Diabetic Neuropathy Disease Health Article

Definition

Diabetic neuropathy (DN) is a neurological disorder caused by consequences of a primary disease—diabetes mellitus. The diabetic neuropathy may be diffuse, affecting multiple parts of the body, or focal, targeting a specific nerve or body part.

Description

Neurological damage is the result of chronically elevated blood sugar. Among all complications of diabetes, DN can be one of the most frustrating and debilitating conditions, because of the pain, discomfort, and disability it may cause, and because available treatments are limited and not always successful.

There are three main types of DN:

• Sensory neuropathy (or peripheral neuropathy, usually just referred to as neuropathy)—affects the nerves that carry sensation information to the brain, from various parts of the body, i.e.: how hot or cold something is, what the texture of something feels like, or the pain caused by a sharp object. This is the most common form of diabetic neuropathy.
• Autonomic neuropathy—affects the nerves that control involuntary activities of the body, such as the action of the stomach, intestine, bladder, and even the heart.
• Motor neuropathy—affects the nerves that carry signals from the brain to muscles, allowing all motions to occur, i.e. walking, moving the fingers, chewing. This form of neuropathy is very rare in diabetes.

The longer a person has diabetes, the more likely the development of one or more forms of neuropathy. Approximately 60–70% of patients with diabetes show signs of neuropathy, but only about five percent experience painful symptoms.

According to the categories described above, DN can lead to muscular weakness, loss of feeling or sensation, and loss of autonomic functions such as digestion, erection, bladder control, sweating, and so forth.

Demographics

In the United States, DN occurs in 10–20% of patients newly diagnosed with diabetes mellitus (DM), and its prevalence is up to 50% in elderly patients with DM. Most studies agree that the overall prevalence of symptomatic DN is approximately 30% of all patients with DM. The incidence of DN in the general population is approximately two percent.

Internationally, DN is found in 20–30% of individuals with type-2 diabetes. This number depends on the fiber type being tested and the sensitivity of the exam. Individuals with type-1 diabetes usually develop neuropathy after more than ten years of living with the disease.

It affects men and women equally, but neuropathic pain appears more frequently in females. Minority group members have more secondary complications, such as lower extremity amputations. These individuals tend to also have more hospitalizations due to neuropathic complications.

Causes and symptoms

Causes of diabetic neuropathy are likely to be different for different types of the disorder. Nerve damage is probably due to a combination of factors, such as:

• Metabolic factors: high blood glucose, long disease duration, low levels of insulin and abnormal blood fat levels
• Neurovascular factors, leading to blood vessel damage and consequent insufficient delivery of oxygen and nutrients to the nerves
• Autoimmune factors, causing nerve inflammation
• Mechanical nerve injury, such as carpal tunnel syndrome
• Inherited traits that increase susceptibility to nerve disease
• Lifestyle factors, such as smoking or alcohol use

Symptoms depend on the neuropathy type and affected nerves. Some people show no symptoms at all. Often, symptoms are minor at first, and because most nerve damage occurs over several years, mild cases may go unnoticed for a long time. Symptoms may include:

• Numbness, tingling, or pain in the toes, feet, legs, hands, arms, and fingers
• Wasting of feet or hands muscles
• Indigestion, nausea, or vomiting
• Diarrhea or constipation
• Dizziness or faintness due to a drop in postural blood pressure
• Problems with urination
• Erectile dysfunction (impotence) or vaginal dryness
• Weakness

In addition, weight loss and depression are not a direct consequence of the neuropathy but, nevertheless, often accompany it.