New Treatments for Neuropathy (Part 3)

Edited Chat on www.diabetesstation.org
Date: October 10, 2000
Moderator: Deb Butterfield
Subject: Neuropathy
Guest: Dr. Aaron I. Vinik, Research Director, Leonard R. Strelitz Diabetes Institutes, Eastern Virginia Medical School, Norfolk, Virginia

Moderator – Deb Butterfield
Dr. Vinik is the director of diabetes research at the Strelitz Diabetes Institutes in Norfolk, Virginia. In addition to his work in islet regeneration to cure diabetes, and the discovery of the INGAP gene, Dr. Vinik is recognized internationally for his research and clinical treatment of neuropathy.

Any one who has been to the doctor to try to stop the pain or numbness caused by neuropathy will want to hear what Dr. Vinik has to say here tonight. Dr. Vinik is perhaps the only doctor specializing in neuropathy who is also o the leading edge of research to treat it. People come from all over the world to the Strelitz Diabetes Institutes to find solutions for neuropathy, so we are privileged to have Dr. Vinik join us tonight.

Dr. Vinik, would you start by telling us in a nutshell, what causes neuropathy and why some diabetics get it and some don’t?

Dr. Vinik
Hi all. There are many varieties of neuropathy, and each has its own particular cause. For example, there are the mononeuritides. These are when single nerves are involved. The cause is either an entrapment or a vascular insult to the blood supply of the nerve. Then there are the proximal neuropathies. These involve the proximal muscles of the legs and shoulder girdle. They are usually inflammatory and require special treatment. Then, there are the autonomic neuropathies and the run-of-the-mill somatic or peripheral neuropathies and each has a different cause.

Yvan
Dr. Vinik, is there any possible way of reversing neuropathy?

Dr. Vinik
Yvan, there are now a number of ways of reversing neuropathies. It depends on the type that you have, and each may be reversed in different ways. There are, of course, some that are more difficult than others and there are stages in which the neuropathy has progressed too far to be reversed.

SueG
Hello, Dr. Vinik. We don’t get much info on neuropathy here in Australia – basically we’re told it only occurs in the feet – after nearly 50 years on insulin and a few problems, could you please tell me if it can occur in places other than the feet? Thank you.

Dr. Vinik
Yes, neuropathy can occur in places other than the feet. For example, when single nerves are involved, then nerves of the face and head are usually affected. When there is entrapment, a common site is in the carpal tunnel in the wrist, and then the first three fingers of the hand are affected. If the autonomic nervous system is affected, then any part of the body from the eyes to the toes may be affected.

Lisa Marie
Dr. Vinik, could you tell me why nerve compression syndromes are so much more prevalent in Type 1 diabetes? I have had two bilat carpal tunnel releases and a spinal fusion. I also had left femoral neuropathy in 1983 and that resolved with better control. How much reversal can one expect?

Dr. Vinik
Lisa Marie, if your problem in the shoulder is secondary to a spinal problem, and you have not had relief from surgery, then treatment may be difficult. Non-steroidal anti-inflammatory drugs can be helpful and even local injections of steroids and local anesthetics. If this does not work, then you may require some form of epidural anesthesia for relief, but you should exhaust all forms of pain relief first.

C J Jutras
Dr. Vinik, I have had a focal neuropathy in my abdomen for the past year! I am currently on 3600 mg of neurontin daily and also taking 50 mg of amitriptilyne at bedtime. I also use Lidocaine 5% patches on the sites! Is there anything else I can do? On a good day my pain is still a 7 on a scale of 1 to 10.

Dr. Vinik
I am sorry to hear that you have not had relief on a maximum does of neurontin coupled with amitriptilyne and lidocaine patches. Is your pain deep seated, or is it burning and superficial? This is important to know since the approach to treatment does differ.

Deb Butterfield
How do you treat diabetic neuropathies - are they autoimmune? How do you know they are caused by diabetes and not some other cause?

Dr. Vinik
Thanks for the question, Deb, and thanks for hosting the program.

The focal neuropathies are vascular and often require only watchful expectancy.

Entrapments require relief of the entrapment.

Proximal neuropathies turn out to be due to inflammatory demyelinating, monoclonal gammopathies and vasculitides in 91% of the cases. These may be treated with immune therapy, anti-inflammatory agents and the like.

The distal symmetric neuropathies are a different story all together. Some involve the small nerve fibers that are important for pain sensation and warm and cold perception, and the others are coated with myelin and subserve movement and position sense. They are affected differently. They can also have reduction in the available oxygen due to “oxidative stress,” have accumulation of the sugar alcohol sorbitol or be due to the deficiencies of important fatty acids. They may also have an autoimmune basis or even be the result of deficiencies of key nerve growth factors.

Clearly, there is no universal balm and the etiology is very heterogeneous. That is why we have struggled for years to come up with answers to this common problem.

C J Jutras
Dr. Vinik, my pain in my abdomen is very superficial. The surface of my skin on my abdomen is so sensitive that just taking a shower and letting the water hit the sites, sends me into terrible pain! What other methods other than neurontin, amitriptilyne and lidocaine patches are available to me? I am in so much pain all the time!

Dr. Vinik
Okay CJ, I recommend that you do the following. Take a teaspoon of cayenne pepper and mix it well in a small 4 oz. jar of cold cream. Use plastic gloves and apply it to the area morning and night. Cover the area with saran wrap. Continue to do this for at least two weeks. The cayenne pepper contains an ingredient that depletes the superficial nerve endings of their substance P that is the cause of the burning pain.

