--although an autoimmune molecular mimicry cascade or toxic exposure is more likely for an acute onset (did your condition come on really fast)?

Also, you say you've had major work-ups, but in my experience most people don't get a complete one that easily--take a look at the www.lizajane.org testing charts and compare (and use them to track your test results over time--very good for spotting patterns/trends and for organizing your history for the 12th neurologist).