Dad's diabetes causes painful peripheral neuropathy in feet


Dear Doctor: My dad is 65 years old and has Type 2 diabetes. He recently developed pain in his feet, which his doctor says is peripheral neuropathy. What is that, and what treatments are available?

Dear Reader: Neuropathy is a condition in which the nervous system malfunctions due to either disease or some kind of damage. The addition of the word "peripheral" means the problem lies in the vast and complex network of nerves that serves the body.

The peripheral nervous system collects and sends vital sensory information to the central nervous system, which is made up of the brain and the spinal cord. When you drop that hot frying pan handle, break into a sweat on a hot day or keep your balance with your eyes closed, that's all thanks to information your peripheral nervous system has sent to your brain.

It's estimated that 20 million people in the United States experience some kind of peripheral neuropathy. Sometimes the damage is limited to a single nerve, but most often the condition affects groups of nerves. Symptoms include numbness, twitching, throbbing or tingling, burning sensations, problems with balance, or skin sensitivity so acute that ordinary stimuli, like the touch of a shirt on bare skin, are interpreted as pain.

When the motor nerves are affected, peripheral neuropathy causes muscle weakness and can often lead to the loss of muscle mass. If the nerves that serve the organs or glands are involved, it can result in impaired digestion, perspiration, urination or sexual function. At its most extreme, peripheral neuropathy causes breathing difficulties, or leads to organ failure. Fortunately, this is rare.

Diabetes is the most common cause of peripheral neuropathy. Other factors include infections such as shingles or the Epstein-Barr virus, certain kidney disorders, vitamin deficiencies, physical damage, cancers that press on or infiltrate nerve fibers, or autoimmune diseases that cause the body to attack its own tissues. Exposure to toxic industrial and environmental substances such as lead, arsenic or pesticides as well as medical agents like chemotherapy drugs can also lead to the condition. So can heavy alcohol consumption.

Elizabeth Ko, MD and Eve Glazier, MD

Your father's symptoms began in his feet, which is common among people with diabetes. He may also experience numbness, a decrease in foot and ankle reflexes, trouble with balance and coordination, and an increase in foot problems like ulcers and infections. This is due to tissue damage resulting from chronic high blood glucose levels, as well as decreased circulation, which occurs because diabetes causes the blood vessels in the foot and leg to become stiff and grow narrow.

Treatment for your father's condition will focus on two things -- carefully controlling his diabetes to prevent further nerve damage, and giving him relief from the existing pain. Mild pain often responds to over-the-counter NSAIDs. Medications like antidepressants, anticonvulsants and narcotics are used for chronic pain. Procedures like electrical nerve stimulation have shown promise. Physical therapy and specialized footwear can also help.

Pain treatment is often most effective when there's an ongoing dialogue. Be sure your dad shares all his symptoms with his doctor, and follows up with regular progress reports.

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