Hemolytic Disease of the Fetus and Newborn Flashcards
What is HDFN defined as?
The destruction of RBC’s of a fetus/neonate by antibodies produced by the mother
What are the mothers antibodies directed against in the newborn?
The antigens on the fetal RBC’s that were inherited from the father
Explain Erythroblastosis Fetalis.
Immature fetal RBC’s are released into circulation
What results from extramedullary hematopoiesis?
Hepatosplenomegaly
When can Hydrops Fetalis develop?
18-20 weeks gestation
What causes the rate of RBC destruction to drop after birth?
No additional maternal antibody is entering the infants circulation
What can serologic and clinical tests determine during pregnancy?
Level of antibody in mother
Potential of antibody for HDFN
Severity of RBC destruction
In the first pregnancy, can we see an ABO HDFN?
Yes in the first, less likely after
What causes toxic levels to the infants brain during episodes of moderate to severe hemolysis?
Unconjugated bilirubin
Kernicterus if left untreated
How quickly does a neonate develop hyperbilirubinemia and how do we treat it?
Develop within 12-48 hrs
Phototherapy at 460 nm - 490 nm
What causes subsequent offspring that inherit the D antigen to be affected?
Mother becoming immunized to D antigen
1 mL can immunize mother
What causes the incidence of detectable fetomaternal hemorrhage to be decreased?
Mother being ABO incompatible with the fetus
What are the two primary uses of RhoGam?
Rh HDFN
Idiopathic Thrombocytopenic Purpura (ITP)
How can we prevent active immunization induced by RBC antigens?
The concurrent administration of the corresponding RBC antibody
When should we give RhIg in pregnancy?
Early on; 3rd trimester/ 28 weeks gestation
When should we give RhoGam to a mother after birth?
72 hours after delivery
What is a regular dose of RhIg considered as?
Enough to protect against 15 mL of pRBC’s or 30 mL of whole blood
When does RhoGam provide no benefit?
If a person has been actively immunized and has formed anti-D
What is used in determining the volume of fetal hemorrhage?
Kleihauer-Betke Test
In the Kleihauer-Betke test, how does it work to provide data?
Fetal cells remain pink while maternal cells appear as ghost cells
What can the measurement of fetal MCA-PSV reliably predict?
Anemia in the fetus
What is a confirmatory test for HDFN?
Cord blood testing
Collected by venipuncture to avoid Wharton’s jelly
What kind of blood units do we use for intrauterine transfusion?
Blood units less than 7 days from collection
What is an Exchange Transfusion?
Use of whole blood to replace neonate’s circulating blood
What is the primary use of an Exchange Transfusion?
Removal of high levels of unconjugated bilirubin
What are other uses of an Exchange Transfusion?
Removal of maternal antibody
Removal of sensitized RBCs
Replacement of incompatible RBCs
What kind of blood do most centers that treat HDFN use?
Group O neg RBCs for intrauterine and transfusions
