What is Diabetic Neuropathy?

Diabetic neuropathy is the nerve dysfunction and damage that is a result of long-standing and often poorly controlled diabetes mellitus (sugar diabetes). It is the most common complication of diabetes mellitus and these neurological disturbances may affect more than half of all cases of long term diabetes.

Diabetic neuropathy is a broad therm that encompasses a variety of clinical neurological syndromes. It can be in the form of focal neuropathy, polyneuropathy, or autonomic neuropathy. Although neuropathy is a common complication of long standing and uncontrolled diabetes mellitus, it is often ignored until the late stages of the disease. At this point, symptoms like paresthesia, numbness or tingling, especially of the legs, affects daily functioning and leads to repeated injuries that predisposes to the formation of diabetic ulcers.

How can diabetes lead to neuropathy?

The exact mechanism behind diabetic neuropathy in not fully understood but it is generally accepted to be due to many factors. There are many other types of neuropathy but in this case it is attributed to diabetes mellitus if the condition is present in a diabetic patient and no other causes of neuropathy is evident.

Acute Diabetic Neuropathy

Diabetes can produce acute and often self-limiting type of neuropathies that is likely to result from vascular effects of diabetes. This means that the nerve damage arises as a result of compromised blood flow through the blood vessels of nerves.

Chronic Diabetic Neuropathy

The more common, chronic type of neuropathies in diabetes often results from metabolic factors related to diabetes. The most prominent factor linked to the development of diabetic neuropathy is long standing hyperglycemia (high blood glucose levels).

With long standing hyperglycemia, excess glucose in nerve cells can lead to activation of the polyol pathway with the production of sorbitol and fructose. These sugars, sorbitol and fructose, can accumulate in the nerve cells and increase the intracellular water content due to osmosis thereby leading to nerve dysfunction.

The hyperglycemia can also lead to non-enzymatic glycation of proteins present in peripheral nerves. The polyol pathway and non-enzymatic glycation can also increase the free radical formation and raises the oxidative stress leading to damage of the peripheral nerves.

A variety of other factors are also found to be related to diabetic neuropathy. An autoimmune mechanism may also play a part as monocytes (a type of white blood cell) infiltrates the autonomic nerve bundles and  antibodies against sympathetic ganglia may also contribute to diabetic neuropathy. In addition, reduced nerve growth factor seen in diabetic patients may limit the ability of the nerves to regenerate.

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Article reviewed by Dr. Greg. Last updated on November 30, 2010