Disease severity and response to treatment in Iranian patients with myasthenia gravis.

PURPOSE: Myasthenia gravis (MG) is a potentially fatal neuromuscular disorder if left untreated. In this study, we tried to address the possible demographic, clinical, and laboratory determinants of severity and outcome in Iranian MG patients over a follow-up period of more than 5 years. METHODS: Demographic and diagnostic data (age, age of onset, antibody status, thymus pathology, and duration of the disease) of the patients with MG were extracted. Maximal disease severity and post-intervention status were assessed according to the recommendations of the task force of the Myasthenia Gravis Foundation of America. RESULTS: In our series of 146 patients, MG was more severe in older, anti-muscle specific tyrosine kinase (MuSK) positive, and thymomatous patients. Seropositivity to the MuSK antibody and the presence of thymoma determined the need for immunosuppressive drugs. However, the number of patients requiring more than one immunosuppressive was not significantly different among various subtypes. CONCLUSIONS: The overall outcome was favorable in the majority of patients, despite differences in the disease course and severity. In contrary to the previous reports, anti-MuSK positive patients in our series did not need a more vigorous treatment regimen comparing other serologic subtypes of MG.