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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 feces.
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.
Pre-hepatic (or hemolytic) jaundice is caused by anything which causes an increased rate of haemolysis (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 hemolyic jaundice. Defects in bilirubin metabolism also present as jaundice.
Hepatic causes include acute hepatitis , hepatotoxicity and alcoholic liver diseaseAlcohol is the major cause of liver disease in Western Countries. In Asian countries viral hepatitis is the major cause). Effects of alcohol Fatty change Fatty change is the accumulation of fat in liver cells which can be seen as fatty globules under the. Less common causes include primary biliary cirrhosisPrimary biliary cirrhosis is a disease of the liver marked by the slow destruction of the bile ducts. When this ducts are damaged bile builds up in the liver and over time damages the tissue. Over time primary biliary cirrhosis can result in liver failure, Gilbert's syndromeGilbert's syndrome or familial benign unconjugated hyperbilirubinaemia is a heritable disorder of bilirubin metabolism, found in about 5% of the population. Signs and symptoms The syndrome produces an elevated level of unconjugated bilirubin in the bloods and metastatic carcinoma . Jaundice commonly seen in the newborn baby is another example of hepatic jaundice.
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 ductThe common bile duct begins at the junction of the common hepatic duct and the cystic duct and ends at the Ampulla of Vater in the second part of the duodenum. It carries bile from the liver and gallbladder to the gastrointestinal tract. This small tube l and pancreatic cancerPancreatic cancer (or adenocarcinoma of the pancreas, also called pancreatica is the growth of a malignant tumour within the pancreas. Each year about 29,000 individuals in the United States alone are diagnosed with the disease (more than 60,000 in Europe in the head of the pancreasThe pancreas is a retroperitoneal organ that serves two functions: exocrine it produces pancreatic juice containing digestive enzymes endocrine it produces several important hormones Anatomy The pancreas is a retroperitoneal organ located posterior to the. 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.
The presence of pale stools suggests an obstructive or post-hepatic cause as normal feces get their colour from bile pigments .