biopsy for small nerve fiber

My neurologist also did extensive lab work and 1 important thing was B6 toxicity. So I am not longer taking it. I am also taking Nortripyline. After about 4 weeks I noticed my pain lessening. I have been on 50 mg for 2 months and the pain and burning is almost gone. The only problem still is wearing shoes for more than a couple of hours.

If you can return to that pain clinic and get the skin biopsy, just follow their frustrating guidelines and do it. It’s one more possible answer. Get ready for a parade of slow, irrational and frustrating series of doctor visits and tests. I won’t tell you how long it took to get a diagnosis of idiopathic length-dependent small fiber polyneuropathy. And treatment that works! And I’m a nurse!
I advise getting the skin biopsy when it’s offered. Start reading, and save hard copies of all your test results and lab results.
You are one of many on this path. Good luck!

If you can return to that pain clinic and get the skin biopsy, just follow their frustrating guidelines and do it. It’s one more possible answer. Get ready for a parade of slow, irrational and frustrating series of doctor visits and tests. I won’t tell you how long it took to get a diagnosis of idiopathic length-dependent small fiber polyneuropathy. And treatment that works! And I’m a nurse!
I advise getting the skin biopsy when it’s offered. Start reading, and save hard copies of all your test results and lab results.
You are one of many on this path. Good luck!

My B6 was high too. The reference range is 2.1 to 21.7. Mine was 30.5. I stopped the multivitamin and fortified yeast, but my symptoms have been worsening. Getting covid on top of it all did not help at all. The burning is now in my neck most of the time.

What you say is true. However, it is only a presumptive diagnosis, based on symptoms and the results of the tests you mention. The biopsy is the gold standard.
Even though I am generally strongly against tests which give you no additional useful information nor additional treatment options, I did have this test. For some reason. I was comforted by the fact that the test directly confirmed that I had a "physical disorder" (less peripheral nerves). Unfortunately, it is also less treatable, even to the extent that most treatments for peripheral neuropathy are usually FDA approved for diabetic neuropathy. New drugs and treatments generally are first FDA approved for diabetic forms. That means insurance generally won't pay for them, although they can be prescribed off label if you're willing to pay for them.

If you can return to that pain clinic and get the skin biopsy, just follow their frustrating guidelines and do it. It’s one more possible answer. Get ready for a parade of slow, irrational and frustrating series of doctor visits and tests. I won’t tell you how long it took to get a diagnosis of idiopathic length-dependent small fiber polyneuropathy. And treatment that works! And I’m a nurse!
I advise getting the skin biopsy when it’s offered. Start reading, and save hard copies of all your test results and lab results.
You are one of many on this path. Good luck!

What treatment worked for you??
I am a nurse also. I am scheduled for a punch biopsy in Nov. Hoping that it leads to some sort of diagnosis or helps to clarify things at least.
I am 75 now. I have led a very active and healthy life. I have no heart disease, diabetes, cancer, hypertension, or osteoporosis. What I do have is lots of degenerative arthritis and have had many orthopedic surgeries related to that: Bilateral knee replacements 2009/2019, Spinal Fusion at L3,4,5 in 2018, Torn hamstring surgically repaired 2021, Kyphoplasty L1 2022. I also have long term familial tremors of both hands that slowly increased over the years.
The history of my current situation actually runs from about 2017 to 2022. During those years I experienced occasional and increasing unexplained falls. My family and I observed that something was different about my gait. That being that I was catching my toe and tripping or misplacing my step. I sought medical help at that time with PCP and referral to neurologist. Had appropriate testing at that time including brain MRI. Testing was negative but toe catching was able to be observed once with observation by that neurologist. To watch and wait was the plan. Along the way, I did perceive increasing muscle fatigue in lower extremities when doing a typical walk of 2.5 miles between 2021-22. Also, I could not walk as fast as I was used to being able to. As listed above I did have ortho surgeries in and around that time frame. Related??
In the spring of 2023, there was a change in my symptoms with increased back pain and weakness in legs and significant decrease in ability to climb stairs due to strength not pain. To begin with my increased back pain and symptoms were thought to be related to the condition of my spine. There were plans for a major back surgery. However, before surgery could be scheduled, there was an acute increase in symptoms of bilateral numbness in toes and feet, inability to lift forefoot or to move my toes and severe loss of balance and ataxic gait requiring 100% use of a walker. I seem to be losing function hour to hour. Sensory Motor Nerve Conduction study showed major change over a matter of days from previous study and indicated nerve demyelination. I was hospitalized at that time and treated for GBS for 5 days with IVIG. I stabilized but the symptoms did not go away.
What followed were months of extensive testing and image studies to rule out whatever could be ruled out. What turned up besides the abnormal S/M conduction studies was a recessive gene (POL G) I inherited and that has potential for pathologic expression, mild elevation of spinal fluid Protein and GAD levels. I also had a Sural nerve biopsy that showed essentially normal nerve i.e. no demyelination. At Multiple consults/2nd opinions at specialty centers followed. You know the drill.
I HAVE seen improvement slowly over time. I can walk now with just the use of a cane and I can cruise counters and walls at home fairly well, but balance is still a major issue as well as a residual L footdrop. I must be very careful and always be conscious of my footfall and balance issues. It is exhausting. I fall about 1 x per month despite my best efforts to stay upright.
I am on monthly IVIG. I cannot correlate anything with IVIG treatments. I could not tolerate steroid blasts.
Your experience has buoyed my hopes that the Skin Biopsy may lead to some additional clarity. Thank you.

I'm glad I could give you hope. My story is quite different from yours. My neuropathy manifested as burning pain in my hands and feet. I lived with a diagnosis of fibromyalgia for about six years before being correctly diagnosed, by skin punch biopsy. I had 3 biopsies on each leg - ankle, knee area and upper thigh. They actually count the number of nerve fibers.
Eight years from my initial noticeable symptoms (I say noticeable, because looking back prior to that, I had many weird neuromuscular issues), my overall activity has decreased due to pain and weakness.
But you are describing symptoms of "large fiber" neuropathy. I can think of two people on this forum with that - NJ Ed @njed and Ray Kemble @ray666 - and am going to tag our moderator, John Bishop @johnbishop. I have seen Ed's posts about a brace for foot drop that he wears in his shoe. Ray seems to have similar mobility issues as you.

Thank you for your remarks. The neurologists think I may have two things
that have interplay between them. Like not one zebra but two (rare
things)my primary neurologist told me.
I do have a professionally fitted OFA. It restricts the amount of normal
movement I do have so I am hesitant to wear it. A hightop sneaker seems to
work better but not great either.