Small Fiber Neuropathy and EM Correlation

So it has been just about 6 months since my EM started after a knee surgery (I am a 24 y.o. male), first in the foot on my surgical leg and then spread to the other side and my knees, hands, and ears. After many doctors visits, I have finally been diagnosed with small fiber peripheral neuropathy, only on my surgical leg. After discussing with the neurologist the results, he stated that often times neuropathy can start in one area and have symptoms present in other areas with the damage only being present in one area. I have been referred to a more academic institution for treatment, Mayo Clinic, where they will be able to try to create a treatment plan tailored to my symptoms and their origin, either inflammatory or genetic (I am awaiting the genetic SCN9A test results from last week). Overall, I am relieved that after many months of “normal” test results and pain with my life put on hold that something abnormal has shown up that can potentially be treated. Mind you I had to push for these tests and was told that there was a very very low likelihood that it was small fiber neuropathy. I will update on my treatment at Mayo but please push your doctors to test for small fiber neuropathy if you have a hunch about it as there has been much research recently that discusses that EM can sometimes merely be a symptom of this disease and can be managed and even cured.

Curious what you are hearing for treatment for SFN. I’ve had EM for 12 years and positive punch biopsy for SFN 10 years ago, but only ever treated the symptoms. Only treatment I’ve heard for SFN is IVIG so wondering if there is something else you are being told. BTW ask Mayo about Mexilitine. Out of everything I’ve tried over the years nothing has worked as well as it. I take 150mg 3x a day and I get pretty good relief. I still flare in heat, but don’t flare too much just randomly although I did a bit tonight. Flares are not as bad though and I can get them under control easier since being on Mexilitine. Others have had good luck too. Might want to check out this FB group as well if you are on FB.

Was the diagnosis for small fiber painful? My doc said it was a series of electrical shocks and I have put it off. I will wait to hear of your experience.

I have em with sfn too. Diagnosed at Hopkins via skin biopsy. Apparently the em is symptom of sfn. No treatment as no associated cause could be found. However, I am b6 toxic so that could cause neuropathy. Detoxing from that and under care of functional med dr. It takes 1-2 years to eliminate and see if neuropathy improves. If they call u idiopathic, keep digging. Put all ur resources against it. Sfn help group on Facebook is great resource. Many also have em and been to many institutions.

@gwadley The doctor that referred me to mayo mentioned Mexiletine and possible IV prednisone or lidocaine depending on my genetic SCN9A test.

@motherlove No, it is a biopsy so they numb the skin up, what you are thinking of is an EMG which tests for large fiber neuropathy which is like carpal tunnel or any other larger somatic neuropathy like muscle atrophy or trouble walking.

@froggy Thank you, it is quite an effort to get anything done with this but have you tried an IV lidocaine or prednisone (or any other immnosuppresant)?

I was on prednisone last summer since I also had a concurrent autoimmune pancreatitis flare. We didn’t have dx for feet but were curious if it might help. High dose with taper for 4 months. It did not help the neuropathy although it stopped the pancreas flare. Very hard on the body. 6 months of adrenal fatigue. I have done this twice over 8 years and takes 1-2 years to recover.

I’m sorry, that does not sound like an easy go of it, especially with it not addressing the EM flares. May I ask how your EM started? I am young and very healthy outside of this (I am an athlete and this has hindered my ability to play sports). Since mine started right after surgery and my SFN is all stemming from my surgical side foot they are thinking it could possibly be dysimmunity after the surgery. I also took a 1 week dose of prednisone in July and my flares ceased for 2 days so I am hoping that a potential IV dose and long taper could help put it into remission.

I hope the IV steroids, etc, helps you.

Whether or not you have a neuropathy mutation - I think IV lidocaine, oral sodium channel blockers, IVIG, steroids are each worthwhile to try. I do not have any known neuropathy mutations, but do respond to IV lidocaine.

Can I ask if you have any blood markers / autoimmune stuffs to suggest dysimmunity? (Just curious).

Just in case you haven’t seen this before, you remind me of the paper below. 20 yro man who has SFN/EM onset (acute) in hands/feet after spraining one ankle. unremarkable bloodwork but biopsy showed mastocytosis, so autoimmune involvement was speculated. Responded transiently to lidocaine iv but cured with high dose steroids.

