ISAACS SYNDROME-ASSOCIATED WITH CHRONIC INFLAMMATORY DEMYELINATING POLYNEUROPATHY

We report the first case of Isaacs' syndrome in which an inflammatory demyelinating neuropathy was documented histologically. For 9 months, the patient developed slowly progressive weakness, muscle spasms and s tiffness, fasciculations, and myokymia in the arms, which were unmodif ied by sleep. Nerve conduction studies showed multifocal motor conduct ion block, abnormal dispersion phenomenon, and abnormal sensory and mi xed nerve conduction. Needle electromyogram showed continuous motor un it potentials at rest with bursts of rapid-firing discharges which wer e unaffected by spinal anesthesia but diminished by peripheral nerve b lock and completely abolished by local curarization. Sural nerve biops y demonstrated an inflammatory demyelinating neuropathy. Muscle crampi ng, twitching, and stiffness responded to phenytoin. The patient's wea kness gradually responded to prednisone and azathioprine. Over a 17-ye ar period, the patient had three relapses which were well controlled w ith prednisone and azathioprine. At this time, the patient is symptom- free without any medication. (C) 1996 John Wiley & Sons, Inc.