Neurológia pre prax 1/2016

Multifocal motor neuropathy

Multifocal motor neuropathy (MMN) is an acquired immune-mediated neuropathy characterized by chronic or stepwise progressive asymmetrical limb weakness without sensory deficits. The upper extremities are more often affected than the lower extremities with distal paresis dominating over proximal paresis. MMN is typically characterized by conduction block most likely caused by focal demyelination. Novel morphological and electrophysiological findings highlight the importance of axonal degeneration and impaired axon-myelin interactions. This paper aims at providing a concise overview on clinical picture, diagnosis and treatment of MMN. Cardinal, supportive and exclusion criteria (clinical, electrophysiological, laboratory) for diagnosis of MMN are reviewed. Nowadays, intravenous immunoglobulin (IVIg) is regarded as first-line therapy. The clinical effect of IVIg is usually impressive within first weeks of treatment, although chronic paresis and muscle atrophy do not recover after IVIg application in most cases. The duration of disease proportionately increases the extent of irreversible myelin and axonal dysfunction, therefore early diagnosis and early IVIg treatment is of crucial importance for the prognosis of MMN.

Keywords: multifocal motor neuropathy, diagnostic criteria, intravenous immunoglobulin, prognosis