W6_10 Approach to Diplopia

Question 1

what’s cerebral polyopia?

Answer 1

an uncommon disorder that has a homonymous visual field defect due to some cerebral lesion

Question 2

how can you decrease monocular diplopia acutely (non-medical)?

Answer 2

using a pinhole

Question 3

if diplopia is worse in left gaze, which cranial nerve is likely affected?

Answer 3

left CN VI

Question 4

a head tilt could indicate a palsy of which cranial nerve?

Answer 4

CN IV of opposite side of tilt of tilt

Question 5

hypotropia, contralateral lid retraction, dermatochalasis, brow ptosis are all what?

Answer 5

pseudoptosis

Question 6

three types of true ptosis?

Answer 6

neurogenic (e.g. CN III, horners);
myogenic;
mechanical

Question 7

the alternate cover test is used for testing what?

Answer 7

binocular diplopia

Question 8

what can cause comitant bip. diplopia?

Answer 8

childhood strabismus or chronic innervational disease

Question 9

what can cause incomitant bip diplopia?

Answer 9

innervational (eg. CN III palsy);
mechanical disease (eg. Graves disease)

Question 10

what should you r/o when you see CN VI palsy? why?

Answer 10

r/o increased ICP, so check for papilledema; recall CN VI has to climb the clivus and has to bend, so it’s susceptible to pressure

Question 11

if patient tilts head to the left, what CN palsy does that indicate?

Answer 11

right CN IV palsy (contralateral to the tilting)

Question 12

what’s the 3 step test for CN IV palsy?

Answer 12

1: hypertropia of affected eye
2: lateral gaze to opposite side increases diplopia
3: head tilt to same side of palsy increases diplopia

Question 13

you see signs of CN III lesions, and see that pupil is affected. what are you worried about?

Answer 13

aneurysm (along the circle of willis arteries, esp PComm)

Question 14

you see signs of CN III lesions, and see that pupil is not affected. what is likely cause?

Answer 14

microvascular ischemic

Question 15

what is amblyopia?

Answer 15

impaired or dim vision of a greater degree than it looks

Question 16

what is internuclear ophthalmoplegia?

Answer 16

lesion of MLF that causes ipsilateral adduction deficit

Question 17

what is orbital apex syndrome?

Answer 17

when multiple CNs of the eye are involved: e.g. II with III, IV, or VI

Question 18

pituitary apoplexy can cause which symptoms?

Answer 18

bitemporal hemianopsia,

CN III palsy

Question 19

difference between recession and resection in strabismus surgery?

Answer 19

recession is to decrease tension;

resection is to increase tension

Question 20

what are the emergency diplopia situations?

Answer 20

aneurysm (CN III)
high ICP (CN VI)
pituitary growth (CN II, III)
giant cell arteritis
myasthenia