I don't think an 'occasional axonal swelling' will be enough to firm a Dx of SFN. It may be a sign that a process has started though. Axonal swelling is NOT normal, so 'something' caused it, and therefore another test 6 months down the road may reveal more important information about what is going on. Your symptoms may be new enough that the fibers aren't showing the damage normally seen with SFN...YET. Maybe Glenntaj will see your post and comment in the morning with more detail information.

Sorry, I don't know your history...How long have you experienced the burning? If more than 6-9 months, that my theory is probably not possible.

You mentioned autonomic symptoms. Can you elaborate on this? How long have these symptoms been present?

Have they considered autoimmune disease? Have you been tested for various autoimmune conditions?