NCC Content Flashcards
1
Q
Pluripotent stem cells
A
all blood cells are made from these
2
Q
bone hematopoiesis
A
predominates from 22 weeks gestation forward
3
Q
liver hematopoiesis
A
- established by 9 weeks gestation
- peaks at 4-5 months gestation
- regresses as bone marrow production increases
4
Q
when and where does hematopoiesis start?
A
starts in the yolk sac during the 3rd week of gestation
5
Q
what is hematopoiesis?
A
the formation, production, and maintenance of blood cells
6
Q
Name the extramedullary sites of hematopoiesis
A
- spleen
- lymph nodes
- thymus
- kidneys
7
Q
What factors influence hematopoiesis?
the rate of differentiation of pluripotent cells
A
hypoxia, bacterial infection, physiologic stress
8
Q
What is erythropoiesis?
A
the production of erythrocytes
9
Q
Where is erythropoietin produced?
A
prenatally: in the liver
postnatally: in the kidneys
10
Q
What factors increase erythropoiesis?
A
- anemia
- low oxygen availability to tissues
- down syndrome
- IUGR
- infants born to women with diabetes or PIH (placental insufficiency)
11
Q
What is erythropoietin?
A
the hormone that regulates erythropoiesis & hemoglobin synthesis
12
Q
Describe hemoglobin
A
- major iron-containing component of RBC
- carries oxygen from the lungs to the tissue cells
13
Q
What is a normal hemoglobin level?
A
normal 14-20 g/dL in infants > 34 weeks, slightly lower in preterm infants
14
Q
Describe the lifespan of fetal hemoglobin (HbF)
A
- begins around 14 days of life
- starts to decline at 30-32 weeks
- drops dramatically by 6 months of life
- virtually gone at 1 year of life
15
Q
At term, how much HbF do babies have?
A
RBCs contain 70-90% at birth
16
Q
What is special about HbF?
A
- it has a higher affinity for oxygen than adult hemoglobin
- this is why babies can tolerate lower levels of oxygen in utero
17
Q
When does adult hemoglobin start production (HbA)?
A
-begins at the end of fetal life
18
Q
What factors affect a baby’s Hgb and Hct level?
A
- gestation
- placental transfusion
- blood sampling site (if capillary Hgb is high, recheck w/ central lab draw)
19
Q
What is hematocrit (Hct)?
A
-% of RBCs in a unit volume of blood
20
Q
What are reticulocytes?
A
immature RBCs
21
Q
Describe the life span of a reticulocyte.
A
- 1 to 2 days in the marrow and 1 more day in the circulation before full maturation
- this cycle takes longer when stress is present
22
Q
Reticulocyte count
A
- the lower the gestation, the higher the count
- 3-7% during first 24-48 hrs of life, can be as high as 10% in preterm infant
- falls to
23
Q
How do reticulocytes function?
A
- oxygen and carbon dioxide transport
- buffer
24
Q
What does an increased retic count suggest?
A
-chronic blood loss or hemolysis
25
Life span length of a RBC
- term infant 60-70 days
| - preterm infant 35-50 days
26
Why do premature infants often need RBC transfusions?
- shortened life span of RBC in preemies
| - lab draws
27
What is a nucleated red blood cell?
circulating immature (prereticulocyte) red cells
28
What do nucleated RBCs indicate or suggest?
- indicative of hemolysis, acute blood loss, hypoxemia, congenital heart disease, infection
- indicative of stress
- their presence suggest problems regarding long-term neurodevelopmental outcomes
29
If you know your Hct, Hgb or RBC count, you can figure out the other two...
Example:
Hgb 15%
multiply by 3 = Hct
divide by 3 = RBC count
30
About WBCs...
- also called leukocytes
- mature in bone marrow and lymphatic tissues
- react to foreign protein in extravascular space
- premature babies have 30-50% less than term
31
What are the three types of WBCs?
- granulocytes (3 types)
- lymphocytes
- monocytes
32
What are the three types of granulocytes?
- basophils
- eosinophils
- neutrophils
33
What do basophils do?
-allergic and inflammatory responses
34
What do eosinophils do?
- allergic and anaphylactic responses, parasitic destruction
- similar to neutrophils, but less effective in response
- prolonged survival in extravascular space
35
What do neutrophils do?
- phagocytes
- physiological stress can increase production and bone marrow release of immature forms (bands, myelocytes, metamyelocytes, promyelocytes)
- may be increased at birth but decrease during first week of life
36
Explain T-lymphocytes
- thymus derived
| - graft vs. host disease, delayed hypersensitivity reactions
37
Explain B-lymphocytes
- bone marrow derived
| - production and secretion of immunoglobulins and antibodies
38
What do monocytes do?
