4th Nerve palsy

Question 1

which muscle does the 4th nerve control?

Answer 1

SO

Question 2

congenital causes:

Answer 2

• abnormally developed muscle
• abnormally inserted tendon

usually seen during surgery

Question 3

acquired causes?

Answer 3

• trauma
• poor blood supply to 4th nerve (diabetic, HTN etc)
• tumours and ICP in young adults

Question 4

if macrovascular, how long will it take to resolve?

Answer 4

3-6 months

Question 5

what will you see on cover test?

Answer 5

hyper + eso

Question 6

CHP?

Answer 6

chin depression
face turn to affected side
tilt towards good eye

Question 7

if bilateral 4th NP, what will you observe on motility>

Answer 7

V ESO pattern

Question 8

symptoms?

Answer 8

diplopia - one image will be twisted to the side
MOSTLY WHEN LOOKING DOWN e.g reading, eating dinner, going down stairs

Question 9

how do you measure torsion?

Answer 9

Maddox rod
synoptophore

Question 10

what will motility look like?

Answer 10

this

Question 11

what test can you do to confirm SO undevraction?

Answer 11

BHTT

Question 12

how does BHTT work?

Answer 12

prism cover test at 3m whilst px tilts their head to the left and right

Question 13

clinical tests you should do ?

Answer 13

• CT
• OM
• PCT
• Funduscopy - look for torsion, check for PAP

Question 14

opthahlmogical management of acquired 4th NP

Answer 14

wait for resolution
- use prism to resolve vertical diplopia
- occlusive CL for diplopia

IF HAS NOT RESOLVED AFTER 12 MONTHS - SO tuck

Question 15

ophthalmological management of congenital 4th NP

Answer 15

• Surgery to eliminate or reduce AHP in children and prevent decompensation
• cosmetic surgery

Question 16

sign that px has 4th NP?

Answer 16

head tilted towards one side

Question 17

why are VARIs and BIFs contraindications in those with 4th NP?

Answer 17

can cause them to decompensated

Question 18

why is it difficult to pick up 4th NP on motility?

Answer 18

main action of SO is intorsion, which is not tested on motility