Small Fiber Neuropathy

Punch biopsies are usually done on the side of the body where you experience the most symptoms (if you happen to notice a difference, and many people do). You've had the biopsy, so you know the drill, but for others who haven't, I'll elaborate. Between two and four (based on the discretion/preference of the doctor and the recommendations of the lab/kit being utilized) 3mm 'punch' biopsies are taken. Frequently three are taken, distal calf (near the ankle), proximal and distal thigh. These 3mm samples are then (again, depending on the kit/lab) frozen, sectioned into 50 micron thick samples, stained, put under a microscope, and the nerve fibers meticulously counted by a pathologist. The number of small fibers present in the samples are then compared to a reference data set for the specific locations biopsied. Taking three or four samples spanning the length of the leg allow the pathologist to differentiation between length- and non-length dependent SFN. Length-dependent SFN is more common, generally has a slower progression, and symptoms characteristically progress from the feet upwards. Non-length dependent SFN is an indicator that SFN is likely widespread throughout the body, and can cause autonomic nervous system dysfunction; affecting organs and glands along with the skin and muscle symptoms seen in length-dependent SFN. Once you have the diagnosis, there is to my knowledge, little to no significance of having it repeated in your other extremities; you know you have it, and wherever you're feeling symptoms, it's likely SFN is present. Not to mention the biopsy is quite expensive. Repeating the punch biopsies after some time has past from when the first set was taken is a great way for your neurologist to track how the disease is progressing/how well treatment is working. Bakodx and Corinthian Reference Lab's websites, can provide you with more information.

Hi @wolfbauer -- welcome to Mayo Clinic Connect. Thank you for sharing your knowledge and experience. It's really helpful. I'm assuming you also have small fiber neuropathy. May I ask what treatments you have found that help you?

I have apparently had non-length dependent SFN for a while, along with a myriad of other conditions including a spinal syrinx between T5 and T9, and three messed up discs from a car accident (C4-C5, L4-L5, L5-S1). I also have a schwannoma on the T8 thoracic nerve which is shielded by my rib and inoperable (radiation is currently the only treatment option being offered to me). I finally had the punch biopsy and was formally diagnosed with it this past summer. It's progressed to autonomic nervous system dysfunction at this point; I have gastroparesis, severe nausea and weight loss (50 pounds in 5 weeks), random tachycardia while resting or sleeping (I've woken up with a heart rate of 110), syncope without prodromal symptoms (that was a gem to find out I can now pass out at any time with no warning), and within the past two months, have begun having what I call 'hot flashes' (I'm a 31-year-old male) alternating with chills, but I DO NOT have a fever during those occasions. My neurologist told me that it was very common in SFN, but that he has yet to learn of any treatment to prevent/treat it. I have terrible insomnia where I can end up sleep anywhere from 1 day to 4 days, so when I do actually get sleep, it's important to me and obviously frustrating to wake up because I feel like I'm in a sauna, ten minutes later freezing, then another ten minutes later on fire again. Has anyone experienced this, and if they have, have you found a treatment for it? I was curious if anyone has tried clonidine (can be used for hot sweats/flashes and excessive sweating).

Hello @wolf bauer. Yes, I am having a terrible time with the exact same sweating attacks, feeling like I have been in a sauna and then weird chills. I was diagnosed in 2015 with severe SFN (firm diagnosis via punch biopsies) and then diagnosed with Autonomic Neuropathy/Dysfunction in 2018. I have been battling syncope for over a year and have fallen to the ground three times (I also have a bad back - broke my thoracic spine in 7 places due to an 8 foot fall. I have hardware fusions, but T5 -T8 compression fractures are inoperable due to being too high risk). I have been taking clonidine 0.1mg tablets, twice a day, to help with the sweating. Sometimes it works well, other times it doesn't. I am going to ask my Neurologist at my next appointment if there is something else I can take for these awful, daily, sweating attacks followed by chills. I was prescribed the clonidine in 2015, after my severe SFN was diagnosed. I am terribly sorry to hear all that you battle with. I certainly can relate and I am hopeful there is something that may help us. Thank you for sharing.

@wolfbauer there is another discussion on Connect where members have mentioned clonidine in their posts.

