What is jaundice?

Jaundice is the term used to refer to a yellow or orange discolouration of the skin and whites of the eyes. Jaundice occurs because a yellow pigment called bilirubin builds up in the blood. Bilirubin is normally found in small amounts in the blood from the natural break down of old, damaged or abnormal red blood cells. Bilirubin is normally removed from the blood by the liver. The liver then converts (conjugates) the bilirubin into another form. Once conjugated, the bilirubin can be excreted as part of bile into the small intestine. From there, bile is removed from the body along with bowel movements.

Anything that speeds up the rate that red blood cells are broken down or interferes with the removal of bilirubin or bile from the body can result in jaundice.

Why do some newborn babies develop jaundice?

Newborn jaundice is a common condition in newborn babies and, for the most part, causes no serious harm. A number of factors can contribute to the development of jaundice in a newborn. These factors include:

• An immature liver that can't convert or excrete bilirubin effectively.
• A temporary lack of bacteria in the intestines -- bacteria in the intestines normally break bilirubin down. The break down of bilirubin prevents it from being reabsorbed. Without the bacteria, bilirubin is excreted into the intestines, but it is then reabsorbed back into the blood (instead of being passed out of the body with a bowel movement).
• More than the normal number of red blood cells being broken down.
• Breastfeeding* -- rarely, full-term newborns who are breastfed, will develop a type of jaundice called 'breast milk jaundice'. The exact reason for this type of jaundice is unknown.
• Newborn jaundice typically appears first in the face, then the chest and then in the legs and feet disappears after the first week.
• Newborn jaundice causes no harm to the baby. In rare cases, however, the level of bilirubin can increase to such a high level that it can cause a type of brain damage called 'kernicterus.'

Diagnosis

Besides watching for the tell-tale yellow color of the skin and whites of the eyes, blood tests can be done to measure the amount of bilirubin present in the blood.

Treatment

Mild increases in bilirubin level usually don't require treatment.

• Frequent feedings (at least 8 to 12 times in 24 hours) can speed up the rate that stool passes through the intestine. This can reduce the amount of bilirubin that is reabsorbed from the bowel.
• Higher bilirubin levels can be treated with phototherapy. This is where the baby is placed, with as little clothing as possible, under a special type of light (often called a bili-lamp). This light causes a chemical change to occur in the bilirubin molecules in the tissues under the skin. Once this chemical change occurs, the bilirubin can be excreted by the liver without the liver having to convert (conjugate) it. During the treatment, the baby will be placed in an isolette to keep him/her warm and the his/her eyes will be protected from the bright light with eye patches.
• Dangerously high bilirubin levels, can also be treated by performing exchange blood transfusions (replacing the blood high in bilirubin with blood that is lower in bilirubin).
• Rarely, breastfeeding may need to be discontinued for 1 or 2 days if bilirubin levels become extremely high in a baby who has 'breast milk jaundice'. In situations like this, the mother can continue to express breast milk regularly so breastfeeding can be restarted once bilirubin levels start to decrease. Restarting breastfeeding at this time poses no risk to the baby.¹

Kernicterus

Kernicterus is a type of brain damage that can occur in babies who have prolonged very high levels of bilirubin in their blood. In most cases. kernicterus can be prevented if newborn jaundice is treated promptly.² Kernicterus is most common in very premature and critically ill newborns.

Signs of kernicterus include:

• jaundice
• increasing drowsiness
• poor feeding
• vomiting
• backward arching of the back and neck
• rolling of the eyes
• seizures

If left untreated, kernicterus can result in permanent brain damage, such as cerebral palsy or deafness, or death.

References:

¹ The Merck Manual of Diagnosis and Therapy, Seventeenth Edition, Centennial Edition, Mark H. Beers, M.D., and Robert Berkow, M.D. (Editors), 1995-2001, Merck & Co., Inc., Whitehouse Station, NJ, USA.

² The Canadian Medical Association - Home Medical Encyclopedia, Dr Peter Morgan (Editor), The Reader's Digest Association (Canada) Ltd., Montreal, 1992.