Hemorrhagic Complications in Pediatric Hematologic Malignancies

Abstract

Hematologic malignancies account for almost 40% of all cancers in children. Hemorrhage is the most common cause of early death in children with leukemia. Furthermore, major bleeding episodes lead to shorter survival and increased resource use. Potential risk factors for bleeding include hyperleukocytosis, immunophenotype of leukemia (especially acute promyelocytic leukemia), thrombocytopenia, and associated infections. Successful management of a bleeding episode is dependent on prompt identification of a child at high risk for bleeding, and should be directed at the replacement of blood products as well as to the aggressive therapy for underlying risk factors. Although in recent years there is a favorable decline in the hemorrhage-related mortality, the overall prevalence and the extent of morbidity posed by this potentially fatal complication, including disease outcome in children with hematologic malignancy, is largely unknown. In addition, there are no evidence-based guidelines for prophylactic blood or blood product transfusions. Prospective studies are required to define the epidemiology and risk factors predisposing children with hematologic malignancy to bleeding and to develop management guidelines.

Bleeding Complications in Patients with Hematologic Malignancies

“…This is mainly due to the retrospective nature of most studies, to differences in the definition of thrombocytopenia, and to the frequent presence of other contributing factors such as hyperleukocytosis, infection, and other coagulopathies. 9 Nevertheless, according to most studies, it is unlikely to observe a spontaneous bleeding at a platelet count of more than 20 Â 10 9 /L and a fatal cerebral hemorrhage at a platelet count of 5 Â 10 9 /L or more in a patient with an otherwise uncomplicated course of the hematologic illness. 10 Although the mainstay of treatment of thrombocytopeniaassociated acute bleeding in patients with hematologic malignancies is platelet transfusion, the limited availability of platelet concentrates from both pooled random and single donors and the development of patients' alloimmunization with consequent platelet refractoriness strongly suggest conservative therapeutic measures.…”

The Significance of Endothelial Heterogeneity in Thrombosis and Hemostasis

“…Hemorrhagic complications is a major cause of death in childhood ALL. 127,128 As in the case of APL, two thirds of the bleeding events in ALL were also ICH.…”

Breathing difficulties in children with cancer

“…17 It is observed in 9---13% of all patients with ALL, and is also common in the chronic phase of myeloid leukemia 2 (in leukemias of this kind, characterized by an increased blast cell depositing and aggregation tendency, the risk of bleeding complications is much higher 18 ). 19 Dyspnea and hypoxemia appear as a result of the alterations in gas exchange caused by the vascular damage. 19 If this occurs within the lung tissues, microcirculatory damage results, with the formation of leukocyte aggregates and bleeding secondary to endovascular damage.…”

“…As a result of the increased cell presence in the bloodstream, blood viscosity is seen to increase----this in turn facilitating leukostasis in zones with small-diameter capillaries. 19 The diagnosis of hyperleukocytosis is confirmed from the complete blood count, though initial suspicion is based on the clinical picture. 19 Dyspnea and hypoxemia appear as a result of the alterations in gas exchange caused by the vascular damage.…”