6 Hematology of the Fetus and the Newborn Flashcards
The appearance of primitive erythroid cells in blood islands of the yolk sac begin at ________ of gestation
Day 18 of gestation
Primitive erythroblasts have extremely large size, with an estimated mean cell volume (MCV) of greater than 400 fL/cell, yolk sac erythroblasts have been termed
Megaloblasts
In humans, primitive erythroblasts begin to enter the embryo proper at days ________of gestation with the onset of cardiac contractions and circulate until approximately _______weeks of gestation
Days 21–22 of gestation
12 weeks of gestation
The initial wave of primitive hematopoietic progenitors is followed by a second wave of yolk sac–derived definitive erythroid progenitors, termed
Burst-forming units–erythroid (BFU-E)
BFU-E are present in the human yolk sac as early as ______ weeks’ gestation and are found in the fetal liver by ______ weeks’ gestation
Yolk sac: 4 weeks gestation
Fetal liver: 5 weeks gestation
Between 7 and 15 weeks of gestation, _______% of the liver cells are hematopoietic.
60%
The liver serves as the primary source of red cells from the ____________week of gestation
9th to the 24th week of gestation
Are smaller than yolk sac–derived primitive megaloblasts and contain one-third the amount of hemoglobin
Fetal liver–derived definitive “macrocytes”
TRUE OR FALSE
Fetal liver–derived erythroid progenitors can differentiate in vitro with erythropoietin alone, in contrast to adult marrow–derived BFU-E, which requires erythropoietin plus interleukin (IL)-3 or stem cell factor.
TRUE
Fetal liver–derived erythroid progenitors can differentiate in vitro with erythropoietin alone, in contrast to adult marrow–derived BFU-E, which requires erythropoietin plus interleukin (IL)-3 or stem cell factor.
Erythropoietin transcripts also are present in the developing human kidney as early as
17 weeks’ gestation
Megakaryocytes are present in the liver by __________weeks of gestation, and platelets are first evident in the circulation at ________ weeks of gestation
6 weeks of gestation
8–9 weeks of gestation
69
Granulopoiesis is present in the liver parenchyma as early as ______ weeks of gestation, and small numbers of circulating leukocytes are present at the ______ week of gestation.
7 weeks of gestation
11th week of gestation
7-11
G-CSF is expressed by hepatocytes at ______ weeks gestation.
14 weeks gestation
B-cell progenitors are present in the fetal liver by ___weeks of gestation, and circulating lymphocytes are present at ____weeks’ gestation.
7 weeks of gestation
9 weeks gestation
7-9
T lymphocytes are found only rarely before _______ weeks’ gestation
12 weeks’ gestation
Hematopoietic cells are first seen in the marrow of _______week embryos, and they remain confined to the ______________ until 15 weeks’ gestation
10- to 11-week
Diaphyseal regions of long bones
Myeloid cells predominate by ______ weeks’ gestation, and the myeloid-to-erythroid ratio approaches the adult level of 3:1 by______weeks’ gestation.
12 weeks’ gestation
21 weeks’ gestation.
TRUE OR FALSE
Macrophage cells in the fetal marrow, but not in the fetal liver, express the lipopolysaccharide receptor CD14.
TRUE
Macrophage cells in the fetal marrow, but not in the fetal liver, express the lipopolysaccharide receptor CD14.
A massive expansion of B-cell progenitors occurs in the fetal marrow between __________ weeks of gestation.
11 and 20 weeks of gestation
The marrow becomes the major site of hematopoiesis after the ________ week of gestation and remains so throughout the remainder of fetal life.
24th week of gestation
Chromosome location
α-globin gene cluster:
β-globin gene cluster:
α-globin gene cluster: Chromosome 16 (ζ , α)
β-globin gene cluster: Chromosome 11(ε-γ A-γ G-δ-β)
The major hemoglobin in embryos younger than 5 weeks’ gestation
Hgb Gower-1 (ζ2ε2)
Found in embryos with a gestational age as young as 4 weeks and is absent in embryos older than 13 weeks.
Hgb Gower-2 (α2ε2)
Found in young embryos but persists in infants with homozygous α-thalassemia
Hgb Portland (ζ2γ2)
The major hemoglobin of fetal life
Hgb F (α2γ2)
Synthesis of Hgb A can be demonstrated in fetuses as young as_____ weeks’ gestation.
9 weeks’ gestation
The fetal hemoglobin concentration in blood decreases after birth by approximately ____ per week and is generally less than 2% to 3% of the total hemoglobin by 6 months of age.
3% per week
Normal adult levels of Hgb A2 are achieved by________months of age.
4 months of age
Increased proportions of Hgb F at birth have been reported in infants who are
- Small for gestational age
- Those who have experienced chronic intrauterine hypoxia
- Trisomy 13
- Thoe who have died from sudden infant death syndrome (SIDS)
Decreased levels of Hgb F at birth are found in
Trisomy 21
Delay of cord clamping may increase the blood volume and red cell mass of the infant by as much as ______%.
55%
TRUE OR FALSE
A venous hemoglobin concentration of less than 14 g/dL in a term infant or a fall in hemoglobin or hematocrit level in the first postnatal day is abnormal.
TRUE
A venous hemoglobin concentration of less than 14 g/dL in a term infant or a fall in hemoglobin or hematocrit level in the first postnatal day is abnormal.
The red cells of newborns are macrocytic, with an MCV in excess of 110 fL
The MCV begins to fall after the first week, reaching adult values by the ______ week
Ninth week
TRUE OR FALSE
In several, but not all,studies, premature infants at birth had lower hemoglobin levels, higher reticulocyte counts, and higher nucleated red cell counts than did the term infants.
