What is small fiber axonopathy and is it terminal or is it like multiple systems atrophy or als?

None of above. This is a peripheral neuropathy, predominantly affecting small fibres, and may be associated with burning pain over feet and hands, but pain maybe more widespread. Exam can show decrease in pin and temperature sensations. There are a limited number of conditions causing this, and diagnosis can readily lead to treatment success. This has little in common with MSA or ALS.
Small Fiber Disease. Small fiber neuropathy (sfn) is caused by damage to the small, unmyelinated fibers in the peripheral nerves that innervate the skin and internal organs, including the cardiovascular system, gastrointestinal tract, and bladder, among others. These fibers convey pain and temperature sensations from the skin, and mediate autonomic functions. It is most often associated with diabetes in the us.