A Case of Refractory Generalized Myasthenia Gravis Treated with Polypharmacy and Plasma Exchange

A 62-year-old man with myasthenia gravis (MG) was admitted with dyspnea, bulbar symptoms (dysphagia and dysarthria), and subsequent muscular weakness of the limbs. Results for anti-acetylcholine receptor antibody and muscle-specific kinase antibody were negative. We introduced periodic plasma exchange as a new therapeutic strategy. Once double-filtration plasmapheresis (DFPP) was adopted, effects became notable, but the response shortened over time. After stepwise increases in PSL up to 60 mg/day with insulin, the interval between DFPP was prolonged from 1 week to 2 weeks. DFPP was significantly beneficial in this case. Combining several effective methods can optimize therapeutic effects against refractory MG.