Jaundice In the Newborn, 6/2001 

The occurrence of jaundice in the newborn infant is an unusual but not rare event; particularly in the premature. Experts in the field recently published a comprehensive article reviewing the present status of knowledge about this area. 

Jaundice is a yellowish-coloring of the skin, white of the eyes (sclera) and deeper body tissues (e.g. brain) due to an increase of bilirubin in the blood. Bilirubin is a normal product of the metabolic breakdown by the liver of the hemoglobin released from red blood cells when they die, thus the term Ahyperbilirubinemia (hyper = high; bilirubin; emia = in the blood; high blood levels of bilirubin). The presence for a short period of time of modest jaundice in the newborn is a physiologic (Anormal) occurrence because the destruction of red blood cells in the newborn occurs at a more rapid rate than later in life. However, a prominent increase of red blood cell destruction such as seen in the Rh factor disorder (incompatible maternal - infant blood types) or due to an improper processing of bilirubin by the liver or its excretion into the gut can lead to high levels of blood bilirubin resulting in the presence of jaundice. 

The infant brain is particularly vulnerable to high levels of blood bilirubin and there can be a generalized adverse brain reaction to it (an encephalopathy) or damage to specific brain areas. When the basal ganglia of the brain -- the brain area controlling the coordination of muscle movement is damaged, a pathology called kernicterus occurs. Kernicterus is a very serious developmental brain disorder. In the past it was often due to Rh blood maternal-child incompatibilities that resulted in a severe movement disorder of infants. Since Rh factor incompatability is now relatively rare, the occurrence of kernicterus has significantly diminished. 

The level of bilirubin in the blood of the newborn can now be relatively easily measured, so treatment of neonatal jaundice can be initiated easily and brain damage prevented. The most common form of treatment is phototherapy --placing the infant under strong lights which convert the bilirubin to a form that can be easily eliminated by the infant. There are also other forms of therapy that can be used in very severe cases; one example is blood replacement. 

There are many causes of increased or prolonged jaundice in the newborn including increased destruction of circulating red blood cells in the newborn, genetic enzyme defects, complications of pregnancy, birth trauma, newborn infection, administration of specific drugs and low intake of breast milk. In regard to low intake of breast milk -- usually due to poor feeding -- an increase in the number of breast feedings and supplemental feedings can be effective in reducing the jaundice, particularly during treatment by phototherapy. 

The present practice of the early discharge of infants from a hospital can result in poor detection of jaundice of the newborn. It is generally recommended that all infants who are discharged from the hospital 48 hours or less after delivery should be examined within 2 to 3 days after discharge. 

Comment:
A mild degree of jaundice shortly after birth is a physiologic process that disappears. However, the more severe forms of jaundice need immediate attention to prevent permanent brain damage. Now that there are methods available to accurately measure the level of bilirubin in the infant's blood and very useful methods of therapy to reduce pathological levels of bilirubin, neonatal jaundice should no longer be an important clinical problem. However, in those infants in which there is a continuing increased destruction of red blood cells or a poor ability to convert the resulting bilirubin to an innocuous form, the reasons for the problem need to be specifically addressed and treated. All infants need to be evaluated within 48 hours after delivery whether still in the hospital or at home to ascertain whether they are jaundiced and if so, the degree and cause of the jaundice. In nearly all instances, brain damage can be prevented by early diagnosis and prompt therapy. There are isolated reports of a recent increase in the occurrence of neonatal jaundice. Whether these are due to early discharge from the hospital of newborns or some other factor are under investigation.
 

UCP Research & Educational Foundation, June 2001

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