--acute onset neuropathies (mine was). The most well-known acute onset neuropathy is Guillain Barre syndrome, but others can be caused by toxic exposures, autoimmune reactions, infections, and some metabolic situations (there are acute onset diabetic neuropathies).

Take a look at:

http://neuromuscular.wustl.edu/time/...htm#neuropathy

On the other hand, if you have a history of back pain, and your symptoms are waist to toes, are they examining your lower spine for compression issues? Do you have a recent MRI of the lumbosacral area? (Typically the MRI's for MS only look at brain and cervical spine.)

It would be unusual for IVIg to be suggested unless there was considerable evidence of autoimmune attack, such as in Guillain Barre--IVIg is an immune modulating treatment.