Diabetic neuropathy is a type of nerve abnormality that can develop in individuals with diabetes. It is a common yet serious complication of diabetes. It can be prevented or ameliorated by tight control of blood sugars. Diabetic neuropathy most commonly damages nerves in the lower extremities but can damage nerves throughout the body. In some individuals the symptoms are mild, but for others, the symptoms can be severe and even disabling.
There are four types of diabetic neuropathy:
- Diabetic peripheral neuropathy: the feet and legs tend to be affected first in an ascending manner, followed by the upper extremities. Symptoms include numbness, tingling, burning, temperature abnormalities, and enhanced sensation to touch. It can lead to ulceration, infection, and bony deformity
- Autonomic neuropathy: the autonomic nervous system controls the internal organs (heart, lungs, gastrointestinal tract, and bladder). Damage to these nerves can cause hypoglycemia unawareness (the inability to sense that the blood sugar level is low), bladder dysfunction, delayed stomach emptying (gastroparesis), and abnormalities with heart rate and blood pressure regulation
- Diabetic amyotrophy: affects the nerves in the proximal legs/hips/buttocks, causing pain, weakness, and muscle atrophy
- Mononeuropathy: involves damage to a single nerve. Comes on suddenly and typically involves the trunk, extremity, or face. Symptoms may include Bells palsy (unilateral facial weakness), double vision, truncal pain, leg pain, or carpal tunnel syndrome
Chronic exposure to elevated blood glucose levels causes damage to delicate nerve tissue. Hyperglycemia directly damages the nerves and also causes damage to the tiny blood vessels that supply oxygen and nutrients to these nerves (via diminished nitric oxide production). Genetic factors likely make some individuals more susceptible than others to the development of this condition. The greatest risk factor is poor glucose control. Keeping sugars under tight control is the best way to protect the nerves and blood vessels. Duration of diabetes is also a factor, with the risk of neuropathy increasing the longer an individual has diabetes. Kidney disease also plays a role, as damaged kidneys are less effectively able to clear damaging toxins from the system.
Treatment of diabetic neuropathy focuses on several issues. First is the prevention of disease progression, by trying to establish tight blood sugar control. There are several classes of medications prescribed to offer pain relief. Finally, the goal is the prevention of complications such as ulceration/infection, Charcot joint deformity, or amputation and the treatment of autonomic complications such as gastroparesis, bladder dysfunction, and orthostatic hypotension.