Therapy in myasthenia gravis and Lambert-Eaton myasthenic syndrome.

Myasthenia gravis (MG) is a heterogeneous disorder, a fact that needs to be kept in mind when considering treatment. Most patients benefit from pyridostigmine. In nonthymomatous ocular MG, prednisolone is often effective. Thymectomy is indicated for thymoma and is an option for acetylcholine receptor antibody-positive patients with generalized weakness developing under the age of 45 years. In older patients and in those failing to respond to thymectomy, prednisone alone or combined with azathioprine is the treatment of choice. Mycophenolate mofetil is an option in those intolerant of azathioprine. Lambert-Eaton myasthenic syndrome (LEMS) can exist in paraneoplastic (P-) and nonparaneoplastic (NP-) forms. Most patients benefit from 3,4-diaminopyridine. In P-LEMS, treatment of the tumor often results in neurological improvement. In both forms, prednisone alone is an option or combined with azathioprine in NP-LEMS. In both MG and LEMS, where weakness is severe, plasma exchange or intravenous immunoglobulin treatment may provide short-term benefit.