Hi again. I've done reading to try to find out answers to my questions, but wasn't able to, so I'm hoping it's okay that I started a new thread with questions b/c I keep having more of them!

1. If the botttoms of my feet burn, why are they taking the biopsy sample from my thigh? Sometimes the tops of my feet burn as well and I get tingling, etc. BUT I don't have any burning on my thighs... the doctor is taking three little punches from my lower thigh, above my knee. I know that he noticed differences when he was testing my legs with his instruments, so I guess I seem to be losing feeling in my feet/lower legs as well, but I'm confused as to why he wouldn't take a sample from the soles of my feet--where my worst pain is located.

2. My pinky toe goes numb sometimes. Does this have anything to do with SFN/PN?

3. This has been going on (the burning feet) for more than five years. I have had a glucose test in that time, and it was fine. There's no way I have diabetes. Is this different than diabetic PN? I'm asking because I have a close friend who ended up with gangreen in his foot b/c of this, but he had Type 1 Diabetes. Will I have to be careful not to get small cuts etc. on my feet?

4. Could I make this worse if I do too much? I mean, I know it FEELS worse when I am on my feet too much they're much worse and they burn more at night, unless I'm in a flare, then it's bad all day, but I have learned how to balance rest and activity, but should I be resting (off my feet) more to stop disease (disorder?) progression?

5. Could this be a precurser to Rheumatoid Arthritis? For the past two years, my joints in my hands have been stiff and painful and a bit swollen in the morning, BUT my bloods are all fine. I guess my question is...doesn't RA (or other autoimmune diseases) come FIRST and the SFN/PN come next? Does that make sense?

Thank you again. This forum is amazing. I am still waiting to get my skin punch biopsy, and am very interested in what that will say.

--with skin biopsies is to take 3mm diameter punches from the outside of the thigh and from the lower outside leg just above the ankle. This is primarily to distinguish length dependency; in many (but not all) neuropathies, including those that are predominantly small fiber, the nerve fibers farther from the center of circulation show damage first (know as "die back") and seeing this, or not seeing it, may lead to the suspicion of various etiologies.

Sometimes especially forward-thinking facilities will take a sample from the arm right above the elbow as well.

The problem is that symptoms of small-fiber neuropathy can be almost exactly mimicked by those caused due to spinal nerve root compression or spinal cord compression itself. And even if the cause of symptoms is peripheral there can be many causes leading to similar symptoms. Investigation into neural symptom cause if often very long and very process-of-elimination (and very expensive), but it should also include nerve conduction studies and spinal MRI's along with blood tests and skin biopsies.

Take a look at the LizaJane spreadsheets just to get a sense of how extensive this testing can get--these were put together to try and encompass anything that could be thought of that would lead to neural symptoms:

www.lizajane.org

Certainly, rheumatoid arthritis or other autoimmune diseases can lead to neuropathy, and can be a presenting symptom--you can see from the spreadsheets there are a LOT of autoimmune conditions that have neuropathy as a component that can be tested for.

Glucose tolerance testing can also not be definitive if it is done for too short a time and without frequent draws. The best protocol for that, I think, is an elongated one with baseline glucose and insulin level draws, and then draws a half-hour, one hour, 1.5 hours, 2 hours, 2.5 hours, 3, 4 and 5 hours to measure the patterns of glucose and insulin rises/falls--specifically, this can help to flag insulin/resistance or impaired tolerance short of frank diabetes, which can itself be a cause of neuropathy, particularly burning small-fiber types. There's plenty of evidence now this can happen before one would be diagnosed with frank diabetes.

Glenntaj did a great job answering some of your questions. I'll add just a couple additional comments:

-Yes, the numb pinky toe, (and numbness in general) can be a symptom of SFN

-The general consensus seems to be that exercise is a good thing, to the extent that your body can handle it. "Exercise to tolerance" is a commonly used term. Everyone's body and condition are different. It's good to exercise, even if there is some nerve pain when you do it. But if it causes major flare ups, you may have to cut back or find a different form of exercise. I ride my bike outside or use the elliptical machine at the gym (vs walking or running) because it puts less impact on my feet and results in less discomfort both during and after

Thank you both very much for taking the time to reply and for all of this useful information that I had difficulty finding by myself! The tests that he's running for now are bloods, CT scans, and the biopsy. I'll update when I get the results.

1. answered already- but did they take one from your ankle as well?
2.yes, that is part of sfn
3.very good answer above. Very important to know if you are pre diabetic.
4. I don't think you can make it worse by doing to much. I think we should do what ever we can and listen to our bodies. I rest when there is pain or in-between activities to recharge.
5.yes, sfn and neuropathy can precede a later diagnosis of many autoimmune diseases.

Good luck and I hope they can figure it out!

The soles of the feet have very thick skin. The nerves in the biopsy have to be easy to access. Also infections are more common in the feet and since some PNers are diabetic, injury to the feet is avoided when possible.

Many pains felt in the lower legs may arise actually in the dorsal roots along the spine. These are the beginning of the peripheral nervous system. When these nerves are damaged then the nerves farther down, start to atrophy. This is because the feedback from the nerves in the dorsal roots are keeping those in the farther periphery working.

This thread explains some of these details:
http://neurotalk.psychcentral.com/thread168511.html

This thread explains some new testing (MRI) for dorsal root damage, and further goes on to explain the biopsies:
http://neurotalk.psychcentral.com/thread147771.html
It is a long technical thread, so read it slowly and perhaps in bits to get the gist of what it all means. The dorsal roots are typically repaired in most people after a damage (this is where shingles causes pain for example), but some lack the DNA genes to do so. Therefore stem cell therapies are being looked at to fix this damage now.

So if the dorsal roots are not working properly you may feel pain anywhere along the paths of those peripheral nerves.

Thank you. I'm hoping the doctor will find the cause of this, if it is indeed SFN (as I said, he is sure, but I'm eager to get this test and see the results). I had no idea that this could precede an autoimmune disease. Ugh...my hands...both hands, every single morning for about two hours--stiffness, slight swelling, and pain, which makes it hard to take care of my family, and even to open my iced tea bottle! Thanks again.


I'll update soon. This forum is great. Did a doctor start it? Did Mrs. D start it? I see her posts a lot. Thanks

As we age the fat pads on the bottom of the feet get thinner.

Hi again. So I got my CT scan, and I should get the results soon. Going to get my biopsy on Friday. WHAT IF my skin biopsy is negative? I asked the dr. that and he said it won't be, but what if it is? Then I'm back to having no answers? Thanks. I just want to know why my feet feel like they're on fire...and tingling.

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