so i went down a rabbit hole after my third specialist told me my symptoms were “too diffuse” to fit any one diagnosis. neurologist, rheumatologist, cardiologist - each one looking at their slice and shrugging. then i found the small fiber neuropathy work coming out of places like Cornell and MGH. specifically Oaklander’s group and some European cohort studies showing reduced intraepidermal nerve fiber density on skin punch biopsy in ME/CFS and long COVID patients.
here’s what clicked for me as a PT: small fiber neuropathy hits the thin nerve fibers - the ones that run autonomic function AND pain AND temperature regulation. standard nerve conduction tests only measure large fibers. so you can have real, structural nerve damage and a completely normal EMG/NCS. which is exactly what happened to me.
if your small autonomic fibers are damaged, you’d expect: orthostatic intolerance, sweating dysregulation, GI dysmotility, cardiovascular instability. sound familiar? and the sensory component covers the weird burning, tingling, cold sensitivity a lot of us have. what i keep thinking about is that “too diffuse” criticism.
of course it’s diffuse. small fibers are everywhere. one pathological process, whole-body expression. it actually makes the symptom picture MORE coherent, not less.
the biopsy isn’t standard of care for long COVID anywhere i’ve looked. most neuros won’t order it without prompting. i asked mine directly after reading a study i pulled from PubMed and he seemed genuinely unsure whether it applied here. has anyone actually gotten a skin punch biopsy as part of their long COVID workup?
and if it came back abnormal, did it change anything practically - treatment, framing with docs, anything?