Hemolytic Disease of Newborns -Krafts

Question 1

Hemolysis diesase in newborn cause? (HDN)

Answer 1

blood- group incompatibility between mother and child

Question 2

HDN Mechanism:

Answer 2

1. Baby inherits blood group Ag that is different than mom
2. Baby’s blood gets into mom’s circulation
3. Mom makes Ab to baby’s blood group Ag
4. Mom’s Ab attack baby’s RBCs

Question 3

Symptoms/ Consequences of hemolysis in baby?

From anemia?
From Hgb degradation?

Answer 3

Anemia –>

1. extramedullary hematopoiesis
2. Heart failure –> Hydrops (edema)
3. Liver failure –> not making albumin –> decrease osmotic pressure –> edema

Hbg degradation –> Bilirubin

1. Jaundice (unconjugated)
2. Kernicterus

Question 4

Kernicterus?

Answer 4

unconjugated bilirubin enters the brain

-not water soluble, binds to lipids

Question 5

Rh Incompatibility

Answer 5

• D antigen
• Response depends on how much blood gets into mom

-Initial exposure evokes IgM (can’t cross placenta so 1st baby is safe)

2nd exposure evokes IgG, second baby may get HDN

Question 6

Diagnosis/Prevention of Rh HDN:

Answer 6

• DAT on baby
• IAT for mom (indirect)
• Rhogam (anti-D Ab) given @ 28 weeks and within 72 hrs of delivery

Question 7

Why is first baby safe but not second?

Answer 7

Initial exposure evokes IgM which CAN’T cross placenta

2nd Rh+ baby evokes IgG which CAN cross placenta

Question 8

Kleihauer-Betke Test:

Answer 8

• used to see how much Rhogam to give depending on how much fetal Hbg is in mom’s blood
• Baby’s cells appear pink, mom’s appear ghostly

Question 9

Flow Cytometry Test for Fetal Cells:

Answer 9

• Apply anti-HbF antibody to MOM’s blood
• run flow
• if present, baby cells are INTENSELY positive

Question 10

ABO Incompatibility

FYI: 25% of pregnancies but only severe in 1/200 cases

Answer 10

Most anti-A and anti-B Abs are IgM so they don’t cross placenta :)

babies don’t have full expression of A and B antigens

-No prevention tx

Question 11

Tx of HDN

Answer 11

Mild–>phototherapy

Severe–> total exchange transfusion (replace all baby’s blood)

Mom can undergo plasmapheresis

-High dose IV immunoglobulin if immune response isn’t stopped with other tx’s. Throws a wrench in the response

Question 12

When do you give Rhogam?

Answer 12

If you have Rh- mom, give Rhogam during FIRST pregnancy and subsequent ones

Trying to prevent the mom from making antibodies.
If you miss giving Rhogam and mom has Rh+ baby, you’ve missed your shot and now she has antibodies that could cause issues in subsequent pregnancies :(