Hemolytic Disease of Newborns -Krafts Flashcards Preview

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Flashcards in Hemolytic Disease of Newborns -Krafts Deck (12)
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1
Q

Hemolysis diesase in newborn cause? (HDN)

A

blood- group incompatibility between mother and child

2
Q

HDN Mechanism:

A
  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
3
Q

Symptoms/ Consequences of hemolysis in baby?

From anemia?
From Hgb degradation?

A

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
4
Q

Kernicterus?

A

unconjugated bilirubin enters the brain

-not water soluble, binds to lipids

5
Q

Rh Incompatibility

A
  • 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

6
Q

Diagnosis/Prevention of Rh HDN:

A
  • DAT on baby
  • IAT for mom (indirect)
  • Rhogam (anti-D Ab) given @ 28 weeks and within 72 hrs of delivery
7
Q

Why is first baby safe but not second?

A

Initial exposure evokes IgM which CAN’T cross placenta

2nd Rh+ baby evokes IgG which CAN cross placenta

8
Q

Kleihauer-Betke Test:

A
  • 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
9
Q

Flow Cytometry Test for Fetal Cells:

A
  • Apply anti-HbF antibody to MOM’s blood
  • run flow
  • if present, baby cells are INTENSELY positive
10
Q

ABO Incompatibility

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

A

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

11
Q

Tx of HDN

A

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

12
Q

When do you give Rhogam?

A

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 :(