TRUE
In several, but not all,studies, premature infants at birth had lower hemoglobin levels, higher reticulocyte counts, and higher nucleated red cell counts than did the term infants.
Physiologic anemia of the newborn is more pronounced during
5–8 weeks
The lowest hemoglobin values in the term infant occur at approximately
2 months of age
Erythropoietin can be measured after the ______ postnatal day, corresponding to the recovery from physiologic anemia.
60th postnatal day
Symptoms of hyperviscosity in infants
Irritability, hypotonia, tremors, or poor suck reflex
TRUE OR FALSE
The i antigen is expressed strongly, whereas the I antigen and the A and B antigens are expressed only weakly on neonatal red cells.
TRUE
The i antigen is expressed strongly, whereas the I antigen and the A and B antigens are expressed only weakly on neonatal red cells.
By 1 year of age, the i antigen is undetectable, and the ABH antigens increase to adult levels by age ____ years
3 years
The ABH, Kell, Duffy, and Vel antigens can be detected on the cells of the fetus in the first trimester and are present at birth
Anti-A and anti-B isohemagglutinins develop during the first 6 postnatal months, reaching adult levels by 2 years of age.
The average of several studies of mean half-life of newborn red cells is ______ days.
60–80 days
The oxygen affinity of cord blood is (lesser or greater) than that of maternal blood, because the affinity of Hgb F for 2,3-bisphosphoglycerate (2,3-BPG) is less than that of Hgb A.
Greater
Consequently, the red cell oxygen equilibrium curve of the newborn is shifted to the left of that of the adult
After birth, the oxygen equilibrium curve shifts gradually to the right, reaching the position of the adult curve by 6 months of age.
TRUE OR FALSE
The absolute number of segmented neutrophils rises in both term and premature infants in the first 24 hours.
TRUE
The absolute number of segmented neutrophils rises in both term and premature infants in the first 24 hours.
The predominant cells in the first few days after birth.
Segmented granulocytes
Becomes the most numerous cell and remains so during the first 4 years of life.
Lymphocyte
An absolute eosinophil count of greater than 0.7 × 109/L was found in 76% of premature infants at 2–3 weeks of age.
Eosinophilia is associated in the ff conditions:
- Coincided with the establishment of steady weight gain
- Use of total parenteral nutrition
- Endotracheal intubation
- Blood transfusions
In term infants, opsonic activity is normal for Staphylococcus aureus, but it is low for _____ and ______________.
Diminished opsonic antibody is associated with ___________ infection and represents one risk factor for neonatal infection.
Yeast and Escherichia coli
Group B streptococcal infection
In premature infants, opsonic activity is low for________ and ___________ but is normal for Pseudomonas aeruginosa.
S. aureus and Serratia marcescens
TRUE OR FALSE
Chemotactic function of leukocytes is low in neonates, whereas random motility is normal.
TRUE
Chemotactic function of leukocytes is low in neonates, whereas random motility is normal.
TRUE OR FALSE
Phagocytosis of bacteria and latex granules by neutrophils from premature and term infants is normal.
TRUE
Phagocytosis of bacteria and latex granules by neutrophils from premature and term infants is normal.
Ig_ levels of term infants are similar to maternal levels because of transplacental transfer
IgG
IgM, IgD, and IgE do not cross the placenta, and the levels of these immunoglobulins and of IgA are low or not detectable at birth.
Breastfeeding provides some transfer of antibodies, particularly _____________
Secretory IgA, lysozyme, and lactoferrin
INCREASE OR DECREASE OR SAME
Factors II, IX, X, XI, XII; prekallikrein; and high-molecular-weight kininogen
Factor VIII
Von Willebrand factor
Factors II, IX, X, XI, XII; prekallikrein; and high-molecular-weight kininogen: DECREASE
Factor VIII : SAME
Von Willebrand factor: INCREASE
These factors decrease during the first 3–4 days after birth
Factors II (prothrombin), VII, IX, and X
**require vitamin K
A hemorrhagic diathesis also may occur later, 2–12 weeks after birth, as a result of lack of vitamin K
Late hemorrhagic disease of the newborn or acquired prothrombin complex deficiency
Frequently is the presenting event in Late hemorrhagic disease of the newborn
Intracranial hemorrhage
The current recommendation of the American Academy of Pediatrics for Vitamin K
Vitamin K1, 0.5–1.0 mg, be administered intramuscularly at birth
Arterial and venous thromboses are relatively frequent in newborns compared with other age groups, but greater than 90% of arterial and greater than 80% of venous clots are related to ___________
Catheters
Spontaneous thromboses are much less common, and most involve the renal veins or, rarely, the pulmonary vasculature.
Drug that cause: Decreased
hemoglobin
Antiretroviral agents in combination
Drug that cause: bleeding
Aspirin: Interference with platelet function
Diazoxide: Thrombocytopenia
Phenytoin (Dilantin/phenobarbital): Depletion of vitamin K–dependent coagulation factors by hepatic enzyme induction and factor degradation
Rifampin/isoniazid: Depletion of vitamin K–dependent coagulation factors
Thiazides: Thrombocytopenia
Warfarin (Coumadin): Known depletion of vitamin K–dependent coagulation factors by blocking carboxylation
Drug that cause: kernicterus
Aspirin: Displacement of bilirubin from albumin
Sulfonamides: Displacement of bilirubin from albumin
