, also known as '''icterus''' (attributive adjective: "icteric"), is a yellowing of the
Skin ,
Sclera (the white of the eyes) and
Mucous Membrane s caused by increased levels of
Bilirubin in the
Human body. Usually the concentration of bilirubin in the
Blood must exceed 2–3
Mg /
DL for the coloration to be easily visible. ''Jaundice'' comes from the
French word ''jaune'', meaning yellow.
When
Red Blood Cell s die, the
Heme in their
Hemoglobin is converted to bilirubin in the
Spleen and in the kupffer cells in the liver. 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
Hemolysis (breakdown of
Red Blood Cell s). In tropical countries,
Malaria can 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 Metabolism also present as jaundice. Jaundice usually comes with high fevers.
Hepatic causes include acute
Hepatitis ,
Hepatotoxicity and
Alcoholic Liver Disease . Whereby cell necrosis reduces the liver's ability to metabolise and excrete bilirubin leading to a build up in the blood. 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.
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
Gallstone s 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 Pseudocyst s. 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 Pigment s. Patients sometimes also complain of itching.
| |
Neonatal jaundice
|
| |
infant jaundice treatmentjpg
|
| |
Infant undergoing home phototherapy for jaundice using a Bili Blanket
|
| |
,
|
| |
,
|
| |
|
| |
001559
|
| |
ped
|
| |
1061
|
| |
8881
|
|
is usually harmless: this condition is often seen in s, 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 sunlight each day and increased feeding are also helpful. A newborn should not be exposed to direct
Sunlight because 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
Breastfed infants, 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.
A small percentage of infants will have "hemolytic jaundice". The infant's red blood cells will be broken down quicker because of antibodies that attack the infant's red blood cells are transferred from the mother to the baby's bloodstream. The antibodies may be due to
ABO (blood group) incompatibility or
Rhesus Factor differences.
1
Rarely, neonatal jaundice may be caused by a
Genetic Syndrome such as
Crigler-Najjar Syndrome .
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 Ganglia leading to neuronal damage.
In neonates, jaundice tends to develop because of two factors - the breakdown of
Fetal Hemoglobin as it is replaced with
Adult Hemoglobin and 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 Atresia should be considered.
- Gilbert's Syndrome , a genetic disorder of bilirubin metabolism which can result in mild jaundice, which is found in about 5% of the population.
