009 Hemolytic Disease of the Newborn PDF

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Hemolytic Disease of the Newborn & Rh Immune Globulin Chapter 19 CLS 306 Immunohematology Fall 2018, Wylen Won  IgG will cross placenta and attack the fetus’s RBC’s Rh(D) HDN Development HDN - Introduction  Caused by the incompatibility between the maternal antibody(ies) and the fe...

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Hemolytic Disease of the Newborn & Rh Immune Globulin Chapter 19 CLS 306 Immunohematology Fall 2018, Wylen Won

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IgG will cross placenta and attack the fetus’s RBC’s

Rh(D) HDN Development

HDN - Introduction  Caused by the incompatibility between the maternal antibody(ies) and the fetal RBCs  Fetal RBCs have antigen(s) that stimulate the production of antibody(ies) in the mother  Ag-Ab reaction occurs leading to the destruction of fetal RBCs  Is a disease where severity ranges from mild to severe o In utero - Destruction of fetal RBCs o Post Birth - causes anemia where unconjugated bilirubin is deposited in the body which results in jaundice; could advance to kernicterus / mental retardation to stillborn  2 common types of HDN that are routinely encountered: o ABO HDN o Rh(D) HDN  There is also HDN caused by other blood group antibodies, but these are rare. Usual Cause for Rh(D) HDN

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Ab formed after birth of first baby IgG Ab against Rh antigen formed

Dangers of HDN BEFORE Birth  Antibody(ies) cause destruction of fetal RBCs  Fetal Anemia  Fetal Heart Failure

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Hydrops Fetalis could develop as a result of Erythroblastosis Fetalis Fetal Death

Hydrops Fetalis & Bilirubin Conjugation

Dangers of HDN AFTER Birth  Antibody(ies) continue to cause destruction of fetal RBCs  Anemia  Hepatomegaly  Splenomegaly  Build up of unconjugated bilirubin jaundice o Kernicterus o Severe Retardation  Heart Failure HDN: Signs & Symptoms  Anemia (Hgb < 16 g / dL) - begins in utero  Increased bilirubin - begins after birth o Baby's liver does not conjugate bilirubin efficiently; Unconjugated (toxic) bilirubin increases in baby's circulatory system as RBCs continue to be destroyed o *If Hgb < 10 g / dL, may have to exchange transfuse  Jaundice / Kernicterus  Hepatomegaly & splenomegaly

Prenatal Care / Testing  ABO, Rh (including Du), & Ab screen on first visit  If Ab screen negative, repeat at 24 weeks: if positive, perform Ab ID  IgM and IgA not a problem because does not cross placenta  IgG Abs are of concern because IgG can cross the placenta o IgG1 and IgG3 are more efficient in RBC hemolysis than IgG2 and IgG4  If fetus possesses the antigen of the maternal antibody, the maternal antibody can cross the placenta and attack the fetal RBCs  The higher the maternal Ab titer, the higher the risk is for HDN  Test father to see if he is Ag positive (if he is negative, not a concern)  If Ab is significant and Dad is positive for Ag, perform Ab titers (> 32 is significant) on mother's serum.  If serum Ab titer is high, test amniocentesis for presence of Ag (amniocytes)

 Amniocentesis If HDN is suspected:  Amniocentesis performed (18-20 weeks)  Amniotic fluid bilirubin is a direct indicator of severity of HDN  Scan fluid in spectrophotometer at steadily increasing wavelengths to determine change in OD when 450nm is reached (absorbance of bilirubin)  If delta OD stays same or increases at a later scan, bilirubin levels are increasing (OD of fluid should decrease during 3rd trimester)

“Other” – unexpected immune antibodies other than Rh => Jk, K (Kell), Fy, S, etc.

Liley's Graph

Queenan Curve

Three Classifications of HDN  ABO: can occur at first delivery  Rh – anti-D alone or may be accompanied by other Rh antibodies => anti-C, -c, -E or -e.

ABO HDN  Most common form of HDN  Baby can have mild to moderate jaundice  Can occur at 1st delivery  Mother is “O” with IgG form of AntiA,B  Baby is “A” or “B”  May occur with first and subsequent pregnancies  Usually less severe than Rh HDN (babies A and B Ag not fully developed)  Occurs in only 3%; is severe in only 1%; and 32, consider further testing o Color Doppler Middle Cerebral Artery-Peak Systolic Velocity (MCA-PSV)

The measurement of the fetal MCA-PSV with color Doppler ultrasonography can reliably predict anemia in the fetus o Amniocentesis  For management, amniocentesis is uncommonly used, because MCA-PSV is noninvasive and gives the same information  The concentration of bilirubin pigment in the amniotic fluid measured by the ∆OD 450 nm procedure as pregnancy proceeds predicts worsening of the fetal hemolytic disease Intervention, if needed: Intrauterine transfusion becomes necessary when one or more of the following conditions exists.  MCA-PSV indicates anemia.  Fetal hydrops is noted on ultrasound examination.  Fetal hemoglobin level is less than 10 g / dL.  Amniotic fluid ∆OD 450 nm results are high.  Risks and benefits of intrauterine transfusion must be weighed and evaluated Always use O Neg packed cells for intrauterine transfusions AND, if other blood group antibody is present, must use antigen negative also. 

