Neonatal jaundice is a medical condition characterized by yellowish discoloration of the skin and eyes. It occurs due to a raised bilirubin level in the blood above 5 mg/dl. About half of all newborn babies develop jaundice in the first week of life. In most cases it does not lead to any complications in babies bur there is a risk of permanent damage in untreated cases. Neonatal jaundice can occur due to a number of causes but is usually not related to any underlying disease in mother or child.
Preterm babies and breastfed babies are usually affected because the underdeveloped liver fails to handle the bilirubin effectively. This type of neonatal jaundice is physiological in nature meaning that it is not due to a disease. Certain pathological conditions (diseases) like internal bleeding and an infection may also lead to neonatal jaundice. Mild jaundice usually does not require any treatment and clears within 2 to 3 weeks but in case of severe jaundice, phototherapy is the mainstay of treatment.
The symptoms of neonatal jaundice usually appear between the second to fourth day after birth. There is yellowish discoloration of the skin which typically starts in the face and involves the “whites” of the eye. It gradually progresses over the rest of the body. Another way to identify jaundice is if upon finger pressing on nose or forehead the area appears yellow. In babies without jaundice, the skin will appear lighter. Examination should be done under natural light as artificial light sources can cause the skin to appear slightly yellower than normal.
The blood brain barrier which prevents the entry of toxic substances in the brain is not well developed in babies. The raised bilirubin level may cross the barrier and damage the brain cells permanently leading to dangerous complications like :
- Acute bilirubin encephalopathy occurs when raised bilirubin enters the brain cells and leads to :
– Inconsolable crying
– Inability to feed
– Excessive drowsiness
– Difficulty in waking up
- Kernicterus occurs due to permanent damage of the brain and common symptoms are :
– Permanent loss of hearing
– Impaired mental growth
– Fixed upward gaze
– Uncontrolled, involuntary and unpredictable jerking movements of the limbs
When red blood cells break down in the body. haem is formed and after metabolism it is converted into unconjugated bilirubin. This type of bilirubin is not soluble in water and therefore cannot be excreted via the kidney. In the unconjugated form, bilirubin is then converted into the conjugated form to facilitate its excretion. The conjugated bilirubin is then secreted from the liver as bile and enters the small and large intestine. Bilirubin is then excreted via the stool and urine. Any defect in any of the steps of bilirubin metabolism will lead to excess bilirubin in the blood and therefore jaundice.
The common causes varies as follows :
- In newborn babies the liver enzymes are not fully functional therefore bilirubin metabolism is impaired.
- The life span of red blood cells is 90 days in babies in contrast to 120 days in adults leading to increased destruction of the cells.
Sometimes there are certain diseases (pathological causes) responsible for neonatal jaundice such as :
- Excessive bleeding.
- Infection leading to sepsis.
- Liver malfunction.
- Complete absence of liver enzymes.
- Incompatibility between mother’s and baby’s blood group.
- Deformed RBCs in baby’s blood.
- Preterm babies especially delivery before 38 weeks.
- Injury during birth causing bleeding.
- Different blood group from mother.
- Breast feeding.
Milder forms of neonatal jaundice does not require any treatment. It passes on its own within a few days to weeks. However, severe cases are managed by :
- Light therapy (phototherapy) where the baby is placed under UVlight which helps in conjugation of unconjugated bilirubin and its subsequent excretion.
- Exchange blood transfusion required when the jaundice is severe and does not respond to other modes of therapy.