Introduction

In nerve disorders, the sense of touch (sensation) may be abnormal or lost. Or, weakness or paralysis may occur. Some nerve disorders cause pain or other unusual, often unpleasant sensations.

Billions of nerves connect the brain and spinal cord with the rest of the body. Some nerves, called sensory nerves, relay information to the brain from the rest of the body about what is happening inside and outside the body. Other nerves, called motor nerves, relay information to the rest of the body from the brain about how to respond to what is happening. Information is sent through nerves by electrical signals. When nerves are damaged, information is distorted or is not sent. Nerves may be damaged by pressure, injury, an inadequate blood supply, toxic substances, autoimmune disorders, or infections. Sometimes the cause is unknown.

Two terms commonly used to describe nerve disorders are neuralgia and neuropathy. Neuralgia refers to pain that does not necessarily involve damage to nerves. Neuropathy refers to nerve damage that does not necessarily cause pain. One or more nerves may be damaged. A neuropathy may cause pain, abnormal sensations, loss of sensation, weakness, or a combination of these symptoms. Less commonly, a neuropathy affects body functions, such as blood pressure or sweating. The line between neuralgia and neuropathy is sometimes blurred, so some doctors do not distinguish between them.

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