptible to damage?

Answer 17

Compression
Tentorial herniation
Paralysis of parasympathetic innervation sphincter of pupil
Lose/slowness of pupillary light reflex,

Question 18

The oculomotor nerve divides the cranial cavity into which 2 major regions?

Answer 18

Falx cerebri

Tentorium cerebelli

Question 19

Where does the trochlear nerve come off of?

Answer 19

The back of the midbrain

Question 20

Paralysis of the superior oblique muscle means the patient cannot look in which direction?

Answer 20

Down and out

Question 21

The abducent nerve comes off of where?

Answer 21

The pons-medullary junction

Question 22

Paralysis of the lateral rectus means what?

Answer 22

The eye cannot move laterally in the horizontal plane meaning there will be medial deviation of the eye