Hemolytic Disease of the Fetus and Newborn (Final Exam)

HDFN occurs when maternal antibodies destroy the ______ of a fetus or neonate.

RBCs

These antibodies are ______, which can cross the placenta via Fc receptors.

Erythroblastis Fetalis occurs when HDFN destroys fetal RBCs, triggering the fetus to increase _______.

erythropoiesis

Increased erythropoiesis causes premature release of many ______ into circulation.

nRBCs

Hydrops Fetalis occurs when worsening anemia/increased erythropoiesis causes ______ and ______ in the liver and spleen.

organ enlargement, portal hypertension

This causes a decrease in liver production of ______, and subsequent ______.

albumin, edema

Bilirubin is a breakdown product of ______.

RBCs

Hyperbilirubinemia occurs when bilirubin accumulates dangerously high in a ______.

newborn infant

Hyperbilirubinemia is primarily a result of the newborn liver's inability to ______ bilirubin efficienctly.

conjugate

Phototherapy is the process of using light to eliminate ______ in the blood stream. How does it do this?

The light causes unconjugated bilirubin to become conjugated (soluble form), which can then be excreted by the infant

Kernicterus is permanent brain damage caused by ______.

hyperbilirubinemia

In order for HDFN to occur, the mother must have IgG antibody, and the fetus must inherit the antigen gene from the ______, which must be expressed on fetal RBCs.

father

What are some effects of RBC destruction on a fetus?

Anemia, erythroblastosis, splenomegaly, hydrops

What are some effects of RBC destruction on a newborn?

Bilirubinemia, kernicterus, continued anemia

What are the types of HDFN?

- ABO

- RhD

- Other Abs (Anti-c, K, E, C, Fy, Jk, etc.)

Why is Lewis blood group antibody not associated with HDFN?

It is a carbohydrate-based blood group, which can easily be destroyed/changed during pregnancy

With ABO ADFN, the mother is usually group ______, and the infant is group ______ or ______.

O, A, B

The ______ antibodies that the mother possesses in ABO ADFN are IgG.

anti-A,B

With ABO HDFN, the first pregnancy ______ be affected.

may

ABO HDFN DAT is usually ______.

weakly positive

ABO HDFN is a ______ disease that rarely required treatment.

mild

Why is ABO HDFN mild?

The ABH antigens on fetal/newborn RBCs are not fully developed until 1 year of age

ABO HDFN eluate results

Anti-A, anti-B, anti-AB

ABO HDFN will show ______ in the blood and high ______.

microspherocytes, bilirubin

The severity of ABO HDFN is independent of the ______ of reactions.

strength

______ is usually a sufficient therapy for ABO HDFN.

Phototherapy

In order to have RhD HDFN, the mother must have been previously ______.

sensitized

RhD HDFN DAT is ______.

strongly positive

RhD HDFN can potentially cause in utero ______ and require in utero ______.

fatality, treatment

RhD HDFN may require post-delivery ______.

exchange transfusions

Maternal stimulation of antibody production can occur due to previous ______ or previous ______.

pregnancies (FMH), RBC transfusions

What are the recommended prenatal tests?

- ABO-Rh Type

- Ab Screen

- Ab ID

- Ab Titration

ABO-Rh Typing is used to identify candidates for ______.

prophylaxis (RhIg)

Antibody titration is a semi-quantitative ______.

estimation

Antibody titration is used to determine when to initiate other methods of ______.

fetal monitoring

Antibody titration is useful in cases of ______ immunization.

Rh(D)

What are some sources of error with antibody titrations?

- Equilibrium constant of the antibody

- RBC concentration

- Preparation of serum dilutions

- Subjectivity endpoint (1+)

A critical titer has an initial value of ______ or more.

16

A significant titer will have a _______ dilution increase or a change in score of over ______ between subsequent titers.

2, 10

What are some controlling variables for antibody titration?

- Semi-automatic pipette

- Standardized RBC phenotype (hetero/homozygous)

- Test previous sample in parallel

- Use standardized grading/scoring of agglutination

Titers should start a the ______ prenatal visit, if a clinically significant antibody is detected at that time.

first

Titers should be performed again at ______ and ______ weeks of pregnancy.

16, 22

Titers should continue every ______ weeks until another form of fetal assessment is decided upon, or until delivery.

2-4

Amniocentesis is the use of a needle into the ______ to withdraw fluid.

amniotic fluid sac

Amniocentesis is used to determine the degree of fetal ______ and the level of fetal ______.

hemolysis, maturity

When should amniocentesis be performed?

- If there is Hx of complicated pregnancies

- Titer >16

- Fetal hydrops

- >18 weeks or earlier if pt Hx warrants

______ is the introduction of a needle into the umbilical vein (cordocentesis).

Percutaneous Umbilical Blood Sampling (PUBS)

PUBS is used to test ...

