In this article,we are going to talk about jaundice.lets get into our topic of jaundice. How can we define jaundice?
Jaundice is yellowish discoloration of skin,mucus membrane and sclera due to increased bilirubin in our blood that is hyperbilirubinemia. Normal serum level of bilirubin is upto 1 mg/dl .It can rise upto 1-2 mg/dl without clinical signs and symptoms called as latent jaundice.Overt jaundice is clinically detected jaundice which is when bilirubin is more than 2mg/dl.
Jaundice is classified into pre-hepatic,hepatic and post-hepatic Jaundice.Pre hepatic jaundice is when liver is not involved.Bilirubin comes from Red blood cell.
When excessive hemolysis occurs due to hemolytic anemia,sickle cell anemia,hereditary spherocytosis and infections like malaria that lead to hemolysis,there is excessive bilirubin production.The liver is normal.The pathology behind this is hepatocyte gets saturated due to its limit.It will conjugate bilirubin upto its maximum capacity,then liver can't uptake bilirubin into it and conjugate it so there is increased in unconjugated bilirubin in circulation.
Hepatic jaundice is when liver is primarily involved.so due to infections causing hepatitis,alcoholic hepatitis, and some congenital disorders that are criggler najar syndrome,dubin-johnson,and rotor syndrome.This leads to increase in both conjugated and unconjugated bilirubin.It happen because when liver injury occurs due to infection or alcohol,cell lyses and content of cell comes out.Conjugated bilirubin leaks into circulation and due to injury,after a time,liver is not able to conjugate .so there is rise in both conjugtaed and unconjugtaed bilirubin.In ciggler najar syndrome,there is deficiency of uridine glucuronate transferrase(UGT) enzyme that is responsible for conjugation of bilirubin.There is rise of unconjugated bilirubin.However the cause is hepato-cellular.
In post-hepatic jaundice ,also called as obstructive jaundice .Here there is obstruction in the flow of bile .It can be either in the intra- hepatic right and left hepatic duct,common hepatic duct,common bile duct.This jaundice is because of obstruction at different level.What is the cause of this obstruction?
It can be many.
Stone,cysts,carcinomas,tumors or strictures and there is something called as "Mirizzi syndrome" when there is stone in cystic duct large enough to obstruct the flow of bile then it is mirizzi syndrome.In obstructive jaundice,there is rise in conjugated bililrubin since bilirubin are conjugated but due to obstruction they are regurgitated back into circulation.Stool is clay colored because there is absence of stercobilin(a product of bilirubin) in intestine due to obstruction and urine is dark colored in obstructive jaundice due to increased urobilin(a product of bilirubin) in circulation.
