Diabetic neuropathy is a group of nerve disorders that can develop in people with diabetes. The word "neuropathy" means nerve damage, and these disorders develop because chronic high blood sugar causes damage to nerve tissue. Diabetic neuropathy symptoms are caused by this nerve damage, and they can include eye damage, numbness of the hands or feet and urinary incontinence. Between 60 percent and 70 percent of people with diabetes have diabetic neuropathy symptoms.
Symptoms of diabetic neuropathy develop as a result of several factors, all of which ultimately are caused by high levels of blood sugar. One factor is damage done to blood vessels themselves, which reduces blood flow to nerve tissue. Other factors relate to cellular imbalances caused by excess glucose in blood or cells. For example, high levels of glucose in cells cause proteins to react abnormally. This can affect many types of tissue, including nerve tissue, and is thought to be partially responsible for many of the long-term side effects of diabetes, including neuropathy.
Diabetic neuropathy symptoms can take many years to develop, because the minor nerve damage that accompanies the early stages of the disease usually is asymptomatic. As the nerve damage progressively worsens, symptoms begin to appear. The pattern of diabetic neuropathy symptoms that a person might experience depends on whether nerve damage is peripheral, proximal or autonomic.
Peripheral nerves control movement and sensation in the arms and legs. The most common symptoms of peripheral neuropathy include tingling or burning sensations in the hands or feet, numbness, cramps or pains and inability to feel pain or temperature extremes. People with peripheral nerve damage are more likely to have diabetic neuropathy symptoms that affect the legs and feet rather than the arms and hands. The main complication of this type of neuropathy is that injury to the feet can go unnoticed because of numbness. This can lead to uncontrolled infection that might necessitate a foot or limb amputation if it spreads to a bone.
Autonomic nerves are located in the trunk of the body and help control several important processes, including heart function, blood pressure and blood sugar. In addition, these nerves are involved in the control of vision, breathing, digestion, urinary function and sexual function. Damage to autonomic nerves can lead to heart problems, vision loss, high blood pressure, blood sugar fluctuation, digestive problems, incontinence and loss of sexual function.
Proximal neuropathy affects the hips, thighs, buttocks and legs. Often, only one side of the body is affected. The main symptoms of this type of diabetic neuropathy are weakness in the legs and difficulty standing. This type of nerve damage also is called diabetic amyotrophy or femoral neuropathy.
A fourth type of neuropathy, focal neuropathy, generally affects older people who have had diabetes for one or two decades. These diabetic neuropathy symptoms tend to appear suddenly, rather than gradually, in the head, trunk or legs. Focal neuropathy can cause vision disturbances, eye pain, facial paralysis and severe pain in the chest, abdomen, lower back, pelvis or thigh. These symptoms usually are temporary or episodic, and pain often can be managed with medication.