DEAR DR. DONOHUE: I have painful legs and feet. It began with a dull ache that came and went. Now pain is there all the time. I thought it might be my circulation, but my doctor said I had good circulation. He’s not sure what I have. He has me on Tylenol. I am 77. Will you contribute your ideas to this? – C.R.

ANSWER: I am guessing it’s peripheral neuropathy, a disorder that afflicts millions and often comes on at older ages. Peripheral nerves transmit messages to muscles and organs from the brain and take back to the brain information in the form of sensations like pain. Peripheral nerves are like the wiring system of a house. Without them, nothing works. When they go bad, everything acts up.

Sensory nerves are involved in supplying the brain with sensations. Disruption of those nerves causes pain. Motor nerves are involved with messages from the brain to muscles, instructing them to move. Disruption of those nerves leads to loss of muscle strength and muscle wasting. Foot drop is a consequence of motor-nerve neuropathy. The nerves to the muscles that control raising the foot have gone bad, and a person cannot lift the foot off the ground. A third kind of nerve, autonomic nerves, controls functions about which we give no thought. They, too, can be affected.

Causes of neuropathy are many. Diabetes is a major cause. Genetic illnesses bring on some neuropathies. Aging is another big cause. For a large number, a definite cause isn’t found. Medicines that can lessen the pain include amitriptyline, Cymbalta, Neurontin and Lyrica. Braces and a number of other devices come to the aid of those with motor peripheral neuropathy. Ask your doctor if he thinks you might have neuropathy, and if you might benefit from a neurologist’s examination. This week has been proclaimed National Neuropathy Week. The Neuropathy Association can be contacted at 800-247-6968 or at www.neuropathy.org.