The symptoms of neuropathy also depend on which nerves and what part of the body is affected. Neuropathy may be diffuse, affecting many parts of the body, or focal, affecting a single, specific nerve and part of the body.
The two categories of diffuse neuropathy are peripheral neuropathy affecting the feet and hands and autonomic neuropathy affecting the internal organs.
The most common type of peripheral neuropathy damages the nerves of the limbs, especially the feet. Nerves on both sides of the body are affected. Common symptoms of this kind of neuropathy are:
Numbness or insensitivity to pain or temperature
Tingling, burning, or prickling
Sharp pains or cramps
Extreme sensitivity to touch, even light touch
Loss of balance and coordination.
These symptoms are often worse at night.
The damage to nerves often results in loss of reflexes and muscle weakness. The foot often becomes wider and shorter, the gait changes, and foot ulcers appear as pressure is put on parts of the foot that are less protected. Because of the loss of sensation, injuries may go unnoticed and often become infected. If ulcers or foot injuries are not treated in time, the infection may involve the bone and require amputation. However, problems caused by minor injuries can usually be controlled if they are caught in time. Avoiding foot injury by wearing well-fitted shoes and examining the feet daily can help prevent amputations.
Autonomic Neuropathy (also called visceral neuropathy)
Autonomic neuropathy is another form of diffuse neuropathy. It affects the nerves that serve the heart and internal organs and produces changes in many processes and systems.
Urination & Sexual Response
Autonomic neuropathy most often affects the organs that control urination and sexual function. Nerve damage can prevent the bladder from emptying completely, so bacteria grow more easily in the urinary tract (bladder and kidneys). When the nerves of the bladder are damaged, a person may have difficulty knowing when the bladder is full or controlling it, resulting in urinary incontinence.
The nerve damage and circulatory problems of diabetes can also lead to a gradual loss of sexual response in both men and women, although sex drive is unchanged. A man may be unable to have erections or may reach sexual climax without ejaculating normally.
Autonomic neuropathy can affect digestion. Nerve damage can cause the stomach to empty too slowly, a disorder called gastric stasis. When the condition is severe (gastroparesis), a person can have persistent nausea and vomiting, bloating, and loss of appetite. Blood glucose levels tend to fluctuate greatly with this condition.
If nerves in the esophagus are involved, swallowing may be difficult. Nerve damage to the bowels can cause constipation or frequent diarrhea, especially at night. Problems with the digestive system often lead to weight loss.
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:
Pain in the front of a thigh
Severe pain in the lower back or pelvis
Pain in the chest, stomach, or flank
Chest or abdominal pain sometimes mistaken for angina, heart attack, or appendicitis
Aching behind an eye
Inability to focus the eye
Paralysis on one side of the face (Bell's palsy)
Problems with hearing.
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.
Diabetic Neuropathy Can Affect Virtually Every Part Of The Body
Diffuse (Peripheral) Neuropathy
Diffuse (Autonomic) Neuropathy
- Digestive System
- Sexual organs
- Urinary tract
- Sweat glands
Information provided by the National Diabetes Information Clearinghouse's fact sheet titled, "Diabetic Neuropathy: The Nerve Damage of Diabetes," publication number 97-3185, July 1995. Prepared for Healthtouch, March 1997.
- Facial muscles
- Pelvis and lower back