Neonatal Jaundice (Hyperbilirubinemia)
Jaundice is a relatively common occurance in human infants. As in adults, jaundice is due to elevated blood concentrations of bilirubin (hyperbilirubinemia). There are at least two significant processes that predispose normal infants to jaundice:
Additionally, there are a number of pathologic conditions that can result in neonatal jaundice. Examples include:
A large majority of cases of neonatal hyperbilirubinemia are mild and resolve over the first few weeks of life. However, persistently high concentrations of bilirubin can be dangerous. Elevated levels of bilirubin interfere with a number of cellular processes, and may be neurotoxic. Kernicterus is a serious and life-threatening form of neonatal jaundice that reflects the toxicity of bilirubin to the central nervous system. Kernicterus, in both acute and chronic forms, is manifest by a variety of neurologic and cognitive deficits ranging from poor suckling and seizures to low IQ. Clearly, this disorder should be treated without delay.
The standard treatment for neonatal jaundice is phototherapy. Affected infants are placed under lights, and photons are absorbed by bilirubin as it circulates in skin capillaries. This energy transfer results in conversion of bilirubin to lumirubin and other products which, in contrast to bilirubin, are more water-soluble and readily excreted. The rate of bilirubin elimination depends upon both the wavelength of light used and its dose. Blue light (460 to 490 nm) is the most effective, but such light causes eye strain in those monitoring the baby, making it difficult to detect other conditions such as cyanosis. The most frequently used form of phototherapy is standard fluorescent white light.
In severe cases of neonatal jaundice, another effective treatment is exchange transfusion. In this procedure, small amounts of blood (and hence bilirubin) are removed from the baby and replaced with donor blood; this procedure is repeated until roughly twice the blood volume has been replaced. Exchange transfusion also eliminates antibodies against red blood cells, which may be the inciting factor in development of hyperbilirubinemia.
Neonatal jaundice almost certainly occurs in animals other than humans, but, by it self, is not recognized as a significant disorder. Immune-mediated hemolytic anemias are relatively common in foals, calves and piglets, and may lead to jaundice. However, the most serious aspect of this disease is the anemia, rather than jaundice per se.
References and Reviews
|The Liver: Introduction and Index|
Last updated on March 2, 2008
|Author: R. Bowen|
|Send comments via form or email to email@example.com|