--is just a subset of peripheral neuropathy, referring to preferential damage to the smaller, unmyelianted or thinly myelinated fibers that subsume the sensations of pain, temperature, and many autonomic functions.

It cannot be detected through standard nerve conduction studies or EMG's, as these only measure larger, myelinated sensory and motor nerves. Sometimes quantitative sensory testing or specialized autonomic testing, such as sudomtotor axon reflex testing, reveals it, but the current gold standard is skin biopsy to measure intraepdiermal nerve fiber density and condition. (There are also some other non-invasive methods being tested to detect small-fiber damage, such as refractive light microscopy, but these seem to have a way to go yet.)

Small fiber neuropathy IS PN.

Anything outside the spinal cord is PN...small fibers are considered outside the spinal cord.

EEO3,
There are 2 main systyems.... the Central nervous system, and the Peripheral nervous system. The Peripheral system is anything outside of the central system.
Neuropathies (damaged nerve cells- either large or small) occur within the peripheral system, more frequently. (I think because there are more nerve cells there).
PN encompasses any nerve cell damage, anywhere in the body (hands, arms, legs, feet, stomach, heart, etc) that is not in the central (spinal column and brain) system.

You may also hear of small fibers referred to as thinly myelinated or unmyelinated or C fibers....one and the same.

Thanks, I understand that these are all peripheral, but I get the sense that there are inherent differences in the symptoms and pronosis, or maybe my fuzzy mind isn't grasping what I'm reading. I believe the neuro ruled out something by comparing the current results with those obtained 7 months ago. I guess I need to wait to see the report and discuss what further tests are being recommended.

With PN, or small fiber neuropathy, prognosis MAY depend on what is the underlying reason for the SFN to begin with. Often they try to find out if it is the result of some disease. If it is idiopathic, prognosis is more difficult to predict....on the other hand, all neuropathy is difficult to predict.

Once you get the test results you will have more direction.

Waiting is hard, and it is always as shock to get the diagnosis.