NOD 1: Lecture 3 NAION

Causes of indistinct margins

papillodema

optic neuritis

NA-AION

A-AION

Neuroretinitis

Disc Drusen

Anomlous disc

Causes of segmental disc edema

Pipilledema

optic neuritis

NA-AION

A-AION

Neuroretinitis

Emboli/ischemia

Diabetic Papillopathy

Ischemic optic neuropathy

acute nerve damage secondary to poor perfusion/blood flow

a stroke to the optic nerve!

Anterior Ischemic Optic neuropathy (AION)

ischemia of papillae/ optic disc edema

short posterior ciliary arteries (SPCA) involved

Posterior Ischemic Optic Neuropathy (PION)

ischemia of optic nerve posterior to papillae/ ONH

no visible optic disc edema

MUCH LESS COMMON

So we have...

Non Arteritic (Anterior) Ischemic Optic Neuropathy (NA-AION)

Non Arteritic (Posterior) Ischemic Optic Neuropathy

Arteritic (Anterior) Ischemic Optic Neuropathy (AAION)

Arteritic (Posterior) Ischemic Optic Neuropathy

Post surgival Ischemuc OPtic Neuropathy

NAION

presumed infarction of the anterior portion of the optic nerve

in the absence of inflammation. demylenation, and compression

_____ arteries are affected in NAION

short posterior ciliary arteries

for NAION we must have negative:

C reactive protein

ESR

Thrombocytosis

Choroidal filling delay

Steroid responsiveness

tests are only helpful when they are negative!

NAION, AAION, and ON may all manifest a

- RAPD

- dyschromatopsia

- decreased VA

- VF loss

- decreased brightness sense

- Abnormal VEP

All afferent problems!

5 ways to differentiate optic neuropathies

Age

Vision loss

fellow eye cupping

hemes

pain

NAION age

55-65

AION age

60+

65-75

ON age

20-40

VISION LOSS

NAION VA

20/60 - 20/200

NAION time to vision loss (NADIR)

days 3.4

NAION VF defect

altitudinal

NAION Recovery

43% 3 lines at 6 mos

NAION fellow eye

18% seq

NAION the better the VA the ___ likely a second attack

less

OPTIC DISC APPEARANCE

Cupped disc in fellow eye

think AION

Anomalous disc in fellow eye

NAION or AION

NAION only occurs in ______ discs, but AION (and ON) can occur in any optic disc

small crowded discs

HEMMORRHAGE

NAION: hemes

yes!

AION: Hemes

yes/no

ON: hemes

RARE

NAION Disc edema

pink

Luxury perfusion

AION disc edema

Pallid

ON disc edema

pink

PAIN

NAION: pain

rare

AION: pain

yes

Optic neuritis: pain

Yes with eye movement

____ is likely if the Visual loss is NLP or OU

AION

AION is unlklely <

40

ON is rare >

60

---- is unlikely if fellow disc is cupped

NAION

____ is alomst alwaus painful and rarely preseny with disc hemorrhage

ON

____ is NOT painful

NAION

NAION predisposing factors

small crowded optic disc

hypertension

Dm

cholesterol

genetic

sleep apnea

tobacco use

cataract surgery

coronary bypass surgery

NAION PRECIPITATING MEDICATIONS

Amiodarone

oxymetazoline

influenza vaccination

interferon

viagra, cliallis

Nitrous oxide (body builders)

Harvoni (Hep C)

More preciptating factors

IOP alteration

Lasik Surgery

in NAION avoid

phenylephrine

vasoconstriction of the watershed posterior ciliary arteries --> worsening of vision

NAION precipitating factors (the important one)

Blood pressure control (too high or too low)

decreased perfusion during transient nocturnal hypotension VS lag to normal blood presssure

Amiodarone optic neuropathy

Amiodorone uses

anti arrhythmic

venticular arrhythmias

atrial fibrillation

Amiodorone half life

(takes 2 mos to get out of system)

Amiodorone bioavailability potentiated by

grapefruit

decreases the activity of cytochrome P450 3A4 enzymes that are responsible for breaking down many drugs and toxins

educate patients to NOT consume grapefruit prodcuts --> toxocoty rosk

Am-ION onset

insidious (months)

NAION onset

rapid

Am-ION vision loss

20/200

NAION vision loss

20/20 - NLP

Am-ION Resolution of optic disc edema

months

NAION Resolution of optic disc edema

weeks

Am-ION bilateral

usually simultaneous

NAION bilateral

sequential

Phosphodiesterase (PDE) inhibitors (ED)

linked to NAION

potentiated with grapefruit

ANY patient with known unilateral NAION should not be medicated with PDE inhibitors!!!!

NAION Work up

immediate lab testing to R/O GCA

C reactive protein

ESR

CBC with diff and platelets

Is there a role for imaging in ION

NOPE

only Optic neuritis

NAION treatment

None

NAION managment

control systemic predisposing and precipitating risk factors

avoid hypertensives at bedtime

don't treat hypertension too aggressively

stop smoking

see slides on DM