Flashcards in Hematology Deck (136)
Loading flashcards...
1
What is anemia?
hematocrit value at least 2 standard deviations below the mean for age
2
What is the normal range of hct in newborns?
45-61%
3
What is the normal range of hgb in newborns?
15-20%
4
What are possible etiologies for EARLY anemia?
1) blood loss
2) congenital erythrocyte underproduction
3) acquired erythrocyte underproduction
4) increased destruction
5
What are etiologies of blood loss in the neonate?
1) sequestered blood/ internal hemorrhage
2) Fetal-maternal
3) Placental
6
What are potential sites for sequestered blood/ internal hemorrhage?
1) intracranial: subdural, intraventricular, subgaleal
2) organ: adrenal, ruptured liver/spleen, retroperitoneal cavity
3) integumentary: bruising, hemangiomas
7
What are potential causes of fetal-maternal hemorrhage?
1) fetal maternal hemorrhage
2) ABO incompatability
* in most pregnancies there are fetal cells in maternal circulation (50-75%)
8
What are potential causes of placentall hemorrhage?
1) abruption
2) abnormal placental insertion (velamentous)
3) placental rupture
4) tight nuchal cord
5) CSX
6) TTTS (acute and chronic)
9
How is Fetal-Maternal Hemorrhage diagnosed?
diagnosis is by detection of fetal RBC in maternal circulation
- done on maternal blood, adult hgb has different solubility than fetal hgb.
- K-B can calculate volume of fetal blood loss (used to estimate Rhogam dose so that it is sufficent to kill fetal cells)
10
What is the incidence of volume transfer in fetal maternal hemorrhage?
1 in 400 pregnancies transfer > 30mL
1 in 2000 pregnancies transfer > 100mL
11
What is the relative occurrence of congenital erythrocyte underproduction?
rare
12
What are the causes of congenital erythrocyte underproduction?
1) hypothyroidism
2) adrenal insufficiency
3) hypopituitarism
Genetic causes, including:
1) congenital hypoplastic anemia (Diamond-Blackfan)
2) constitutional aplastic anemia (fanconi's anemia)
13
What are the causes of acquired erythrocyte underproduction?
1) infection
2) maternal drug ingestion
3) drugs
4) nutritional deficits
5) lead toxicity
14
What infections are likely to cause acquired erythrocyte underproduction?
1) Parvo B 19 (most common)
2) hepatitis
3) HIV
4) syphillis
15
What maternal drugs are known to cause acquired erythrocyte underproduction?
azathioprine
16
What drugs are known to cause acquired erythrocyte underproduction?
chloraphenicol
17
What nutritional deficits are known to cause acquired erythrocyte underproduction?
1) Fe
2) folic acid
3) Vitamin B 12
18
What are causes of increased RBC destruction?
1) isoimmunization
2) minor blood group incompatibilities
3) structural abnormalities of the cell
4) RBC biochemical defects
5) infections
19
What isoimmunization states can lead to increased RBC destruction?
Rh incompatibility
ABO incompatibility
20
What structural abnormalities of RBCs can lead to increased RBC destruction?
- spherocytosis
- eliptocytosis
21
What biochemical defects of RBCs can lead to increased RBC destruction?
- G6PD
- pyruvate kinase deficiency
22
What is the etiology of erythroblastosis fetalis?
Rh incompatibility
23
What is the incidence of ABO incompatibility?
approximately 3%
24
What is the cumulative effect of ABO incompatibility with subsequent pregnancies?
may occur in first pregnancy, no sensitization req'd, subsequent pregnancies are not more severely affected
25
What immunoglobulin do mother's with type A or B blood produce?
IgM
26
What immunoglobulin do mother's with type O blood produce?
IgG; crosses the placenta; reason why mothers who are O tend to have hemolysis
27
What other effects can be expected with a mother with type B blood and an ABO incompatible fetus?
may also have thrombocytopenia since B antigen is expressed on platelets (usually mild)
28
What are the laboratory findings a/w ABO incompatibility?
Direct Coombs: weakly positive, or negative
Indirect Coombs: positive
29
What is the incidence of Rh incompatibility?
before Rhogam 1%, now 11/10,000
30
