In response to member requests, this meeting was dedicated entirely to answering participant questions, beginning with the written questions submitted on index cards, and progressing to fielding questions from the floor. An attempt was made to keep the questions and answers general enough to serve various individuals with like types of neuropathy and refrained from diagnosing individual symptoms.

Following is an informal recap of the questions, answers, and ensuing discussion. No attempt has been made to attribute these responses to a specific doctor, as generally both doctors contributed to the responses. The answers are intentionally brief and are not intended to substitute for other good sources of information.

In opening, the doctors remarked that there have been some advances in some types of neuropathy. There are now 200 known causes of peripheral neuropathy, and 30% of the time we still don't know the exact cause of the neuropathy.

1. What is an EMG and what will it show?
   An EMG is useful to confirm findings of the physical exam as to what class of neuropathy (axonal, demyelinating or mixed) is suspected. It uses tiny electric shocks and needle sticks to test the nerve and muscle signals. The test can confirm damage to the large fiber nerves with thick myelin sheaths. It can tell if there is a diminished number of fibers or if there has been loss of the myelin coating. Myelin sheath loss (demyelination) is associated with inherited or some acquired forms of neuropathy and the latter type has good potential to respond to therapy.

2. Is a hemoglobin A1c reading of 6.5 indicating impaired glucose tolerance enough to produce severe peripheral neuropathy and abdominal neuropathy? Should EMG tests be done to investigate other possible causes or should it just be presumed to be diabetic neuropathy?
   There is no such thing as diabetic "neuropathy," but we have diabetic "neuropathies". The emphasis is on plural, that is, there are several different forms of diabetic neuropathy. Each may have different causation, treatment and prognosis. For example, peripheral neuropathy of the feet, which is sometimes painful (distal peripheral neuropathy) is different from the type that involves the hips or proximal legs (proximal diabetic neuropathy) both in terms of causation, prognosis and treatment. The abdominal/chest pain caused by diabetic thoracoabdominal neuropathy can happen even in cases of mild diabetes, and is typically associated with a significant weight loss and depression. It often spontaneously improves, but the painful distal peripheral neuropathy doesn't typically get better, but it may not progress (worsen) as rapidly with good control of blood sugar. Yes, additional investigative testing such as an EMG would be a good idea. In case of abdominal (thoracoabdominal) neuropathy some other tests to exclude other causes of chest-abdomen pain may become necessary. As diabetes is a common condition the mere association of diabetes and a neuropathy is not sufficient to call it diabetic neuropathy. Other causes should be looked for and excluded. It is not uncommon to see patients who come to us with neuropathy having only a very mild diabetes, or a previously undiagnosed diabetes.

3. Does low blood sugar (hypoglycemia) have an effect on neuropathy?
   Yes, repeated and severe hypoglycemia can adversely affect nerve function (hypoglycemic neuropathy), so it is important to avoid lowering blood sugar too much.
4. Can you tell us the names of the two new statin cholesterol lowering drugs that don't adversely affect neuropathy?
   All of the statin types of cholesterol lowering drugs (Lipitor, Zocor, Pravachol, etc.) after taken for many years, in a small percentage of patients, could cause a mild form of neuropathy. The doctor does not generally advise patients that are taking statins to come off of them if they have this form of neuropathy. The health benefits of lowering cholesterol far outweigh the risks of contributing to the mild neuropathy. If a person takes a combination of these drugs, or if they have diabetes or kidney problems or take some anti-fungal and some other medications, the risk of contributing to neuropathy symptoms increases. Patients over age 65 may also experience increased risk. Niacin has been given in high doses to treat high cholesterol in those who cannot take statins. There has been at least one report that high doses of niacin supposedly produced neuropathy symptoms, which did improve once niacin was withdrawn. Extremely high fat or lipid levels, especially the triglycerides, can, in itself, cause neuropathy (hyperlipidemic neuropathy). Both doctors are not aware of any new class of statin cholesterol lowering drug that so far carries no risk of contributing to neuropathy.

   Editor's note: from Parade Magazine, Dec. 8, 2002. "There's a new player on the cholesterol-lowering scene. It's called ezetimibe and marketed under the trade name Zetia. The dose is one 10 mg tablet a day. It works by inhibiting the absorption of cholesterol in the intestine. (By contrast, the commonly used statin drugs prevent cholesterol production in the liver.) Zetia is not a statin and is not meant to replace the statins but to complement them. This new drug is important because 60% of patients on a statin drug alone don't reach optimal cholesterol levels. But adding a Zetia tablet to a statin regimen resulted in 72% of patients in one study reaching their treatment goal. In the past, one had to take more of the statin drug, which might lead to increased side effects. Although it costs a little more to add this new drug to your regimen, the clinical result is better and safer."

5. Can you have neuropathy in one leg and one foot?
   Yes. There can be neuropathies that affect only a single nerve (mononeuropathy) or those that affect multiple nerves (multiple mononeuropathy). Compression based neuropathies are examples of mononeuropathies (single nerve). A motor vehicle accident, or other trauma could cause a blunt nerve injury at the knee, elbow or wrist causing mononeuropathy. Polyneuropathies affect many nerves as in those caused by inflammation, amongst others.

   It is important to note that the term neuropathy is just a medical description of "damage to the nerve or nerves". It does not address the cause. Patients should do everything possible to find the cause of their neuropathy, and only when all possibilities have been ruled out, then accept a diagnosis of "idiopathic neuropathy", i.e a "neuropathy without a known cause".

6. What role does a Glucose Tolerance Test have in diagnosing neuropathy?
   A glucose tolerance test (involves having blood tested before after drinking a very sugary drink) is used to diagnose diabetes or impaired glucose tolerance, not neuropathy. However, neuropathy is a common complication of diabetes. A patient should have an appropriate diet for few days preceding the Glucose Tolerance Test.

7. Can a Hemoglobin A1c test substitute for the Glucose Tolerance Test?
   The A1c, usually, is not as sensitive a test for "diagnosing" diabetes as the Glucose Tolerance Test. It is a good tool to monitor blood sugar control over the preceding months.

8. Can an EMG test result be negative and one still have neuropathy? What if both the EMG and the skin biopsy are negative?
   The EMG looks at large, myelinated nerve fibers, so it can't detect impairment of smaller nerve fibers. The skin biopsy test is used to look at the damage to the small nerves. A tiny disk of skin is removed and stained, and then it is possible to count the number of healthy and damaged nerve twigs. This twig count is then compared to the standard count expected for the patient's age group. Skin biopsy does not reveal the cause of neuropathy, it just shows the presence or absence of skin nerve damage. It is still in experimental stages and its day-by-day usefulness in practice has not been fully established. A negative result on the tests can't exclude the possibility of neuropathy. The clinical exam and patient's report of symptoms must be considered in the diagnosis, and can indicate neuropathy despite negative test results.

9. Can Restless Leg Syndrome cause peripheral neuropathy?
   It's the other way around. Peripheral neuropathy is a likely cause of restless leg syndrome. There are several neuropathies that can be associated with restless-leg syndrome.

10. Have you heard of pineapple as a treatment to diminish neuropathy pain? No, neither doctor has heard of pineapple to treat neuropathy. They did inquire as to the source of this treatment as they are interested in what people find helpful. It was reported in Neuropathy News, the national association's newsletter and on the online bulletin board. There is, however, no scientific studies in this regard.

11. What about Alpha Lipoic Acid (ALA) as a treatment? What dosage is appropriate? Alpha Lipoic Acid is an anti-oxidant. One theory in the causation of diabetic neuropathy, stated in very simple terms, is that nerves sort of break down and oxidize or "rust" and the anti-oxidant properties of alpha lipoic acid helps to prevent this "rusting" phenomenon. It has also been credited with lowering blood sugar which can help those with diabetic neuropathy.

    Testing of ALA in the USA is not complete. Dr. Harati is in the second year of a four-year study of Alpha Lipoic Acid in oral and intravenous forms. German tests showed there was some improvement in patients given the IV form of the drug. Short-term studies showed that the IV form of the drug had some ability to vasodilate blood vessels, and thus possibly aid further in improving neuropathy symptoms.

    Some alpha Lipoic Acid products sold in drugstores are not titrated for a usable dosage and cannot be compared to that used in the study, and thus the doctors declined to provide a recommended quantity of the drug.

12. What are the most common causes of neuropathy?
    The most common cause is diabetes.
    Second cause is excess consumption of alcohol.
    Third cause is systemic based, such as those being caused by low thyroid function over a long period of time, kidney problems, lupus, cancer etc.
    Fourth cause is toxic or drug induced, such as too much Vitamin B6 (take no more than 50 mg/day) or some forms of chemotherapy, heart drugs, etc. There are many toxins and drugs that can cause neuropathy. A Vitamin B12 deficiency is caused by problem of absorption of vitamin can cause neuropathy and must be treated with B12 injections.
    After these and other causess are fully excluded, it then may be called "idiopathic" (meaning no identifying cause) neuropathy. But even with a diagnosis of "idiopathic neuropathy", patients should continue to pursue a cause. Check with your neurologist each six months or a year to see if there are new tests that can be done to identify the cause of your type of neuropathy.
    A study in the Netherlands indicates that peripheral vascular disease could be a risk factor for some neuropathies that were previously called "idiopathic". Celiac sprue, an allergy to gluten products, is a relatively newly identified cause of neuropathy.

13. Can neuropathy cause toes to curl?
    If all of the toes curl, it is possible a motor nerve impairment has caused muscle tightness or weakness. A single curled toe is more likely due to another cause. The doctors always include an examination of the feet and toes in order to observe any such abnormalities.

14. If 10 people had the same symptoms, but had different causes, would they get the same treatment?
    No. Someone who was deficient in Thyroid hormone, would be given thyroid supplements. Someone with a toxic chemical source would have the source withdrawn. The appropriate therapy depends on the discovery of the exact causation.

