Rationale for the clinical guidelines for myasthenia gravis in Japan.

According to the 2014 Japanese clinical guidelines for myasthenia gravis, the most important priority in treatment is maintaining patients' health-related quality of life. Therefore, the initial treatment goal is defined as maintaining a postintervention status of minimal manifestations or better (according to the Myasthenia Gravis Foundation of America classification) with an oral prednisolone dose of 5 mg/day or less. Every effort should be made to attain this level as rapidly as possible. To achieve this goal, the guidelines recommend minimizing the oral prednisolone dose, starting calcineurin inhibitors early in the course of treatment, using intravenous methylprednisolone infusion judiciously (often combined with plasma exchange/plasmapheresis or intravenous immunoglobulin), and effectively treating patients with an early, fast-acting treatment strategy. The early, fast-acting treatment strategy enables more frequent and earlier attainment of the initial goal than other strategies. Thymectomy is considered an option for treating nonthymomatous early-onset myasthenia gravis in patients with antiacetylcholine receptor antibodies and thymic hyperplasia in the early stages of the disease.