Jaundice

 ICD9           = 782.4|
 OMIM           = |
 MedlinePlus    = 003243 |
 eMedicineSubj  = |
 eMedicineTopic = |
 DiseasesDB     = 7038 |

}} Jaundice, also known as icterus (adjective:"Icteric"), is yellowing of the skin, sclera(the white of the eyes) and mucous membranescaused by increased levels of bilirubinin the humanbody. Usually the concentration of bilirubin in the bloodmust exceed 2–3mg/dLfor the coloration to be easily visible. Jaundice comes from the Frenchword jaune, meaning yellow.

Causes of jaundice

When red blood cellsdie, the hemein their hemoglobinis converted to bilirubin in the spleenand in the kupffer cells in the liver. The bilirubin is processed by the liver, enters bileand 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

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

Hepatic

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

Post-hepatic

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

The presence of pale stools and dark urine suggests an obstructive or post-hepatic cause as normal feces get their colour from bile pigments. Patients sometimes also complain of itching.

Neonatal jaundice

 ICD9           = 773, 774|
 OMIM           = |
 MedlinePlus    = 001559 |
 eMedicineSubj  = ped |
 eMedicineTopic = 1061 |
 DiseasesDB     = 8881 |

}} Neonatal jaundice is usually harmless: this condition is often seen in infantsaround the second day after birth, lasting till day 8 in normal births, or to around day 14 in premature births. Serum bilirubin normally drops to a low level without any intervention required: the jaundice is presumably a consequence of metabolic and physiological adjustments after birth. Infants with neonatal jaundice are often treated with bili lights, exposing them to high levels of colored light to break down the bilirubin. This works due to a photo oxidation process occurring on the bilirubin in the subcutaneous tissues of the neonate. Light energy creates isomerization of the bilirubin and consequently transformation into compounds that the new born can excrete via urine and stools. Blue light is typically used for this purpose. Green light is more effective at breaking down bilirubin, but is not commonly used because it makes the babies appear sickly, which is disturbing to observers.

Brief exposure to indirect sunlight each day and increased feeding are also helpful. A newborn should not be exposed to direct sunlightbecause of the danger of sunburn, which is much more harmful to a newborn's thin skin than that of an adult.

"Breastfeeding jaundice" occurs in more than 10% of breastfedinfants, caused by insufficient milk intake. More rarely, "breast milk jaundice" occurs in about 0.5% of babies during the second or third week, caused by high levels of beta-glucuronidase in breast milk. Neither condition is a reason to stop nursing, though in these cases caregivers usually advise supplements to breastfeeding to ensure the baby is not dehydrated.

With high doses of bilirubin (severe hyperbilirubinemia) there can be a complication known as kernicterus. This is the chief reason for neonatal jaundice to be treated. The effects of kernicterus range from fever, seizures, and a high-pitched crying to mental retardation. This is due to a staining effect on the basal ganglialeading to neuronal damage.

In neonates, jaundice tends to develop because of two factors - the breakdown of fetal hemoglobinas it is replaced with adult hemoglobinand the relatively immature hepatic metabolic pathways which are unable to conjugate bilirubin as fast as an adult.

All jaundice should be medically evaluated before treatment can be given. If the neonatal jaundice does not clear up with simple phototherapy, other causes such as biliary atresiashould be considered.

Popular culture

In his novel The Silence of the Lambs Thomas Harrishas Hannibal Lecterfalsely give the name of killer as "Billy Rubin" (bilirubin) to mock his captor's lack of medical knowledge, and links the letters of the latter's name to make the chemical equation for the same on a paper left behind after his escape, as bilirubin is also the pigmentation in feces.de:Ikterus es:Ictericia eo:Iktero fr:Ictère it:Ittero he:???? ms:Demam kuning jaundis nl:Geelzucht pl:?ó?taczka (medycyna) pt:Icterícia sl:Hiperbilirubinemija sv:Gulsot zh:??

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It uses material from the http://en.wikipedia.org/wiki/Jaundice Wikipedia article Jaundice.