Pulmonary thromboembolism in childhood leukemia: 8-years' experience in a pediatric hematology center.

Abstract

PURPOSE To assess the occurrence and possible causes of pulmonary thromboembolism (PTE) in children with hematologic malignancies evaluated in a single pediatric hematology center. PATIENTS AND METHODS Four hundred fifty-two patients admitted for leukemia in different stages of disease were evaluated whenever they presented with PTE-related acute respiratory failure (ARF). Diagnosis was based on a perfusional lung scan and a digital pulmonary angiography in most cases. When necessary, patients with ARF were transferred to the pediatric intensive care unit (ICU) for cardiorespiratory monitoring and support. Thrombolytic treatment was usually performed with urokinase at a loading dose of 2,000 to 4,560 IU/kg as single bolus followed by 2,000 to 4,530 IU/kg/h for 12 to 42 hours. Before thrombolytic therapy was discontinued, heparin was started at a daily dose of 100 to 500 IU/kg as a continuous infusion and continued for 6 to 26 days. RESULTS Twelve of 452 children developed 17 PTE episodes, which were resolved completely after appropriate therapy in 15 cases. Univariate analysis showed a statistical correlation between PTE and the diagnosis of acute myeloid leukemia (AML) (P < .001). No major bleeding was observed after thrombolytic treatment. CONCLUSION Our findings indicate that PTE is not an extremely rare event in children with leukemia and should be ruled out when sudden tachypnea develops in patients with risk factors such as previous tumor lysis, central venous catheter (CVC) malfunction, coagulation abnormalities, and drug-induced pulmonary toxicity. Complete resolution of PTE may be obtained in a high proportion of cases with early diagnosis and proper treatment.