What Is Diabetic Neuropathy?

An estimated 20 million people in the United States have some form of peripheral neuropathy. More than 100 types of peripheral neuropathy have been identified, each with its own symptoms and prognosis, according to the National Institute of Neurological Disorders and Stroke. Additionally, an estimated 23% of neuropathy patients can be diagnosed with idiopathic neuropathy, or neuropathy coming from an unknown cause, which typically occurs in middle-aged and elderly people.

Diabetic neuropathy, which you may hear called diabetic nerve pain, is diabetes-related nerve damage. It develops over time; the longer you have diabetes, the more at risk you are for diabetic neuropathy. In fact, the National Institute of Diabetes and Digestive and Kidney Diseases reports that 60% to 70% of people with either type 1 diabetes or type 2 diabetes will develop a type of diabetic nerve pain.

There are four types of diabetic neuropathy: peripheral (the most common type), proximal, autonomic, and focal. Peripheral neuropathy is the most likely to cause pain, but proximal neuropathy can also cause pain.

Diabetic Neuropathy Causes

Even though the exact cause of diabetic neuropathies isn't fully understood, researchers in the medical community do know that poor blood glucose control (blood sugar) is related to the development of nerve damage.

What they don't understand is how long-term exposure to high blood glucose levels leads to nerve damage. There is an idea that elevated blood glucose levels damage the blood vessels over time. Damaged blood vessels can't bring oxygen and nutrients to the nerves as well as they should be able to, eventually leading to nerve damage.

Most likely, diabetic neuropathy develops because of a mix of factors:

• Lifestyle: Smoking and excessive alcohol use can contribute to diabetic neuropathy.

• Age: The longer you have diabetes, the more likely it is that you will develop diabetic neuropathy.

• Nerve injury: Your nerves can be injured because of other conditions, such as carpal tunnel syndrome, or they may be injured because of inflammation. Injured nerves may be more likely to develop diabetic neuropathy.

• Autoimmune factors: In autoimmune diseases—and type 1 diabetes is an autoimmune disease—the immune system, for some reason, turns against the body. An autoimmune disorder can cause inflammation, which can damage the nerves.

• Genetic factors: You may inherit a gene that makes you more susceptible to nerve damage.

• Metabolic factors: In addition to high blood glucose and duration of diabetes, abnormal blood fat (cholesterol) levels may contribute to neuropathy. Researchers are also looking into the role of low insulin levels.

Diabetic Neuropathy Symptoms 


The symptoms of diabetic neuropathy are dependent on which type you have, as well as which nerves are damaged. For many people, the first symptom is pain, tingling, or numbness in the feet, legs, arms, and hands. The lower extremeties usually are affected earlier than the upper extremeties. This may be minor at first because it takes awhile for diabetic neuropathy to develop. Gradually, as more nerves are damaged, the symptoms can become more severe.

Other symptoms of nerve damage include:

• Inability to feel temperature (hot or cold)

• Wasting of muscles of the hands and feet

• Indigestion, nausea, and vomiting

• Diarrhea and constipation

• Dizziness or faintness due to a drop in blood pressure

• Problems with urination

• Sexual dysfunction (erectile dysfunction in men, vaginal dryness in women)

• General weakness

Diabetic Neuropathy Types

Peripheral

Peripheral neuropathy is the most common type of diabetic neuropathy. It causes pain or loss of feeling in lower legs, feet, and toes, as well as in the arms and hands. When peripheral neuropathy gets worse, patients may not realize that they have hurt themselves or cut themselves. Unattended wounds can develop ulcers, which may get infected. In the worst-case scenarios, this can lead to amputations in some patients with diabetes. Nearly 80% of the amputee population worldwide will then likely experience phantom limb pain, according to the Amputee Coalition.

Focal

In focal neuropathy, the onset of pain is usually sudden and intense. It usually affects one nerve or group of nerves in the head, torso, or legs—but any nerve in the body can be affected. However, focal neuropathy symptoms usually go away in a few weeks.

Proximal

Proximal neuropathy can cause symptoms related to the motor system—your ability to move. You may, for example, have trouble standing up from a seated position. Proximal neuropathy causes pain the legs, thighs, hips, buttocks, and less frequently shoulders.

Autonomic

Autonomic neuropathy affects the autonomic nervous system, which controls involuntary functions—it's what keeps your heart beating, lungs breathing, digestive tract moving, etc. If your autonomic nerve system is affected, you may have dizziness upon standing up, feelings of being about to faint, or problems with urination.

If you have diabetes and notice pain, tingling, or numbness, or other nerve-related symptoms, talk to your doctor right away. The progression of diabetic neuropathy can be slowed down with the proper treatment. The best way to prevent diabetic neuropathy is by keeping your blood glucose levels as close to normal as possible.