11 - HEMOLYTIC DISEASE OF THE NEWBORN

Ervthroblastosis Fetalis (EF)

Hemolytic Disease of the Fetus and the Newborn (HDFN) is also called?

Hemolvtic Disease of the Fetus and the Newborn (HDFN)

It is a feto-maternal incompatibility.

HDN

the destruction of the RBC of the fetus and neonate by antibodies produced by mother

HDFN

The mother can be stimulated to form antibodies by previous pregnancy or transfusion or a small number occur during the pregnancy itself.

IgG

In HDFN, what class of Ig antibodies are only actively transported across the placenta, where other classes such as IgA and IgM are not?

HDN

The IgG antibodies are directed against antigens on the fetal RBC that were inherited from the father.

Anemia

The sensitized RBC are destroyed by the fetal reticuloendothelial system, resulting in what condition?

• severe anemia ; erythroblasts

• hepatosplenomegaly ; portal hypertension and hepatocellular damage

• Severe anemia ; hypoproteinemia ; hydrops fetalis

• indirect ; direct

• hyperbilirubinemia and jaundice

• 18 mg/dl ; kernicterus

PATHOGENESIS OF HDN:

• The destruction of RBC results to _____________, which then simulates the fetal bone marrow to produce RBC at an accelerated rate even to the point that ____________ are released into the circulation. Hence, HDN is called erythroblastosis fetalis.

• lf fetal bone marrow cannot cope up with the rate of RBC production, hematopoietic tissues of spleen and liver are under stress and become enlarged (_________________________), resulting to (2).

• _____________ along with ______________ caused by decreased hepatic production lead to high-output cardiac failure with generalized edema, effusions and ascites. This condition is called _______________, which develops at 18 to 20 weeks gestation.

• The hemoglobin released through RBC destruction are metabolized into _________ bilirubin, which then crosses the placenta and conjugated in the maternal liver to __________ bilirubin prior to excretion.

• After birth, the newborn liver cannot conjugate bilirubin efficiently (especially in immature infants), thereby leading to (2).

• The indirect bilirubin (or unconjugated bilirubin) can reach levels beyond ________ and if left untreated can cause __________ (bilirubin deposits in the brain) or permanent damage to parts of the brain.

ABO HDN

Most commonly seen and often less severe

ABO HDN

The mother is Type 0 and the infant is either Type A, B or AB

Rh HDN

Usually the most severe

Rh HDN

Mother is Rh negative and the infant is Rh positive

HDN

It is caused by other antibodies (other than ABO and Rh antibodies), which include:

• Rh antibodies: anti-C, anti-E, anti-c, anti-e

• Kell system antibodies: Anti-K, anti-k

• Duffy system antibodies: Anti-Fya, anti-Fyb

• Kidd system antibodies: Anti-Jka, anti-Jkb

• MNSs system antibodies: Anti-S, anti-s

• Anti-Lea, anti-Leb

• Anti-I

• Anti-P1

ANTIBODIES THAT ARE NEVER IMPLICATED IN HDN (3)

• Feto-maternal hemorrhage or FMH

• father ; subsequent

• maternal anti-Rh antibodies ; fetal positive cells

• anemia

• macrophages

RH HDN

Mechanism:

• During gestation and particularly at delivery (when placenta separates from the uterus), fetal RBC enters the maternal circulation (_________________________________)

• The fetal RBC carrying the Rh antigen (inherited from the ________), immunize mother and stimulate the production of anti-Rh antibodies. Once the mother is immunized to Rh antigen, all __________ offspring inheriting the Rh antigen will be affected

• The __________________ cross the placenta and binds to the ___________________

• The sensitized RBC of the fetus are destroyed (hemolyzed) by the fetal reticuloendothelial system, resulting in ______

• The lyzed RBC are then removed from the circulation by the _________ of the spleen

unaffected

In Rh HDN, the Rh-positive first born infant of an Rh-negative mother is ___________ because of the mother has not been immunized

• Rh (D) or weak D negative ; anti-D

• Rh (D) or weak D positive ; positive ; anti-D

The findings in Rh HDN include:

• The mother is ____________________________. The antibody screen of the mother is positive for ______.

• The baby is _______________________________. The direct antiglobulin test is ________. After elution, ______ is found in the eluate.

