Correlation of sonographic and electrophysiological findings in a patient with multifocal motor neuropathy

Multifocal motor neuropathy (MMN) is an acquired, immune mediated, and commonly associated with antiganglioside antibodies against GM1 lower motor neuropathy, with an incidence of 1 per 100,000. The usual age of onset is between 20 and 50 years and men appear to be more often affected than women. Patients usually present with multifocal weakness that can be localized to named nerve distributions.

The gold standard for the diagnosis is the electrophysiological detection of focal, partial conduction block of motor fibers without involvement of sensory fibers, at sites that are uncommon areas of compression. The diagnostic sonography of the peripheral nervous system is a rapidly evolving and constantly expanding imaging field in the last years, especially in patients presenting with signs of polyneuropathy.

We report for the first time a correlation of the sonographic and electrophysiological findings in a patient with MMN.

We draw the attention on the usefulness of ultrasonography for detecting and diagnosing segmental lesions of the peripheral nerves in MMN and other immune mediated neuropathies, especially in cases where a nervous segment cannot be easily explored in terms of inching technique.