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.

Causes of jaundice

When red blood cells die, the heme in their hemoglobin is converted to bilirubin in the spleen. The bilirubin is processed by the liver, enters bile and is eventually excreted through faeces.

Related Topics:
Red blood cell - Heme - Hemoglobin - Spleen - Liver - Bile - Faeces

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Consequently, there are three different classes of causes for jaundice. Pre-hepatic or hemolytic causes, where too many red blood cells are broken down, hepatic causes where the processing of bilirubin in the liver does not function correctly, and post-hepatic or extrahepatic causes, where the removal of bile is disturbed.

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Pre-hepatic

Pre-hepatic (or hemolytic) jaundice is caused by anything which causes an increased rate of hemolysis (breakdown of red blood cells). In tropical countries, malaria can cause jaundice in this manner. Certain genetic diseases, such as glucose 6-phosphate dehydrogenase deficiency can lead to increase red cell lysis and therefore hemolytic jaundice. Defects in bilirubin metabolism also present as jaundice.

Related Topics:
Hemolysis - Red blood cell - Malaria - Bilirubin metabolism

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Hepatic

Hepatic causes include acute hepatitis, hepatotoxicity and alcoholic liver disease. Less common causes include primary biliary cirrhosis, Gilbert's syndrome and metastatic carcinoma. Jaundice commonly seen in the newborn baby is another example of hepatic jaundice.

Related Topics:
Hepatitis - Hepatotoxicity - Alcoholic liver disease - Primary biliary cirrhosis - Gilbert's syndrome - Metastatic carcinoma

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Post-hepatic

Post-hepatic (or obstructive) jaundice, also called cholestasis, is caused by an interruption to the drainage of bile in the biliary system. The most common causes are gallstones in the common bile duct and pancreatic cancer in the head of the pancreas. Other causes include strictures of the common bile duct, ductal carcinoma, pancreatitis and pancreatic pseudocysts. A rare cause of obstructive jaundice is Mirizzi's syndrome.

Related Topics:
Bile - Gallstone - Common bile duct - Pancreatic cancer - Pancreas - Ductal carcinoma - Pancreatitis - Pancreatic pseudocyst - Mirizzi's syndrome

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The presence of pale stools suggests an obstructive or post-hepatic cause as normal feces get their colour from bile pigments.

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