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Multiple Mononeuropathy

by Michael Rubin, MDCM

Multiple mononeuropathy (mononeuritis multiplex) is the simultaneous malfunction of two or more peripheral nerves in separate areas of the body. It causes abnormal sensations and weakness.

Multiple mononeuropathy typically affects only a few nerves, often in different areas of the body. In contrast, polyneuropathy affects many nerves, usually in about the same areas on both sides of the body (see Polyneuropathy). However, if multiple mononeuropathy involves many nerves, it may be difficult to distinguish from polyneuropathy.

Several disorders can cause multiple mononeuropathy, and each disorder produces characteristic symptoms. The most common cause is probably

  • Diabetes, although diabetes more commonly causes polyneuropathy (see Diabetes Mellitus)

Other common causes of multiple mononeuropathy include

  • Vasculitis (inflammation of blood vessels, as occurs in polyarteritis nodosa)

  • Systemic lupus erythematosus (lupus)

  • Sjögren syndrome

  • Rheumatoid arthritis

  • Sarcoidosis

  • Amyloidosis

  • Infections (such as Lyme disease and HIV infection)

  • Direct invasion of the nerve by bacteria, as occurs in leprosy

A disorder may affect the nerves all at once or affect them progressively, a few at a time.

People have pain, weakness, abnormal sensations, or a combination of these symptoms in the areas supplied by the affected nerves. Symptoms often begin on one side of the body. When diabetes is the cause, nerves anywhere in the body can be affected, and as a result, weakness may affect any muscle.

Doctors base the diagnosis on symptoms and results of a physical examination, but electromyography and nerve conduction tests (see Tests for Brain, Spinal Cord, and Nerve Disorders : Electromyography and Nerve Conduction Studies) are usually done to confirm the diagnosis.

Treatment depends on the cause.