Diabetic Nerve Pain: It's Not Just in Your Feet

By Rebecca Buffum Taylor
WebMD Feature

Reviewed by Brunilda Nazario, MD

For people with diabetes, nerve pain can be a serious problem. Would you recognize the symptoms of diabetic nerve pain?

Nearly 21 million Americans have diabetes, and at least six out of 10 of them have some kind of nerve damage, called diabetic neuropathy, says the American Diabetes Association (ADA).

Nerve pain or numbness can happen anywhere in your body - not just in your feet - although that's a common spot if you're over 40.

Nearly one in three people over age 40 with diabetes have lost some feeling in their feet, says the ADA. A little numbness sound like a minor problem? Actually, it's major. Amputation, having a toe, foot, or lower leg surgically removed, is 10 times more likely in people with diabetes.

Just as dangerous are symptoms of neuropathy that go unnoticed, dismissed, or simply aren't seen as diabetes-related. "A good example is when a person is at rest, perfectly calm and comfortable, and yet the heart's racing," says Dace L. Trence, MD, an endocrinologist and director of the Diabetes Care Center at the University of Washington Medical Center in Seattle. "Or people lose sensation - this is probably what we fear the most - and can't tell they're having chest pain."

If you can no longer feel the symptoms of a heart attack or blood sugar drops, it can be a sign that the autonomic nerves that send signals to and from your organs have been damaged by diabetes. "When I tell people about this, I talk about the involuntary nervous system," says Trence. "Either the signaling is overly disrupted, as with pain, or it goes in the other direction, where you no longer appreciate any pain or sensation whatsoever."

You may wonder: If you have peripheral neuropathy, is it typical to have some autonomic neuropathy, too? "There isn't anything typical about it at all," Trence tells WebMD. You could have one or the other, or you could have both." That's why knowing the range of symptoms of neuropathy is a key step in taking care of yourself and managing your diabetes.

Symptoms of Peripheral Neuropathy In Your Feet and Hands

If you have diabetes, you may be all-too-familiar with nerve pain and damage in your feet, legs, and hands, called peripheral neuropathy. Your peripheral nerves serve the farthest reaches - the periphery - of your body.

The nerves to your feet are the longest in your body, and they're often the first to be affected. (Nerve pain, numbness, and muscle weakness can also appear in your hips, thighs, and buttocks, called proximal neuropathy, making it hard to walk.

Do you have:

• Tingling or burning in your toes, feet, legs, fingers, hands, or arms?
• A "pins and needles" feeling?
• Pain or cramping?
• Numbness or loss of sensation?
• Insensitivity to heat and cold?
• Extreme sensitivity to even the lightest touch?
• Muscle weakness in your hands or feet?
• Loss of coordination or balance that makes it harder to walk?

Symptoms of Autonomic Neuropathy: Throughout Your Body

Autonomic nerves play a key role in controlling a wide range of basic body functions, most of them involuntary: your heart rate, blood pressure, sexual response, bowels, bladder, sweating, and your ability to sense the signs of high blood sugar or a heart attack.

Most people feel weak or shaky when their blood sugar levels drop below 70 mg/dL, but people with this kind of neuropathy have a hard time feeling these sensations. A vicious cycle can result, since being unaware that your blood sugar's too high (hyperglycemia) or too low (hypoglycemia) makes it harder to keep your blood sugar leveled out throughout the day.

Your social life can be affected, too. If nerves in your urinary tract are damaged, you may not be able to feel or control your bladder and may have incontinence. If nerves in your digestive system are damaged, you may have chronic constipation or a stomach that empties too slowly, resulting in bloating, nausea, even vomiting. If nerves leading to sex organs are damaged, men may have difficulty maintaining an erection, called erectile dysfunction or ED, while women may no longer enjoy their usual sexual response. For both men and women, orgasm may be out of reach.

Do you have:

• Trouble feeling when your blood sugar is low?
• Chronic constipation or diarrhea?
• Frequent indigestion, nausea, or vomiting?
• Problems with urination?
• Problems with sex or orgasm?
• Faintness or dizziness when you stand up?
• Trouble seeing well enough to drive at night?
• Changes in sweating, either much more or less than usual?

Other Kinds of Neuropathy

Slow stomach emptying. Other common neuropathies can be caused by diabetes, such as the inability to empty the stomach, called gastroparesis, says Trence. "People may notice fluctuations in blood sugar that don't seem to correspond to anything related to food, medication dosing, or activity," she says. "They often report feeling very full, having just a few bites of food. And it's not unusual, when they get up in the morning, to feel full before they've eaten. They can actually throw up, and it's last night's dinner."

Diabetic diarrhea. Another common problem is diabetic diarrhea, Trence says, which is diarrhea that can come at any time. "Socially, it's a major concern," she says. "You can't predict it. It's a rapid transit problem that can occur where there are abnormalities in how fast food is absorbed or how well it's absorbed, so it can cause chaos with blood sugars."

Cardiovascular nerve damage. If nerves in your circulatory system are damaged, your body may lose its natural ability to adjust heart rate and blood pressure. You may frequently feel light-headed or dizzy when you stand up after sitting for awhile, or your blood pressure may stay high too long after exercise, rather than dropping to normal levels after resting.

Focal neuropathy. You can think of this type of nerve pain and damage as suddenly "focusing" in one part of your body with sudden, severe pain or weakness. It can show up as sudden pain in your feet, or sharp pain in one eye, double vision, or trouble focusing one eye. Or you may suddenly be unable to move the muscles on one side of your face.

Why Does Diabetes Cause Nerve Pain?

What's the current theory of why glucose damages nerves? It all boils down to two main theories, says Trence. Both target the protective covering of nerves, called the myelin sheath.

"One theory is that it's either glucose directly, or a byproduct of the metabolism of glucose - something that chemically irritates the nerve sheath," Trence says. When this sheath is destroyed, a bare nerve is exposed - just as you'd expose an electrical wire if you stripped off its plastic coating. "The bare nerve is very painful," she says, "and then over time, the sensation is completely lost."

The other camp thinks the problem lies in the vascular system and a cutting-off of the blood supply to the nerves. If the tiny blood vessels that feed the nerve are destroyed, Trence tells WebMD, then you see a "starvation" of the nerve sheath. "There's some evidence for one or the other theory, and there's some evidence that both may be going on, too," says Trence. "It's a question that has not yet been resolved."

So while modern medicine doesn't yet know for sure what causes nerve pain, one thing is certain: Keeping your blood sugars at your target level is the first step in protecting the health of your nerves. And be open and talk with your doctor at the first sign of unusual nerve pain, numbness, or sensation -- no matter where they may happen in your body

 

SOURCES: Dace L. Trence, MD, endocrinologist, director of the Diabetes Care Center at the University of Washington Medical Center, Seattle. National Diabetes Information Clearinghouse (NDIC): "Diabetic Neuropathies: The Nerve Damage of Diabetes" and "Prevent Diabetes Problems: Keep Your Nervous System Healthy." American Diabetes Association: American Diabetes Association: "Diabetic Neuropathy (Nerve Damage) and Diabetes," "Complications of Diabetes in the United States," and "Could You Have Diabetic Neuropathy and Not Know It?"

Reviewed on August 28, 2008