Is small fiber neuropathy or polyneuropathy the same as small fiber axonopathy ?

Neuropathy: Small fiber neuropathy/axonopathy refers to the small unmyelinated fibers that transmit mainly pain and temperature. Polyneuropathy refers to neuropathy of the peripheral nerves that include large or small fibers or both.

Neuropathy: Yes. Axonopathy is a type of neuropathy.

Definitions: Small fibers which mediate pin and temperature sensations lack myelin, and are indeed pure axons, so the terms small fibre neuropathy or axonopathy are synonymous. Polyneuropathy usually refers to a larger fibre process which is distal bilateral and symmetrical, and can be either axonal or schwann cell predominant, and affects strength, balance, proprioception, and light touch.