Alterations of Hematologic
Function in Children
Chapter 28
1
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
2
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Hemolytic Disease of the Newborn
3
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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
4
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Fetal and Neonatal Hematopoiesis

Postnatal changes



Erythrocytes
Leukocytes
Platelets
5
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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
6
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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
7
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Acquired Disorders of Erythrocytes

Hemolytic disease of the newborn (HDN)

Manifestations




Anemia
Hyperbilirubinemia
Icterus neonatorum
Kernicterus
8
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Hemolytic Disease of the Newborn
9
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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
10
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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
11
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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
12
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Hereditary Spherocytosis
13
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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
14
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Inherited Disorders of Erythrocytes

Sickle cell disease

Sickle cell trait


Can result in:


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
15
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Sickle Cell Disease
16
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Sickle Cell Disease
17
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Sickle Cell Disease
18
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Sickle Cell Disease
19
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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
20
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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
21
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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
22
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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
23
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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
24
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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
25
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Leukemia
26
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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)
27
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