Flashcards in Hematology Deck (136)
What is anemia?
hematocrit value at least 2 standard deviations below the mean for age
What is the normal range of hct in newborns?
What is the normal range of hgb in newborns?
What are possible etiologies for EARLY anemia?
1) blood loss
2) congenital erythrocyte underproduction
3) acquired erythrocyte underproduction
4) increased destruction
What are etiologies of blood loss in the neonate?
1) sequestered blood/ internal hemorrhage
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
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%)
What are potential causes of placentall hemorrhage?
2) abnormal placental insertion (velamentous)
3) placental rupture
4) tight nuchal cord
6) TTTS (acute and chronic)
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)
What is the incidence of volume transfer in fetal maternal hemorrhage?
1 in 400 pregnancies transfer > 30mL
1 in 2000 pregnancies transfer > 100mL
What is the relative occurrence of congenital erythrocyte underproduction?
What are the causes of congenital erythrocyte underproduction?
2) adrenal insufficiency
Genetic causes, including:
1) congenital hypoplastic anemia (Diamond-Blackfan)
2) constitutional aplastic anemia (fanconi's anemia)
What are the causes of acquired erythrocyte underproduction?
2) maternal drug ingestion
4) nutritional deficits
5) lead toxicity
What infections are likely to cause acquired erythrocyte underproduction?
1) Parvo B 19 (most common)
What maternal drugs are known to cause acquired erythrocyte underproduction?
What drugs are known to cause acquired erythrocyte underproduction?
What nutritional deficits are known to cause acquired erythrocyte underproduction?
2) folic acid
3) Vitamin B 12
What are causes of increased RBC destruction?
2) minor blood group incompatibilities
3) structural abnormalities of the cell
4) RBC biochemical defects
What isoimmunization states can lead to increased RBC destruction?
What structural abnormalities of RBCs can lead to increased RBC destruction?
What biochemical defects of RBCs can lead to increased RBC destruction?
- pyruvate kinase deficiency
What is the etiology of erythroblastosis fetalis?
What is the incidence of ABO incompatibility?
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
What immunoglobulin do mother's with type A or B blood produce?
What immunoglobulin do mother's with type O blood produce?
IgG; crosses the placenta; reason why mothers who are O tend to have hemolysis
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)
What are the laboratory findings a/w ABO incompatibility?
Direct Coombs: weakly positive, or negative
Indirect Coombs: positive
What is the incidence of Rh incompatibility?
before Rhogam 1%, now 11/10,000