What is diabetic neuropathy?

DEFINITION:
Diabetic neuropathy is, in simplest terms, nerve damage experienced by diabetics. Both type I and type II diabetics can develop neuropathy. These problems can occur at any time, but the risk increases with age and the duration of the diabetes. It is estimated that 60 to 70 percent of diabetics have or will have some form of this condition; primarily, those who have difficulty keeping blood glucose levels in balance.
TYPES:
There are four common types of diabetic neuropathy:
* Peripheral Neuropathy causes progressive pain, tingling, or numbness in the legs, arms, feet, and hands.
* Autonomic Neuropathy affects involuntary nervous systems such as digestion, breathing, vision, and heart function.
* Proximal Neuropathy creates pain in the area of the hips, buttocks, and thighs that often precedes weakness in the legs.
* Focal Neuropathy results in sudden weakness or pain in a single nerve or, less frequently, a group of nerves, anywhere in the body.




SYMPTOMS:
The symptoms of diabetic neuropathy vary with the type and location of the affected nerves, and tend to worsen with time. Some people have no symptoms at all. Others experience tingling or numbness; loss of muscle in the extremities; indigestion or nausea; diarrhea or constipation; or dizziness on standing, depending on the affected nerve group. Individuals with focal neuropathy suffer sudden, often severe pain.




CAUSES:
While unsure of the exact causes of diabetic neuropathy, researchers are aggressively studying the relationship between nerve function and blood sugar levels.

It is believed that the leading cause of diabetic neuropathy is extended periods of elevated blood sugar. High blood sugar causes chemical changes in nerves, weakens the walls of the capillaries that deliver oxygen and nutrients, and interferes with the nerves' ability to transmit signals. Individuals who are unable to control their blood glucose levels or who consistently have lower than normal insulin levels are at greatest risk.

Other potential causes of diabetic neuropathy include:
* Microvascular Disease - Blood vessels depend on nerve function and nerves are dependent on proper blood flow. Initial symptoms of microvascular disease include constriction, a reduced blood flow to the nerves, which is a documented characteristic of diabetic neuropathy.
* Glycated Proteins - High levels of glucose in the body's cells cause a reaction with proteins that alters their structure and function. These altered proteins have been linked to diabetic complications, including neuropathy.
* Polyol Pathway - While insulin can reduce blood sugar levels in many of the body's cells, those in the retina, kidney, and nerve tissues are insulin-independent. Glucose not metabolized in these tissues enters this alternative pathway and is turned into sorbitol. High levels of sorbitol are believed to reduce the activity of the plasma membrane pump required for nerve function.
* Autoimmune Response - Occasionally, for reasons not entirely understood, the body's immune system will attack part of the body as though it were foreign tissue. Transplant patients and other individuals on immuno-suppressant therapy are also at risk.
* Genetic factors, unrelated to diabetes, can make some people more vulnerable to nerve damage and neuropathy.
* Alcohol and tobacco use are known to constrict capillaries and, consequently, blood flow, which can contribute to increased nerve problems in diabetics.