Diabetic neuropathy is a group of nerve disorders related to diabetes. Nerves run throughout the body connecting the spinal cord to muscles, skin, blood vessels and organs. Some nerves provide information to the brain from these body areas; others carry signals to the body areas from the brain.

Damaged nerves are unable to transmit correct signals. The result is impaired sensation, motor function or autonomic (regulatory) functions, causing symptoms such as pain, numbness, weakness or sexual dysfunction. Nerve injuries may be temporary or permanent, and the symptoms may change over time.

Diabetic neuropathy, a common complication in patients with diabetes, is generally caused by high levels of glucose (blood sugar) and poor blood flow. Other causes of neuropathy may include autoimmune disorders, immune system disorders such as AIDS, injury, alcohol abuse, poor diet, genetic factors, thyroid disorders, kidney diseases, nerve diseases such as Guillain-Barre syndrome, infections and chemotherapy drugs. Nondiabetics can develop neuropathies, as well, such as carpal tunnel syndrome or cranial neuralgias.

Not all diabetes patients will experience nerve damage. Neuropathy is most likely to occur in people who have:

• A long history of diabetes
• Difficulty controlling glucose (unstable diabetes)
• High levels of blood fats)
• High blood pressure (hypertension)

Diabetic neuropathy can affect people with type 1 diabetes, type 2 diabetes and lesser-known forms of the disease, such as maturity-onset diabetes of the young (MODY) and latent autoimmune diabetes of adulthood (LADA). In addition, diabetic neuropathy can already be present in people with prediabetes. In fact, symptoms of neuropathy (such as tingling, pain or numbness in the hands, feet or legs) can be the first indication that a person has prediabetes or diabetes.

About 60 to 70 percent of diabetic patients have some form of neuropathy, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) estimates. Chances of developing nerve damage increase the longer a person has diabetes. There is no apparent difference among racial groups for developing neuropathy. This condition is more common in:

• People over 40
• Males
• Overweight individuals
• Smokers

Neuropathy can occur anywhere in the body, including:

• Limbs (legs, feet, arms, hands)
• Senses (touch, sight and hearing)
• Systems (cardiovascular, neurologic, respiratory and digestive)
• Functions (bladder, bowel and sexual)

Research continues into the causes of diabetic neuropathy, ways to prevent it and how to cure it. Experimental treatments using nerve growth factors and gene therapy may offer a promising future for recovery from diabetic neuropathy.