Transcript Chapter_028 - IHMC Public Cmaps (2)

Alterations of Hematologic
Function in Children
Chapter 28
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Fetal and Neonatal Hematopoiesis
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The embryo becomes too large for
oxygenation by simple diffusion
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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
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Fetal hemoglobin
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Two alpha chains; two gamma chains
Embryonic hemoglobins
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Gower 1, Gower 2, and Portland
Fetal hemoglobin
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Hgb F
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Fetal and Neonatal Hematopoiesis
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Postnatal changes
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Erythrocytes
Leukocytes
Platelets
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Acquired Disorders of Erythrocytes
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Iron deficiency anemia
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Most common blood disorder of infancy and
childhood
Lack of iron intake or blood loss
Manifestations
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Irritability, decreased activity tolerance, weakness,
and lack of interest in play
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Acquired Disorders of Erythrocytes

Acquired congenital hemolytic anemia
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Hemolytic disease of the newborn (HDN)
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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)
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Manifestations
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Anemia
Hyperbilirubinemia
Icterus neonatorum
Kernicterus
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Hemolytic Disease of the Newborn
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Acquired Disorders of Erythrocytes
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Anemia of infectious disease
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Diseases initially acquired by the mother and
transmitted to the fetus
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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)
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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
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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
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Sickle cell disease
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Disorders characterized by the presence of an
abnormal hemoglobin (Hgb S)
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
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
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Sickle cell disease
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Sickle cell trait
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Can result in:
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Child inherits Hgb S from one parent and Hgb A from
another
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
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Thalassemias
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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
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In alpha thalassemia, the alpha chains are
affected; beta chains in beta thalassemia
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Beta-thalassemia minor
Beta-thalassemia major
Alpha trait
Alpha-thalassemia minor
Hemoglobin H disease
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Inherited Coagulation and Platelet
Disorders
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Hemophilias
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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
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Congenital hypercoagulability and thrombosis
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Thrombophilia
Protein C deficiency
Neonatal purpura fulminans
Protein S deficiency
Antithrombin III (AT III) deficiency
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Antibody-Mediated Hemorrhagic
Disease
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Idiopathic thrombocytopenic purpura
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Autoimmune or primary thrombocytopenic
purpura
Autoimmune neonatal thrombocytopenia
Autoimmune neonatal thrombocytopenia
purpura
Autoimmune vascular purpura
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Leukemia
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Most common malignancy of childhood
80% to 85% are acute lymphoblastic
leukemias
FAB classification
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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
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Non-Hodgkin lymphoma
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Nodular and diffuse
Hodgkin lymphoma
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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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