Neonatal jaundice

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Overview
Neonatal jaundice is a yellowing of the skin and other tissues of a newborn infant caused by increased levels of bilirubin in the blood. Neonatal jaundice is usually harmless: this condition is often seen in infants around the second day after birth, lasting till day 8 in normal births, or to around day 14 in premature births. Serum bilirubin normally drops to a low level without any intervention required: the jaundice is presumably a consequence of metabolic and physiological adjustments after birth.

All jaundice should be medically evaluated before treatment can be given.

Causes
In neonates, benign jaundice tends to develop because of two factors - the breakdown of fetal hemoglobin as it is replaced with adult hemoglobin and the relatively immature hepatic metabolic pathways which are unable to conjugate and so excrete bilirubin as fast as an adult. This causes an accumulation of bilirubin in the body (hyperbilirubinemia), leading to the symptoms of jaundice.

Severe neonatal jaundice may indicate the presence of other conditions contributing to the elevated bilirubin levels, of which there are a large variety of possibilities (see below). These should be detected or excluded as part of the differential diagnosis to prevent the development of complications. They can be grouped into the following categories:

Intrinsic causes of hemolysis

 * Membrane conditions
 * Spherocytosis
 * Hereditary elliptocytosis
 * Systemic contitions
 * Splenomegaly
 * Sepsis
 * Arteriovenous malformation
 * Enzyme conditions
 * Glucose-6-phosphate dehydrogenase deficiency (also called G6PD deficiency)
 * Pyruvate kinase deficiency
 * Globin synthesis defect
 * Alpha-thalassemia

Extrinsic causes of hemolysis

 * Alloimmunity (The neonatal or cord blood gives a positive direct Coombs test and the maternal blood gives a positive indirect Coombs test)
 * Hemolytic disease of the newborn (ABO)
 * Rh disease
 * Hemolytic disease of the newborn (anti-Kell)
 * Hemolytic disease of the newborn (anti-Rhc)
 * Other blood type mismatches causing hemolytic disease of the newborn

Non-hemolytic causes

 * Cephalohematoma
 * Polycythemia
 * Sepsis
 * Hypothyroidism
 * Gilbert's syndrome
 * Crigler-Najjar syndrome

Hepatic causes

 * Infections
 * Sepsis
 * Hepatitis B, TORCH infections
 * Metabolic
 * Galactosemia
 * Alpha-1-antitrypsin deficiency
 * Cystic fibrosis
 * Drugs
 * Total parenteral nutrition
 * Idiopathic

Post-hepatic

 * Biliary atresia
 * Bile duct obstruction

Treatment
Infants with neonatal jaundice are often treated with bili lights, exposing them to high levels of colored light to break down the bilirubin. This works due to a photo oxidation process occurring on the bilirubin in the subcutaneous tissues of the neonate. Light energy creates isomerization of the bilirubin and consequently transformation into compounds that the new born can excrete via urine and stools. Blue light is typically used for this purpose. Green light is more effective at breaking down bilirubin, but is not commonly used because it makes the babies appear sickly, which is disturbing to observers. A recent study has shown that light therapy may increase the risk of skin moles (or "nevi") in childhood which in turn also increases the risk of melanoma (skin cancer).

Brief exposure to indirect sunlight each day and increased feeding are also helpful. A newborn should not be exposed to direct sunlight because of the danger of sunburn, which is much more harmful to a newborn's thin skin than that of an adult.

If the neonatal jaundice does not clear up with simple phototherapy, other causes such as biliary atresia, PFIC, bile duct paucity, Alagille's syndrome, alpha 1 and other pediatric liver diseases should be considered. The evaluation for these will include blood work and a variety of diagnostic tests. Prolonged neonatal jaundice is serious and should be followed up promptly.

Breast feeding jaundice
"Breastfeeding jaundice" is caused by insufficient milk intake resulting in dehydration, and can be prevented by frequent breastfeeding sessions of sufficient duration to stimulate adequate milk production.

Breast milk jaundice
Very rarely, "breast milk jaundice" occurs during the second or third week of life, and may be caused by high levels of beta-glucuronidase in breast milk. Neither condition is a reason to stop nursing, though caregivers may advise IV or other fluid administration to ensure the baby is not dehydrated.

Non-physiologic causes
A small percentage of infants will have "hemolytic jaundice". The infant's red blood cells will be broken down quicker because antibodies that attack the infant's red blood cells are transferred from the mother to the baby's bloodstream. The antibodies may be due to ABO (blood group) incompatibility or Rhesus factor differences.

Rare causes
Rarely, neonatal jaundice may be caused by a genetic syndrome such as Crigler-Najjar syndrome.

Complications
With high doses of bilirubin (severe hyperbilirubinemia) there can be a complication known as kernicterus. This is the chief condition that treatment of jaundice is aimed at preventing. The effects of kernicterus range from fever, seizures, and a high-pitched crying to mental retardation. This is due to a staining effect on the basal ganglia leading to neuronal damage. With aggressive treatment such as exchange transfusion to lower very high bilirubin levels, the neurological effects are almost always transient.