Groups > Heart & Blood Health > New to the world of Hypertension Meds
-- https://connect.mayoclinic.org/discussion/new-to-the-world-of-hypertension-meds/

I'm tagging @predictable to see if he may have any information or suggestions for you. Also, Mayo Clinic has some information here that may be helpful:

Clonidine (Oral Route)
-- https://www.mayoclinic.org/drugs-supplements/clonidine-oral-route/description/drg-20063252

Hi @johnbishop ,
I've worked in pharmacy since I was 16 (31 now) and studied to be a doctor of pharmacy so I nerd out pretty hard when it comes to medicine. I've been unemployed since 2015 due to my health issues which include small fiber neuropathy, myofascial pain syndrome, fibromyalgia, Raynaud's, migraines, severe insomnia, cervical dystonia from the disc problem in my neck, and autonomic nervous system dysfunction (mainly from the small fiber, but my neurologist assumes that the syrinx in my spinal cord, thoracic schwannoma, and the two lumber disc problems are also contributing factors to the wide range of symptoms). I was in a car accident in 2011 where my car's tires lost grip in the rain while going 65mph and ended up hitting a wall head on. It's assume that most of the above issues stemmed from that. I also have a second ultrasound and a mammogram coming up after two previous appointments and an ultrasound suggested the possibility of male breast cancer. I have a history of treatment resistant major depressive disorder and anxiety as well so it can be difficult to tell which issue is causing which symptom. I was in a clinical trial at Mount Sinai for depression which used sub-anesthetic doses of ketamine, and the anesthesiologist who continued the treatment recognized neurological symptoms that suggested MS. The first neurologist I saw, who had formerly treated me for migraines, would not order an MRI and concluded that my physical exam was normal. I wanted a second opinion, and I was lucky enough to find my current neurologist who has been amazing. Not only did he order MRIs of my brain, cervical, thoracic, and lumbar spine which revealed numerous problems, his more attentive physical examination found abnormal reflexes and sensory nerve damage. My current treatment consists of physical therapy twice a week, a 60 minute myofascial massage whenever I can scrape together the money, meditation, trigger point injections, nerve blocks, ibuprofen, oxycodone, diazepam, amphetamine salts (Adderall), lidocaine patches and cream, and botox injections every 12 weeks. Up until two weeks ago I was also on baclofen, tizanidine, and gabapentin together (I've also tried cyclobenzaprine), but they had no effect on my muscle spasms/tightness, and as a result discontinued them. I've tried Lyrica, literally every antidepressant or medication used off label as an antidepressant or adjunct for depression including those used for small fiber, ondansetron for nausea, sumatriptan injections for migraines, topiramate, the aforementioned ketamine infusions I had monthly worked so phenomenally well that I was prescribed oral ketamine to take daily, which also worked amazingly for my pain (it's a dissociative anesthetic). The high oral dose I was on, however, was beginning to trash my kidneys and urinary tract so I had to stop that (it can cause interstitial cystitis and long-term users have had to have their bladders removed due to such extensive damage). I was prescribed IVIG, but my insurance does not cover it. I've been vitamin B, D, and E deficient for a while despite taking supplements of each, and also am dehydrated despite drinking at least half a gallon of water a day. I have difficulty keeping weight on as well, so malabsorption seems like another likely problem. My neurologist's current treatment plan is to run blood work again in March when I go in for botox injections, and if my vitamin levels are normal and I'm no longer dehydrated, I'm going to start plasmapheresis. We have yet to come to a solid conclusion as to the primary cause of the small fiber neuropathy. My neurologist is 95% sure it's autoimmune (I have a history of autoimmune issues such as idiopathic autoimmune hemolytic anemia my senior year of high school, and have a standing prescription for epi-pens as I have, thrice, gone into anaphylaxis but do not show any signs of an allergy [each occurrence had nothing in common]). I've been tested for just about everything including Lyme, Lupus, Sjogrens, MS, Rheumatoid Arthritis, Celiac's, Mayo's myositis and neuritis panels... all the stuff everyone here has surely been tested for. I'm not sure if it is a national chain store, but I have a 6 ft x 2 ft x 2 ft giant bean bag from 'Yogibo' that is very supportive (my neck, shoulders, and back get severe pain whenever I sit or stand for prolonged periods of time... laying supine is the only position that helps keep my pain at a more manageable level). My main frustrations have been the new symptom of what I refer to as hot flashes alternating with chills, severe nausea, insomnia, and severe pain in certain muscle groups that seem to be in a constant state of contraction. I get fasiculations and spasms all over, but this is different; my physical therapist, neurologist, and massage therapist have each noticed that I am unable to relax different muscles such as my biceps and trapezii (they feel like they are relaxed to me, but the practitioners can feel them contracted). I have tried progressive muscle relaxation meditation, and countless muscle relaxants without any relief. I've tried CBD gummies for pain and muscle spasms which didn't work, but am open to trying a topical. I qualify for a medical marijuana card here in NY, but 1, cannot afford the actual product and 2, cannot use it due to my job in pharmacy (as I said, I'm not currently able to work, but my primary goal is to get back to work). I got some capsaicin cream to try, (I've always recommended it to my patients, friends and family members, and those who have used it correctly have all had positive results, including a middle-aged friend with bad arthritis who was able to start pitching softball again). I searched SFN support groups today, as mine seems to be progressing quicker than what I've expected from my personal research. Once I seem to address a symptom with one of my doctors, I feel like two more pop up. I'm really curious to hear any tips, tricks, or advice others here may have. With all the specialists I see, I average 1 doctor appointment a day, and over the past few months have had weeks with 10 or more appointments. I hear about people having periods of remission, but looking back I've realized that I've had some of these symptoms for over five years. Because of my high impact hobbies and the nature of my job standing all day compounding 1-4L IV bags, those symptoms were ignored. Their intensity has been steadily increasing without any periods of relief, and are no longer something I can ignore. The symptoms that have recently popped up relating to autonomic nervous system dysfunction are quite uncomfortable and very unpredictable. This makes it difficult and stressful to manage them and my schedule day to day. I make a conscious effort to be thankful each day, as I can still physically take care of myself without help from a caregiver, and I know that there are countless others out there that whose symptoms are much more severe and who are unable to do the things I sometimes take for granted like walking, driving, and getting myself ready in the morning. As my cluster of conditions progress, and new symptoms pop up, I have found I'm having a harder time coping with the progressive nature of it all. I'm curious to what extent IVIG, plasmapheresis, or corticosteroids have helped people in this group, and how long any relief lasted. Has anyone found a different treatment or medication that has brought them relief? I apologize for the novel I've written, haha, and hope everyone is enjoying the beginning of the weekend!

