Multifocal motor neuropathy (MMN) is a treatable autoimmune polyneuropathy, which may prove challenging diagnostically in the setting of absent conduction blocks or advanced axonal loss. Relatively few studies have examined the role of ultrasound (US) in MMN.
Retrospective, cross-sectional study of patients with MMN who underwent peripheral nerve US. Charts were reviewed to extract clinical, sonographic, and electrophysiological data.
Eleven patients with MMN underwent US between 2013 and 2015; of these 11 patients, 7 had ≥3 abnormal nerve segments, and 6 had ≥5 sites of increased cross-sectional area (CSA). There was moderate correlation between the degree of amplitude drop observed in the median and ulnar motor nerves, and CSA. Significant correlation between CSA and limb strength was only observed for the median nerve.
Peripheral nerve US shows promise as a diagnostic tool in MMN and may be helpful to distinguish MMN from motor neuron disease.
*Department of Medicine (Neurology), The Ottawa Hospital, The Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON, Canada;
†Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada;
‡Ellen & Martin Prosserman Centre for Neuromuscular Disorders, Toronto General Hospital, Toronto, ON, Canada; and
§Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada.
Reprints: Ari Breiner, MD, MSc, FRCPC, The Ottawa Hospital, Civic Campus, 1053 Carling Avenue, Room ES-08, Ottawa, ON KY 4E9, Canada (e-mail: email@example.com).
The work was partially funded by CSL Behring.
The authors report no conflicts of interest.