Jaundice Health Article

Definition

Jaundice is a yellowing of the skin and/or whites of the eyes caused by high levels of bilirubin—a dark yellow-green or orange-red pigment—in the blood.

Description

Jaundice, also called icterus or hyperbilirubinemia, is a very common condition in newborns. Newborn or neonatal jaundice, sometimes referred to as physiologic or physiological jaundice, affects more than half of all full-term newborns and 80 percent of premature newborns within the first few days of life. It commonly lasts for one to two weeks. Jaundice that is present at birth or that lasts more than a couple of weeks may be abnormal jaundice and a symptom of an underlying problem. Jaundice in older children or adults is a symptom of hepatitis (inflammation of the liver) or some other liver disorder.

Jaundice results from higher than normal levels of bilirubin in the blood. Bilirubin is a breakdown product of red blood cells. Red blood cells normally are removed and broken down in the spleen after about 120 days in circulation. Heme (component of hemoglobin in red blood cells that carries oxygen throughout the body) is broken down into bilirubin, which moves to the liver where it is processed and added to bile, a digestive fluid. The bile travels through the bile ducts to the intestine and is excreted in the stool.

Infants are born with excess red blood cells that are rapidly recycled by the spleen and liver, releasing bilirubin. This pigment gives a newborn's stools their yellow color. If more bilirubin is produced than can be processed by the liver, blood levels of bilirubin rise, and the excess is deposited in tissues causing the skin to appear yellow.

Demographics

Although jaundice affects the majority of newborns, it often is more severe in Asian or Native American children. It also is more common in infants who are not breastfeeding efficiently, resulting in low fluid intake.

In 2001 the U.S. Centers for Disease Control and Prevention (CDC) reported that cases of brain damage associated with hyperbilirubinemia (called neonatal encephalopathy, bilirubin-induced brain injury, or kernicterus) had been increasing since about 1990, perhaps due to shorter hospital stays following birth. One cause of hyperbilirubinemia in seemingly healthy full-term or near-term infants is biliary atresia, an obstruction or inflammation of the bile ducts. This condition occurs in about one in every 15,000 live births, and girls are slightly more at risk than boys.

Neonatal jaundice

Prior to birth the mother's liver processes bilirubin for the fetus. At birth, particularly with preterm births, an infant's immature liver may not be able to process all of the bilirubin formed as red blood cells are removed from circulation. The excess bilirubin causes jaundice by the third or fourth day after birth. The jaundice usually appears first on the face and progresses downward to the chest, abdomen, legs, and feet. If newborn feeding is delayed for any reason, such as illness, a digestive tract problem, or low fluid intake due to inefficient breast-feeding; the infant produces fewer stools, resulting in critically high blood levels of bilirubin and severe jaundice.

Most full-term babies with neonatal jaundice have no other symptoms. However, if bilirubin levels continue to rise, other symptoms may include:

• sleepiness
• lethargy
• slow or reluctant feeding

Risk factors for hyperbilirubinemia include:

• birth more than two weeks before the due date
• jaundice within the first 24 hours after birth
• significant bruising or bleeding under the scalp caused by labor and delivery
• high bilirubin levels prior to hospital discharge
• difficulty breastfeeding, resulting in low fluid intake
• a parent or sibling who had high bilirubin levels at birth

Abnormal jaundice in newborns

Jaundice at birth or within the first 24 hours after birth can be a sign of abnormal jaundice. Abnormal jaundice can be dangerous, particularly in preterm or unhealthy newborns. Depending on the cause and extent of the jaundice, it also may be harmful in full-term infants.

The most common cause of abnormal jaundice is an ABO blood type incompatibility between mother and child. If the mother has O-type blood and the infant has either A or B blood type, or if the mother has A-type blood and the child has B-type or vice versa, the mother's antibodies circulating in the baby's blood attack the child's foreign blood type, causing damage to and destruction of the baby's red blood cells. This process, called hemolysis, is accompanied by the release of excess amounts of bilirubin.

In the past Rhesus (Rh) blood factor incompatibility between the mother and child was a major cause of kernicterus. An Rh-negative mother who was exposed to her fetus's Rh-positive blood during a previous pregnancy or delivery or who has accidentally received an Rh-positive blood transfusion has antibodies against Rh-positive blood cells. These antibodies can circulate in her Rh-positive newborn, initiating hemolysis and causing severe abnormal jaundice.