[Thrombotic thrombocytopenic purpura associated with myasthenia gravis]

A case of thrombotic thrombocytopenic purpura (TTP) associated with myasthenia gravis (MG) is reported. A 56-year-old woman was admitted to our hospital on April 27, 1988, because of easy fatigue and double vision. She was diagnosed as having myasthenia gravis from her neurological and laboratory findings. On the 14th hospital day, she developed fever, jaundice, hematuria, purpura and consciousness disturbance. Hematological examination revealed marked anemia, thrombocytopenia, fragmented red blood cells, elevated bilirubin and LDH level. Coagulation studies were almost normal. She was diagnosed as having TTP and treated with corticosteroid, antiplatelet agents and plasma exchange. Clinical condition and laboratory findings improved by the 23rd hospital day. It has been reported that TTP is associated with various autoimmune disease such as systemic lupus erythematosus, rheumatoid arthritis, Sjögren's syndrome or idiopathic thrombocytopenic purpura. However TTP associated with MG appears the first report. This case may suggest that one of pathogenesis of TTP is autoimmune mechanism.