Hemolytic Newborn Diseases

Question 1

Hemolytic Disease of Newborn

Answer 1

Hemolysis in a newborn or fetus caused by blood-group incompatibility between mother and child

Question 2

Mechanism of hemolytic disease of newborn

Answer 2

1. Baby inherits blood group Ag (from dad) that are foreign to 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

Extramedullary hematopoiesis

Answer 3

• -Trying to make red cells outside the marrow space. Just trying to make as many RBC’s as possible.
• -If enough of it, can clog up organs and prevent them from functioning properly.

Question 4

Cardiac decompensation

Answer 4

Too anemic and can’t get enough blood to organs

Question 5

Immune Hydrops

Answer 5

Edema. Fluid build-up behind heart or liver not making enough proteins (causing fluid in vascular space).

Question 6

Jaundice

Answer 6

Hb broken down into bilirubin. Usually not dangerous. Just want to prevent unconjugated bilirubin around.

Question 7

Kernicterus

Answer 7

If enough unconjugated bilirubin, can enter the brain. Binds to lipids and causes a lot of damage to the brain.

Question 8

Rh incompatibility characteristics (4 of them)

Answer 8

• Only the D Ag is involved
• Ab response depends on how much Ag mom is exposed to
• Initial exposure evokes IgM (which can’t cross placenta); first baby usually safe
• Second exposure evokes IgG; second baby may get HDN.

Question 9

Diagnosis of Rh HDN

Answer 9

DAT (baby), IAT (mom)

Question 10

Treatment of Rh HDN

Answer 10

Rhogam (anti-D Ab) admin at 28 wks and within 24 hrs of delivery. Must quantify amount of feto-maternal hemorrhage to dose Rhogam
–Rhogam can’t cross the placenta!

Question 11

Tests to dose Rhogam based on feto-maternal hemorrhage

Answer 11

Kleihauer-Betke test or flow cytometry

Question 12

Kleihauer-Betke test

Answer 12

1. Make smear of mom’s blood
2. Expose smear to acid bath (removes HbA)
3. Stain smear
4. Baby’s cells appear pink; mom’s appear ghostly

Question 13

Flow cytometry test for fetal cells

Answer 13

1. Use mom’s blood
2. Apply anti-HbF antibody
3. Run flow
4. Baby cells, if present, are intensely positive

Question 14

ABO incompatibility occurs in how many pregnancies? How many are severe?

Answer 14

25% of pregnancies. 1 in 200 are severe.

Question 15

ABO incompatibility protection

Answer 15

None

Question 16

ABO incompatibility reasons why it doesn’t cause more severe problems more often (3 points)

Answer 16

• -Most anti-A and anti-B Ab are IgM
• -Neonatal red cells express A and B poorly
• -Many cells besides red cells express A and B Ag (thus sopping up some of mom’s Ab)

Question 17

ABO incompatibility treatment

Answer 17

• -Mild cases: phototherapy
• -Severe: total exchange transfusion
• -Mom can undergo plasmapheresis.
• -High-dose IV Ig