Small Fiber Skin Punch Biopsy
 

Well after 21 years of large fiber sensory motor axonal peripheral neuropathy, diagnosed and confirmed by numerous Electromyography/ Nerve Conduction Studies on my feet, legs, hands, and arms since 2003, with the latest in 2021, i finally decided to do a skin punch biopsy to diagnose and confirm small fiber peripheral neuropathy..

I have had the symptoms of small fiber neuropathy, and was sure I had it as well as large fiber, I just didnt see the point in doing the biopsy, since it wouldnt change the treatment. i have had extensive testing done to determine the cause of large fiber neuropathy over the two decades, so it wasnt because i was adverse to testing.

Anyway, I did the biopsy, which was sent to Therapath labs. Therapath only does examination on two sites on the leg, which were the right leg thigh and the right leg calf.

My results were a little shocking to me, though i was sure I had small fiber neuropathy, I didnt expect the nerve fiber density to be as low as it is.

The epidermal nerve fiber density at the right thigh was 1.26 nerve fibers per millimeter with less than 6.2 being abnormal.

The epidermal nerve fiber density at the right calf was 0.07 nerve fibers per millimeter with less than 2.9 being abnormal.

The sweat gland nerve fiber biopsy at the right calf was 12.8 %, with less than 36. 5 % being abnormal.

There were no sweat glands present in the sample from the right thigh.

all of the above confirms small fiber peripheral neuropathy at the calf and thigh.

apparently therapth doesnt remark on axonal branching or swelling unless the results are normal.

looking back i should have done the skin punch biopsy many years ago to keep track of the progression of small fiber neuropathy like i was and continue to do with large fiber neuropathy.

Hi echoes,
You sure have had a lot going on all these years.
If you don't mind my asking... if I remember correctly you were diagnosed with an autoimmune disease as well don't you? I was wondering if that is connected to the small fibre neuropathy or is that a separate condition?

Not an autoimmune disease exactly, its sarcoidosis which is an immune mediated inflammatory disease. Sarcoidosis, to be precise neurosarcoidosis caused by toxic exposures, caused large fiber and small fiber peripheral neuropathy. It took 18 years from the toxic exposures for neurosarcoidosis to be diagnosed.

i also have pulmonary , lymph, hepatic, thyroid and skin sarcoidosis.

you have a very good memory!

echoes,
I meant to reply earlier but I had some medical test things happening myself.
I didn't remember the actual name but I most certainly remember the injustice of it all.
That's an absolutely terribly long time to have waited for that particular diagnosis. I hope that you are getting some pain relief or other medications specific to the Sarcoidosis. I imagine that would cause so much pain let alone your neuropathy.

(You have said that about my memory before and I always laugh. I'm very fortunate that it still works at all.) :/

Glenntaj, Glenn i know what the results of my small fiber skin punch biopsy mean: the number of small fiber nerves per millimeter for the epidermal layer and the number of small fiber nerves on the sweat gland. What I cannot find is what those numbers mean as to degree of severity of the small fiber neuropathy. For instance 0.07 sounds severe to me when abnormal starts at less than 2.9, but i have not been able to find a source that delineates that. Are you aware of a source i could use to determine degree of severity of the resultant numbers? or is anything under the abnormal considered severe?

Anything under or over the range--
 

--which were originally set at the 5th and 95th percentiles of a large group of non-neuropathy sufferers of varied ages through the MacArthur protocols at Johns Hopkins (which is basically where skin biopsy for intraepidermal small fiber density was invented) is considered to be evidence of small fiber neuropathy. (You can look at the original papers if you search for "MacArthur small fiber" at PubMed.)

The determination of "mild", "moderate", or "severe", though, usually doesn't involve these numbers, but more the perceived symptomology of the patient, as there is not a direct correlation between the numbers and what the patient is objectively feeling.

Nevertheless, you're pretty low on the scale, so you can term it severe neuropathy if you'd like--and certainly your symptom profile would match that

Thank you for the information Glenn. It is much appreciated....as always!