Hi JSmythe:

Sounds like you are facing a difficult decision.

It has been said that 5% of MS patients don't show lesions. Some neuro's say that after 3 negative MRI's then it's time to start looking elsewhere for a dx.

MS is a dx of exclusion. I had my first symptom 30 years ago and only in the past few years have I been given a dx of possible MS. I have no lesions, just brain atrophy and clinical signs.

MG can cause weakness. So can many other neurological diseases.

http://www.nationalmssociety.org/Sourcebook-Topic.asp

At the top of the forum you can find sticky's that will give you links to other sources of information.

Hope that helps. It's frustrating trying to get to the bottom of something that is affecting your whole life.