W6_08 Optic Neuropathies

Question 1

where is the most common site for injury in traumatic optic neuropathies?

Answer 1

optic canal

Question 2

ganglion cells synapse where?

Answer 2

LGN

Question 3

what’s the most common pathology affecting ganglion cells?

Answer 3

glaucoma

Question 4

what percentage of fibres cross from each nerve through the chiasm?

Answer 4

53%

Question 5

what three things to look for when evaluating optic nerve clinically?

Answer 5

Borders - distinct rim;
Colour - pinkish;
Cup - 0.3-0.4 of the nerve

Question 6

if papilledema is present, under what circumstances will the patient show unilateral swelling?

Answer 6

atrophy of one of the optic nerves will have decreased swelling

Question 7

what’s the difference between papilledema and other optic neuropathies?

Answer 7

papilledema usually has normal vision (unless progression for too long and the axons die from compression)

Question 8

how does papilledema look on fundoscopy?

Answer 8

borders: not sharp
colour: pink but too pink (hemorrhage)
cup: can’t see the cup

Question 9

DDx of inflammatory optic neuropathies?

Answer 9

infection (syphillis, TB, HSV,HZV);

idiopathic demyelinating optic neuritis, sarcoidosis, wegner’s

Question 10

most common optic neuritis for under 50?

Answer 10

demyelinating (e.g. MS)

Question 11

most common optic neuritis for over 50?

Answer 11

ischemia (non-arteritic and arteritic)

Question 12

non-arteritic optic neuropathy symptoms?

Answer 12

wake up with altitudinal vision loss;

presumably due to hypo-perfusion of optic nerve head

Question 13

what to rule out when older patients > 70 present with optic problems?

Answer 13

giant cell arteritis

ask about jaw claudications and test for ESR and CRP

Question 14

how to treat giant cell arteritis?

Answer 14

high doses of steroids