Jaundice

Jaundice, also known as icterus, is yellowing of the skin, sclera (the white of the eyes) and mucous membranes caused by increased levels of bilirubin in the human body. Usually the concentration of bilirubin in the blood must exceed 2–3mg/dL for the coloration to be easily visible. Jaundice comes from the French word jaune, meaning yellow.

Neonatal jaundice

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. Infants with neonatal jaundice are typically 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.

Related Topics:
Infants - Bili light

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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. Notably breastfeeding has been shown to increase the risk of jaundice due to high levels of beta-glucuronidase in breast milk. However many midwives will argue that Breastfeeding in conjunction with phototherapy is helpful as it increases the 'good' bacteria in the digestive system of the neonate. In adults these bacteria ensure that bilirubin is not reabsorbed by the body as they convert bilirubin glucuronide to stercobilins and urobilins which are more easily excreted. Additionally, steroids in the breastmilk act as antagonists to the enzymes that break down the red blood cells. This usually occurs after the first two weeks of life.

Related Topics:
Sunlight - Sunburn - Breastfeeding - Breast milk - Midwives - Steroid

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With high doses of bilirubin (severe hyperbilirubinemia) there can be a complication known as kernicterus. This is the chief reason for neonatal jaundice to be treated. 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.

Related Topics:
Kernicterus - Basal ganglia

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In neonates, 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 bilirubin as fast as an adult.

Related Topics:
Fetal hemoglobin - Adult hemoglobin

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If the neonatal jaundice does not clear up with simple phototherapy, other causes such as biliary atresia should be considered.

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