A Patient with Intravenous Immunoglobulin-Responsive Lower Motor Neuron Syndrome

We report a 50-year-old woman who developed localized proximal muscle weakness, in addition to transient elevation of antibodies to GM1 ganglioside, without multifocal conduction block. She was treated with intravenous immunoglobulin (IVIg) and steroid pulse therapy, which were effective for over 10 years. Her clinical course and laboratory tests were consistent with lower motor neuron syndrome (LMNS) with localized proximal muscle weakness. We suggest that some patients diagnosed as LMNS may remain responsive to IVIg or steroid pulse therapy for a long time.