Leukostasis by hyperleukocytic childhood acute leukemia: pathophysiology, clinical presentation, and emergency care

Hyperleukocytosis (HL), defined by a peripheral white blood cell (WBC) count exceeding 100,000/mm³, is occasionally observed in childhood acute leukemia. The increased viscosity in the micro-circulation by HL and the interaction between the leukemic blasts and endometrium of blood vessels sometimes result in leukostasis. Leukostasis can incur life-threatening manifestations, such as respiratory distress, brain infarction and hemorrhage, and renal failure, needing an emergency care. Although early stage of leukostasis is difficult to detect due to nonspecific manifestations, an emergency care is mandatory because leukostasis can proceed to a fatal course. Initial management includes an aggressive fluid therapy that can reduce WBC count, and prevent other metabolic complications implicated by HL. Packed red blood cells should be judiciously transfused because it increases blood viscosity. Conversely, transfusion of platelet concentrates or fresh frozen plasma, which does not affect blood viscosity, is recommended for prevention of hemorrhage. To reduce tumor burden, leukapheresis or exchange transfusion is commonly performed. However, the efficacy is still controversial, and technical problems are present. Leukapheresis or exchange transfusion is recommended if WBC count is 200,000–300,000/mm³ or more, especially in acute myelocytic leukemia, or manifestations of leukostasis are present. In addition, early chemotherapy is the definite treatment of leukostasis.

Therapeutic Efficacy of a Single Dose of Anti-D Immunoglobulin 50 microgram/kg in Childhood Acute Immune Thrombocytopenic Purpura

BACKGROUND: To investigate the efficacy and adverse effects of a single dose of anti-D immunoglobulin (50 microgram/kg) in Korean children with acute immune thrombocytopenic purpura (ITP). METHODS: We serially evaluated the platelet count in 21 acute ITP patients that were treated with anti-D immunoglobulin (50 microgram/kg) to determine how many patients achieved platelet counts over the levels of 20 x 10(3)/mm3, 50 x 10(3)/mm3 and 100 x 10(3)/mm3 after the infusion of anti-D immunoglobulin. In addition, constitutional symptoms were monitored and changes in the hemoglobin levels were serially evaluated. RESULTS: By three days after treatment, 90.5% of the patients had achieved a platelet count over 20 x 10(3)/mm3. At seven days after treatment, 66.7% of patients achieved a platelet count of 50 x 10(3)/mm3. In addition, at seven days after treatment 61.9% of patients achieved a platelet count of 100 x 10(3)/mm3. Constitutional adverse symptoms were observed 61.9% of patients, and the symptoms diminished spontaneously without any severe sequelaes. The decline of hemoglobin concentration after treatment recovered to the initial level after two weeks. CONCLUSION: A single dose of anti-D immunoglobulin (50 microgram/kg)was effective in Korean children with acute ITP to raise the platelet count rapidly. The adverse effects of anti-D immunoglobulin, including hemolytic anemia, were not severe to prevent the use of the anti-D.