Jaundice

Alternative Names: Icterus.

Jaundice (from the French word jaune, meaning yellow) is an abnormal condition in which the body fluids and tissues, particularly the skin and eyes, take on a yellowish color as a result of an excess of bilirubin.  It is important to recognize that jaundice itself is not a disease, but rather a symptom of an underlying pathological process that occurs at some point along the normal physiological pathway of the metabolism of bilirubin.

Causes and Development

Jaundice is classified into three categories, depending on which part of the physiological mechanism the pathology affects.  The three categories are:

• Pre-hepatic: The pathology is occurring prior the liver
• Hepatic: The pathology is located within the liver
• Post-Hepatic: The pathology is located after the conjugation of bilirubin in the liver.

In order to understand how jaundice results, it is important to understand where the pathological processes that cause jaundice take their effect.  During the normal breakdown of old red blood cells, their hemoglobin is converted into bilirubin.  Normally the bilirubin is removed from the bloodstream by the liver and eliminated from the body in the bile, which passes from the liver into the intestines.  Any disease that causes the red blood cells to break down can also cause jaundice.

There are several conditions that may interrupt the elimination of bilirubin from the blood and cause jaundice.  Hemolytic jaundice is caused by excessive disintegration of erythrocytes; it occurs in hemolytic and other types of anemia and in some infectious diseases such as malaria.  Another type of jaundice results from obstruction in or about the liver; usually a stone or stricture of the bile duct blocks the passage of bile from the liver into the intestines.  A third type of jaundice occurs when the liver cells are damaged by diseases such as hepatitis or cirrhosis of the liver; the damaged liver is unable to remove bilirubin from the blood.

Signs and Symptoms

Jaundice is yellowish discoloration of the skin, sclera (whites of the eyes) and mucous membranes caused by hyperbilirubinemia (increased levels of bilirubin in the blood).  This hyperbilirubinemia subsequently causes increased levels of bilirubin in the extracellular fluids.  Typically, the concentration of bilirubin in the plasma must exceed 1.5 mg/dL, three times the usual value of approximately 0.5mg/dL, for the coloration to be easily visible.

Treatment and Prevention

Treatment of jaundice is directed to the underlying cause.  Many instances of obstructive jaundice may require surgery.