Neonatal Jaundice

I survived my first week of college (I'm studying Health & Life Sciences at VU University Amsterdam).
So far, it's been an alright experience. I found out I really, really dislike cell biology, although I do like writing about disorders and ailments.
I just finished my first writing assignment regarding neonatal jaundice, and although I'm no expert, I'll be blabbering about it in this post.

The info regarding Neonatal Jaundice has been updated as of November 16th, 2012.
Neonatal Jaundice 
Also known as: Icterus Neonatorum.
Derived from the Greek word 'Ikteros', meaning jaundice, and the Latin word 'Neonatus', meaning infant.

What is jaundice anyway?
Alright, why in good heavens did I color neonatal jaundice yellow back there? Because it's a condition which causes your skin, mucous membranes and sclerae(white of the eyes) to turn yellow. [1]

What causes (neonatal) jaundice?
Jaundice is caused by an elevated level of the yellow-orange pigment called 'bilirubin' (bil-i-ROO-bin). Bilirubin is a breakdown product of hemoglobin, which is found in your red blood cells.
Your body continuously creates and breaks down red blood cells, and your liver is responsible for taking care of the waste products such as bilirubin. In order to get rid of bilirubin, your liver links it to two glucuronic acid molecules, and then transports it to the gallbladder.
Bilirubin is excreted in bile and urine. [1][2]

If for some reason bilirubin doesn't leave your body, it'll migrate to your skin and make you a temporary Asian (read: yellow). If you for some reason start turning yellow, you might want to get your liver and biliary tracts checked.

For neonates, the yellowing of the skin and sclerae is a common problem which appears a few days after birth and disappears about a week later. [1]

There are several causes for neonatal jaundice:
- Insufficient liver function
- Insufficient food intake
- Diseases/conditions such as Hepatitis.

During the fetal phase, the unborn child's blood differs from an adult's. The kid produces fetal hemoglobin(HbF) instead of adult hemoglobin(Hb). HbF easily binds oxygen(compared to Hb), making it a necessity when the child is still inside the mother's womb.
After birthing, it is no longer a necessity, and it is gradually broken down and replaced with regular Hb.[1][3]
Since breaking down Hb produces bilirubin, the child suddenly has to deal with a lot of waste products. At this age, the kid's liver is still growing and can't handle the excess waste products.[1]
Aside from this, the newborn's liver only links ONE glucuronic acid molecule to the bilirubin, instead of two. Because of this, it's easier for the bilirubin to get reabsorbed into the bloodstream.[2]
 
Another possible cause for neonatal jaundice is insufficient milk intake. This slows down its digestion, which in turn slows down the excretion of bile.[2]

Difference between HbF and Hb in more detail
To make sure the blood transports and diffuses oxygen and carbon dioxide in just the right way (it's a delicate process! Really!), the body uses allosteric regulation.
This is a process in which allosteric regulators stick to a protein in order to affect it in some way.
Hb is a protein, and one of the most important allosteric regulators is biphosphoglycerate (BPG). BPG binds itself to deoxygenated Hb to make sure the oxygen which will later bind itself to it will not cling to the Hb. Without BPG, the red blood cells won't readily give up oxygen.

The difference in HbF and Hb is that HbF contains two alfa-chains and two gamma-chains, whereas Hb contains two alfa-chains and two beta-chains. BPG generally doesn't bind to the gamma-chains found in HbF, which makes it a lot easier for oxygen to bind itself to HbF.[3]

Treating neonatal jaundice
Newborns with neonatal jaundice will receive light therapy (photo-therapy). They're exposed to blue light (this is not UV-light!) which helps the body process the bilirubin so it can get rid of it.
While the kid is receiving photo-therapy, the doctors will monitor the bilirubin levels in the blood.[5]

Aside from photo-therapy, mothers are advised to feed the baby (preferably with human milk) at least 8 times a day. This boosts the digestive system, so more bilirubin is excreted with the urine and feces.[2]

Complications
If the child is born with a yellow color and you're absolutely sure that none of the parents are Asian, you really should talk to a doctor. It could be hemolysis, which is when red blood cells burst prematurely. It could also be hepatic, meaning that the liver isn't functioning as it should.
When the child remains weak even though a lot of food is offered to him/her, is feverish and has trouble moving, call a doctor. Your baby could be suffering from Kernicterus.
Kernicterus is when bilirubin starts to build up in the brains. This could cause fever, brain damage, loss of hearing, strange or weak movements and ultimately, death.[4]

Enough for today.
See ya!

Sources
[1] Barthelomew, N., Fundamentals of Anatomy & Physiology, 9^th Edition, 2012

[2] Semmekrot, B.A., Vries, de, M.C., Gerrits, G.P.J.M., Wieringen, van, P.M.V., Optimale borstvoeding ter preventie van hyperbilirubinemie bij gezonde, voldragen pasgeborenen, October 12th, 2004
http://www.ntvg.nl/publicatie/optimale-borstvoeding-ter-preventie-van-hyperbilirubinemie-bij-gezonde-voldragen-pasgebor/volledig

[3] Wilber, A., Nienhaus, A.W., Persons, D.A., Transcriptional regulation of fetal to adult hemoglobin switching: new therapeutic opportunities, February 14th, 2011

http://bloodjournal.hematologylibrary.org/content/117/15/3945.full

[4] A.D.A.M., Kernicterus, May 9th, 2011
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004562/ 
[5] St Antonius Hospital, Hyperbili (bij kinderen), 2012
http://www.antoniusziekenhuis.nl/etc/aandoeningen/h/hyperbili/



This post was written by a former student of VU University Amsterdam / current student of the University of Amsterdam. I hereby give other students my permission to use the info provided in this blog for their own school assignments, but I cannot guarantee high marks.