First pregnancy

During delivery, Rh antigens enter mother’s circulation through breaks in the placenta

Mother makes anti-Rh antibodies

Subsequent pregnancy

Mother has anti-Rh antibodies

Anti-Rh antibodies cross the placenta and destroy fetal RBCs

ANTIBODY TITER OF MATERNAL SERUM

PARALLEL TESTING

Antibody titer

It is determined by performing a set of serial dilutions of mother's serum and reacting the diluted serum with Rh-positive cells

ANTIBODY TITER OF MATERNAL SERUM (PARALLEL TESTING)

As pregnancy progresses, serum antibody titers are determined from the mother's blood 4 weeks apart

ANTIBODY TITER OF MATERNAL SERUM (PARALLEL TESTING)

A significant change is when the titer increases by TWO tubes or more (positive). If the titer remains stable, the fetus most likely does not have the antigen that corresponds to the antibody in mother's serum

ANTIBODY TITER OF MATERNAL SERUM (PARALLEL TESTING)

If the titer significantly increases, decisions on treatment of the baby must be made. Interventions such as intrauterine transfusion may be done before birth whereas exchange transfusion is an option after birth

cord blood or a capillary blood

Specimen for testing neonates:

Neonates are tested using either (2) sample collected from the heel

thoroughly washed with isotonic saline

Specimen for testing neonates:

When a cord blood is contaminated with Wharton's jelly, RBC must be ____________________________________ prior to testing

false positive agglutination

Specimen for testing neonates:

The sticky nature of Wharton jelly may-cause?

1. ABO forward grouping (reverse is not performed since the infant has not developed antibodies)

2. Rh typing

3. DAT

Tests done on neonates (3)

eluate

Tests done on neonates:

If DAT is positive, what may be performed on the sample?

Administration of Rh immune globulin (Rh lg) to the mother

Prevention of HDN

Rh Ig

a concentrated anti-D

Rh Ig

Ilt is a human product commercially purified, tittered and packaged for sale under trade names such as Rho Gam

300 ug

first

300-ug

30 ml

Rh Ig is packaged in ______ doses for use with any pregnancy beyond the ____ trimester. A _____ dose can neutralize up to ____ of fetal Rh-positive fetal whole blood

1. Rh-negative or D-negative

2. Antibody screen negative for anti-D

1. Rh-positive (or potentially Rh-positive)

Criteria for administration of Rh lg:

• Mother must be (2)

• Infant must be (1)

• Rh-positive fetal RBC

• fetal Rh-positive cells ; no antibody

RH HDN PREVENTION OF RH HDN

Mechanism of Rh Ig:

• Rh lg (or conc. Anti-D) coats ____________________ that entered the maternal circulation. The antibody coated fetal RBC are recognized as foreign by the mother as abnormal and hence removed from her circulation

• Due to immediate neutralization of ______________________, the mother has no opportunity to process the antigen hence; the mother forms _____________

• 28th ; ante-natal

• 72 ; post partum

Methods of administration of Rh lg:

• Rh lg is routinely administered to the mother twice:

  • At ___ weeks gestation (___________)

  • Within ____ hours after giving birth of an Rh-positive infant (____________)

1. Following the termination of any pregnancy (spontaneous or induced abortion and ectopic pregnancy)

2. After amniocentesis in an Rh-negative mother

3. After chronic villus sampling

4. After abdominal trauma

5. After accidental or inadvertent transfusion

Rh lg is also administered (5)

FETOMATERNAL HEMORRHAGE (FMH)

May occur either before or during delivery that may result in more than 30 mL of fetal blood passing into the maternal circulation

1. Fetal Screen Test (qualitative test)

2. Kleihauer-Betke Acid Elution Stain (quantitative test)

Tests to determine the extent of FMH (2)

FETAL SCREEN ROSETTE METHOD

Cells obtained from mother's blood are incubated with anti-D reagent. This allows attachment of anti-D to fetal cells in the sample

FETAL SCREEN ROSETTE METHOD

After incubation, cells are washed to remove excess antibody

FETAL SCREEN ROSETTE METHOD

Indicator cells (Rh-positive cells) are added. If fetal RBC have attached anti-D antibody during incubation, the Rh-positive indicator cells will attach to free arm of the anti-D that are attached to fetal RBC

FETAL SCREEN ROSETTE METHOD

The binding of the indicator cells will occur so that they surround the fetal cells and appear as a rosette (POSITIVE)

FETAL SCREEN ROSETTE METHOD

Patient's test results must be compared with positive and negative controls

KLEIHAUER-BETKE ACID ELUTION STAIN

The method consists of a buffer with an acid pH.

When applied to thin smears of a mother's blood, this buffer will cause the mother's RBC to burst and lose hemoglobin while fetal RBC are resistant and remain intact.

pale ghost cells

dark pink

KLEIHAUER-BETKE ACID ELUTION STAIN:

The smear is then stained.

Adult cells appear?

Fetal cells stain?

