A case of monofocal motor neuropathy with GM1 and GD1b antibodies improved with intravenous immunoglobulin

Multifocal motor neuropathy is a purely motor neuropathy with a probably dysimmune pathogenesis, supported by the presence of anti-GM1 IgM antibodies in about half of the cases. Single nerve involvement allows for diagnosis of possible multifocal motor neuropathy. We present the case of a middle age man presenting with progressive weakness and hypotrophy in the left leg and difficulty in walking, in which we have diagnosed a dysimmune mononeuropathy. Treatment with IVIg was performed with substantial improvement. Although only one nerve is involved, early diagnosis of dysimmune mononeuropathy is important to start IVIg treatment that is often decisive.