Nerve ultrasound in a case of multifocal motor neuropathy without conduction block

Multifocal nerve enlargements and ultrastructural changes either corresponding or not to sites of existing conduction blocks have been described in demyelinating polyneuropathies using multiple imaging techniques.

Using the emerging technique of peripheral nerve ultrasonography we investigated the peripheral nerves of a patient with multifocal motor neuropathy (MMN) without conduction block.

In this case of MMN without conduction blocks we found multifocal nerve enlargements in the ultrasonography and electrodiagnostic signs of acute and chronic denervation associated with positive anti-GM1 IgM antibodies.

This case shows that nerve ultrasound can be a complementary tool for diagnosing multifocal motor neuropathy without typical electrodiagnostic features.