Icterus/ Jaundice/ Hyperbilirubinemia

 

Icterus/ Jaundice/ Hyperbilirubinemia

Icterus is increased amount of bile pigments in the blood circulation. Concentration of bilirubin in blood plasma is normally below 1.2 mg/dL. A concentration higher than approximately 3 mg/dL leads to jaundice.

It is of three types-

Ø  Hemolytic icterus,

Ø  Toxic icterus and

Ø  Obstructive icterus. 

Hemolytic Icterus

Hemolytic icterus results from excessive hemolysis of erythrocytes in circulating blood. It is also known as prehepatic jaundice.

Etiology/Causes

Ø  Piroplasmosis (Babesia bigemina),

Ø  Anaplasmosis (Anaplasma marginale),

Ø  Leptospirosis (Leptospira ictehaemmorrhagae),

Ø  Equine infectious anemia virus,

Ø  Anthrax (Bacillus anthracis),

Ø  Bacillary hemoglobinuria (Clostriduum hemolyticum),

Ø  Haemolytic streptococci infection

Toxic icterus

Toxic jaundice results from damage in liver leading to increased amount of unconjugated and conjugated bilirubin in blood. It is also known as hepatic jaundice.

Etiology/Causes

• Toxin/ Poisons (ricin, nitrobenzene, drugs),

• Chronic copper poisoning,

• Leptospirosis (also in hemolytic jaundice).

Obstructive Icterus

Obstructive jaundice results from the obstruction in bile duct causing block in normal flow of bile. It is also known as post hepatic jaundice.

Etiology/ Causes

• Blocking of bile canaliculi by swollen hepatocytes

• Obstruction in bile duct by endoparasites (Liver flukes, tapeworms and ascarids).

• Biliary cirrhosis, Cholangitis and Cholelithiasis

• Pressure on bile duct due to abscess, neoplasm.

• Inflammation and swelling at duct opening in duodenum.

Macroscopic features

• Mucous membrane yellow in color.

• Omentum, mesentery, fat become yellow.

• Increased yellow color in urine.

• Conjunctiva becomes yellowish.

Diagnosis

• Van-den-Bergh’s reaction

• Direct reaction detects bilirubin diglucuronide (Obstructive jaundice)

• Indirect reaction detects unconjugated bilirubin (Hemolytic jaundice)

• Both reactions (Toxic jaundice)