- H/H

- Bilirubin

- ABO/Rh

- DAT

- Genotype/phenotype

- Reticulocytosis

- Access for possible intrauterine transfusion

Testing for fetal hemolysis via amniocentesis uses ______ to determine the absorbance of ______ at 450nm.

spectrophotometry, bilirubin

This scan is performed at wavelengths 350-650nm and plotted against absorbance, creating a ______ graph.

Liley Curve (Lileygram)

Amniocentesis and fetal blood sampling are very ______ and risky.

invasive

______ can be used to assess fetal anemia.

MCA-PSV

This procedure measures the blood ______ and is ______.

velocity, nonivasive

Intrauterine transfusion (IUT) can be ______ or ______.

intraperitoneal, intravascular

The goal of IUT is to maintain a fetal Hgb above ______g/dL.

10

When is IUT necessary?

- MCA-PSV indicates anemia

- Fetal hydrops

- Cordocentesis shows Hgb under 10g/dL

- Amniotic fluid deltaOD are high and increasing

What are the selection criteria for blood for an IUT?

- O- RBCs

- Compatible with maternal serum

- <7 days old

- Irradiated

- CMV- or leukoreduced

- Hgb S-

What maternal serologic testing is done at delivery?

- ABO/Rh

- Ab screen

- Ab ID

Cord blood is collected on infants born to _______ or type ______ mothers.

Rh-, O

______ interferes with cord blood testing and requires washing away.

Wharton's jelly

Wharton's jelly contains ______ and causes rouleaux

hyaluronic acid

What newborn serologic testing is done on cord blood?

- ABO

- Rh(D) and weak D

- DAT

- Cord Hgb/Hct

- Cord bilirubin

If the mother has a negative Ab screen and the cord DAT is negative, but the infant is showing signs of HDN, consider ______.

ABO HDN

______ may be recovered via elution even if the cord DAT is negative.

Anti-A and/or anti-B

Elution is a technique designed to dissociate ______ from a cell surface.

antibodies

Eluate is made up of the ______ product.

free antibody

Photodegradation is only effective in controlling ______.

mild/moderate hyperbilirubinemia

Phototherapy is often referred to as using the ______.

"Bili blanket"

Exchange transfusion is the process of replacing a neonate's circulating blood with ______.

whole blood/equivalent

Exchange transfusion is good for ...

- Decreasing bilirubin

- Correcting anemia

- Removing Ab-coated cells

- Decreasing circulating maternal Ab

What are indications for exchange transfusion in a neonate?

- Cord Hgb less than or equal to 13g/dL

- Bilirubin rise of over 0.5 mg/dL/hr

When the indirect bilirubin is ______mg/dL or greater, kernicterus is almost certain.

25

What are the criteria for exchange transfusion blood units?

- ABO identical or group O RBCs

- Rh compatible

- Compatible with maternal serum or an eluate from infant's cells

- <7 days old

- Irradiated

- CMV negative or leukoreduced

- Hgb S negative

- AB plasma

Reconstituted whole blood used for exchange transfusion consists of ______ + ______.

RBCs + plasma

RhIg is a concentrated solution of ______.

IgG anti-D

1mL dose of RhIg = ______ug.

300ug

Equation for vials of RhIg

Number of vials of 300ug RhIg = volume fetal bleed/30mL

RhIg is used to remove fetal cells from maternal circulation to prevent ______.

Rh(D) immunization

Without RhIg, Rh(D) negative mothers of D positive infants could form ______.

anti-D

When is RhIg administered?

Postpartum, post-abortion/miscarriage, following maternal trauma

Ideally within 72 hours

Antepartum, at 28 weeks

If a postpartum RhIg failure occurs, what happened?

The FMH is larger than a single RhIg dose can treat (more than 15mL fetal RBCs)

If the case of postpartum RhIg failure, ______ may be necessary.

more RhIg

For RhIg, ______ or Fetal Screen is used for excessive FMH.

Rosette Testing

If this test is positive, it must be followed with a ______ test.

quantitative

To perform the rosette test, maternal sample is incubated with ______, which coats D+ fetal cells present in maternal circulation.

anti-D

D+ indicator cells adhere to individual ______ cells, forming rosettes.

anti-D coated

Quantitation of FMH is done through use of the ______ stain.

Kleihauer-Betke

The Kleihauer-Betke stain will cause maternal cells to show up as ______.

ghost cells

The Kleihauer-Betke stain will cause fetal cells to show up as ______.

red/visible/intact

Once the Kleihauer-Betke stain is complete, ______ are counted.

fetal cells

______ is a more precise way to quantify FMH.

Flow cytometry

Kleihauer-Betke Stain

RhIg may also be used in the rare event of an inadvertent or purposeful transfusion of ______ RBCs into an Rh(D) negative female recipient.

Rh(D) positive