A case of Lewis-Sumner syndrome showing dramatic improvement after plasma exchange.

We report a patient with Lewis-Sumner syndrome (LSS) who showed an improvement only with plasma exchange (PE). The patient, 32-yr old man, had progressive multifocal motor-sensory deficits with persistent, multiple conduction blocks and marked slowing of NCVs. Nerve pathology supported a diagnosis of demyelinating neuropathy by revealing marked loss of myelinated fibers with inter- and intrafascicular variation. Although the patient was refractory to treatment with corticosteroid and intravenous immunoglobulin, PE produced a dramatic improvement. Our experience strongly proposes that PE should be tried for refractory LSS.