What Is Diabetic Peripheral Neuropathy?
Diabetic neuropathy is nerve damage caused by diabetes. When it affects the arms, hands, legs and feet, it is known as diabetic peripheral neuropathy. Diabetic peripheral neuropathy is different from peripheral arterial disease (poor circulation), which affects the blood vessels rather than the nerves.
Three different groups of nerves can be affected by diabetic neuropathy:
- Sensory nerves, which enable people to feel pain, temperature and other sensations
- Motor nerves, which control the muscles and give them their strength and tone
- Autonomic nerves, which allow the body to perform certain involuntary functions, such as sweating
Diabetic peripheral neuropathy does not emerge overnight. Instead, it usually develops slowly and worsens over time. Some patients have this condition long before they are diagnosed with diabetes. Having diabetes for several years may increase the likelihood of having diabetic neuropathy. The loss of sensation and other problems associated with nerve damage make a patient prone to developing skin ulcers (open sores) that can become infected and may not heal. This serious complication of diabetes can lead to loss of a foot, a leg or even a life.
Causes
The nerve damage that characterizes diabetic peripheral neuropathy is more common in patients with poorly managed diabetes. However, even patients living with diabetes who have excellent blood sugar (glucose) control can develop diabetic neuropathy. There are several theories as to why this occurs, including the possibilities that high blood glucose or constricted blood vessels produce damage to the nerves.
As diabetic peripheral neuropathy progresses, various nerves are affected. These damaged nerves can cause problems that encourage development of ulcers. For example:
- Deformities (such as bunions or hammertoes) resulting from motor neuropathy may cause shoes to rub against toes, creating a sore. The numbness caused by sensory neuropathy can make the patient unaware that this is happening.
- Because of numbness, a patient may not realize that s/he has stepped on a small object and cut the skin.
- Cracked skin caused by autonomic neuropathy, combined with sensory neuropathys numbness and problems associated with motor neuropathy, can lead to developing a sore.
- Motor Neuropathy (Deformity) + Ill-Fitting Shoes + Sensory Neuropathy (numbness) = Ulcers (sores)
- Symptoms
- Depending on the type(s) of nerves involved, one or more symptoms may be present in diabetic peripheral neuropathy.
For sensory neuropathy:
- Numbness or tingling in the feet
- Pain or discomfort in the feet or legs, including prickly, sharp pain or burning feet
For motor neuropathy:
- Muscle weakness and loss of muscle tone in the feet and lower legs
- Loss of balance
- Changes in foot shape that can lead to areas of increased pressure
For autonomic neuropathy:
- Dry feet Cracked skin
Diagnosis
To diagnose diabetic peripheral neuropathy, the foot and ankle surgeon will obtain the patients history of symptoms and will perform simple in-office tests on the feet and legs. This evaluation may include assessment of the patients reflexes, ability to feel light touch and ability to feel vibration. In some cases, additional neurologic tests may be ordered.