Fetal cells

2,000 cells

KLEIHAUER-BETKE ACID ELUTION STAIN:

All cells are counted in a field with a tally counter. __________ are counted a second time as a separate count. A total of __________ are counted and the numbers of fetal RBC are counted in the total

No. of fetal cells / 2000 × 100 = %

KLEIHAUER-BETKE ACID ELUTION STAIN:

The percentage of fetal cells in total 200o cells counted is computed?

The total volume of FMH is calculated by multiplying the percentage by 50

The number of vials of Rh Ig is determined taking into consideration that each vial of 300 ug can counteract 30 ml of fetal blood

50

KLEIHAUER-BETKE ACID ELUTION STAIN:

The total volume of FMH is calculated by multiplying the percentage by?

30 mL

KLEIHAUER-BETKE ACID ELUTION STAIN:

The number of vials of Rh Ig is determined taking into consideration that each vial of 300 ug can counteract how many mL of fetal blood?

FMH

The dosage of Rh Ig is dependent on the extent of?

• 50

• 30

The methods of determining the dosage

Simple method:

• Multiply the percentage of fetal cells by ____ which give the volume of FMH in mL

• The calculated volume of FMH is then divided by ___ to determine the number of required vials of Rh lg

mL of FMH = No. Fetal cells x maternal blood vol. / No. of maternal cells

No. of vials = mL FMH / 30

The methods of determining the dosage

Another method?

HDN

ABO Compatibility between the mother and newborn infant can cause?

Maternal

fetal

ABO HDN:

________ ABO antibodies that are IgG can cross the placenta and destroy the fetal RBC. However, destruction of _____ RBC rarely leads severe anemia

1. Onset of hyperbilirubinemia

2. Jaundice within 12-48 hours after birth

ABO HDN is more commonly manifested by (2)

phototherapy

exchange transfusion

The increasing level of bilirubin is treated by ______________ and seldom require ______________________

ABO HDN

It is usually mild because ABO antigens are poorly developed in the fetus

Yes

First pregnancy

ABO

Rare

First pregnancy

Rh

No

Disease predicted by titers

ABO

Yes

Disease predicted by titers

Rh

Yes (anti A,B)

Antibody IgG

ABO

Yes (Anti-D)

Antibody IgG

Rh

Normal

Bilirubin at birth

ABO

Elevated

Bilirubin at birth

Rh

No

Anemia at birth

ABO

Yes

Anemia at birth

Rh

Yes

Phototherapy

ABO

Yes

Phototherapy

Rh

Rare

Exchange transfusion

ABO

Common

Exchange transfusion

Rh

None

Intrauterine transfusion

ABO

Sometimes

Intrauterine transfusion

Rh

Yes

Spherocytosis

ABO

Rare

Spherocytosis

Rh

1. Intrauterine transfusion (IUT)

2. Early Delivery

3. Photo Therapy

4. Exchange Transfusion for Newborn

TREATMENTS OF HDN (4)

• 450 ; ll ; Ill

• 10g/dl

• Fetal hydrops

• fetal peritoneal activity ; cordocentesis

• 2 to 4 ; 34 to 36 ; mature

Intrauterine transfusion (IUT)

• Becomes necessary when one or more of the following conditions exist:

  • Amniotic fluid AOD ____ nm results are in high zone __ or in zone __ (absorbance of bilirubin)

  • Cordocentesis blood sample has hemoglobin level less than ____

  • ___________ is noted on ultrasound examination

  • In IUT, RBC is injected into the _________________________ where the RBC can be absorbed into the circulation. More recently, ______________ has been used to inject donor RBC

  • Once initiated, IUT is repeated every __-__ weeks until ___-___ weeks gestation or until lungs are ______ where early delivery can be performed

Early Delivery

Done to interrupt the transport of maternal antibodies to the fetus and to allow exchange transfusion

Photo Therapy

with ultraviolet light is done to destroy excess bilirubin in the blood (hyperbilirubinemia) and avoid the need for exchange transfusion

Exchange Transfusion for Newborn

The beneficial effects are:

• Removal of bilirubin

• Removal of sensitized RBC

• Removal of incompatible antibody

• Replacement of incompatible RBCs with compatible RBCs

• Suppression of erythropoiesis (reduce production of incompatible RBCs)

• O ; CMV ; Rh

• 7 days

• gamma irradiated

Selection of Blood for Exchange Transfusions:

• The preferred blood for newborn transfusion is Group RBC (compatible with mother), ___-negative, ___-negative

• The blood units must be less than ______ from collection

• Blood for fetal and premature infant transfusion should also be ________________ to prevent graft versus-host disease (GVH)