Lisa Marie
Dr. Vinik, that is very interesting – how to treat the pain. What about just having freezing feet all the time – is that the first sign of neuropathy of my feet? Will the cayenne pepper warm up my feet? LOL, but seriously?

Dr. Vinik
If the small fibers are affected so that you don’t feel hot and cold pain, you need to take every precaution not to injure yourself and cause an ulcer. People should never go around barefoot. They should always test the bathwater with their hands or elbows to be sure not to be scalded.

Walking on hot tar or the beach is particularly bad. Shoes must be inspected for foreign objects, such as nails, teeth, keys and the like to avoid injuring the insensate foot. These small fibers have now been shown to regrow with certain compounds in the research arena, for example, the aldose reductase inhibitor currently being investigated has induced growth of new small fibers after one year of treatment of human subjects. These are a number of new trophic factors for small fibers in the wings that hold great promise.

Bertie
Is cayenne the active ingredient in capsaicin?

Dr. Vinik
Capsaicin cream and cayenne pepper have the same active ingredient. The trouble with those on the market is expense and the low dose. Also, people apply them once and it burns so they stop. One has to apply it properly, for a long enough period of time to deplete the chemical causing the pain, and go through the burning before relief occurs.

SueG
Sorry to be a nuisance, but my feet absolutely freeze in the winter and my ankles swell so much in summer that my shoes won’t fit my feet – is this from neuropathy?

Dr. Vinik
If your feet freeze in the winter, and swell a great deal, there may be other causes. First, cold feet may be due to a poor blood supply. I will presume that this is ruled out. Swelling of the feet can be due to congestive heart failure, liver disease, kidney disease, low protein levels, malnutrition and varicose veins for example, and this list is not exhaustive. If all are excluded, and you have cold dry feet and only sweat on your upper body, you may have neuropathy of the autonomic system of the feet causing your edema. This responds quite nicely to ephedrine One further caution is that some of the drugs used to treat blood pressure and sugar in people with diabetes also cause a great deal of foot swelling. You should review these with your doctor.

CJ Jutras
Dr. Vinik, I already have the 75% capsaicin cream. I tried it twice, but I thought it burned too much. Is this cream powerful enough to use other then the pure cayenne pepper? I also want to thank you for helping me cope and heal this pain!

Dr. Vinik
The trick with cayenne pepper is that you can start with a low dose, one teaspoon and when you find that you can tolerate it, you can increase the dose, two, three or even four spoons. Its like eating in an Indian restaurant, at first the curry seems hot, but when you get used to it, you want it hotter and hotter.

T-angellady
Dr. Vinik, I have had trigger fingers, carpal tunnel and also neuropathy – is that all from the diabetes attacking my circulation?

Dr. Vinik
Carpal tunnel and trigger finger are not due to vascular problems nor are they a form of neuropathy. In diabetes, especially long-standing, there are accumulations of AGE’s or advanced glycation endproducts in the connective tissues of the palms of the hand and foot and also around joints. These can cause nerve entrapments like the carpal tunnel, the trigger finger and also lead to shortening of tendons like the Achilles. When this becomes shortened, then it changes the gait to an equines which means that the person walks up on their toes. This creates a greater pressure in the ball of the foot and leads to destruction of bone. Well, what can we do about all this? Keeping the blood glucose normal is important. Local treatments with steroid injections, diuretics and splints all help. There is some exciting new research that indicates that we may have compounds that can break these AGE’s and help with the process. There is good news around the corner.

Deb Buttefield
Do you use immunosuppression agents for treatment of autoimmune derived neuropathies?

Dr. Vinik
Deb, yes, we do treat people with clearly proven autoimmune neuropathies with immunotherapy. We have had some very striking examples of success with intravenous gamma globulin, plasma exchange and steroids – azothrioprine and tacrolimus.

There are certain neuropathies that respond well, for example, in the early phase of motor neuropathies or even some of the severe autonomic neuropathies. We recently had a young man from Georgia who was incapacitated by his postural hypotension, diabetic diarrhea, and gastroparesis. He is now leading a nice normal life – free of all these features after one course of therapy. We have other examples of people unable to rise from chairs who could get up and walk and play tennis thereafter. We need to have a firm diagnosis and to observe the course of the condition before embarking on these therapies. Although we are avante garde in this respect, we are nonetheless very cautious in patient selection.

Hypoboy
Does myoinositol therapy help with neuropathy in your opinion? Or is the fructose/inositol balance only a symptom? Is the abnormal fructose/inositol levels in neuropathies a cause or a symptom of the disease?

Dr. Vinik
The fructose myoinositol story is complex. It was long believed and shown in animal studies of diabetic neuropathy that there was an excess of glucose, leading to shuttling of glucose into the sorbitol pathway with fructose accumulations and deficiency of myoinositol. Supplementation of the animal diets with myoinositol produced some improvement in the nerve function. Unfortunately, this does not turn out to be the case in human diabetic neuropathy and myoinositol supplementation is of no value.

T-angellady
What about the paraffin baths – are they good for people with neuropathy or does this cause more harm?

Dr. Vinik
Paraffin baths are great for people with dry skin, palmar and plantar fasciitis and can give people relief from painful discomfort due to neuropathy. The temperature is controlled so that the risk of burning is negligible.

Deb Butterfield
Thank you very much for sharing your knowledge with us on Diabetes Station tonight Dr. Vinik. We look forward to having you as our guest again!

Dr. Vinik
Thanks to you all and have a good night. Take care.