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Jaundice is a yellow discoloration of the skin, mucous membranes and the whites of the eyes that is caused by increased amounts of bilirubin in the blood. The yellow pigment results from excess bilirubin, a byproduct of old red blood cells. Generally, jaundice is a sign of another, underlying disease process.
Approximately one percent of our red blood cells are replaced by new red blood cells every day. The old cells are processed by the liver and disposed of via bilirubin, which is eliminated through the stool. If there are too many red blood cells retiring for the liver to handle, yellow pigment builds up in the body. Jaundice occurs when there is enough yellow pigment to be visible.
The specific issues that disrupt normal bilirubin metabolism and/or excretion in adults are either: (1) pre-hepatic, (2) hepatic, or (3) post-hepatic.
Pre-hepatic jaundice occurs when there is a rapid increase in the breakdown of red blood cells that overwhelms the liver’s ability to adequately remove the increased amounts of bilirubin from the blood. Some examples of conditions that may cause this to occur include malaria, sickle cell crisis, thalassemia and certain autoimmune disorders.
Hepatic jaundice occurs when there is a problem that arises within the liver, rendering the liver unable to properly metabolize and excrete bilirubin. Underlying issues that may cause this to occur include cirrhosis of the liver, hepatitis and drugs.
By contrast, post-hepatic jaundice (also referred to as obstructive jaundice) is caused by conditions that interrupt the normal drainage of conjugated bilirubin as bile from the liver into the intestines. Some of the most common causes of post-hepatic jaundice include gallstones in the bile ducts, pancreatic cancer, congenital malformations, pancreatitis, or parasites.
In addition, it's not uncommon for babies born before 38 weeks gestation (preterm babies) to have jaundice, as the baby's liver isn't mature enough to efficiently eliminate bilirubin in the bloodstream. Breastfed babies also have a higher risk of jaundice, particularly those who are having difficulty nursing or are not getting enough nutrition from breastfeeding.