Intrauterine Transfusion

HDN: Lab Testing - Postnatal  Repeat ABO / Rh testing and Ab screen on mother  Determine ABO / Rh (including weak D) of baby; no reverse typing done  Perform DAT on baby RBCs (often strongly positive in Rh HDN)  Perform elution & Ab ID on eluate only if necessary (Ab found in eluate is usually maternal)  Enumerate # of fetal cells in mother, if necessary HDN: Lab Testing - Postnatal  Fetal Hgb Screen Test (Rosette Test) - demonstrates small number of Dpositive cells in a D-negative cell suspension; qualitative not quantitative  Kleinhauer-Betke test o Sample from mother treated with acid then stained o Fetal cells resistant to acid; mothers RBCs become “ghost cells” o Determine # of fetal cells in first 2,000 maternal cells counted o Volume of fetal cells = # of fetal cells x maternal blood volume divided by 2,000 o Vol. fetal cells / 30 = # vials given + 1 more vial HDN: Fetal Treatment After Birth, the neonate can develop hyperbilirubinemia from unconjugated bilirubin. Choice of treatments are:  Phototherapy (at 460 to 490 nm) is used to change the unconjugated

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bilirubin to isomers which are less lipophilic and less toxic to the brain. Exchange transfusion, if necessary (Hgb < 10 g / dL); see benefits of exchange o Use of whole blood to replace neonate’s circulating blood o Exchange with < 5 day old "O" type, D negative RBCs that are CMV (cytomegalovirus) negative, has been irradiated o Removes high levels of unconjugated bilirubin to prevent kernicterus o "AB" plasma (prepare RBCs from whole blood units but use AB plasama to reduce amt of blood group Abs transfused), CMV negative

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weeks gestation and within 72 hours after delivery of infant if: o Baby is Rh positive o Rh of fetus is unknown, and o Mother is known to be negative for allo anti-D Administered following termination of any pregnancy / abortion & after amniocentesis in an Rh (-) mother Dosage calculated using results of the Kleihauer-Betke test

Rh Immune Globulin

Rh Factor Sensitization Prevention

HDN - Fetal Treatment Beneficial Effects of Exchange Transfusion: 1. Removal of bilirubin 2. Removal of sensitized RBCs 3. Removal of incompatible antibody 4. Replacement of incompatible RBCs with compatible RBCs 5. Suppression of erythropoiesis (reduced production of incompatible RBCs Rh (D) HDN: Maternal Treatment  Rh Immune Globulin full dose (300 ug) - approx. 1 ml given intramuscularly to mother at 28

Other Uses of Rh Immune Globulin  Following accidental transfusion with Rh(+) red cells o Intramuscular injection may not be the choice of therapy may use IV Rh Immune Globulin, e.g., WinRho o Must calculate the amount to be given based on how much Rh(+) RBCs were transfused

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Treatment of Idiopathic Thrombocytopenic Purpura (ITP) o Elevates the platelet count in these types of patients

IV Rh Immune Globulin (WinRho)

Transfuse an Rh negative person with Rh positive blood IVIG can be used to treat hyperbilirubinemia. IVIG competes with Fc receptor on macrophages in spleen, thus decreasing amt of hemolysis. Treatment of ITP

HDN Comparison: ABO vs Rh(D) Characteristic First pregnancy Disease predicted by titers Antibody IgG Bilirubin at birth Anemia at birth Phototherapy Exchange transfusion Intrauterine

ABO Yes No Yes (antiA,B) Norm Elevate No Yes Rare None

Rh(D)

Rare Yes Yes (anti-D) Elevated Yes Yes Common Sometimes Rare

transfusion Yes Spherocytosis HDN Caused by Other Antibodies  Uncommon, occurs in ~0.8% of pregnant women. xa  Immune allo antibodies usually due to: anti-E, - c, -Kell, -Kidd, or -Duffy.  Anti-K o Disease ranges from mild to severe o Over half of the cases are caused by multiple blood transfusions o Is the second most common form of severe HDN HDN Caused by Other Antibodies...