急性白血病常合併肺部併發症，例如;咳血、肺部感染及肺出血等，都俱有潛在致命的危險。雖然肺部併發症在急性白血病病人身上常見，但若為初期症候，則會造成臨床診療上的困難。我們在此報告一位急性淋巴性白血病(ALL)的病人，在血球母細胞(blastcell)比例不高的情況下，以發燒、咳血及肺浸潤作為初期表現， 病人在接受化學治療後，病情及肺部浸潤迅速獲得改善。急診醫師必需了解這種白血病性的肺部浸潤可能是急性白血病初期的表徵，因為即時的給予類固醇及化學治療，可能避免掉進一步呼吸支持的需要性。

Acute leukemia associated pulmonary complications， such as hemoptysis， infection and pulmonary hemorrhage， are all potentially life-threatening. Although pulmonary complications in patients with acute leukemia are common， they pose a diagnostic and therapeutic dilemma when they occur as the initial presentation. We present a 32 year-old man with acute lymphoblasitic leukemia (ALL) who had fever， pulmonary infiltration， hemoptysis， pending respiratory failure， and a low blast cell count at presentation. The patient was treated with chemotherapy and resulted in rapid resolution of the chest pulmonary infiltration，as well desaturation. Emergency physicians should be alert to leukemic pulmonary infiltrates as a first manifestation of ALL， since early initiation of steroids and chemotherapy may obviate the need for advanced airway management and mechanical ventilation.