JAUNDICE

excess of bile pigments in the bloodstream and bodily tissues. There is a yellow to orange and, sometimes, even greenish discoloration of the skin, the whites of the eyes, and the mucous membranes. Jaundice is best seen in natural daylight and may not be apparent under artificial lighting. The degree of coloration depends on the concentration of bile pigment (bilirubin) in the blood, its rate of tissue diffusion, and the absorption and binding of bilirubin by the tissue. Bilirubin enters the tissue fluids and is absorbed more readily at sites of inflammation and edema (abnormal accumulation of fluids in the tissues). These pigments also seem to favour localization in elastic tissue fibres. The most common mechanisms causing jaundice are an overproduction of bile by the liver, so that more is in the body than can be readily excreted; congenital defects, which may impair the removal of bile pigments or cause an overproduction; inability of liver cells to remove bile pigments from the blood because of liver disease; leakage of bilirubin removed by the liver back into the bloodstream (regurgitation); or obstruction of the bile ducts. Because the normal liver is capable of removing enormous quantities of bilirubin from the blood, a liver's inability to remove bilirubin indicates severe malfunction. Jaundice is usually classified as either retention jaundice or regurgitation jaundice. In retention jaundice, the pigments are retained in the bloodstream because of some removal problem. Usually this can be clinically diagnosed by finding increased amounts of pigments in the fecal matter but finding none in the urine. With regurgitation jaundice, there is an abnormal leak of bilirubin back into the bloodstream, either after it has been removed from the blood by the liver or else directly from the bile ducts. Some of the various diseases that can cause jaundice are anemia, congestion in the circulatory system, pneumonia, congenital liver abnormalities, degeneration of the liver cells by poisons or infectious organisms, scarring of the liver tissue (cirrhosis), and obstructions or tumours in the liver, bile ducts, and the head of the pancreas. In a type of jaundice of unknown cause, called idiopathic jaundice, there seems to be a metabolic error in the body. The liver cannot chemically transform bilirubin in the proper manner, resulting in a much darker pigmentation of the liver and body. In most cases, jaundice is an important symptom of some inherent bodily disturbance, but the retention of bilirubin itself does not usually cause any greater damage than skin discoloration that lasts until the systemic problem is corrected. Regurgitation jaundice, on the other hand, can produce profound secondary disorders. This is generally due to the failure of bile salts to reach the intestinal tract. The bleeding that occurs in the intestines is directly related to the absence of bile salts, for without them the fat-soluble vitamin K cannot be absorbed by the body properly. Without this vitamin, blood clotting is impaired, so that there is a greater tendency for bleeding to occur.