- immature circulating macrophages
- mature once in tissues
- "The cleaners"
39
Describe platelets.
- small, non nucleated disk-shaped cells
| - functions: hemostasis, coagulation, thrombus formation
40
What stimulates platelets to work?
response stimulated by disruption of the endothelium
41
Where are platelets produced?
- derived from megakaryocytic in the bone marrow
| - circulate in the blood for 7-10 days before being removed by the spleen
42
What population of newborns have lower platelet counts?
-SGA infants have 20-25% lower platelet counts, probably from stress
43
How much blood volume does a term baby have?
around 80-100 ml/kg
44
How much blood volume does a preterm baby have?
around 90-105 ml/kg
45
What is the definition of anemia?
-central venous hgb
46
What can cause anemia?
- hemorrhage
- hemolysis
- prematurity
- iatrogenic
47
What clotting factors require Vitamin K?
II, VII, IX, X
48
What are the types of hemostasis reactions?
- vascular (vessel contraction)
- intravascular (platelet plug formation)
- extravascular (compression by surround tissue, release of thromboplastin)
49
What is the prothrombin time? (PT)
extrinsic (faster) and common portions of coagulation cascade, requires factor VII which requires vitamin K
-time it takes for plasma to clot after the addition of tissue factor
50
What is the partial thromboplastin time? (PTT)
intrinsic (slower) and common portions of the coagulation cascade
-used to monitor treatment effects of heparin
51
What is d-dimer?
fibrin degradation product
52
What is hemorrhagic disease?
hemorrhagic tendency caused by vitamin K deficiency and decreased activity of factors II, VII, IX, X
53
What is vitamin K affected by?
-lack of bacterial presence (intestinal flora is needed for vitamin K synthesis)
54
Describe EARLY hemorrhagic disease
- least common
- bleeding with 1st 24 hours of life
- typically associated with maternal anticonvulsant therapy
- cannot be prevented with administration of vitamin K
- therapy=treatment of mother with large doses of vitamin K > or = 10 days prior to delivery
55
Describe CLASSIC hemorrhagic disease
- onset 2-5 days of life
- generalized and occasional dramatic bleeding
- typically breast fed infant who has not received prophylactic vitamin K and is not taking adequate amounts of EBM
56
Describe LATE hemorrhagic disease
- onset after 7 days
- more devastating d/t increased incidence of intracranial hemorrhage, permanent sequelae, mortality rate
- associated with chronic diseases that interfere with fat absorption or performance of intestinal flora
57
what supplement is important for babies with liver dysfunction?
ADEKs
58
What has "virtually" eliminated hemorrhagic disease?
prophylactic vitamin K!!
| -0.5 to 1 mg IM, or IV in ELBW
59
what is in cryoprecipate?
factor VIII and fibrinogen
60
What is DIC?
an acquired hemorrhagic disorder associated with an underlying disease manifested as uncontrolled activation of coagulation & fibrinolysis
61
What are the warning signs for DIC?
Hi-YA
- hemorrhage
- ischemia
- anemia
62
Pathophysiology for DIC
- depleted clotting factors and platelets
- blood loss & red cell fragmentation
- microvascular thrombi lead to ischemia and necrosis of any organ (like the kidneys)
63
How do you treat DIC?
provide supportive therapy while attempting to treat the underlying disease
**this is the only treatment!**
64
What is thrombocytopenia?
a platelet count of
65
What is autoimmune thrombocytopenia? (80%)
THIS IS A MATERNAL AUTOANTIBODY CONDITION
| -mom has idiopathic thrombocytopenia purpura, systemic lupus erythematosus
66
What is the pathophysiology of autoimmune thrombocytopenia?
maternal IgG antibodies cross the placenta and destroy fetal platelets
- nadir occurs on DOL 2
- counts are low as long as antibodies are present, typically as long as 4 months
67
is maternal platelet count low, normal, or high with autoimmune thrombocytopenia?
LOW
68
What is alloimmune thrombocytopenia? (20%)
- similar to Rh incompatibility
- fetal platelets contain antigen that is lacking in mother (inherited from father)
- fetal platelets enter maternal circulation and antibodies are created
- Antibodies cross into fetal circulation and destroy fetal platelets
69
Characteristics of alloimmune thrombocytopenia
- nadir occurs in first few days of life; normalizes by 1 month
- fetal thrombocytopenia can occur as early as 20 weeks' gestation
- more severe sequelae than autoimmune
70
Is maternal platelet count low, normal or high in alloimmune thrombocytopenia?
normal
71
Treatment for alloimmune thrombocytopenia?
give maternal platelets or matched platelets
72
Why does birth depression (apgar
fetal megakaryocytic have increased sensitivity to hypoxic injury
73
What are rare causes of impaired production of platelets?
