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Neonatal Pathophysiology > Hematology > Flashcards

Flashcards in Hematology Deck (136)
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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

What is the cumulative effect of Rh incompatibility with subsequent pregnancies?

primary response (with first pregnancy) is IgM (not transmitted), followed by production of IgG (transmitted). With repeat exposure IgG response is more rapid (worse over time and with future pregnancies)