Bilirubin index jaundice in newborns

The bilirubin in the newborn's blood is the basis for assessing the level of jaundice in the baby. Combining the high bilirubin index in infants with the age, health status, and clinical manifestations, the doctor will prescribe appropriate therapy. Let's find out the causes and consequences when the bilirubin level in the blood of babies is high through the article below.

In the body, when red blood cells degrade and break down, the hemoglobin in red blood cells breaks down into bilirubin, a yellow pigment, and excretes them through the intestines. Unlike adults, babies have a high number of red blood cells and they are constantly being broken down and replaced. However, the liver in newborns is not yet complete, and at the same time, the microflora in the intestines is still poor, so bilirubin is not eliminated and reabsorbed into the circulatory system, causing jaundice.
The bilirubin in the newborn's blood is an indicator of the bilirubin concentration and shows the level of jaundice in the baby. The normal bilirubin level is prescribed as follows:
Total Bilirubin: Less than 10mg/dl or 171μmol/L in neonates and between 0.3 - 1.2 mg/dl or 5.1 - 20.5 μmol/ L in infants over 1 month of age. Direct bilirubin: From 0 - 0.4 mg/dl or 0 - 7 μmol/L. Indirect Bilirubin: From 0.1 - 1.0 mg/dL or 1 - 17 μmol/L. Direct bilirubin/total bilirubin ratio: Less than 20%. The level of bilirubin in the blood of a newborn is usually high in the first days after birth and gradually decreases in the following days. When testing bilirubin to check the level of jaundice in children, depending on the age and risk of the disease, the doctor will recommend a treatment regimen suitable for the bilirubin level.

Causes of high bilirubin in newborns include:
Physiological: Neonatal jaundice is a transient phenomenon, common in both sick premature babies or healthy term babies. The infant's body continuously produces red blood cells and bilirubin, which, combined with a low clearance and bacterial concentration, causes bilirubin levels to rise. At that time, the concentration of total bilirubin in the blood can increase to 18 mg/dl when the baby is 3 - 4 days old. But then, this concentration will gradually decrease, the child will stop having jaundice without treatment. Pathological: High bilirubin in neonates due to pathological causes is defined when the baby has jaundice during the first 24 hours after birth and persists for more than 2 weeks. Blood tests show total bilirubin levels higher than 18 mg/dL and hyperbilirubinemia of more than 5 mg/dL per day. The level of jaundice in children is also more severe, with yellowing of the whole body, yellowing of the eyes, accompanied by vomiting, fatigue, or crying. The conditions causing this condition are known to be neonatal hepatitis , cholestasis , neonatal sepsis .

Depending on the cause of hyperbilirubinemia, the consequences may or may not be harmful. In some cases, regardless of bilirubin levels, spontaneous jaundice is still dangerous for infants. And when the bilirubin in the baby's blood rises to a certain level, it will be assessed as causing harm. This threshold depends on the age, the degree of preterm birth and the child's health status, specifically:
Full-term and healthy newborn: When the bilirubin in the blood is higher than 18 mg/dL, equivalent to 308 μmol/L. Premature babies, children with sepsis, low body temperature, hypoxemia: There is no such thing as a safe increase in bilirubin, the higher the bilirubin level, the higher the risk of toxicity. Consequences of high levels of bilirubin in the newborn's blood include:
Neurotoxicity: This is the main consequence of hyperbilirubinemia in newborns and leads to acute encephalitis, cerebral palsy, heart failure. reduced motor function, poor cognition. Jaundice of the cerebellum: This is the most serious consequence, but it is very rare and can be prevented. Cerebral palsy is a condition in which bilirubin is deposited in the nucleus and basal ganglia of the brain stem and attacks the blood-brain barrier.

