Nerve Palsy

Question 1

What condition is associated with CN III palsy, headache and pupillary defects?

• painful CN III palsy -

Answer 1

Posterior communicating artery aneurysm

Question 2

Majority of cases of CN VI palsy are caused by microvascular blockages to cranial nerves.
However the most serious potential cause is raised ICP, what ocular condition must be ruled out in patients with CN VI palsy?

Answer 2

Papilledema

Question 3

How does VI palsy present?

How will patients try to compensate?

Answer 3

LR6 - lateral rectus muscle affected

Medial deviation of the eye when looking ahead

Unable to abduct so have to turn whole head to see

Question 4

What palsy is associated with a ‘down and out’ squint?

Answer 4

CN III

Question 5

Signficant blunt trauma can lead to bilateral IV palsy.

How would a patient compensate with this?

Answer 5

Chin down and eyes up to try make sure they are looking straight ahead

(both eyes will be squinting upwards)

Question 6

How does a CN IV squint present when looking straight on?

Answer 6

Lateral upward squint - no longer have SO to move eye medially inferiorally

Question 7

What clinical symptom will patients with a palsy present with?

Answer 7

Diplopia - seeing double

Question 8

What is the most common cause of CN IV palsy?

Answer 8

Congenital

Question 9

CN III innervates the following muscles. Explain what happens as a result of CN III palsy in regards to each muscle:

• superior rectus
• inferior rectus
• medial rectus
• inferior oblique
• sphincter pupillae
• levator palpebrae superioris

Answer 9

SR, MR, IR and IO = down and out position
Sphincter pupillae = dilated pupil
LPS = ptosis