DIABETIC NEUROPATHY DEFINITION
Diabetic neuropathy is a peripheral nerve disorder caused by diabetes or poor blood sugar control. The most common types of diabetic neuropathy result in problems with sensation in the feet. It can develop slowly after many years of diabetes or may occur early in the disease. The symptoms are numbness, pain, or tingling in the feet or lower legs. The pain can be intense and require treatment to relieve the discomfort. The loss of sensation in the feet may also increase the possibility that foot injuries will go unnoticed and develop into ulcers or lesions that become infected. In some cases, diabetic neuropathy can be associated with difficulty walking and some weakness in the foot muscles. There are other types of diabetic-related neuropathies that affect specific parts of the body. For example, diabetic amyotrophy causes pain, weakness and wasting of the thigh muscles, or cranial nerve infarcts that may result in double vision, a drooping eyelid, or dizziness. Diabetes can also affect the autonomic nerves that control blood pressure, the digestive tract, bladder function, and sexual organs. Problems with the autonomic nerves may cause lightheadedness, indigestion, diarrhea or constipation, difficulty with bladder control, and impotence.
DIABETIC NEUROPATHY CAUSES
DAMAGE TO NERVES AND BLOOD VESSELS
Prolonged exposure to high blood sugar can damage delicate nerve fibers, causing diabetic neuropathy. Why this happens isn’t completely clear, but a combination of factors likely plays a role, including the complex interaction between nerves and blood vessels.
High blood sugar interferes with the ability of the nerves to transmit signals. It also weakens the walls of the small blood vessels (capillaries) that supply the nerves with oxygen and nutrients.
Other factors that may contribute to diabetic neuropathy include:
- Inflammation in the nerves caused by an autoimmune response. This occurs when your immune system mistakenly attacks part of your body as if it were a foreign organism.
- Genetic factors unrelated to diabetes that make some people more susceptible to nerve damage.
- Smoking and alcohol abuse, which damage both nerves and blood vessels and significantly increase the risk of infections.
DIABETIC NEUROPATHY PATHOPHYSIOLOGY
Recent studies in patients with impaired glucose tolerance provide important insights into the role of the degree of glucose dysmetabolism in the development of neuropathy. The deleterious effect of hyperglycemia is confirmed by the occurrence of neuropathy associated with impaired glucose tolerance. In this setting, the neuropathy is milder than it is in newly diagnosed diabetes, and small-nerve-fiber involvement is the earliest detectable sign of the neuropathy.
Accumulation of polyols, which is observed in animal model of diabetes, also occurs in humans, but whether the accumulation of polyols in nerves leads to neuropathy is not established, and most aldose-reductase inhibitors tested to treat diabetic polyneuropathy have failed to produce any clinical improvement. In 2006, a study in an adolescent diabetic cohort showed that AKR1B1 polymorphisms might influence the decline of nerve function.
DIABETIC NEUROPATHY SYMPTOMS
- Blacking out when you stand up quickly
- Faster heartbeat
- Low blood pressure
- Feeling full sooner than normal
DIABETIC NEUROPATHY DIAGNOSIS
Diabetic neuropathy is usually diagnosed based on your symptoms, your medical history and a physical exam. During the exam, your doctor is likely to check your muscle strength and tone, tendon reflexes, and sensitivity to touch, temperature and vibration.
Your doctor may also conduct tests that include:
- Filament test. Sensitivity to touch may be tested using a soft nylon fiber called a monofilament.
- Nerve conduction studies. This test measures how quickly the nerves in your arms and legs conduct electrical signals. It’s often used to diagnose carpal tunnel syndrome.
- Electromyography (EMG). Often performed along with nerve conduction studies, electromyography measures the electrical discharges produced in your muscles.
- Quantitative sensory testing. This noninvasive test is used to assess how your nerves respond to vibration and changes in temperature.
- Autonomic testing. If you have symptoms of autonomic neuropathy, your doctor may request special tests to look at your blood pressure in different positions and assess your ability to sweat.
DIABETIC NEUROPATHY TREATMENT
The goal of treating diabetic neuropathy is to prevent further tissue damage and relieve discomfort. The first step is to bring blood sugar levels under control by diet and medication. Another important part of treatment involves taking special care of the feet by wearing proper fitting shoes and routinely checking the feet for cuts and infections. Analgesics, low doses of antidepressants, and some anticonvulsant medications may be prescribed for relief of pain, burning, or tingling. Some individuals find that walking regularly, taking warm baths, or using elastic stockings may help relieve leg pain.