Diabetic neuropathy refers to a group of nerve disorders caused by diabetes. Diabetic neuropathy can affect nerves throughout the body, although it most commonly affects nerves in the feet and legs. People with diabetes should be especially careful about their feet and lower legs.
Neuropathies can develop in people with type 1 or type 2 diabetes. In type 1 diabetes, neuropathy may not develop for many years. In type 2 diabetes—particularly for people who let their condition go untreated—it may occur sooner.
What Are the Types of Diabetic Neuropathy?
Neuropathies are classified based on the affected nerves:
Peripheral neuropathy affects the peripheral nerves in the limbs. It can cause numbness or pain in the toes, feet, legs, hands, and arms.1 It is one of the more common forms of diabetic neuropathy.
Autonomic neuropathy affects nerves that regulate autonomic function, such as digestion, heart rate, and blood pressure. This neuropathy can create problems with bowel (gastroparesis) or bladder control, and even with the ability to recognize low blood sugar reactions. Autonomic neuropathy can also cause erectile dysfunction in men and sexual issues for women.2
Focal neuropathy can occur in any peripheral (non-central nervous system) nerve. It creates a sudden weakness in one nerve or more and can cause pain or muscle weakness.
Proximal neuropathy (also called lumbosacral plexus neuropathy) affects nerves in the thighs, hips, or buttocks. It can cause pain or numbness in those areas and can lead to weakness in the legs.3 Proximal neuropathy is less common than peripheral or autonomic neuropathies.
What Causes Neuropathy?
Research suggests that diabetic neuropathy is one of the complications that can result from sustained high blood sugar levels.4 However, because not everyone develops neuropathy, researchers think there may be other factors involved, including:
Lifestyle factors, such as smoking or alcohol consumption, both of which can lead to nerve damage5
Metabolic factors, such as duration of diabetes and cholesterol levels
Autoimmune factors that may inflame the nerves, causing damage5
Nerve and blood vessel factors that can cause damage to the blood vessels, making them less able to carry oxygen and other nutrients that nerves need
Genetic traits that increase susceptibility
Nerve injury, such as carpal tunnel syndrome6
People with diabetic neuropathy can slow its development by maintaining target blood sugar levels.
What Are the Symptoms of Neuropathy?
Some people may have diabetic neuropathy and not know it, since nerve damage often takes years to occur. Symptoms are usually slight at first and may go unnoticed. Some people experience numbness, a “pins and needles” sensation or pain in their feet, legs or arms. After several years, neuropathy can lead to muscle weakness in the affected areas.
In cases of focal neuropathy, the onset of the pain or numbness may be severe and sudden, most often in the torso, head or leg. Focal neuropathy can also occur in the nerves in the eye, causing sudden vision changes.7
Other symptoms of diabetic neuropathy can include:
Shrinking of muscles in the feet or hands (peripheral neuropathy)
Indigestion, vomiting or nausea (autonomic neuropathy)8
Fainting or dizzy spells caused by blood pressure changes (autonomic neuropathy)
Urinary or bowel difficulties (autonomic neuropathy)8
Impotence or vaginal dryness (autonomic neuropathy)
How Is Neuropathy Prevented or Treated?
Keeping blood sugar levels within the target range can help prevent diabetic neuropathy. People who already have neuropathy should work with their health-care providers to bring their blood sugar levels into the target range.
Good foot care is also of particular importance to people with diabetes. As neuropathy progresses, sensation may be lost in the feet, making it possible to have a wound or an ulcer without knowing it. Foot care should be part of the daily routine of anyone with diabetes.9
A mild soap should be used to wash feet, including between the toes. They should then be patted dry.
The tops, bottoms and between the toes of each foot should be inspected (with a mirror, if necessary) for any sign of dryness, cracking or redness.
A moisturizer should be applied to dry or cracked skin, but should not be applied between the toes.
Any redness, drainage, ulceration, wounds or swelling on the feet should be reported to a health care provider.
Toenails need to be trimmed carefully without clipping any skin. People with corns, calluses or very thick or ingrown toenails might need to see a podiatrist (a doctor who specializes in foot care). People with diabetes can protect their feet by:
Wearing shoes that fit well with room for the toes to move.9 Shoes should be checked before being put on to make sure nothing is stuck inside.
Wearing soft socks that are changed daily. Socks with lots of elastic should be avoided.
Not wearing sandals or open-toed shoes.9
Not going barefoot.
People who already have diabetic neuropathy may need to have their doctors inspect their feet regularly.
Depending on the type of diabetic neuropathy, other complications -- such as retinopathy (eye disease) or nephropathy (kidney disease) -- may develop. People with diabetes should check with their health-care providers to see if they recommend visiting a kidney specialist or an ophthalmologist who specializes in retinopathy.