Harbor Foot & Ankle Podiatric Medical Group



Diabetic Peripheral Neuropathy

Neuropathy is a general term for physical damage to or impairment of the human nervous system. It has many causes, and many symptoms. Because a long period of time with elevated blood glucose can damage nerve fibers, diabetes is one cause of neuropathy. The Centers for Disease Control suggests up to 70% of diabetics may have measurable neuropathy, though a number of other diseases (and some medications) can also cause this condition.

"Diabetic neuropathy occurs in both type 1 and type 2 diabetes" (says Johns Hopkins' InteliHealth, an Internet magazine), "and it is most common in those whose blood glucose levels have been poorly controlled. Although diabetic neuropathy can occur in patients who have had diabetes for a short time, it is most likely to affect those who have been diabetic for more than a decade, especially those over age 40. Diabetics who smoke are especially at risk."

The human nervous system is enormously complex. The peripheral nerves carry information to and from the brain, connecting it with the rest of the body. These nerves can be motor, sensory, or autonomic. Motor nerves carry messages from the brain for the contraction of different muscles. Sensory nerves relay to the brain sensations of touch, temperature, position and pain, from the body's periphery. Autonomic nerves carry the brain's commands to organs such as the heart, the stomach, lungs, and liver and autonomic neuropathy, a potentially severe condition though thankfully rare, will receive its own separate coverage later.

The longer the nerve fibers, the more likely they are to show damage from long-term high blood glucose. Such damage 'generally appears at the nerve terminus, at the end furthest away from the central nervous system (brain and spine). For peripheral neuropathy, the damage commonly manifests at the nerve terminals of feet, lower legs, and hands. Doctors call this common form distal sensory polyneuropathy.

Symptoms can include diminished tactile sensation, numbness, loss of reflex reaction, and various types and degrees of pain, from "pins and needles" to extreme burning sensations. As neuropathy progresses, the symptoms frequently change. Caution: Diabetics experiencing neuropathy sometimes have other ramifications as well, and these have their own symptoms. Sometimes symptoms overlap, and diagnosis can be confusing. Diabetic nephropathy kidney failure, can exacerbate neuropathy, due to the uremic toxicity of the condition. Other pain can be a symptom of undiagnosed orthopedic problems, other medical conditions, drugs, or exposure to toxic chemicals. If you are experiencing pain or abnormal sensations in hands, feet, or legs, check with your doctor.

The simplest way your doctor can check for the diminished sensation that can be an early sign of neuropathy in your feet is with a monofilament, a thin, flexible filament of nylon or broomcorn.

The doctor will press it gently against areas of your foot and lower leg, and ask you if you can feel the touch. Where you cannot, early neuropathy may be present. The monofilament, the only tool this test requires, is extremely inexpensive, and the test is highly advisable.
More sophisticated tests can be carried out with a tuning fork, and where the doctor needs to inspect a nerve path more closely, by a test called an electromyelogram (EMG). The EMG tracks the movement of electrical impulses along the nerve path, and can reveal whether impairment is due to diabetes or follows a compression injury, such as back problems or carpal tunnel syndrome.

As diabetic neuropathy follows extended periods of hyperglycernia, its best prevention is good blood glucose management, "tight control," with numbers down in the normal range. A healthy lifestyle, with plenty of exercise and careful attention to diet, helps too. Incidentally, the same "tight control" regime can help those with already established neuropathy. Although it is not clear exactly how it happens (there are several theories), experience shows that getting your diabetes under control, and keeping it there, can, over a several-month period, alleviate at least some of neuropathy's symptoms.

Individual symptoms are as varied as individuals, but the most common complaint is pain, and pain control becomes the single biggest challenge in dealing with established neuropathy. Doctors have prescribed aspirin, acetaminophen, and various other nonsteroidal anti-inflammatory drugs, the anticonvulsants Dilantin and carbamazepine (Tegretol), and tricyclic antidepressants such as paroxetine (Paxil) and amytriptaline or a combination of vitamins B1, B6, and Glutamine, with varying results. Along with the drugs, some are prescribing capsaicin cream (Zostrix and its equivalents), a topical ointment originally formulated for arthritis pain. Some use the epilepsy drug gabapentin (Neurontin), while others relieve symptoms with local anesthetics or muscle relaxants. Still others are investigating acupuncture, although not enough is known about it to, say for certain if it works in such cases. T.EN.S., transcutaneous electrical stimulation (of the affected nerves) with a short jolt of electricity, appears to interrupt the transmission of pain signals, and works for some. Researchers are also experimenting with aldose reductase inhibitors such as Sorbinil and Zenerstat, but these have not yet been approved in the USA. And of course the search for new treatments goes on,with tests of antioxidants, nerve growth factors (rhNGF), blood vessel expanders, and various herbal/naturopathic substances.

