Hemolytic Disease of the Newborn--Krafts Flashcards
What is the most common potential cause of HDN?
Rh incompatability
How does extramedullary hematopoiesis negatively affect the fetus?
may obstruct organs
How does HDN cause heart and liver failure in newborns?
severe anemia causes hypoxic injury
How do you get hydrops fetalis from HDN?
liver failure: less albumin
heart failure: increased venous pressure
Jaundice is due to
increased indirect/non-conjugated billiruben
Kernicterus is
unconjugated billiruben building up in newborn brain, BBB isn’t very good–binds to lipid in brain
Mechanism of Rh-mediated HDN
- mother has to be Rh-
- treat always because father might be Rh+
- baby blood gets into mom’s circulation
- mom makes antibody (IgM first pregnancy) against baby Rh
- IgG (in second pregnancy) crosses placenta and attacks baby’s Rh+ blood
- boom: hemolytic anemia
When does Rh-mediated HDN become an issue?
usually 2nd Rh+ pregnancy for an Rh- mother, reactivation of response leads to IgG formation that can cross the placenta because it is a monomer!
What is the drug you give mom to prevent her from making antibodies against baby Rh?
rhogam
Mechanism of RhoGAM
- anti-Rh antibody
- injected into mother
- binds all of baby’s Rh+ blood in mom
- mom’s immune system doesn’t recognize the Fc region of these antibodies
- they are essentially hidden from the immune system
- mom doesn’t make antibodies against something that her body doesn’t see
Dosing of rhogam
depends on the amount of fetal blood in maternal circulation
Kleihauer-Betke and flow cytometry…
test the amount of fetal blood in mom
ABO-mediated hemolytic anemia occurs most often in mothers of this blood type
O
What is the preventative Tx for ABO-mediated HDN?
none–just going to have to deal with it
Tx of HDN
phototherapy
total exchange transfusion through umbilical vein
plasmapharesis for mother
high dose IvIg if you’re very, very desperate (throws wench in whole thing)
