If you have had diabetes for more than 10 years and you have not kept your blood glucose levels close to normal, you likely have some symptoms of nerve damage. It affects as many as 75% of all people with diabetes. Symptoms can range from muscle weakness, cramps, numbness, tingling, pins and needles, and burning sensations, to changes in bowel habits, bladder control, or sexual functioning. Your may also notice that your feet bother you more at night. Even unexplained episodes of fainting or vomiting can be attributed to nerve damage.
Although there is no one specific test that all doctors use to check for neuropathy, there are some that are widely accepted. Your doctor may touch your feet with a small, thin fiber called a monofilament. If you can’t feel this light touch, you have lost sensation. Similarly, you should be able to feel the vibrations of a tuning fork on your feet. A nerve conduction study, which tests the speed of electrical transmission through the nerves, may also be used. A trained neurologist or physiatrist will be consulted to perform this test.
Three types of neuropathy are associated with diabetes: autonomic, sensory, and motor. In the feet, autonomic neuropathy affects perspiration and the dryness of the skin. Although this dryness can be a problem, it does not change the shape of the feet.
Sensory neuropathy affects how the feet feel. This type of neuropathy causes numbness, burning, tingling, and/or pain. If your feet are numb, you often will not feel pain, and you may walk on a foot that is being damaged. You may also step on a nail or piece of glass and not know it. A Charcot foot is a breakdown of the structure of the foot—multiple fractures and a destruction of the bony architecture. The arch area may become so deformed it looks convex rather than concave.
Motor neuropathy affects the way the muscles work. The muscles deteriorate and over time, patients with longstanding diabetes and motor neuropathy may lose as much as half of the muscle volume of their feet. When the muscles of the foot do not work properly, an imbalance occurs and toes are often pulled out of their normal position. These are called hammertoes. When the toes move upward, they also pull with them soft tissue structures like the fat pad on the ball of the foot. This increases pressure on the bottom of the foot, and calluses and ulcers often form. These deformities must be addressed.
The best treatment for neuropathy is to keep your blood glucose levels on target. Studies show that near-normal blood glucose levels can also help prevent nerve damage from getting worse. If you have painful neuropathy and start taking insulin or oral medications to lower your blood glucose, you may notice a short increase in pain until your body becomes accustomed to the lower blood glucose levels.
Medications such as antidepressants, anticonvulsants (seizure medicine), muscle relaxants, local anesthetics (such as a lidocaine patch), and anti-inflammatory drugs, as well as vitamins, evening primrose oil, and capsaicin creams made from hot peppers, have been used to treat neuropathy symptoms.
Capsaicin is a substance found in hot peppers. Capsaicin cream removes a chemical—substance P, from the nerve ends below your skin and may interrupt your feeling pain. Apply it lightly several (3 to 4) times a day. Wear gloves or wash your hands carefully after applying capsaicin—you do not want to get hot pepper cream in your eyes, your mouth, or any other sensitive area! When you first use capsaicin, you may have a stinging or burning sensation that should disappear in a few days to a few weeks. Don’t give up just because it burns.
Do not use capsaicin if you are sensitive or allergic to hot peppers. Capsaicin cannot be used on damaged or irritated skin, wounds, or rashes. Don’t put tight clothing or bandages over the cream. Use it 3 to 4 times a day for 3 to 4 weeks before deciding whether it is working. Since capsaicin comes in different strengths, discuss what strength to use with your health care provider.
Physical therapy treatments such as stretching exercises, massage, and electrical nerve stimulation have also been tried. Some doctors have reported success with surgery performed on affected nerves. Although studies of these therapies report some improvement in painful symptoms for some patients, there is no single treatment that works for everyone. It may be difficult to get complete relief. Discuss your symptoms with your provider and try the treatment you both think might work. If that treatment doesn’t help, let your provider know so you can try another one.
Numbness in your feet is a very serious condition. Most people go to the doctor because their feet hurt, but may not realize if they’ve lost sensation. It is important to look at your feet and touch them every day. Keeping your blood glucose on target may help prevent the numbness from getting worse. See your podiatrist regularly. You may also need to have your shoes fitted properly by a pedorthist (certified shoe fitter) and find out whether you need special shoes to protect your feet. Check your shoes before each wearing for foreign objects, nails, or anything that may injure your foot. Be sure your socks are not wrinkled or twisted. You may want to switch to socks without a toe seam, because seams can put too much pressure on your toes.
If you find that the numbness is uncomfortable, discuss treatments for neuropathy with your health care provider. Whenever there is any injury to your feet or a change in shape or a change in the skin, see your foot care specialist right away. Do not wait until an infection develops!
A decrease in foot sweating can be a sign that diabetic nerve damage is occurring in the nerves that control sweating. This is called autonomic neuropathy. However, foot sweating also tends to decrease as we age, especially if we become less active. Wearing different shoes or socks can affect foot sweating, as well. You may have recently started wearing shoes that do not hold in moisture, so your feet are drier.
The problem with a decrease in foot sweating, whatever the cause, is that the foot skin tends to become very dry and prone to cracking. Cracks in the skin may become infected. It is a good idea to use a moisturizing cream or lotion on your feet (but not between the toes) if you have dry skin.
An unsteady gait can be related to diabetic nerve damage. When a person has loss of feeling in his or her feet, the positioning system of the body does not get normal responses about where the feet are being placed. This can cause the person to feel unsteady or to trip and stumble. An unsteady gait can be a sign of other problems, too—some of which can be quite serious. If you are having trouble with your balance or walking, talk with your provider about a consultation with a neurologist or physiatrist.
If your unsteadiness is due to nerve damage, it may be time to get a cane. It’s better to be safe and use a walking aid than to risk a fall and a broken hip! Your provider or physical therapist can help you get the right length and give you tips on how to walk with a cane. A physical therapist can also teach you balance exercises and how to increase awareness of the position of your feet.
Sometimes diabetes-related muscle weakness can contribute to unsteadiness in walking. Your provider or physical therapist can show you muscle-strengthening exercises. Some people need a lightweight brace or ankle support to stabilize the ankles when muscle weakness is the problem.
Not all pain or numbness in your feet may be diabetes related. Some vitamin deficiencies, such as vitamin B12, can cause neuropathy. A neuroma (sometimes called Morton’s neuroma) can manifest itself with tingling, burning, or pain in your two middle toes. At first this problem may only occur when you wear tight shoes, but the numbness and pain will eventually progress so you feel pain in any shoes. Compression of a nerve in this area, between the third and fourth toes, causes the nerve to thicken and creates these symptoms. People with and without diabetes may get neuromas. Treatment for this problem may include shoe inserts (orthotics), wider shoes, injections of cortisone, injections of alcohol to “kill” the nerve, or surgery to release pressure on the nerve or to remove the neuroma entirely.
One of the most serious complications possible in people with diabetes is peripheral vascular disease (PVD) or peripheral arterial disease (PAD). PAD is commonly called “poor circulation” and refers to blockage in the blood supply, often to the feet. A buildup of plaque inside the arteries that carry blood to the feet causes them to thicken and harden. Plaque is a substance