Hemolytic Disease of the Fetus and Newborn Module 3 Quiz

10 Questions

What must the crossmatch for a neonate always be compatible with?

Mother and child

What is the maximum age of the donor unit preferred for intrauterine or exchange transfusions?

5 days

Describe Rh Immune Globulin (RhIG).

RhIG is used to prevent hemolytic disease of the newborn (HDN) due to the presence of anti-D antibodies.

What are the requirements for the use of Rh Immune Globulin (RhIG) in preventing HDN due to anti-D antibodies?

a) Dosage and eligibility criteria; b) Timing intervals; c) Principle of RhIG.

Define and explain both the Rosette and the Kleihauer-Betke tests.

a) Rosette and Kleihauer-Betke tests are used to detect fetomaternal hemorrhage; b) They help in quantifying fetal-maternal hemorrhage; c) A positive rosette test indicates fetomaternal hemorrhage.

Describe the criteria necessary for Hemolytic Disease of the Fetus and Newborn (HDFN) to develop.

HDFN develops when a mother is exposed to antigens on fetal RBCs that she lacks, leading to alloimmunization.

Compare and contrast ABO versus HDFN due to RBC alloimmunization (Rh and/or Other IgG) in terms of severity of the disease.

ABO HDFN is usually milder compared to HDFN due to Rh or other IgG alloimmunization.

Contrast the metabolism of bilirubin in the fetus versus bilirubin in the newborn.

In the fetus, bilirubin is largely unconjugated and crosses the placenta to be metabolized by the mother, while in the newborn, bilirubin is conjugated in the liver and excreted in bile.

Describe the intervention procedures used in the diagnosis and management of Hemolytic Disease of the Fetus and Newborn.

Intervention procedures include antibody titration, direct antiglobulin test (DAT), bilirubin level monitoring, and possible intrauterine transfusions.

State the possible ABO donor group(s) that would be selected for an exchange transfusion.

For an exchange transfusion, ABO-compatible donor blood is usually preferred to prevent further hemolysis.

Study Notes

Crossmatching for Neonates

A crossmatch for a neonate must always be compatible with the mother and child.

Blood Components for Intrauterine or Exchange Transfusions

Preferred blood components are:
- Red blood cells (RBCs)
- Maximum age of donor unit: 5-7 days

Rh Immune Globulin (RhIG)

Definition: RhIG is a medication used to prevent hemolytic disease of the fetus and newborn (HDFN) due to Rh incompatibility.
Dosage: 300 μg at 28 weeks' gestation and within 72 hours of delivery.
Eligibility criteria: Rh-negative mothers with an Rh-positive fetus.
Timing intervals: 28 weeks' gestation and within 72 hours of delivery.
Principle: RhIG prevents the formation of antibodies in the mother's blood, thereby preventing HDFN.

Rosette and Kleihauer-Betke Tests

Rosette test:
- Principle: Detects the presence of fetal RBCs in the maternal circulation.
- Interpretation: A positive result indicates fetomaternal hemorrhage.
- Significance: Helps diagnose HDFN and determine the dose of RhIG required.
Kleihauer-Betke test:
- Principle: Quantifies the amount of fetal RBCs in the maternal circulation.
- Interpretation: Results are used to calculate the dose of RhIG required.

Hemolytic Disease of the Fetus and Newborn (HDFN)

Definition: Immune destruction of RBCs of the fetus or newborn due to sensitization of these cells by the mother's IgG antibody.
Characteristics: HDFN occurs when maternal antibody crosses the placenta and reacts with an RBC antigen that the baby has inherited.
Criteria for HDFN to develop:
- Maternal antibody that causes the disease must cross the placenta.
- Reaction with an RBC antigen that the baby has inherited.

Autoantibodies and Immune Hemolytic Anemias

Autoantibody: An antibody produced by the body against its own RBCs.
Immune hemolytic anemias: Autoimmune hemolytic anemia (AIHA) and drug-induced immune hemolytic anemia.
Warm autoimmune hemolytic anemia (WAIHA):
- Definition: AIHA caused by IgG antibodies that react at body temperature.
- Characteristics: Idiopathic or secondary to lymphoproliferative disorders.
Cold autoagglutinins:
- Definition: Autoantibodies that react at temperatures below 37°C.
- Characteristics: Common specificities include anti-I, anti-H, and anti-M.

Investigation and Treatment of Hemolytic Disease

Serologic testing: Used to detect underlying clinically significant alloantibodies in the presence of autoantibodies.
Techniques for investigating serologic findings:
- Use of enzyme-treated RBCs
- Use of chemical-treated RBCs
- Adsorption studies
Treatment of HDFN:
- Exchange transfusion
- Phototherapy
- RhIG administration