Hi @wolfbauer . Thank you for taking the time to share your thorough history! I know I will be reading through it again, as your treatments and diagnoses are ones I have had or currently have. One of your current treatments popped out to me, as it was recently deemed a "no no" by my Neurologist. I can no longer have my nerve blocks - ganglion impar at coccyx area (busted up my coccyx and sacrococcygeal junction at the time of my fall) and the sacrococcygeal nerve block. He says they are a big "no no" because they can mess with our sympathetic nervous system? I was extremely bummed, because the relief I get from those blocks are excellent. I have not had a Ketamine infusion yet, but plan to this year. I have been taking the Ketamine nasal spray for over a year now and it does help with my migraines. That bean bag sounds awesome - I am unable to sit, stand or walk for long periods at all these days. Good for you on keeping as positive an attitude as possible, with the plethora of conditions you deal with every day. I try my best to do the same. There are different treatments, medications, etc., out there and I am always open to exploring them.

Hi @wolfbauer . I was wondering if you could tell me about the relief you experienced with the Ketamine infusions and how many of them did you have per month? I do know it varies with each individual - I am just wondering how long did you feel relief after each infusion, etc. I am sorry you had to discontinue this treatment, but you are wise to take care of your bladder. I am hoping the infusions work for me, just so I can get out of the house for special occasions. It's a very expensive treatment. I wanted to ask if you have had Toradol shots? I get those once a month and the last one I got actually helped with the horrible sweating and chills that particular night. I had the first comfortable as possible night, in a very long time.

