Multifocal motor neuropathy is a progressive muscle disorder. It is characterized by muscle weakness in the hands, with differences from one side of the body to the other in the specific muscles involved.

Multifocal motor neuropathy is a very rare condition, affecting only about 1 per 100,000 people in the population. Multifocal motor neuropathy affects men about three times more than women. Most patients are between the ages of 30 and 50 when symptoms are noted, with the average age of onset being 40 years.

Multifocal motor neuropathy is thought to result from an autoimmune disorder.

Besides muscle weakness in the hands, symptoms also include:

• Muscle wasting
• Cramping
• Involuntary contractions or twitching of the leg muscles

The disorder is sometimes mistaken for amyotrophic laterial sclerosis (ALS, or Lou Gehrig’s disease) but unlike ALS, it is treatable. An early and accurate diagnosis allows patients to recover quickly.

Treatment for multifocal motor neuropathy varies. Some individuals experience only mild, modest symptoms and require no treatment. For others, treatment generally consists of intravenous immunoglobulin (IVIg) or immunosuppressive therapy with cyclophosphamide.

Improvement in muscle strength usually begins within 3 to 6 weeks after treatment is started. Most patients who receive treatment early experience little, if any, disability. However, there is evidence of slow progression over many years.