title: Multifocal motor neuropathy: diagnosis, pathogenesis and treatment strategies.
abstract: Multifocal motor neuropathy (MMN) is a rare inflammatory neuropathy characterized by slowly progressive, asymmetric distal limb weakness without sensory loss. The clinical presentation of MMN may mimic amyotrophic lateral sclerosis, other variants of motor neuron disease, or chronic inflammatory demyelinating polyneuropathy with asymmetric onset. Differentiation is important, as these diseases differ in prognosis and treatment. The electrophysiological finding of conduction block in the absence of abnormalities in sensory nerves is the hallmark of MMN, but can be difficult to detect. Intravenous immunoglobulin is efficacious in most patients, but long-term maintenance therapy does not prevent slowly progressive axonal degeneration. Moreover, cyclophosphamide, although effective, has substantial adverse effects, and the efficacy of other immunosuppressive drugs, including rituximab, is not established. The underlying pathological mechanisms of MMN are unclear, but IgM autoantibodies against the ganglioside GM1 may cause changes in nodal and perinodal structures that compromise nerve conduction. Further elucidation of the disease mechanisms may ultimately lead to improved treatment strategies. In this Review, we discuss the diagnostic criteria for MMN, and provide an update on the current understanding of MMN pathogenesis. We also describe available treatments and promising new therapeutic strategies.
authors: Rudolf Magnus Institute of Neuroscience, Department of Neurology, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, The Netherlands.
authors: Lotte
authors: L
authors: Vlam
authors: W-Ludo
authors: WL
authors: van der Pol
authors: Elisabeth A
authors: EA
authors: Cats
authors: Dirk C
authors: DC
authors: Straver
authors: Sanneke
authors: S
authors: Piepers
authors: Hessel
authors: H
authors: Franssen
authors: Leonard H
authors: LH
authors: van den Berg
mesh_terms: D006801:Humans; D016472:Motor Neuron Disease / Q000175:diagnosis* / Q000503:physiopathology* / Q000628:therapy; D011115:Polyneuropathies / Q000175:diagnosis* / Q000503:physiopathology* / Q000628:therapy