Acute promyelocytic leukemia (APL) is a distinct subtype of acute myelogenous leukemia (AML) that is considered to be a medical emergency because it is associated with disseminated intravascular coagulation (DIC), hyperfibrinolysis and bleeding. The abnormal promyelocytic leukemia/retinoic acid receptor alpha (PML-RARa) fusion gene produces an abnormal retinoic acid alpha receptor that interferes with promyelocyte differentiation and increases expression of tissue factor. The latter induces a consumptive coagulopathy in many patients. There is also increased expression of proteins that promote fibrinolysis such as annexin II, tissue plasminogen activator (tPA) and urokinase plasminogen activator (u-PA).

Because of the increased risk of hemorrhage, the National Comprehensive Cancer Network (NCCN) and the European Leukemia Net (ELN) have recommended higher transfusion thresholds for patients with APL than for other types of AML. Prophylactic platelet transfusions are recommended when the platelet count falls below 50,000/uL in APL compared to 10,000/uL in other types of AML. Cryoprecipitate is recommended when the fibrinogen falls below 150 mg/dL in APL compared to below 100 mg/dL in other types of AML.

Coagulation parameters should be monitored every six hours. Invasive procedures, such as central venous catheters and lumbar puncture, should be avoided until induction chemotherapy is completed. Leukapheresis for elevated white blood counts is not recommended for APL, because it may exacerbate DIC.

Nicole Draper, Special Blood Product Requirements of Acute Promyelocytic Leukemia, Oncology Times, April 10, 2016, pages 5-6.


Ads

Login Form

Follow Us On Social

Follow clinlabnav on Twitter

Amazon Books

Sponsors