- trisomy 13, 18: bone marrow hypoplasia
- TAR syndrome (thrombocytopenia w/absent radii): megakaryocytic progenitor cell is defective, presents at birth but improvement follows
- fanconi anemia: rarely presents in neonatal period; thumb, skeletal, renal, CNS anomalies w/ cafe-au-lait spots
- rare syndromes: unusually small or large platelets
74
Platelet problems from maternal drugs
interferes with platelet aggregation
- demerol
- phenergan
- ASA
- sulfonamides
- quinidine
- quinine
- thiazides
75
Why are neonates at a greater risk for thrombosis?
d/t diminished fibrinolysis r/t decreased plasminogen levels
76
About renal vein thrombosis
- most common, often in LGA babies
| - often from indwelling umbilical venous catheter
77
symptoms of renal vein thrombosis
- flank mass/enlarged kidney
- hematuria
- hypertension
- renal failure
- proteinuria
- thrombocytopenia (platelets are used up on clots)
- depletion of coagulation factors
78
about renal artery thrombosis
- often from indwelling umbilical arterial catheter
| - often less common and less severe than renal vein thrombosis
79
symptoms of renal artery thrombosis
- flank mass/enlarged kidney
- hematuria
- renal failure
- may have hypertension
80
What is purpura fulminans and what is it associated with?
- life threatening problem with an acute onset characterized by cutaneous hemorrhage and necrosis of tissue, low blood pressure, fever and DIC
- associated with congenital and acquired thrombophilias
81
Describe congenital thrombophilias
- deficiencies of protein C, protein S, antithrombin, activated protein C resistance, MTHFR deficiency
- look for family history, early age of onset, recurrent disease, unusual/multiple locations of thrombosis
82
Describe acquired thrombophilias
-coagulation factor deficiency r/t placental transfer of maternal anti-phospholipid antibodies (i.e. maternal lupus)
83
What is the other name for Christmas disease?
hemophilia B
84
How is hemophilia passed on?
X-linked recessive inheritance
(gene is on X chromosome)
-females are carriers only due to XX
-males are affected due to XY - no normal X to counterbalance bad X
85
What is von Willebrand disease?
- component of factor VIII functioning as ligand between the platelet and vessel
- autosomal dominant or recessive inheritance
- males and females affected equally
- each pregnancy with 50% chance of occurrence
86
How does von Willebrand disease present in the neonatal period?
-it rarely does; may present with mucus membrane bleeding
87
How is von Willebrand disease diagnosed?
with ristocetin factor
88
What is factor XIII deficiency?
- autosomal recessive inheritance; males and females equally affected
- symptoms are prolonged bleeding from umbilical stump or several days after circumcision
- treat with cryo, factor XIII concentrate
- most likely to present in the neonatal period??
89
which cell is the most sensitive indicator of sepsis?
the neutrophil
90
what are the mature neutrophils called?
polymorphonuclear (PMNs) or segs?
91
what are the immature neutrophils called?
promyelocytes, myelocytes, metamyelocytes, bands
92
define neutropenia
ANC
93
is neutrophilia predictive of infection?
-somewhat, not as reliable as neutropenia
94
What is the most common transfusion reaction in a neonate?
fever
95
Why is graft vs host disease rare now with blood transfusions?
d/t irradiation of blood products
96
What is the HCT in whole blood vs. PRBCs respectively?
35%; 60-90%
97
Describe a partial exchange transfusion
- done with normal saline to combat polycythemia
- goal is to decrease HCT without decreasing blood volume
- calculation: blood volume x (measured HCT - desired HCT) divided by measured HCT
98
Describe PRBC administration for hydrops
- goal is to correct anemia without increasing blood volume
| - calculation: blood volume x (desired HCT - measured HCT) divided by PRBC HCT - measured HCT
99
Describe a complete exchange
- removes 70-85% of infants blood
| - may cause hypoglycemia, hypocalcemia, hypomagnesemia
100
How much should platelet count rise with a transfusion?
around 75K-100K
| -lack of rise is indicative of destruction
101
albumin for volume expansion
5% in increments of 10 ml/kg
102
albumin for oncotic pressure
25% in increments of 4 ml/kg
103
erythropoietin for anemia of prematurity
- 500-1400 units/kg/week
| - need to be on iron supplement to support increased erythropoiesis!
104
ferrous sulfate administration
- 2-5 mg/kg/day elemental iron daily
| - iron fortified formula can provide up to 2 mg/kg/day
105
How long should preterm infants receive iron supplements?
until 12 months of age
106
What is the antidote for heparin overdose?
protamine sulfate
