What Is It?
Diabetic neuropathies include several nerve disorders that affect people with diabetes.
Peripheral neuropathy - This is the most common type of diabetic neuropathy, affecting the longest nerves in your body. These nerves are part of your peripheral nervous system, the network of nerves that carry signals from your brain and spinal cord to the rest of your body and back. The most common symptoms of peripheral neuropathy are numbness or pain in the feet and lower legs.
Autonomic neuropathy - This neuropathy damages important collections of nerves that control your unconscious body functions. It especially may affect your digestion, your circulation and your sexual function.
Localized nerve failures (focal neuropathy) - A nerve that controls a single muscle can lose its function. Examples of problems that this may cause are eye movement problems with double vision and drooping of the cheek on one side of the head (commonly known as Bell's palsy). One or more individual nerve failures sometimes is called mononeuritis multiplex.
Diabetic neuropathies occur in both type 1 and type 2 diabetes, and they are most common in people whose blood glucose (blood sugar) levels have not been well controlled. Although the various forms of diabetic neuropathy can occur in people who have had diabetes for a short time, they are most likely to affect those who have had the disease for more than a decade, and they are more common in people older than 40. Diabetics who smoke are especially at risk.
There are several changes in the nerves that combine to cause a diabetic neuropathy. When your nerve cells are surrounded by a high concentration of blood glucose, they must adjust their internal sugar content to be in balance with their surroundings, or else they would lose water through their cell membranes. To adjust to high blood glucose, nerve cells manufacture and store the sugar sorbitol. Sorbitol can gradually damage nerve cells. Damage to blood vessels also contributes to diabetic neuropathy, because the nerves may not get enough oxygen and nourishment.