--is a good idea, as in ambiguous cases it may distinguish symptoms arising from the central nervous system from those arising int he peripheral nervous system (it is often used to help diagnose multiple sclerosis, for example, in those with inconclusive MRI or lumbar puncture test results).

It is certainly possible to have both large and small fiber neuropathy at the same time--mixed types often point to a more systemic autoimmune, toxic, or nutritional cause, though compressive effects can certainly exacerbate the symptoms (as in the "double crush phenomenon").

Another possibility (common in Sjogren's, for example, though many cases are idiopathic), is neuronpathy. a sort of subset in which the cell bodies in the dorsal root ganglia are compromised, and this can have both large and small fiber components:

http://neuromuscular.wustl.edu/antib...uron.html#sfsn