I had an acute-onset body-wide burning neuropathy that developed within hours on April 12, 2003. It has been likened to a sensory Guillain Barre in that it has an acute onset and is suspected to have been sparked by autoimmune molecular mimicry, as Guillain Barre often does.

Supposedly, the process starts when the body is invaded by a pathogen, whether naturally or by inoculation, which it then mounts an immune response to. If, by chance, though, the pathogen has a molecular structure similar to some bodily tissue (and this varies from person to person, but immunity works greatly by shape, by antibodies being created tht act like a "key in a lock", so to speak), the now-activated immune system may not be able to shut off; it attacks anything with the same molecular configuration, including bodily tissue.

Many people have antigens on nerve, especially in myelin sheathing, that do resemble the shape of certain pathogens (particularly H. Pylori, Epstein Barr Virus, and Campylobacter Jejuni ), and sometimes this autoimmune process eats away at the myelin quickly, resulting in neuropathic symptoms. Classic Guillain Barre often starts with sensory disruption and progresses rapidly to motor; in severe cases it can threaten paralysis of the autonomic systems. There are, though, many variants--it's entirely possible in my case the molecular similarity was to my small, unmyelinated fiber nerves that subsume the sensation of pain and temperature, leaving me with symptoms of burning pain but no motor disruption (this is referred to as acute onset small-fiber neuropathy). Yours may have been similar and/or involved slightly different nerve categories.

Acute onset neuropathies such as Guillain Barre will generally receed over time, but they do often leave lingering symptoms/disabilities--the general prognosis is "slow, partial recovery". I know I'm still prone to flares,a nd I'm very sensitive to nerve compressive effects; I probably have a degree of permanent damage, although I've undoubtedly have had considerable re-enervation over time, which skin biopsy confirms.

BTW, many people think that chronic inflammatory demyelinating polyneuropathy, or CIDP, may represent a slower onset, relapsing/remitting version of Guillain Barre, and it too has various variants depending on the original target of the attack.

One other thing--don't assume that this may not have been primarily due to B12 deficiency. B12 deficiency is the great mimicker--it's been confused with Guillain Barre, CIDP and other neuropathies, MS, other demyelinating diseases of the spinal cord, etc. Lack of B12 will evenutally cause deterioration of all kinds of bodily nervous tissue, and depending on whether the deterioration occurs faster in the central or peripheral nervous systems, or in the brain (B12deficiency can actually cause white matter lesions there that may look like the aftermath of stroke or MS), one can get all sorts of confusing symptoms.

Fortunately, B12 deficiency is treatable, if recognized--many have good results with injections, but people who need a more steady supply should go the oral supplementation route, taking 1000-5000mcg/day, so that one ensures that one gets enough through the 1-2% passive absorption the intestines allow--people with deficiency are usually not absorbing through the stomach, due to lack of intrinsic factor or some other reason.

Also, as far as that doc you're talking about--I know of no known toxic B12 level--there've been studies in Japan supplementing with 36000mcg/day with no side effects beyond increase in energy.