Plasma exchange and immunosuppressive drug treatment in the Lambert‐Eaton myasthenic syndrome

Abstract

We undertook serial clinical and electromyographic muscle action potential (MAP) amplitude assessments in nine patients with the Lambert-Eaton myasthenic syndrome (LEMS) over 0.5 to 2.5 years who received plasma exchange (PE; 5 to 15 exchanges over 4 to 19 days) and immunosuppressive drug (IS) treatment (prednisolone 60 to 100 mg on alternate days, azathioprine 2.5 mg/kg for 0.5 to 2.5 years), and who had no signs of carcinoma at entry. Eight patients responded to PE. The peak MAP response occurred 10 to 15 days post-PE, representing a 2.5-fold mean increase and was significant < 0.01). Two of three patients who developed carcinoma responded initially to IS. Three of six noncarcinoma patients developed sustained clinical and MAP remission after 0.5 to 1 year; the three others, of whom two were intolerant of azathioprine, improved. IS and PE may benefit LEMS patients, but caution is required when carcinoma risk is high.