Diabetic Neuropathy

Diabetic neuropathy is a group of nerve disorders caused by diabetes. People with diabetes can develop nerve problems at any time, but the longer a person has diabetes, the greater the risk of diabetic neuropathy. Diabetic neuropathy leads to numbness, pain, and weakness in the hands, arms, feet, and legs. Approximately 50 percent of those with diabetes have some form of diabetic neuropathy.

 

Diabetic Neuropathy: An Overview

Diabetic neuropathy is a family of nerve disorders caused by
 diabetes. People with diabetes can, over time, have damage to nerves throughout the body. Diabetic neuropathy leads to numbness and sometimes pain and weakness in the:
 
  • Hands
  • Arms
  • Feet
  • Legs.
     
Diabetic neuropathy problems may also occur in every organ system, including the:
 
  • Digestive tract
  • Heart
  • Sex organs.
     
People with diabetes can develop nerve problems at any time, but the longer a person has diabetes, the greater the risk of diabetic neuropathy.
 
An estimated 50 percent of those with diabetes have some form of diabetic neuropathy, but not all of those people will exhibit symptoms. The highest rates of neuropathy are among people who have had the disease for at least 25 years.
 
Diabetic neuropathy also appears to be more common in:
 
  • People who have had problems controlling their blood glucose levels
  • Those with high levels of blood fat and blood pressure
  • Overweight people
  • People over the age of 40.
     
The most common type of diabetic neuropathy is peripheral neuropathy, also called distal symmetric neuropathy, which affects the arms and legs.
 

Diabetic Neuropathy: Understanding the Nervous System

Nerves carry messages back and forth between the brain and other parts of the body. All of your nerves together make up the nervous system.
 
Some nerves tell the brain what is happening in the body. For example, when you step on a tack, the nerves in your foot tell the brain about the pain. Other nerves tell the body what to do. For example, nerves from the brain tell your stomach when it is time to move food into your intestines.
 

Impact of Diabetic Neuropathy on the Nervous System

Having high blood glucose for many years can damage the blood vessels that bring oxygen to some nerves. High blood glucose can also hurt the covering on the nerves, called myelin. Damaged nerves may stop sending messages. Or they may send messages too slowly or at the wrong times.
 

Causes of Diabetic Neuropathy

The causes of diabetic neuropathy are probably different for different varieties of diabetic neuropathy. Researchers are studying the effect of glucose on nerves to find out exactly how prolonged exposure to high glucose causes diabetic neuropathy. Nerve damage is likely due to a combination of:
 
  • Metabolic factors, such as high blood glucose, long duration of diabetes, possibly low levels of insulin, and abnormal blood fat levels
     
  • Neurovascular factors, leading to damage to the blood vessels that carry oxygen and nutrients to the nerves
     
  • Autoimmune factors that cause inflammation in nerves
     
  • Mechanical injury to nerves, such as carpal tunnel syndrome
     
  • Inherited traits that increase susceptibility to nerve disease
     
  • Lifestyle factors, such as smoking or alcohol use.
     

Types of Diabetic Neuropathy

 
  • Peripheral
  • Autonomic
  • Proximal
  • Focal.
     
Each type of diabetic neuropathy affects different parts of the body in different ways.
 
Peripheral Neuropathy
Peripheral neuropathy causes either pain or loss of feeling in the:
 
  • Toes
  • Feet
  • Legs
  • Hands
  • Arms.
     
Autonomic Neuropathy
Autonomic neuropathy causes changes in:
 
  • Digestion
  • Bowel and bladder function
  • Sexual response
  • Perspiration.
     
It can also affect the nerves that serve the heart and control blood pressure. Autonomic neuropathy can also cause hypoglycemia (low blood sugar) unawareness, a condition in which people no longer experience the warning signs of hypoglycemia.
 
Proximal Neuropathy
Proximal neuropathy causes pain in the:
 
  • Thighs
  • Hips
  • Buttocks.
     
This form of neuropathy also leads to weakness in the legs.
 
Focal Neuropathy
Focal neuropathy results in the sudden weakness of one nerve, or a group of nerves, causing muscle weakness or pain. Any nerve in the body may be affected.
 

Symptoms of Diabetic Neuropathy

Symptoms depend on the type of diabetic neuropathy and which nerves are affected. Some people have no diabetic neuropathy symptoms at all. For others, numbness, tingling, or pain in the feet is often the first sign.
 
Often, symptoms are minor at first, and since most nerve damage occurs over several years, mild cases may go unnoticed for a long time. Symptoms may involve the sensory or motor nervous system, as well as the involuntary (autonomic) nervous system. In some people, mainly those with focal neuropathy, the onset of pain may be sudden and severe.
 
Symptoms of diabetic neuropathy may include:
 
(Click Diabetic Neuropathy Symptoms for more information about the specific symptoms that can occur with each type of diabetic neuropathy.)
 
In addition, the following symptoms are not due to neuropathy but nevertheless often accompany diabetic neuropathy:
 

Diagnosing Diabetic Neuropathy

Diabetic neuropathy is diagnosed on the basis of symptoms, a physical exam, and the results of certain tests.
 
(Click Diabetic Neuropathy Diagnosis for more information about how a diabetic neuropathy diagnosis is made.)
 

Treating Diabetic Neuropathy

The first step is to bring blood glucose levels within the normal range to prevent further nerve damage. Controlling blood glucose levels involves:
 
  • Blood glucose monitoring
  • Meal planning
  • Exercise
  • Oral drugs or insulin injections.
     
Although symptoms may get worse when blood glucose is first brought under control, over time, maintaining lower blood glucose levels helps lessen diabetic neuropathy symptoms. Most importantly, good blood glucose control may also help prevent or delay the onset of further problems.
 
Additional diabetic neuropathy treatment depends on the type of nerve problem and symptoms. Possible diabetic neuropathy problems include:
 
  • Diabetic feet
  • Pain
  • Gastrointestinal problems
  • Dizziness and weakness
  • Urinary and sexual problems.
 
(Click Diabetic Neuropathy Treatment for more information about treatments for these diabetic neuropathy problems.) 

 

Preventing Diabetic Neuropathy

The best way to prevent diabetic neuropathy is to keep your blood glucose levels as close to the normal range as possible. Maintaining safe blood glucose levels protects nerves throughout your body.
 
(Click Diabetic Neuropathy Prevention for more information about preventing diabetic neuropathy.)
 

Diabetic Neuropathy: Summary

The following points are important to keep in mind regarding diabetic neuropathy:
 
  • Diabetic neuropathy is a grouping of nerve disorders caused by many of the abnormalities common to diabetes, such as high blood glucose.
     
  • Diabetic neuropathy can affect nerves throughout the body, causing numbness and sometimes pain in the hands, arms, feet, or legs, and problems with the digestive tract, heart, and sex organs.
     
  • Treatment for diabetic neuropathy first involves bringing blood glucose levels within the normal range. Good blood glucose control may help prevent or delay the onset of further problems.
     
  • Foot care is another important part of treatment. People with diabetic neuropathy need to inspect their feet daily for any injuries. Untreated injuries increase the risk of infected foot sores and amputation.
     
  • Treatment also includes pain relief and other medications as needed, depending on the type of diabetic neuropathy.
     
  • Smoking significantly increases the risk of foot problems and amputation. If you smoke, ask your healthcare provider for help in quitting.
     
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Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD