If you’re a mother who just delivered a baby, you might have noticed a tinge of yellowish colour in the skin and the eyes of your newborn. That’s what we called neonatal jaundice.
Encountering this situation might put you in a panic mode, after all that is the last thing you want to see happening to your beloved baby.
But do not panic just yet, because neonatal jaundice is the most common problem in newborn.
In fact, half of the newborns will have mild to moderate jaundice in their first week of life.
What causes neonatal jaundice?
Basically neonatal jaundice can take place under physiological or pathological condition. The yellowish colour is due to the increased bilirubin level in the blood.
So how do we determine whether a newborn is having physiological or pathological jaundice?
In physiological jaundice, the signs appear within the first week of life. The total serum bilirubin level rarely exceeds 5mg/dL within 24 hours.
On the other hand, pathological jaundice will show on the first day of life, having bilirubin level that increases more than 5mg/dL within 24 hours.
By the way, pre-term infants tend to have more severe and persisting jaundice in both scenarios.
1.) Shorter RBC lifespan
This is caused by a rapid red blood cell turnover rate in the spleen because of their lower lifespan.
In a normal healthy adult, our red blood cell can live up to 120 days. While in the newborn, red blood cells have a life span of approximately 60-90 days only.
When red blood cells get broken down in the liver, they release haemoglobin. Then, the heme molecule in haemoglobin gets converted to unconjugated bilirubin. Since the unconjugated bilirubin is not soluble in the water, most of the bilirubin found in our blood are tightly bound to plasma albumin.
2.) Decreased hepatic conjugation of bilirubin
These unconjugated bilirubin are transferred to the liver to be conjugated, thus making them water soluble. Only after that, the conjugated bilirubin can be stored in the gall bladder as bile. When the body needs to digest fat, bile will be released to the small intestines through the common bile duct.
However, the conjugation process will not be feasible without the help of an enzyme called UDP-glucuronyltransferase. Now here’s the problem, many newborns do not have a mature glucuronyltransferase activity.
As a result, the level of unconjugated bilirubin will rise in the blood stream, thus giving the yellowish appearance.
3.) Increased enterohepatic reabsorption
Well, this is most prevalent when the baby is not well-fed after delivery. This could be due to various reasons such as insufficient nutrients or problem with breastfeeding.
As a result of the prolonged intestinal transit time, more bilirubin will be absorbed into the blood stream and transferred back to the liver. This will bring extra workload to the newly mature liver in newborns.
4.) Rare genetic disorders
There is an autosomal recessive hereditary disorder called Gilbert syndrome. In this disorder, the mutation in the UGT1A1 gene causes the under-production of UDP-glucoronyltransferase. This is especially prominent during illness, fatigue or starvation when the body is put under stress.
Gilbert syndrome affects mostly male gender due to genetic reason. There is no effective cure for Gilbert syndrome. If you are diagnosed with Gilbert syndrome, your doctor will advice you to try to avoid stressful situations that might trigger a flare up.
There are other rare genetic disorders such as Crigler-Najjar Syndrome, Dubin-Johnson Syndrome and Rotor Syndrome that will cause neonatal jaundice. Each disorder differs from each other by pathophysiological mechanism, extent of severity, presenting signs and laboratory investigation results.
5.) Red blood cell disorders
There is an array of red blood cell disorders that can cause neonatal jaundice. Ultimately, excessive breakdown of red blood cell will increase the release of haemoglobin into the bloodstream.
Blood group incompatibilities (ABO or Rh) is one of the most common causes of neonatal jaundice in newborns. This can occur in transfusing blood products that are not screened through in developing countries. In some developing countries, the scarce of resources often results in the inability of newborn and mother to be screened for various diseases.
Apart from that, there may be defects in the production of enzymes that play significant roles in the red blood cell metabolic pathways. In some cases, it is the structural abnormalities of the red blood cells that cause pathological jaundice. Some of the most common disorders include sickle cell anaemia, G6PD deficiency and hereditary spherocytosis.
You will notice whatever the pathophysiology behind is, it is the increased in unconjugated bilirubin level that causes neonatal jaundice.
Fortunately, physiological jaundice is not a serious issue as it is self-resolving within a few weeks in most of the cases. What you should be concerned is pathological jaundice, because it may indicate more severe underlying causes that warrant further investigations.
How does your doctor evaluate neonatal jaundice?
Certainly, a mild to moderate jaundice might not be obvious enough to be seen at first sight. If the jaundice is mild, perhaps it can only be detected through a blood test.
Having that said, an experienced doctor will almost never miss seeing a jaundiced newborn if there are solid reasons that raise his or her suspicion.
Initially your doctor will perform a visual inspection to see how severely the jaundice has affected your newborn. Some doctors prefer to use the Kramer’s Index to estimate serum bilirubin level. The Kramer’s Index states that once the hands and legs show yellow discolouration, serum bilirubin level is probably more than 15mg/dL already.
Studies have shown that the Kramer’s index is effective in evaluating a newborn with jaundice because it is a safe and non-invasive method. Therefore, it is recommended to introduce the use of Kramer’s index in hospital practice especially in places with limited resources.
Once the physical examination is done, your doctor will order a blood test to determine the level of bilirubin in the serum. If the total serum bilirubin level is increased, it is important to carry out the next step of evaluation, which is to find out whether the increase comes mainly from the unconjugated or conjugated form of bilirubin.
Besides that, the doctor will also take other parameters into consideration such as red blood cell count, haemoglobin, hematocrits, blood type and Rh factors to rule out different causes of neonatal jaundice.
If you are interested to find out how to interpret a blood test result, you can read here.
If indicated, your doctor may order other tests like G6PD assay or electrophoresis to find out if your newborn is at the risk of developing the aforementioned rare genetic disorders.
Another quick way to test for neonatal jaundice is through the use of ultrasonography. This is because some infants are born with abnormal bile ducts, in some cases it might even be absent. So the bile flow might be obstructed, causing it to backflow and leak into the bloodstream.
The consequence? You guessed it right, neonatal jaundice.
How to treat neonatal jaundice?
Sometimes when the line between physiological and pathological jaundice is obscured, the doctor might suggest to put your newborn in close observation. This is done by repeated blood test to trace the bilirubin level. The purpose of doing so is to avoid unnecessary treatment option that might put the baby in the risk of complications.
Once the doctor has confirmed that your baby needs a treatment after considering various factors and referring to the table of treatment algorithm (shown in below).
As you can see, there are two main treatment methods to bring the bilirubin level back to baseline. Different level of serum bilirubin will indicate whether or not treatment is needed, if so which method is preferable.
The most common method is called phototherapy. Remember those blue-ray boxes in the hospital where newborns are placed?
By putting the newborn into the chamber, the blue-ray will help to increase the rate of conversion of unconjugated bilirubin to conjugated bilirubin.
Alternatively, exchange transfusion is also used to treat neonatal jaundice, albeit less frequently because of its invasiveness. The idea behind this treatment is to remove some of the newborn’s blood and replace it with the donor’s blood.
More importantly, the doctor has to find out the underlying causes of the neonatal jaundice. For example if the newborn has an abnormally formed biliary tract, the baby will need to undergo surgical treatment for permanent cure.
If the above treatment methods are contraindicated or not available for use, bilirubin level can also be lowered through the use of medication.
Some studies have shown that Phenobarbitals, which is a type of anti-seizure drug is effective in lowering the level of serum bilirubin. However, they are not used to treat physiological jaundice.
What if neonatal jaundice is not treated?
While most neonatal jaundice cases are not dangerous if they are recognised and treated promptly.
But in some cases when the newborn is left untreated, the high level of serum bilirubin level may put the baby’s life in danger.
Even if the life of the baby is secured, there is a high chance of brain damage known as kernicterus.
Recent study suggest that a serum bilirubin level higher than 20mg/dL is the cutting point for brain damage to occur.
Let me know if you have experience in dealing with neonatal jaundice or if you have any other questions, please leave a comment in the comment section down below.