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1
Alterations of Hematologic Function in ChildrenChapter 28
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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
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Hemolytic Disease of the Newborn
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Fetal and Neonatal Hematopoiesis Fetal hemoglobin
Two alpha chains; two gamma chains Embryonic hemoglobins
Gower 1, Gower 2, and Portland
Fetal hemoglobin Hgb F
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Fetal and Neonatal Hematopoiesis Postnatal changes
Erythrocytes Leukocytes Platelets
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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
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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
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Acquired Disorders of Erythrocytes Hemolytic disease of the newborn (HDN)
Manifestations Anemia Hyperbilirubinemia Icterus neonatorum Kernicterus
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Hemolytic Disease of the Newborn
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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
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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
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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
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Hereditary Spherocytosis
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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
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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
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Sickle Cell Disease
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Sickle Cell Disease
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Sickle Cell Disease
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Sickle Cell Disease
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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
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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
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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
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Inherited Coagulation and Platelet Disorders Congenital hypercoagulability and thrombosis
Thrombophilia Protein C deficiency Neonatal purpura fulminans Protein S deficiency Antithrombin III (AT III) deficiency
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Antibody-Mediated Hemorrhagic Disease Idiopathic thrombocytopenic purpura
Autoimmune or primary thrombocytopenic purpura
Autoimmune neonatal thrombocytopenia Autoimmune neonatal thrombocytopenia
purpura Autoimmune vascular purpura
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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
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Leukemia
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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)
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