Veterinary Clinical Biochemistry and Laboratory Diagnosis-II

TYPES OF JAUNDICE 

Pre-Hepatic Jaundice: (Haemolytic Anaemia):              

• Any condition , which increases erythrocytes destruction,also increases the formation of bile pigment.
• In haemolytic jaundice, there is an an increase in total bilirubin, maily unconjugated bilirubin. The increase in the level of bilirubin causes the increased production of urobilinogen, which appears in urine in large amounts.
• Vitamin - B12 deficiency.
• Bilirubin is not found in urine in haemolytic jaundice because unconjugated biirubin does not pass into urine. So increased urobilinogen and absence of bilirubin in urine is suggestive of haemolytic jaundice. 

Hepatic Jaundice:

• It is caused by liver dysfunction resulting from damage to the paranchymal cells.
• Viral hepatitis, hepatitis produced by toxins (drugs, organic compounds, CCl4 & CHCl3), cirrhosis or intrahepatic cholestasis.
• In severe hepatocellular damage less bilirubin will be conjugated leading to unconjugated hyperbilirubinaemia.
• In this case both the conjugated and unconjugated bilirubin increases. The level of Alkaline phosphatase, ALT and AST increases.

Obstructive Jaundice:

• This is due to the blockage of the hepatic or bile duct or gall bladder, which is caused by stricture, neoplasm or stone formation.
• In this case there is increase in total bilirubin primarly conjugated bilirubin. There is little or no urobilinogen in urine.
• Presence of the bilirubin in urine without urobilinogen suggestive of obstructive jaundice.

Cholestasis - failure of bile excretion.

• It is a combination of clinical, biochemical and histological findings in which the main abnormality is a failure of bile secretion.
• Earliest biochemical abnormality is the elevation of serum bile acids together with other biliary constituents such as cholesterol and conjugated bilirubin.
• Other abnormality is the characteristic elevation of alkaline phosphatase.
• Obstruction of the extrahepatic biliary system, and from the obstruction of intrahepatic interlobular bile ducts, parasitic infestations.

 

DIFFERENTIAL DIAGNOSIS OF THREE TYPES OFJAUNDICE