Bilirubinemia in Neonates

[Gfunk6]

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While on my newborn nursery rotation, this question came up: Why does bilirubinemia progress craniocaudally?

None of us, including the attending, knew the answer. I've googled it and looked in PubMed but can't find a reason.

Could any of you guys in the Peds forum shed some light on this?

 

[jackjinju]

For what it's worth, no one I knew knew the answer either.....or thought that there was a defined answer.

Andrew PL-2

 

[oldbearprofessor]

For what it's worth, no one I knew knew the answer either.....or thought that there was a defined answer.

Andrew PL-2

Greetings from the NICU.

Here's the answer. I don't know what it means so don't ask

Regards

OBP

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=9197337

The influence of several clinical factors on the cephalocaudal progression of neonatal jaundice was investigated in 377 newborns admitted to the neonatal intensive care unit for various reasons. Multiple regression analysis showed that, beyond the relationship to the plasma bilirubin concentration, the cephalocaudal color gradient was significantly, negatively related to gestational and postnatal age. Furthermore, the cephalocaudal progression of jaundice seemed more extended in females compared to males. The results are in agreement with a theory explaining that the cephalocaudal color gradient is due to conformational changes in the newly formed bilirubin albumin complexes.

 

[Gfunk6]

Thanks Prof!

The key term that I was missing was "cephalocaudal." I was using "craniocaudal." Now I can impress my attending with my knowledge of "newly formed bilirubin albumin complexes." 😎

 

[kristing]

Here's another question...

If there is a source of the bilirubinemia (eg hematoma of some sort), is the risk for kernicterus the same as if it were pathologic jaundice with the same levels of bilirubin? I just thought of this and I'm kind of thinking as I type.

 

[Homunculus]

Here's another question...

If there is a source of the bilirubinemia (eg hematoma of some sort), is the risk for kernicterus the same as if it were pathologic jaundice with the same levels of bilirubin? I just thought of this and I'm kind of thinking as I type.

it doesn't matter where it comes from-- unconjugated bili is unconjugated bili. with a hematoma, i imagine the bump is transient, but with pathologic processes the rise will be more brisk and sustained-- necessitating some type of treatment. I've seen some nasty hematomas that weren't hemolytic setups that peaked out around 10-13 then returned to baseline.

speaking of bili-- anyone have much experience with transcutaneous bilis? we recently started testing all the kiddos before discharge with it. so far it seems to be *fairly* accurate under 15, but loses it's serum correlation if you get much higher than that.

bilis are interesting. i'm currently on a NICU block, so we are more careful obviously, but on my healthy newborn rotation there seemed to be as many techniques of bili management as there are attendings-- some get all bent out of shape over a 12 at 48 HOL, others couldn't care less, lol.

--your friendly neighborhood neo bili checkin' caveman

 

[oldbearprofessor]

In general all unconjugated bili is comparably toxic. But, there is some evidence that sepsis makes one more susceptible to kernicterus just as premies are more susceptible at any bili level.

The AAP has recently revised its bili management guidelines and published an extremely detailed set of "guidelines" which are designed for full-term infants without hemolytic disease. This will greatly reduce the treatment variabillity in that group as they become more widely adopted. They allow for transcutaneous measurement as a screen.

Regards

OBP

 

[Tazmaniac]

The explanation I have heard from the NICU attendings for craniocaudal progression of jaundice:

The face (and thereby sclera) have exellent perfusion, which has better perfusion than the trunk, which has better perfusion than the extremities (preserve the brain, then heart, then fingers). Therefore bilirubin deposits into the face with noticeable jaundice at a low bili level of 4-5 and higher levels are required to see it in the trunk and legs.