Chapter 12 Multifocal and other motor neuropathies

Abstract

Publisher Summary This chapter discusses the extensive literature on multifocal motor neuropathy (MMN) reported in recent times, much of which is also applicable to the pure motor form of chronic inflammatory demyelinating polyneuropathy (CIDP). Acquired motor neuropathies that mimic motor neuron diseases are MMN and, to a lesser extent, the pure motor form of CIDP. MMN is characterized by slowly progressive, asymmetric weakness initially without muscle atrophy of limbs that develops gradually or in a stepwise manner over several years. Men are more frequently affected than women. Conduction block on motor conduction studies is the electrophysiological hallmark of MMN. The hypothesis that MMN is an immune-mediated neuropathy has led to the trial of several immunological treatments. Several noncontrolled studies have shown a beneficial effect of intravenous immunoglobulin (IVIg) treatment. The effect of IVIg in MMN was confirmed in four double-blind placebo-controlled trials.