Successful treatment of refractory polymyositis with pulse intravenous cyclophosphamide and low-dose weekly oral methotrexate therapy.

A 36-year-old woman gradually developed dysphagia and muscle weakness of the lower extremities. Diagnosis of polymyositis was given from elevation of serum creatine kinase and pathological findings of a muscle biopsy. Despite oral prednisolone and intravenous pulse methylprednisolone therapy, her muscle weakness persisted, and then pulse intravenous cyclophosphamide (IVCY) therapy was initiated and repeated five times in total, which resulted in significant improvement in muscle strength. Thereafter, weekly administration of methotrexate at low dosage further normalized the serum creatine kinase level. We may conclude that IVCY and low-dose weekly methotrexate together could be an alternative in refractory polymyositis.