There is a lot of disagreement over effective treatments for neuropathy pain. Folks swear by their particular remedy. You need to find and use what works for you. Beware of extravagant claims for pill or technique; there are no "miracle cures."

None of the pills and creams is as effective in bringing relief as is getting your blood sugars into good control and keeping them there. The International Diabetes Center's website advises:

"The best way to treat or prevent neuropathy in any area of the body is to control your blood glucose levels. Good glucose control may not reverse numbness or tingling, but it can slow or stop additional nerve damage. Good control also can bring on dramatic pain relief. Medications can be used to control the symptoms of painful neuropathy and gastroparesis (autonomic neuropathy of the digestive system) as well."

The main reason we, as human beings, have a pain reflex, is because pain lets us know something is wrong in the affected area. If it hurts, we do something about it. With its biggest symptoms being pain (when nothing is there) and diminished sensation/numbness (when something is present), neuropathy can seriously interfere with a diabetic's self-care, especially care of the feet. Circulatory problems stemming from diabetes can lead to dry skin on the feet, with the risk of ulcers and lesions. Lacking normal pain reflexes, the diabetic with neuropathy may not be aware his or her feet are in trouble, Even stepping on a tack may be pain-free. This means otherwise treatable lesions are allowed to progress into severe infection, sometimes into gangrene.

Amputation is a common result of this progression of events, and complications of diabetes account for the majority of nontraurnatic amputations in the U.S. today. All diabetics need to frequently inspect their feet, but individuals with neuropathy need to be especially thorough, as early detection of foot problems can be critical to saving the infected foot.

Although there are lots of variations, with the rule being "do what works for you," there are a number of non-medicinal ways folks cope with neuropathy pain. One individual, who reported "burning feet" at night, slept with her feet uncovered, and a fan blowing cool air on them. Many others cushion aching feet with thick, seamless hikers' socks, especially those made of cotton, or of man-made materials such as Thorlo.

Some folks report that exercise brings relief; however temporary. Others use meditation-based relaxation techniques to help them manage. Another approach, followed by many, is to wear high-quality, proper-fitting athletic shoes with good support, or support sandals such as Birkenstocks, along with the socks mentioned above.

Many individuals whose feet are affected by diabetic neuropathy are also dealing with circulatory/microvascular problems. Their ability to heal from otherwise minor cuts and scrapes may be seriously impaired, leading to a history of ulceration, or even a partial amputation. Special therapeutic shoes, with custom inserts, or "extradepth shoes," or several other shoe modifications, are covered by Medicare as durable medical equipment. Discuss this with your doctor.

Although many medicines are used for treatment of neuropathy's symptoms, none are yet officially FDA licensed for such use. However, doctors have wide leeway in such "off-label" prescribing, and these medications have passed safety inspection and are now being evaluated for their efficacy as neuropathy treatments.

There are also new medications under investigation - some to treat symptoms, and others that might someday treat the underlying cause, the demyelinating nerve damage. At press time, CenterWatch, a clinical trials listing service, lists 56 separate FDA-mandated clinical trials of new neuropathy medications underway in the United States on human subjects' One such study is of the drug memantine, which has been proved effective in rat-based pain-reduction studies, and is now in FDA-mandated Phase 11 clinicals. There are many more studies at the "test tube" stage, or currently in animal trials.

Unexplained pain or abnormal sensation is a serious matter. It may indicate neuropathy, which may be from diabetes, or it may stem from some other condition - and your doctor needs to promptly determine its source. Neuropathy is NOT an inevitable ramification of diabetes, but you shouldn't just "grin and bear it," either. A lot of different therapies and interventions bring relief to many diabetics. Keep the best blood glucose control you can, keep your doctor informed, and don't lose hope.

1360 West 6th Street
Suite 150 West Bldg.
San Pedro, CA 90732
(310) 548-1191