Multifocal acquired demyelinating sensory and motor neuropathy: The Lewis-Sumner syndrome

We report 11 patients with multifocal acquired demyelinating sensory and mo tor (MADSAM) neuropathy, defined clinically by a multifocal pattern of moto r and sensory loss, with nerve conduction studies showing conduction block and other features of demyelination. The clinical, laboratory, and histolog ical features of these patients were contrasted with those of 16 patients w ith multifocal motor neuropathy (MMN), Eighty-two percent of MADSAM neuropa thy patients had elevated protein concentrations in the cerebrospinal fluid , compared with 9% of the MMN patients (P < 0.001). No MADSAM neuropathy pa tient had elevated anti-GM, antibody titers, compared with 56% of MMN patie nts (P < 0.01). In contrast to the subtle abnormalities described for MMN, MADSAM neuropathy patients had prominent demyelination on sensory nerve bio psies. Response to intravenous immunoglobulin treatment was similar in both groups (P = 1.0), Multifocal motor neuropathy patients typically do not re spond to prednisone, but 3 of 6 MADSAM neuropathy patients improved with pr ednisone, MADSAM neuropathy more closely resembles chronic inflammatory dem yelinating polyneuropathy and probably represents an asymmetrical variant. Given their different clinical patterns and responses to treatment, it is i mportant to distinguish between MADSAM neuropathy and MMN. (C) 1999 John Wi ley & Sons, Inc.