Introduction: Knowledge of the chronic auto-immune acquired neuropathies has progressed rapidly since the recent description of the Lewis-Sumner syndrome and multifocal motor neuropathy. Some of the most interesting aspects of these conditions are the presence of persistent conduction blocks and the challenge of understanding the mechanisms involved. These blocks are difficult to identify.
Clinical case: We describe the case of a female patient with Lewis-Sumner syndrome, with persistent sensory and motor blocks. The electrophysiological characteristics and differential diagnosis of the two conditions are reviewed.