15. Are some neuropathies genetic?
    Yes, some neuropathies have a definite genetic basis. These usually show up during the first two decades of life. Blood tests can detect several forms of these. As a group they are called hereditary neuropathies,but Charcot-Marie-Tooth diseases (CMT) is the most common variety. There are several forms of CMT, with different pattern of inheritance, and for some blood genetic tests are commercially available.

    About 50% of diabetics have neuropathy. What protects the other 50%? The answer may be genetically based. The study of the human genome may give us the answer in the next two decades. In some cases it may be a matter of genetic differences of some enzymes activities, such as a hyperactive aldose reductase enzyme that convert glucose to harmful sorbitol in some diabetics but not the others. New drugs to inhibit aldose reductase are being tested. But most of these drugs, tested earlier, were proved ineffective, or toxic.

    Editor's Note: from www.hereditaryneuropathy.org/cmt.html Charcot-Marie-Tooth (CMT) is the most common inherited genetic neuromuscular disease that affects the peripheral nerves. There are approximately 150,000 known cases of CMT in the United States, although it is believed that CMT is often misdiagnosed as other neurological conditions. CMT is usually characterized by the slow degeneration of muscles of the feet, lower legs, hands, and forearms. CMT can vary significantly from mild symptoms to severe deformities. Common signs of the disease may include abnormally high arched feet, flat feet, and hammer toes, which usually result in awkward gait and balance, and poor hand coordination. Over time, CMT can progress to extreme weakness, atrophy, and loss of sensation of these muscles.
    Symptoms of CMT are typically noticed in childhood or early adulthood, but CMT can manifest at any life stage. Although there is no cure or specific treatment for CMT, the disease is not fatal, and it does not affect life span or intellectual ability. To minimize discomfort, treatment may include physical therapy, foot care, such as customized shoes or braces, and surgery.
    CMT is most often diagnosed with an electromyogram (EMG), or motor nerve conduction velocity (MNCV) tests. These procedures can detect abnormal muscle activity by recording the ability of nerves to send and receive electrical impulses.

16. Does eating foods sweetened with Sorbitol affect neuropathy?
    No. The sorbitol used to sweeten foods is not absorbed and is a good option for diabetics trying to reduce consumption of carbohydrates.

17. How do you diagnose CIDP?
    (Chronic Inflammatory Demyelinating Polyneuropathy) It is based on a clinical diagnosis with weakness in at least 2 limbs for 2 or more months. It may affect toes, feet, hips, and arms and be evidenced by an absence of reflexes. CIDP can be confirmed by a spinal fluid test for elevated protein level, EMG tests to look for damage to myelin (showing slowed conduction velocity), or sometimes by nerve biopsy. CIDP is treatable, but not curable.

    One of the treatments is IVIg (intravenous gammaglobulins infusions) which can be effective for true cases of CIDP. The doctors offered a strong caution about widespread abuses of expensive IVIg infusions being prescribed for non-CIPD neuropathies , or "over-diagnosed" CIDP, by physicians who benefit financially from the administration of such treatments. Do not be shy about questioning the physician if he benefits financially from your getting this treatment and, if necessary, obtain another opinion. Medicare, insurance companies and law enforcement agencies are particularly sensitive to such abuses.

    IVIg treatments sometimes can damage kidneys to the point of requiring dialysis. It can enhance the risk of heart attack or stroke in those predisposed to these conditions. It has even been known to cause aseptic meningitis. If the patient lacks a certain protein/immunoglobulin, he/she can go into anaphylactic shock and possibly die. Suffice to say that IVIg which being a good and very expensive treatment is not entirely safe.

18. What about Neurontin as a treatment for symptoms of neuropathy. How does it compare to Topamax?
    Neurontin is one of the newest treatments for pain of diabetic neuropathy. It is an anticonvulsant medication originally prescribed for control of epileptic seizures. It stabilizes the nerve cells, calming them down from the firings that cause the pins and needles pain. It is now the subject of a government investigation because the manufacturer began promoting it as a treatment for neuropathy without initially conducting any new tests for that purpose. It has been prescribed in very high doses - up to 2,500 to 3,600 mg per day in some studies. At such high doses, there are often side effects such as fatigue, headache swelling of the ankles, excessive sleepiness, tremor, confusion, memory impairment or balance problem. Most patients, however, benefit from smaller doses.

    Topamax may be an alternative, but it also has not been FDA approved for use in treating neuropathy, only as an anticonvulsant. The studies on its benefit are equivocal and not entirely positive. It works by a different mechanism than neurontin. Some patients can not tolerate the side effects.

    There are other newer drugs that can be prescribed. The doctors will devote one entire future meeting to this subject.

    There were many other written questions for the doctors but due to the late hour, they could not be covered. The doctors indicated they will return, along with their other colleagues, during future meetings and they will keep the members informed on the latest developments. They thanked the audience for their support of the Neuropathy Association and the local support group.

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