What is multifocal motor neuropathy (MMN) with conduction block?

Updated: Nov 12, 2018
  • Author: Sasa Zivkovic, MD, PhD; Chief Editor: Nicholas Lorenzo, MD, MHCM, CPE, FAAPL  more...
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Multifocal motor neuropathy (MMN) with conduction block is an acquired immune-mediated demyelinating neuropathy with slowly progressive weakness, fasciculations, and cramping, without significant sensory involvement.

Clinically, it may resemble amyotrophic lateral sclerosis (ALS) with predominant lower motor neuron involvement, but muscle atrophy and more rapid progression are lacking. Duration of disease prior to diagnosis ranges from several months to more than 15 years.

Unlike ALS, MMN usually responds to treatment with intravenous immunoglobulin (IVIG), subcutaneous immunoglobulins (SCIG) or cyclophosphamide, even after many years of duration. [1, 2, 3]

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