Babies are not miniature adults. They have a different physiology compared to that of adults. This is especially evident in the newborn period, when many adaptive changes take place in the various organ systems after birth, to survive independently after being in the protective environment of the mother’s womb.
Causes of juvenile jaundice
Jaundice or hyperbilirubinemia is a common occurrence during the newborn period. While most often, it is physiological and occurs due to the immaturity of the liver, rarely it can be due to disease conditions.
Bilirubin is a breakdown product of heme, a pigment found in the red blood cells. This pigment is metabolised by the liver and is then excreted through the urine and faeces.
All newborns will show some rise in the bilirubin levels in the first week of life and about 60% become visibly jaundiced. It appears on the 3rd day, peaks at 5-6 days and returns to normal by 8-10 days.
This is termed physiological jaundice, implying it is not a disease state. It occurs due to a combination of factors. Babies have a greater red blood cell mass and their life span is shorter. After birth, red cells are destroyed and new cells are formed at a faster rate. Bilirubin is released at higher levels than the immature liver is able to handle, resulting in jaundice. As the liver matures, it is better able to handle the bilirubin load and the red cell turnover also slows down, with a spontaneous resolution of the jaundice.
More risk factors of newborn jaundice
When the baby is preterm, the liver is even more immature and the bilirubin level can get quite high. When it exceeds certain levels, it can enter the brain and damage certain areas. This is termed as Kernicterus and causes one type of cerebral palsy. Some other risk factors which lead to higher levels of jaundice are dehydration and excessive weight loss, bruising and blood clot in the scalp, baby born to a diabetic mother and a previous sibling who may have required phototherapy.
Breast milk may increase hyperbilirubinemia in healthy babies. Since it is a self-limiting condition and the benefits of breastfeeding far outweigh any possible risk to the baby, mothers are advised to continue breastfeeding.
Jaundice appearing on the first day of life or after 2 weeks should not be ignored as it is due to disease conditions. When it appears on the first day of life, it may be due to blood group incompatibilities. A baby with positive blood group born to a negative group mother, or a baby with A or B blood group born to O group mother can develop dangerously high levels of jaundice due to greater destruction of red cells. Doctors diagnose this condition based on some blood tests.
To know more about liver infections in children, click here.
Jaundice can also be caused by some disorders of red cells or haemoglobin, congenital infections transmitted from mother when the baby was in the womb or acquired after birth, hypothyroidism and some errors in the metabolic pathways of the liver. Structural abnormalities during development or those causing obstruction to bile flow can also cause jaundice. These are however, less common.
Symptoms of newborn jaundice
Jaundice causes yellow discoloration of the skin and is diagnosed reliably by measuring the bilirubin level in the blood. The direct and indirect components give a clue to the cause of jaundice. Physiological jaundice results in indirect hyperbilirubinemia. Jaundice appears on the face and progresses down the trunk and then involves the extremities. Bilirubin can also be detected by probes placed on the babies’ skin, though these are not as accurate.
Treatment of newborn jaundice
In most cases, no treatment is required. If the baby is born at full term and the bilirubin levels are not high, nothing further is done apart from assessing the child regularly. If the baby is near term or preterm, or has any risk factors, or the bilirubin level is high or increasing fast, a decision to start phototherapy is taken based on plotting the bilirubin level against the age on special graphs called nomograms.
Phototherapy is administered by placing the baby under a special light panel of specific wavelengths in the blue-green spectrum. The light helps to convert the bilirubin into a water soluble form, which is then easily excreted. The babies’ eyes and genitals have to be covered under the light. They can be fed and cared for like any other baby apart from being under the light.
Sunlight is a natural form of phototherapy and babies with milder forms of jaundice can be managed this way; sunlight has the added advantage of forming vitamin D in the skin. It is advisable to expose babies to slanting rays of the sun at dawn and dusk and avoid the direct rays around noon.
When phototherapy does not reduce the bilirubin levels to a desired extent or if the initial levels are considered dangerously high, blood exchange therapy is performed in the neonatal ICU.
Treatment for other causes of jaundice depends on the cause. A baby who passes pale clay coloured stools and dark yellow urine with jaundice persisting beyond 2 weeks of life needs to be referred to a specialist urgently.
In conclusion, while jaundice in the newborn is a common and harmless entity occurring due to an imbalance between the increased bilirubin load and decreased clearance by the liver, it can at times lead to serious consequences if not identified and treated promptly. Points which should raise a red flag are excessive weight loss, jaundice appearing on the first day, an increase of bilirubin by over 5 g in less than 24 hours, jaundice persisting after 2 weeks, baby passing pale stools, poor feeding and activity and bleeding from any site.
The author is Consultant Intensivist at MIOT Children's Cardiac Care Centre.