1 Alterations of Hematologic Function in Children Chapter 28

Mosby items and derived items © 2006 by Mosby, Inc. 2 Fetal and Neonatal Hematopoiesis  The embryo becomes too large for oxygenation by simple diffusion Erythropoiesis begins within the vessels of the yolk sac At 8 weeks’ gestation, erythrocyte production shifts to the liver sinusoids By the fifth month of gestation, erythrocyte production begins to occur in the bone marrow

Mosby items and derived items © 2006 by Mosby, Inc. 3 Hemolytic Disease of the Newborn

Mosby items and derived items © 2006 by Mosby, Inc. 4 Fetal and Neonatal Hematopoiesis  Fetal hemoglobin Two alpha chains; two gamma chains Embryonic hemoglobins  Gower 1, Gower 2, and Portland Fetal hemoglobin  Hgb F

Mosby items and derived items © 2006 by Mosby, Inc. 5 Fetal and Neonatal Hematopoiesis  Postnatal changes Erythrocytes Leukocytes Platelets

Mosby items and derived items © 2006 by Mosby, Inc. 6 Acquired Disorders of Erythrocytes  Iron deficiency anemia Most common blood disorder of infancy and childhood Lack of iron intake or blood loss Manifestations  Irritability, decreased activity tolerance, weakness, and lack of interest in play

Mosby items and derived items © 2006 by Mosby, Inc. 7 Acquired Disorders of Erythrocytes  Acquired congenital hemolytic anemia Hemolytic disease of the newborn (HDN)  Alloimmune disease  Maternal antibody directed against fetal antigens  ABO incompatability occurs in 20% to 25% of cases  Rh incompatibility occurs in less than 10%  Also termed erythroblastosis fetalis Presence of red cell precursors on the peripheral blood

Mosby items and derived items © 2006 by Mosby, Inc. 8 Acquired Disorders of Erythrocytes  Hemolytic disease of the newborn (HDN) Manifestations  Anemia  Hyperbilirubinemia  Icterus neonatorum  Kernicterus

Mosby items and derived items © 2006 by Mosby, Inc. 9 Hemolytic Disease of the Newborn

Mosby items and derived items © 2006 by Mosby, Inc. 10 Acquired Disorders of Erythrocytes  Anemia of infectious disease Diseases initially acquired by the mother and transmitted to the fetus  Results in hemolytic anemia  Likely due to injury to the erythrocyte membranes or erythrocyte precursors

Mosby items and derived items © 2006 by Mosby, Inc. 11 Inherited Disorders of Erythrocytes  Glucose-6-phosphate dehydrogenase deficiency (G6PD) Inherited, X-linked, recessive disorder G6PD is an enzyme that helps erythrocytes maintain metabolic processes despite injurious conditions Asymptomatic unless stressors are present

Mosby items and derived items © 2006 by Mosby, Inc. 12 Inherited Disorders of Erythrocytes  Hereditary spherocytosis Autosomal dominant trait Abnormality of proteins or spectrins of the erythrocyte membrane leading to an increased concentration of intracellular sodium Causes splenomegaly and microcytic spherocytes

Mosby items and derived items © 2006 by Mosby, Inc. 13 Hereditary Spherocytosis

Mosby items and derived items © 2006 by Mosby, Inc. 14 Inherited Disorders of Erythrocytes  Sickle cell disease Disorders characterized by the presence of an abnormal hemoglobin (Hgb S)  Mutation causes valine to be replaced by glutamic acid Deoxygenation and dehydration cause the red cells to solidify and stretch into an elongated sickle shape

Mosby items and derived items © 2006 by Mosby, Inc. 15 Inherited Disorders of Erythrocytes  Sickle cell disease Sickle cell trait  Child inherits Hgb S from one parent and Hgb A from another Can result in:  Vasoocclusive crisis (thrombotic crisis), aplastic crisis, sequestration crisis, and hyperhemolytic crisis Other forms  Sickle cell-thalassemia disease and sickle cell-Hb C disease

Mosby items and derived items © 2006 by Mosby, Inc. 16 Sickle Cell Disease

Mosby items and derived items © 2006 by Mosby, Inc. 17 Sickle Cell Disease

Mosby items and derived items © 2006 by Mosby, Inc. 18 Sickle Cell Disease

Mosby items and derived items © 2006 by Mosby, Inc. 19 Sickle Cell Disease

Mosby items and derived items © 2006 by Mosby, Inc. 20 Inherited Disorders of Erythrocytes  Thalassemias Autosomal recessive disorders Synthesis of the globin chains of the hemoglobin molecule is slowed or defective Major—homozygous inheritance Minor—heterozygous inheritance

Mosby items and derived items © 2006 by Mosby, Inc. 21 Inherited Disorders of Erythrocytes  In alpha thalassemia, the alpha chains are affected; beta chains in beta thalassemia Beta-thalassemia minor Beta-thalassemia major Alpha trait Alpha-thalassemia minor Hemoglobin H disease

Mosby items and derived items © 2006 by Mosby, Inc. 22 Inherited Coagulation and Platelet Disorders  Hemophilias Serious bleeding disorders Hemophilia A (classic hemophilia) Hemophilia B (Christmas disease) Hemophilia C (factor XI deficiency) von Willebrand disease

Mosby items and derived items © 2006 by Mosby, Inc. 23 Inherited Coagulation and Platelet Disorders  Congenital hypercoagulability and thrombosis Thrombophilia Protein C deficiency Neonatal purpura fulminans Protein S deficiency Antithrombin III (AT III) deficiency

Mosby items and derived items © 2006 by Mosby, Inc. 24 Antibody-Mediated Hemorrhagic Disease  Idiopathic thrombocytopenic purpura Autoimmune or primary thrombocytopenic purpura  Autoimmune neonatal thrombocytopenia  Autoimmune neonatal thrombocytopenia purpura  Autoimmune vascular purpura

Mosby items and derived items © 2006 by Mosby, Inc. 25 Leukemia  Most common malignancy of childhood  80% to 85% are acute lymphoblastic leukemias  FAB classification Acute lymphoblastic leukemias L1, L2, and L2 Acute non-lymphoblastic leukemias M1-7  Immunoclassification Surface marker identification

Mosby items and derived items © 2006 by Mosby, Inc. 26 Leukemia

Mosby items and derived items © 2006 by Mosby, Inc. 27 Lymphoma  Non-Hodgkin lymphoma Nodular and diffuse  Hodgkin lymphoma Rare in childhood Infectious mode of transmission Many children with Hodgkin lymphoma demonstrate a high antibody titer to Epstein-Barr virus (EBV)