Best wishes

@standing_cat I have had a basic autoimmune panel done which was negative, however, I do believe that it is still a possibility. My symptoms occurred after a knee surgery in February of this past year and when they came, they came fast and relentless. I am still having inflammation problems with my knee and excessive scar tissue formation which has been puzzling doctors but I believe that the two could be correlated which backs my thoughts about immunosuppresion therapy. I am waiting on the SCN9A genetic test so if that is negative then I doubt lidocaine would do much for me but I’m ready to try anything.

My EM also began after a knee injury. My doctor put me on mexiletine. It’s a little bit of an annoyance to have to plan my meals around a pill (I take it 3 times a day with food), but i’d say it’s about 98% effective. The heat index today was 105 degrees. I wore black crew socks and sneakers. I had no problems.

I may be the exception though. Other community members haven’t had similar success with mexiletine.

Mex is about 70% effective for me, but I get no side effects. I can take it without food fine. I’d be really careful with prednisone. It turns me into a tomato.

@CarterDK I have actually read all of your posts on it and it opened my eyes up to it. I plan on pushing for either a Prednisone or lidocaine infusion first to see if it can put it in remission completely but mexilitene seems to working wonderfully for you so I hope it could do the same for me.

@gwadley that’s really nice actually as I intermittent fast and would have to change my whole diet in order to take it with food if I do. And I actually took a Prednisone pulse back in July as the first line of treatment and it helped but only while on high doses but I didn’t worsen. What made me worse was actually Bob’s protocol which I tried for a month and saw no improvement.

Hi Joe,
Thanks for sharing your story. I have been a part of this group for a year but rarely post but your story sounds very similar to mine. I developed EM of my feet 3 months after having neck surgery in 2011. I did not know at the time those symptoms were EM. I have only determined this about a year ago when the symptoms started in my hands. About 6 months ago I had a skin biopsy done in my lower extremities and tested positive for “mild” SFN. I am a healthy female who has always been active. I still run but recently the EM has gotten worse and it’s difficult to get through 3 miles bc of the burning. I have found I can get through the burning but the ache that follows the next day is at times unbearable. My pain has gotten worse since I reduced my Elavil dose from 75 to 25mg. I could no longer tolerate the eye and mouth dryness.
But, I find it interesting that your symptoms started after surgery. I have always known there was a correlation. I have been tested for autoimmune and have had a positive ANA (low 1:160) but everything is negative. I am at a point where I have stopped trying to figure it out and just deal with the symptoms best I can. I also have raynauds so I am on a low dose of amlodipine which has helped. I’m tired to dealing with doctors who don’t care and don’t have a clue. I have not been tested for the SCN9A gene but have considered it. I did test positive for the MTHFR gene mutation and took Metanex for a while but saw no change. But, it does seem the EM and SFN go together. Your story gives me encouragement and new motivation to find more answers. Thank you and
welcome to the group.


That’s wonderful that you are still able to go for runs, I too think that if my EM persists when my knee is healed that I will just run through it (hopefully I can find a treatment for it though). I too got tested for MTHFR and factor V leiden when my EM first started because it started initially in my surgical foot and they thought it was a blood clot. I am heterozygous for MTHFR but doubt it is related. With you positive ANA, have you tried any immunosuppresion therapy such as a high dose prednisone pulse? It has been shown to help with immune-related EM. I had a negative ANA but still believe that it could potentially be some inflammatory neuropathy following the surgery. Don’t give up on finding answers, EM is more a symptom, and the harder you try the more likely you will find an answer. One quote from Winston Churchill has been my daily motivation and that is, “if you’re going through hell, keep going”.

Did your physicians do a skeletal scintigraphy on your surgical knee or foot?

No, that is just essentially a bone scan right and what would that show? I had an MRI of my surgical knee in July to check for a foreign body response and all that was shown was scar tissue in my patellar tendon (what I had surgery on). Thankfully the tear was healed so at least the surgery was a success. My nerve biopsy also only showed small fiber neuropathy in my surgical foot and my flaring remains nearly twice as bad as my right foot. Have you heard of others symptoms starting like this?