Evidence required for diagnosis of MS after optic neuritis of unknown cause?

In April 2010 I had an episode of typical idiopathic AON. I was referred to an ophthalmology department and the ON followed a typical course. With me being discharged at 18 months. I did not see a neurologist. No MRI scans were taken.

This year I have possible neurological symptoms and my GP has referred me to the neurology department. (The neurology department sent a letter that they would contact me with an appointment in 12 weeks. 3 weeks to go now. My GP did try to have that shortened.)

What is needed now as evidence of neurological symptoms? I was thinking that there was reasonable progress in looking at my problems and that if this year’s symptoms were corroborated I would likely be diagnosed with MS. But, would a neurologist even accept my diagnosis of ON as a CIS?. I read that MS like lesions are common on MRI scans taken at the onset of ON. So am I to expect a least to two MRI scans to be needed. Possibly one will be taken in a month or so and then another when (if I suppose) there is another attack?

Thanks for any help.

Hi Jon, I see you are new, so welcome to the site!

I am not an expert about ON (I have MS but have never had ON), but I know that typically the neurologist will refer you for an MRI scan of your brain to see if lesions are showing. Sometimes, even with lesions showing, they will still require more evidence before diagnosing MS. I think the neuro will see your episode of ON as possibly caused by MS but will require a lot more evidence. They will also look at your other symptoms.

There is not one test for MS. It is sometimes difficult to diagnose (dx) so they very often carry out a series of tests over a period of time to try and dx. If there are lesions on the brain (or spine) they will sometimes then want to do a lumbar puncture. The result of that can help toward a dx.

I suppose what I am saying is, even though you have had ON and have what seems to be neurological symptoms, it does not mean that it will lead to a quick and easy dx. You still might have to go through the (often frustrating) series of tests and appointments with a neuro.

Make a short list of symptoms for when you see the neuro. Don’t expect an immediate dx (that does happen but very rarely). Take it one day at a time and wait to see what neuro says.

Hope this helps,

Pat x

Hello, and welcome to the site

There are pretty clear cut rules for a diagnosis of MS. You need dissemination in time (i.e. at least two relapses/attacks/episodes) OR gradual progression over at least a year (or that is sure to happen) and dissemination in space (i.e. at least two areas of the central nervous system affected). Your ON will very probably count as one attack (more likely if it was diagnosed by a medical professional and properly documented). Whether or not your current symptoms count as a second is impossible to say as you don’t give details, but even if they do, MS is not the only cause of ON or of neurological symptoms so it is still possible that something else is behind your symptoms so you should try and keep an open mind.

I suggest that you google Polman et al (2011). Diagnostic Criteria for Multiple Sclerosis: 2010 Revisions to the McDonald Criteria. ANN NEUROL 2011;69:292–302. This paper details the latest diagnostic criteria and should explain how your ON, as one attack, fits in with this.

To more directly answer your question, whether or not these latest symptoms qualify you for a diagnosis of MS depends on two things: if the neuro accepts the ON as a first attack and this latest batch of symptoms as the second, and how many lesions you have on MRI, as well as where they are. If the neuro accepts the ON and the current symptoms as two attacks, then you are relying on MRI / lesions for a diagnosis. If there is at least one lesion in two different MS-typical areas, then nothing else is needed. If there is only one in an MS-typical area, then you will have to wait for another lesion in a typical area (according to the rules). It is normal for a second scan to be a least a month later, but there is no set rule.

The only time a second MRI comes into play is either to show a new lesion (dissemination in time) or to show a second area of the nervous system (dissemination in space). So, if your MRI shows multiple lesions, satisfying the McDonald criteria, then there is no need for a second.

As far as lesions at the onset of ON go, no, I would not describe them as common. Basically, 50% of people with ON go on to develop MS. Many of these will have no lesions when they first present with ON. IF they have lesions, they are more likely to develop MS, but even then it is not guaranteed.

As far as ON = CIS goes, then yes, it does. CIS is basically part dissemination in time (i.e. one attack) and part dissemination in space (i.e. one part affected). Neuros are funny creatures though - they may not accept a diagnosis of something they haven’t witnessed personally: so your ON is more unlikely to be accepted as a CIS unless it has been properly documented by an ophthalmologist.


Karen x

Pat and Karen thanks so much for the help…

I will bear in mind that it could be something else. I guess ruling out other possibilities is part of the testing.

Thanks for the reference Karen and detailed further information.

Thanks again,


Sorry, more questions

Polman et al. (2011), 2010 Revisions to the McDonald Criteria, as I was pointed to (thanks!), says that DIS can be demonstrated by (MRI) if there are at least 1 lesion in at least 2 of 4 locations considered characteristic for MS (juxtacortical,periventricular, infratentorial, and spinal cord). Are optic nerves included in that list? I guess not in the spinal cord but I have no idea about the other regions.

Thanks for any help,


Juxtacortical means next to / into the cortex. The cortex is the outside layers of the brain, made up of gray matter which is the stuff that does all the encoding, processing, storage, etc (basically the “thinking”).

Periventricular means next to the ventricles. The ventricles are the lakes of CSF in the brain, a bit like the oil reservoir(s) in an engine.

Infratentorial means under the tentorium, a membrane that separates the cerebellum from the cerebrum. The cerebrum is the big bit of the brain, on the top - the bit that everyone thinks of as the brain. The cerebellum is the smaller, rounded bit that lies at the back, underneath the cerebrum. The part in front of the cerebellum and at the top of the spinal cord is the brain stem. The brain stem joins the spinal cord and the cerebrum. It is also considered infratentorial because it is below the level of the tentorium.

I actually don’t know what an optic nerve lesion counts as! How embarassing!

The optic nerves run from the eyes to the lateral geniculate nucleus (LGN) of the thalamus which is in the “deep gray matter” of the cerebrum, lying above the top of the brain stem. That rules out infratentorial I think. But whether it can be juxtacortical or periventricular I don’t know. I suspect it depends where on the optic nerve the lesion is. I also suspect it isn’t strictly either of these. It might even be counted as infratentorial because the optic nerve is a cranial nerve, even if it doesn’t terminate in the brain stem. Sorry - confusing!

It’s a question for your neuro next time you see him/her I think - let me know what the answer is please (or anyone else who’s reading)?!

Karen x

Karen, your a star! Thanks for your answer. Now I know a lot more about the brain than I did (pretty much zero I must admit). I will post what I find out from the neuro. Two weeks to go till when they said they’d give me an appointment date. 12 weeks from being added the waiting list! I found a report that said the 90%ile for waiting time was 11 weeks. It seems like a long time!

Thank you very much,


Hurray! I seem to have an appointment with neuro on 27th. GP surgery phoned me today to let me know. GP did say, yesterday, he would chase it up.