Diabetic Peripheral Neuropathy: Causes and Treatments

By Brian K. Bailey, DPM – Body-Mind-Spirit Podiatric Center

Diabetic Peripheral NeuropathyDiabetic peripheral neuropathy accounts for significant medical problems and predisposes the lower extremities to debilitating complications such as infection, ulceration, and eventually amputation. This month, we’ll look at some of the causes of peripheral neuropathy as well as prescription medications for the condition. Next month, we’ll focus on nutritional aspects of diabetic neuropathy.

Nearly 70 percent of adults with diabetes have some manifestation of neuropathy. Diabetic peripheral neuropathy involves progressive deterioration of nerve fibers and results in chronic pain in as many as 16 percent of patients with diabetes.

The annual medical costs per patient with neuropathy were more than twice that of diabetics without neuropathy – over $20,000. The annual incidence of lower extremity ulcers in the population with diabetes is about 7 percent. One in six people with diabetes will develop a foot ulcer at some point. Peripheral neuropathy is a contributing cause in as many as 70 percent of all diabetic foot ulcers. It is one of the most common factors leading to ulceration.

More people die from diabetic wounds than from any type of cancer except lung cancer.

In my practice, I diagnose about 15 patients a month with neuropathy. A number of prescription drugs may be used to treat the condition, but all have side effects, and none can correct the underlying nerve defect that causes the pain. Nutrient therapy and a special diet offer a promising alternative for people who want to avoid the side effects of prescription drugs.

Neuropathies can originate within the central nervous system or in the peripheral nerves, which lie outside the central nervous system.

Peripheral neuropathies account for the majority of cases. They can have many causes, such as toxins (heavy metal, pesticides, solvents), alcohol, some drugs, including statins (cholesterol lowering drugs) and metabolic diseases.

Diabetes is the most common cause of peripheral neuropathies, and according to the National Institutes of Health (NIH), more than one in 10 Americans over age 20 have diabetes; 27 percent of those over 65 have the disease. Three times that number are considered pre-diabetic. When I was in medical school diabetes was diagnosed with a fasting blood sugar of 140 mg/dl. Medical students are now learning diabetes starts at 120 mg/dl but research shows damage begins at 85 mg/dl.

NEARLY ONE IN THREE AMERICANS HAS OR IS BECOMING DIABETIC

What causes neuropathic pain?
Pain is caused by abnormal stimulation of nerves or by damage to the nerves. Peripheral nerves are like wires, carrying impulses from the body to the brain by electrical charges that are caused by chemical changes. Special chemicals, called neurotransmitters, transfer messages between nerves.

Nerves, like electrical cords, are covered by an insulating sheath called myelin. To make it simple, elevated levels of blood sugar damages the blood supply to the nerves. Starved for nutrients, the nerves become damaged. This usually begins with the sensory nerves causing intense pain that may be described as cutting, stabbing, crushing, burning, shooting, gnawing, or grinding. In some cases, a minimal stimulus, such as a light touch, can trigger severe pain. Pain also may be felt even in the absence of stimulus.

In time, this process damages nerves to the muscle tissue, causing shrinkage and weakness. This leads to loss of balance, leading to use of a cane, then walker, then wheelchair. Neuropathy can also damage the autonomic nervous system, resulting in bowel/bladder incontinence. Abnormal heart rhythms may arise, which can lead to sudden death.

Neuropathies can also be caused by:
• Nutritional deficiencies, such as vitamin B1, B6, B12 and Folate.
• Excess alcohol consumption or exposure to certain solvents/toxic metals
such as lead or mercury, or to medications.
• Autoimmune disorders, such as rheumatoid arthritis, lupus, or Guillain-
Barre. Treatment is aimed at the underlying inflammatory condition.
• Nerve entrapment such as in Carpal and Tarsal tunnel syndromes.

Treating Neuropathies
A number of medications may be prescribed or recommended to help deal with the pain. The most commonly used ones include over-the-counter medications (ibuprofen, aspirin, and other NSAIDS). Because of the risk of serious liver and kidney toxicity, I do not recommend the long-term use of acetaminophen for treatment of neuropathies.

For more serious neuropathies, drugs such as gabapentin (Neurontin®), Lyrica®, carbamazepine (Tegretol®), and phenytoin (Dilantin®) may be prescribed. These drugs were originally developed to treat epilepsy, but they also work to reduce the pain associated with neuropathy. Side effects include dizziness and weight gain.

Pentoxifylline (PTX) is a prescription drug approved by the FDA to treat peripheral vascular disease. PTX helps make the blood less “sticky” and thus able to flow more easily through the blood vessels. Diabetic rats treated with PTX experienced a correction of nerve conduction deficit of more than 50 percent.

Studies also suggest that Cytomel®, a drug used to treat hypothyroidism, is also effective at regenerating damaged peripheral nerves. In animal studies, administration of Cytomel, caused nerve axons to regenerate after the sciatic nerve was surgically cut.

Antidepressants are sometimes used. These drugs may have side effects that discourage people from continuing them, including dry mouth, nausea, tiredness, constipation, and weight gain.

My favorite medical treatment is a compounded topical medication with six medications. The medication is rubbed into the affected area, limiting side effects. It’s important to note that medications do not fix the underlying nerve damage. They can only reduce the pain.

Next month, we’ll look at nutrition and neuropathy and discuss several diet and supplement based approaches to managing the condition.

Brian K. Bailey, D.P.M., is a podiatrist with Body-Mind-Spirit Podiatric Center in Ashland, Ky. Dr. Bailey also is Clinical Professor of Podiatric Medicine & Surgery at Pikeville College of Osteopathic Medicine and a Personal Wellness Coach & Fitness Trainer. The office is located at 500 14th St., at the intersection with Central Avenue. New patients are welcome. For more information, please call the office at (606) 324-FOOT (3668).

Body-Mind-Spirit Podiatric Center

500 14th Street, Ashland, Kentucky, 41101
Phone (606) 324-FOOT

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