For physiological hyperbilirubinemia, the baby only needs to be closely monitored without treatment, the jaundice will disappear on its own when the baby is 2 weeks after birth, when the baby's liver is fully developed and the baby is breastfed. full. However, neonatal jaundice needs to be treated when bilirubin levels are too high, to avoid brain complications caused by bilirubin attacking the brain and causing damage. In premature babies and in poor health, there are When the bilirubin index is elevated, the treatment depends on the age and clinical manifestations in the child. Currently, treatment of high bilirubin status in newborns includes 2 main methods: phototherapy and blood transfusion.
4.1 Illumination Phototherapy (also known as phototherapy), is a method of using a special lamp, with blue light and a wavelength between 400 - 500 nm, the extreme point corresponding to the absorption peak. Bilirubin receptors have wavelengths in the range 450-460 nm. The light from the lamp will pass through the skin and break down indirect bilirubin molecules in the fat layer below the skin, then they are eliminated by the liver and kidneys.
In children diagnosed with pathological jaundice due to indirect hyperbilirubinemia, the child is indicated for phototherapy after the first 24 hours when there are no signs of neurotoxicity. Indications for prophylactic phototherapy when the bilirubin index is high in infants with hemolytic disease, large skulls, serous tumors, premature babies, specifically:
Premature babies from 35 weeks of gestation: Indications irradiation when bilirubin is higher than 12 mg/dL (equivalent to 205.2 μmol/L). Phototherapy is possible for 25-48 hours postpartum when bilirubin is higher than 15 mg/dL, for 49-72 hours when bilirubin is 18 mg/dL, and over 72 hours when bilirubin is 20 mg/dL. Premature babies under 35 weeks of gestation: The threshold for bilirubin to be treated is lower than that of children from 35 weeks of age due to a higher risk of toxicity.

Note, light when the bilirubin level in the blood of the newborn is high, the baby's clothes need to be removed but the eyes and genitals must be covered. Children are rotated frequently to increase exposure to lights, intermittently or continuously.
In full-term and healthy babies, after 3 hours of light exposure, the baby can be taken out to change diapers or breastfeed. Phototherapy is the mainstay of treatment in neonates with hyperbilirubinemic jaundice, as most infants respond well.
4.2 Blood Transfusion Transfusion is a treatment for jaundice caused by high bilirubin in newborns that allows rapid elimination of bilirubin, indicated in cases where the blood bilirubin level is too high to be dangerous to the body. child's health (common in children with immune hemolysis). This technique involves taking a small amount of the baby's blood and replacing it with another amount of blood.
Indications for blood transfusion in case of high bilirubin index in term neonates are as follows:
When bilirubin ≥ 20mg/dL in 24 - 48 hours. When bilirubin ≥ 25 mg/dL after 48 hours. The child was given light but it was not effective. As soon as the baby is born, if the bilirubin is already higher than 25 mg/dL at the initial examination, be prepared for a blood transfusion in case phototherapy does not reduce the bilirubin. For premature babies, depending on the week of age, the threshold for bilirubin for blood transfusion is different.
Depending on the cause of the high levels of bilirubin in the blood of a newborn, the doctor will assess whether it is dangerous or not and prescribe appropriate treatment to reduce bilirubin levels.
Pediatrics Department - Vinmec International General Hospital is the address for receiving and examining diseases that babies are susceptible to, including jaundice. At Vinmec, it is equipped with a safe and easy-to-implement lighting system, babies can still breastfeed when under lights, can be combined with 10% Glucose infusion. In addition, at Vinmec, there are many types of projector lamps suitable for each jaundiced object that needs to be illuminated: Crib-shaped lights (children lie directly on top, dual lights that project above and below (used in cases where lights are needed). positive), blanket lamps, bags wrapped around the young (very convenient for mothers to take care of the baby: just pick it up to breastfeed, light up). effective or the child has late severe jaundice, has too high levels of bilirubin in the blood, the doctor will prescribe the use of blood transfusion as a last resort. circulating in the blood vessels, leading to a decrease in blood bilirubin and thereby also a decrease in extracorporeal bilirubin.