Diabetic Peripheral Neuropathy (DPN)

Definition

Diabetic neuropathies are a family of nerve disorders caused by diabetes. People with diabetes can, over time, develop nerve damage throughout the body. Some people with nerve damage have no symptoms. Others may have symptoms such as pain, tingling, or numbness—loss of feeling—in the hands, arms, feet, and legs. Nerve problems can occur in every organ system, including the digestive tract, heart, and sex organs.

About 60 to 70 percent of people with diabetes have some form of neuropathy. People with diabetes can develop nerve problems at any time, but risk rises with age and longer duration of diabetes. The highest rates of neuropathy are among people who have had diabetes for at least 25 years. Diabetic neuropathies also appear to be more common in people who have problems controlling their blood glucose, also called blood sugar, as well as those with high levels of blood fat and blood pressure and those who are overweight.

Peripheral neuropathy is the most common form of diabetic neuropathy. Peripheral neuropathy, also called distal symmetric neuropathy or sensorimotor neuropathy, is nerve damage in the arms and legs. Feet and legs are likely to be affected before hands and arms.

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Causes

Diabetic peripheral neuropathy doesn’t emerge overnight. Instead, it usually develops slowly and worsens over time. Some patients have this condition long before they are diagnosed with diabetes. Having diabetes for several years may increase the likelihood of having diabetic neuropathy.

The nerve damage that characterizes diabetic peripheral neuropathy is more common in patients with poorly managed diabetes. However, even diabetic patients who have excellent blood sugar (glucose) control can develop diabetic neuropathy. There are several theories as to why this occurs, including the possibilities that high blood glucose or constricted blood vessels produce damage to the nerves.

As diabetic peripheral neuropathy progresses, various nerves are affected. These damaged nerves can cause problems that encourage development of ulcers.

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Symptoms

Possible signs and symptoms of peripheral neuropathy include:

  • Numbness or reduced ability to feel pain or changes in temperature, especially in your feet and toes
  • A tingling or burning feeling
  • Sharp, jabbing pain that may be worse at night
  • Pain when walking
  • Extreme sensitivity to the lightest touch — for some people even the weight of a sheet can be agonizing
  • Muscle weakness and difficulty walking
  • Serious foot problems, such as ulcers, infections, deformities, and bone and joint pai

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Exams and Tests

Foot Exams

Your health care provider should look at your feet at each office visit to check for injuries, sores, blisters or other problems. As a reminder, take off your shoes and socks when you’re in the exam room.

Have a complete foot exam once a year. If you already have foot problems, have your feet checked more often. A complete foot exam includes a check of the skin on your feet, your foot muscles and bones, and your blood flow. Your provider will also check for numbness in your feet by touching your foot with a monofilament. It looks like a stiff piece of nylon fishing line or a bristle in a hairbrush.

Other ways to check your nerves include using a tuning fork. It may be touched to your foot to see if you can feel it moving.

Nerve Conduction Studies and Electromyography (EMG)

If the doctor thinks you might have nerve damage, you may have tests that look at how well the nerves in your arms and legs are working. Nerve conduction studies check the speed with which nerves send messages. An EMG checks how your nerves and muscles work together.

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Treatments

To treat nerve damage, you will need to keep your blood glucose levels in your target range, manage your pain and protect your feet. Many people get depressed when they have nerve damage and may need medication for depression as well as counseling.

Medications

Medications to relieve pain and reduce burning, numbness and tingling are available. Some of these are known for their use in other conditions but they still seem to help those with nerve damage.

Speak with your doctor to find out what treatments are best for you.

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Possible Complications

Diabetic neuropathy can cause a number of serious complications, including:

  • Loss of a limb. Because nerve damage can cause a lack of feeling in your feet, cuts and sores may go unnoticed and eventually become severely infected or ulcerated — a condition in which the skin and soft tissues break down. The risk of infection is high because diabetes reduces blood flow to your feet.Infections that spread to the bone and cause tissue death (gangrene) may be impossible to treat and require amputation of a toe, foot or even the lower leg. More than half the nontraumatic lower limb amputations performed every year in the United States are due to diabetes.
  • Charcot joint. This occurs when a joint, usually in the foot, deteriorates because of nerve damage. Charcot joint is marked by loss of sensation, as well as swelling, instability and sometimes deformity in the joint itself.
  • Social isolation. The pain, disability and embarrassment caused by nerve damage can rob people — particularly older adults — of their independence, leaving them increasingly isolated and depressed.

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Preventions

The patient plays a vital role in minimizing the risk of developing diabetic peripheral neuropathy and in preventing its possible consequences. Some important preventive measures include:

  • Keep blood sugar levels under control.
  • Wear well-fitting shoes to avoid getting sores.
  • Inspect your feet every day. If you notice any cuts, redness, blisters, or swelling, see your foot and ankle surgeon right away. This can prevent problems from becoming worse.
  • Visit your foot and ankle surgeon on a regular basis for an examination to help prevent the foot complications of diabetes.
  • Have periodic visits with your primary care physician or endocrinologist. The foot and ankle surgeon works together with these and other providers to prevent and treat complications from diabetes.

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