@teetee7 , I'm sorry to hear you're having a terrible time with it too! I absolutely hate the heat/summer/fevers, so when this started happening it really bothered me. I had just gotten over the flu so I thought I was having a fever until my thermometer kept reading normal, and it continued happening. I got officially diagnosed with SFN last year too, and had no idea about having autonomic neuropathy/dysfunction (I'll abbreviate it AN/D) until my local hospital called me to set up 16 physical therapy appointments, and finally asked them who prescribed it and why, haha. It's only really been since November that I've been experiencing more and more autonomic symptoms. I fell down the stairs at the end of November (from a combo of AN/D and SNF symptoms), and in December, I was turning my bedroom doorknob to leave the room, and then all I remember is waking up on the floor (I'm really lucky I didn't hit my head on anything as there's a lot of hard furniture and stuff packed into my room except for the exact spot where my passed out body landed). I feel bad for you and your back; was your 8 foot fall and broken spine from a syncopal episode, or did it happen before your SFN? I do have to say, my last college pharmacy class was in 2011 so when you said you were prescribed clonidine for it, I celebrated in my head (for the past 2 years I've had pretty bad anomic aphasia [word recall], so actually remembering an off-label, non-FDA approved usage of a medicine made me happy that I'm not losing my memory too haha). I'm just remembering, I actually stopped sweating for several months leading up to my first hot flash/chill/sweating attack (good think air conditioners exist). I also never thought about the hair loss until reading your other post. I've always had thick hair on my head, medium hairy arms, a little on my abs, and quite hairy legs. My head hair (sounds weird to say it that way) thinned out quite noticeably, but for now, I believe it was from stress/malabsorption/vitamin deficiencies as it grew back in thick again, and now that I'm stressed and vitamin deficient, it's thinning again. I forgot that I was also finding short arm and leg hairs all over my sheets (I still have hair on both, but it was definitely falling out). I've been doing research tonight with the online pharmacy reference resources from my college... does this site have private messaging? I can't post links, and I can send you what I've found. I also wanted to ask you about the nasal ketamine spray and give you info about the infusions as an infusion is WAYYYY DIFFERENT than taking it orally. Also, I've only seen the nasal spray supplied as esketamine, the S (left optical isomer) and wondered if we compared experiences, we would notice a difference between the nasal and oral racemic mixture. And to address the nerve blocks, I've only had a couple, and it was to rule out T7 and T9 and other possible causes of the pain I believe is being caused by the schwannoma on T8 in my back. It's shielded by my rib, and surgically un-resectable, but the neurosurgeon offered a plan of radiation, or actually severing the nerve if it's at fault. One last SNF question for you (especially since you've used ketamine and at first I thought that was causing it)... have you experienced intense pain where the gallbladder is located? I've had numerous ultrasounds and a HIDA scan, and my gallbladder is fine, but I have literally passed out from the episodes. It's without a doubt the most severe pain I have ever felt; what I imagine getting shot in the gut feels like (it could be the schwannoma, side effect of ketamine, SNF, or something entirely else... no one can figure out what causes it and nothing has any effect on it. I've been given IV fentanyl and I was still in excruciating pain.

@teetee7 So the toradol shot worked just for that night? I'm going to make a claim without being able to back it up yet, and you and I might have just found a successful treatment for our sweats/chills completely randomly. So Toradol is the brand name for ketorolac tromethamine, an NSAID like Ibuprofen. Of all people, my gastroenterologist wrote me a prescription for 600mg ibuprofen when she asked about chest pain and I told her about how my ribs hurt... she thought it could be costochondritis and there was no harm in trying it out. I used to take 800mgs 4 times a day, nearly every day for pain since I was in high school. I finally stopped; figured I had put enough stress on my liver, kidneys, and was due for an ulcer. Anyway, after picking up the prescription, I didn't take it for a while because I wasn't eating, and I didn't want to take it on an empty stomach and get nauseous or an ulcer. I started taking it this past week, and now that I think of it, I either haven't had the fever-chills this week, or it hasn't been anywhere near as frustratingly bad as usual. Both toradol and ibuprofen are NSAIDs that inhibit prostaglandin synthesis. Prostaglandins are hormones that regulate homeostasis, inflammation, and act on the thermoregulatory center of the hypothalamus causing fever. Maybe we just figured out by accident that prostaglandins are the cause of this symptom of SFN, and NSAIDs can treat it!!!!!! If I'm right, I'll give you credit when I write the research paper on it, but I'm putting my name first, HAHAHAHA!