Jaundice is the yellowish discoloration of the skin, mucous membrane and the white portion of the eyes due to increase in the levels of billirubin in blood.
When the billirubin content in the blood increases to three times (1.5mg/dL) as that of the normal value, the skin becomes yellow.
The whites of the eye are the first tissue to become yellow with increase in billirubin level.
Physiological jaundice is the jaundice in healthy babies. Pathological jaundice is the jaundice which has a risk to the health.
Jaundice is classified into 3-categories, depending on which part of the physiological mechanism the pathology affects. The three categories are:
Pre-hepatic: The pathology is occurring prior the liver.
Hepatic: The pathology is located within the liver.
Post-Hepatic: The pathology is located after the conjugation of bilirubin in the liver.
Pre-hepatic jaundice occurs due to causes that increase the breakdown (hemolysis) of red blood cells. The causes here could be malaria, spherocytosis (a type of hemolytic anemia), sickle cell anemia and hemolytic uremic syndrome.
Hepatic jaundice is characterized by cell necrosis which reduces liver’s ability to metabolize and excrete bilirubin leading to buildup of bilirubin in the blood. The common causes include acute hepatitis, hapatotoxocity and alcoholic liver disease. Some other less common causes include primary billiary cirrhosis, Gilbert’s syndrome (a genetic disease), Crigler-Najjar syndrome, Neimann-Pick disease and metastatic carcinoma.
Post-hepatic jaundice (also called obstructive jaundice) is characterized by an interruption to the drainage of bile in the biliary system. It is commonly seen in conditions like gallstones in the common bile duct and pancreatic head cancer. Other causes include biliary atresia, ductal cancer, pancreatitis and pancreatic pseudocysts. Also, a group of parasites known as ‘liver flukes’ can live in the common bile duct, causing obstructive jaundice.
The presence of pale stools and dark urine suggests an obstructive or post-hepatic cause as normal stool get their color from bile pigments.
Various tests are done to differentiate the jaundice into the three caterories pre-hepatic, hepatic and post-hepatic. They are total bilirubin, conjugated bilirubin, unconjugated bilirubin, urobilinogen, and color of the urine, color of the stool, alkaline phosphatase test, alanine transferase levels and aspartate transferase levels.
Other tests are prothrombin time, blood cholesterol level, complete blood count, sonography of the abdomen and liver biopsy.
Treatment for jaundice depends on the cause. Generally treatment is given to cure the cause. Once the primary condition is under control then symptoms (yellowing of the skin or eyes) also disappear.
