A Female Patient with Anti-Muscle-Specific Kinase Antibody Positive Generalized Myasthenia Gravis Responded to Salbutamol but not Pyridostigmine: A Case Report

Anti-muscle-specific kinase (MuSK) antibody positive generalized myasthenia gravis (MuSK-MG) is an autoimmune disease, in which deterioration of myasthenic symptoms may occur by cholinesterase inhibitor (ChE-I) treatment. Salbutamol, a sympathetic β2 receptor agonist, was an effective therapeutic drug in congenital myasthenic syndrome patients with MuSK gene abnormalities and in MuSK-MG animal model. Salbutamol was attempted to treat a female MuSK-MG patient who did not respond to ChE-I. Any acute benefit of salbutamol was not observed but her myasthenic symptoms gradually improved over a year without adversive effects. Salbutamol may be a therapeutic drug to alleviate myasthenic symptoms in MuSK-MG patients.