Peripheral nerves carry messages from the brain and spinal cord to muscles, organs, and other body tissues. Damage or disease of these nerves is called peripheral neuropathy. Sometimes one nerve or a group of related nerves is involved in neuropathy; in polyneuropathy, multiple nerves are affected in different areas of the body. Because nerves are made up of several different types of nerve fibers affecting sensation, movement, pain transmission, or balance, symptoms and signs are based on the involved type of nerve fiber. The April 21, 2010, issue of JAMA includes an article about diabetic neuropathy. This Patient Page is based on one previously published in the March 5, 2008, issue of JAMA.