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Optic neuritis, the final (latest) word

25 yo woman 7 day hx central visual loss, swollen disc: is this typical or atypical?

Will discuss what is typical

- relatively young, female, central unilateral evolving over days, RAPD, 2/3 show normal disc at first

- if do an MRI scan, will it enhance? - turns out yes in 95%

- typically gets better over weeks whether or not tx'd

- only 8% had central defect in ONTT study, though termed typical

- most common pattern was generalized depression (48%) but it is really a central scotoma over a bigger area, more dense centrally

- natural hx is pain to resolve over days-weeks

- visual recovery within 2-3 wks and complete at months

VA outcome generally quite good

Now, the atypical (don't go on to MS):

- systemic illness viral or vasculitis

- atypical demographic

- immune compromised or other immune disease

- no pain

- slow progression of vision loss

- non resolution of pain

- bilateral simultaneous

- macular star (neuroretinitis) ie exudates and hemorrhages

- infectious and non-infectious inflammations

Back to Typical optic neuritis:

Chance of recurrence same or other nerve 36% at 15 years and multiple recurrences more likely to lead to permanent visual loss.

If have optic neuritis, what is the change of getting MS?

- all these are based on ONTT

- overall 30% at 5 years but ranges from 15-51% based on lesions on MRI, eg 51% if more than 2 lesions

- 10 year data overall 38% but 22% with normal scan and 56% with any lesion%

- 15 year overall 50% with 25% if 0 lesions and 72% if at least one lesion!

- corroborated by other international studies

Things that might further increase risk include:

- periphlebiitis

Decreases the risk:

- preceding viral illness, bilat and simultaneous, neuroretinitis, etc

- ie if atypical presentation

Value of MRI?

- best single test of MS risk

- confirm diagnosis if otherwise not sure

- assess end visual prognosis based on location and extent of the demyelinating plaque (if intracanalicular or over a long portion of the nerve)

- this last point variably confirmed over the years

- rule out compressive lesion eg large pituitary adenoma

Treatment:

- oral pred at dose in ONTT, should not be used as no visual benefit and increased the recurrence rate (but perhaps if gave equivalent dose to the IV dosing, it would have helped)

- IV methylprednisolone showed to speed recovery rate but no long-term benefit

- once followed patients beyond 2 years, no longer saw any benefit in avoiding progression to MS with the IV treatment ie reduced 2 year risk progression to MS but same risk beyond 2 years

- ONTT concluded everyone should get MRI to decide whether to treat with IV steroid but MS attacks axons to cause damage so perhaps everyone should just be treated with pulse steroids for every attack

CHAMPS study looking at use of other immune modulating agent

- interferon beta-1a (avonex) treatment vs no treatment

- helped

Other immunomodulation agents being investigated at this time eg copaxone

Problem is treating alot of patients with little risk of progressing anyway.

Summary

Be sure ON is typical

Consider IV methylpred or high dose oral

Don't use low dose

Do MRI in all to assess risk

Based on risk, consider immunomodulation