qw098

zyzzbrah
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Oct 23, 2011
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Da fuq... have a theoretical paper case I can't get my head around.

Baby has jaundice within 18hours of being born... u do the usual workup:

Unconjugated bilirubin is high.
Blood type: Baby is A+, Mother O+
Direct coombs is positive

However... hemoglobin is @ 15.1g/dl which is perfectly normal. I'm confused as **** why this baby doesn't have anemia.. cuz I'm 100% sure this baby has erythroblastosis fetalis (aka hemolytic anemia of the new born due to ABO incompatibility)... can anyone enlighten me on this theoretical paper case :D
 

Entadus

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CBC? and is it warm or cold agglutination? (IgG or IgM?)
Did you get liver enzymes?
 

Entadus

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Infants get jaundiced all the time... ask yourself "how sick is this kid", take a look at the smear (it's probably going to be normal)
 

MCATUMOR

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Da fuq... have a theoretical paper case I can't get my head around.

Baby has jaundice within 18hours of being born... u do the usual workup:

Unconjugated bilirubin is high.
Blood type: Baby is A+, Mother O+
Direct coombs is positive

However... hemoglobin is @ 15.1g/dl which is perfectly normal. I'm confused as **** why this baby doesn't have anemia.. cuz I'm 100% sure this baby has erythroblastosis fetalis (aka hemolytic anemia of the new born due to ABO incompatibility)... can anyone enlighten me on this theoretical paper case :D
it is incorrect to say that ABO incompatibility is less serve than Rh. As someone with blood bank experience. ABO antigen are not fully developed at birth. Since they are not fully developed they are less likely to cause an immune reaction from the mom. Also ABO antibodies are predominantly IgM. IgM is too big to cross the placenta .
 

Donald Juan

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Coombs tests are not the most accurate way of monitoring clinically significant hemolytic disease of the newborn. The PPV is only about 50%.
 

MCATUMOR

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Coombs tests are not the most accurate way of monitoring clinically significant hemolytic disease of the newborn. The PPV is only about 50%.
The Coombs test only tell you if there is antibody attached to the cells, further testing is neccasry to determine if the attached antibody is significant.
 

Spirit of the Student Doc

Worrying will never change the outcome
Mar 24, 2014
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Da fuq... have a theoretical paper case I can't get my head around.

Baby has jaundice within 18hours of being born... u do the usual workup:

Unconjugated bilirubin is high.
Blood type: Baby is A+, Mother O+
Direct coombs is positive

However... hemoglobin is @ 15.1g/dl which is perfectly normal. I'm confused as **** why this baby doesn't have anemia.. cuz I'm 100% sure this baby has erythroblastosis fetalis (aka hemolytic anemia of the new born due to ABO incompatibility)... can anyone enlighten me on this theoretical paper case :D
Put 'em under light to reduce the bilirubin do not go nuts for an exchange transfusion immediately (No, I'm not joking, yes it happens and the nurse never catches it, the doctor is new, and if the lab tech doesn't catch it you are going to have a very bad situation.... also everyone in that situation should face discipline including the nurse.)

ABO HDFN: Is usually mild. When the mother is O she produces an >A,B antibody that is IgG. Whereas a A or B mom produces an >B or >A that is IgM (can't cross placenta, it's a gigantic pentamer w/ 10 binding sites). Also, A and B antigens are present on many cell types not just erythrocytes and, as alluded to earlier, A and B surface antigens are not fully developed at birth.

Rh HDFN: An Rh- mother produces an IgG3 and IgG1 antibody that is the most competent at crossing the placenta. (IgG has 4 subclasses 3 & 1 are the most effective at crossing the placenta while 2 & 4 do so at more marginal levels - the order from most to last is 3,1,4,2, a large gap exists between 1 & 4 and 2 is the largest IgG of the bunch so it has the most difficulty in crossing over...... Usually it's said 2 doesn't cross because it's next to near impossible for it to do so)

Thus,
-ABO-HDFN w/ POS DAT= IgG 1 sufficient in quantity to cause hemolysis
-ABO-HDFN w/ NEG DAT = IgG3 is sufficient in quantity while remaining too low for the DAT. (IgG3 is has an extreme affinity for the Fc region and is the most likely to start the Complement Cascade of all IgG subclasses)
-NO HDFN, but POS DAT = IgG 1/2 bound to RBC's but not enough to cause hemolysis (Also, 2 essentially can't cross the placenta anyways and has a weak affinity for the Fc region, 1 isn't as effective as 3... Essentially, enough IgG1 didn't cross over to have an actual impact).

Rh-HDFN is both 3 and 1 or sometimes just IgG 1


Hope that helps;)
 
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Spirit of the Student Doc

Worrying will never change the outcome
Mar 24, 2014
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The Coombs test only tell you if there is antibody attached to the cells, further testing is neccasry to determine if the attached antibody is significant.
I would dislike your post if I could.

If it's ABO or Rh HDFN it's ABO or Rh HDFN. No point charging the patient to do a pointless test where the results are known BEFORE running it. On the oddball chance it's anti-K1 or anti-c take the 15 minutes and test the fetal blood for the antigen (cheaper, quick, and more efficient). Also, it's a huge time killer nearly sideling a tech to just one pointless test.

And before you respond, this test in this scenario is only done because the BB automatically does so in certain hospitals. The doctor usually wants to know why you did it and then backs down when he realizes it's pointless moneymaking coming from straight up top. Garbage like this is the definition of frivolous testing.
 
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MCATUMOR

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I would dislike your post if I could.

If it's ABO or Rh HDFN it's ABO or Rh HDFN. No point charging the patient to do a pointless test where the results are known BEFORE running it. On the oddball chance it's anti-K1 or anti-c take the 15 minutes and test the fetal blood for the antigen (cheaper, quick, and more efficient). Also, it's a huge time killer nearly sideling a tech to just one pointless test.

And before you respond, this test in this scenario is only done because the BB automatically does so in certain hospitals. The doctor usually wants to know why you did it and then backs down when he realizes it's pointless moneymaking coming from straight up top. Garbage like this is the definition of frivolous testing.
Your post is totally pointless and misses the point I was trying to make. I think you need to take your ego down a notch.
 

Freezer

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In this case, an exact diagnosis is not needed for appropriate short term management. In your example, you are worried about anemia and hyperbilirubinemia. Get a retic count, daily CBC and Daily total Bili(direct hyperbilirubinemia does not jaundice so if you are jaundiced and totbili is high, you know its an indirect bilirubinemia). If retic is low, you should have a lower threshold to transfuse if given a low HgB. As for the indirect bili, plot your bili curve and use phototherapy if you feel bili formation is greater than bili excretion or if levels are significant enough to warrant a little boost in detoxification. Long story short, I dont treat EF on just a positive coombs test nor would I withhold treating a severe acute anemia should it arise because Coomb's was negative. Oh and make sure you ruled out hydrops!

An rH negative woman named Alice,
Meets an rH positive man from Dallas
With honeymoon's glitter
They'll have to consider
Erythroblastosis fetalis