--and absolutely think, given that you've indicated an acute onset to your symptoms, you should have a full battery of MRI's--cervical spine as well as thoracic and lumbar. Too many doctors assume that lower extremity pain can only come from cord or nerve root impingment in the lumbar spine, but it can also come from impingment at any higher up level.

That is not to say that you might not have an acute onset peripheral neuropathy that has nothing to do with the spine, but more often than not such an acute onset suggests some compressive force involved. There are acute onset peripheral neuropathies that have autoimmune or toxic etiologies--I see you've had a good deal of toxicity testing--but I doubt you've had as complete a testing profile as people with neuro symptoms should; have you seen the spreadsheets at www.lizajane.org yet? Many of us use these to help suggest what kinds of tests might be done and to track our test results over time.

The sad part of this is that many problems of the central nervous system can produce exactly the same symptoms as problems of the peripheral nervous system, making the search for a cause long, elusive, and expensive. But it is doubtful you've had a really full work-up unless you've been seen by a neurologist or at a center that specializes in neuropathy. Can you list all your test results for us (many of us will likely have additonal suggestions)?