The Nerve Damage of Diabetes
Autonomic neuropathy can affect the cardiovascular system, which controls the circulation of blood throughout the body. Damage to this system interferes with the nerve impulses from various parts of the body that signal the need for blood and regulate blood pressure and heart rate. As a result, blood pressure may drop sharply after sitting or standing, causing a person to feel dizzy or light-headed, or even to faint (orthostatic hypotension).
Neuropathy that affects the cardiovascular system may also affect the perception of pain from heart disease. People may not experience angina as a warning sign of heart disease or may suffer painless heart attacks. It may also raise the risk of a heart attack during general anesthesia.
Autonomic neuropathy can hinder the body's normal response to low blood sugar or hypoglycemia, which makes it difficult to recognize and treat an insulin reaction.
Autonomic neuropathy can affect the nerves that control sweating. Sometimes, nerve damage interferes with the activity of the sweat glands, making it difficult for the body to regulate its temperature. Other times, the result can be profuse sweating at night or while eating (gustatory sweating).
Focal Neuropathy (Including Multiplex Neuropathy)
Occasionally, diabetic neuropathy appears suddenly and affects specific nerves, most often in the torso, leg, or head. Focal neuropathy may cause:
This kind of neuropathy is unpredictable and occurs most often in older people who have mild diabetes. Although focal neuropathy can be painful, it tends to improve by itself after a period of weeks or months without causing long-term damage.
People with diabetes are also prone to developing compression neuropathies. The most common form of compression neuropathy is carpal tunnel syndrome. Asymptomatic carpal tunnel syndrome occurs in 20 to 30 percent of people with diabetes, and symptomatic carpal tunnel syndrome occurs in 6 to 11 percent. Numbness and tingling of the hand are the most common symptoms. Muscle weakness may also develop.