[A case of acute exacerbation of chronic pulmonary thromboembolism with essential thrombocythemia during treatment for hemoptysis].

An 89-year-old woman with essential thrombocythemia and chronic respiratory failure was admitted for treatment of hemoptysis. She stopped taking aspirin and was given tranexamic acid. Though her hemoptysis improved, respiratory failure suddenly worsened. As a result of various examinations and laboratory findings, acute exacerbation of chronic pulmonary thromboembolism was diagnosed. Though there was the risk of recurrence of hemoptysis, she started taking aspirin again. Her respiratory failure improved but hemoptysis did not reappear. Thrombosis and hemorrhage are common complications of essential thrombocythemia, however, pulmonary thromboembolism is a rare complication. There is a possibility that the exacerbation of this case was caused by tranexamic acid as well as rest and cessation of aspirin. If a patient with essential thrombocythemia bleeds, we should be careful when using tranexamic acid.