3 Types of Jaundice (Icterus) and Their Causes

Overview

• Jaundice (Icterus): Yellowing of skin and eyes caused by excess bilirubin in blood (hyperbilirubinemia).
• Jaundice clues the underlying issue related to red blood cell destruction, liver function, or bile flow.

Types of Jaundice (Icterus) and Their Causes

Overview

• Jaundice results from excess bilirubin in the blood, leading to yellowing of skin and eyes.
• The type of jaundice helps identify the underlying problem:
  • Pre-hepatic: Excessive RBC destruction.
  • Intrahepatic: Liver dysfunction.
  • Post-hepatic: Bile duct obstruction.

1.  Pre-Hepatic Jaundice

• Cause: Excessive destruction of red blood cells before reaching the liver.
• Pathophysiology:
  • Increased breakdown of RBCs (hemolysis).
  • Liver’s capacity to conjugate bilirubin becomes overwhelmed.
  • Mainly unconjugated bilirubin accumulates in blood.
• Common Causes:
  • Hemolytic anemia (e.g., sickle cell disease).
  • Blood transfusions with incompatible blood.
  • Physiologic jaundice in newborns (common in first 2-3 days).
• Newborn Jaundice:
  • Immature liver.
  • RBCs last about 60-90 days (less than adult 120 days).
  • Phototherapy: Blue light converts bilirubin into water-soluble form for excretion.
• Signs: Yellowing of skin and eyes; high unconjugated bilirubin.

2.  Intrahepatic Jaundice

• Cause: Liver dysfunction or damage.
• Pathophysiology:
  • Liver cells cannot conjugate bilirubin effectively.
  • Inflammation, cirrhosis, or trauma damages hepatocytes.
  • Conjugated bilirubin may back up into blood due to deterioration of bile ducts.
• Characteristic:
  • Elevated conjugated bilirubin in blood.
  • Deteriorating liver (e.g., cirrhosis) causes scarring and shrinking.
  • Bile duct obstruction due to scarring leads to bilirubin buildup.
• Signs:
  • Jaundice.
  • Liver scarring visible as shrunken, fibrotic liver.
  • Poor excretion of bilirubin causes tissue deposits.

Summary

• Pre-hepatic jaundice: Excessive RBC destruction → high unconjugated bilirubin.
• Intrahepatic jaundice: Liver damage or disease → high conjugated bilirubin.
• Proper diagnosis involves blood tests, imaging, and sometimes biopsy.
• Treatment depends on cause, aiming to reduce hemolysis or improve liver function.

3.  Post-Hepatic Jaundice (Obstructive Jaundice)

Cause

• Normal liver function: Liver conjugates bilirubin.
• Problem occurs after bilirubin leaves the liver:
  • Usually due to obstruction in the bile ducts (e.g., gallstones, tumors).

Formation of Gallstones

• Cholelithiasis:
  • Chole-: cholesterol.
  • Lith: stone.
• Gallstones lodged in bile ducts cause obstruction.

Visual Illustration

• Blocked bile flow prevents bilirubin excretion.
• Bilirubin accumulates in blood, causing jaundice.
• Fecal color depends on bilirubin:
  • Normal: brown.
  • Blocked bile: light-colored stool due to lack of bilirubin in the intestines.

Pathophysiology

• Bile cannot flow into the duodenum.
• Conjugated bilirubin builds up in the blood.
• Bile salts leak into tissues, causing:
  • Pruritis (itching).
  • Jaundice.

Effects on Digestion and Nutrition

• Reduced bile in the intestine:
  • Impaired emulsification of fats.
  • Leads to malabsorption of fats and nutritional deficiencies over time.

Summary of Jaundice Types and Causes

Diagnostic Tests

• Blood tests measure total, conjugated, and unconjugated bilirubin.
• Subtract conjugated bilirubin from total to find unconjugated.
• Imaging (ultrasound, ERCP) helps locate obstructions.

Final Notes

• Recognizing bilirubin levels helps pinpoint where the problem is.
• Early detection allows for appropriate treatment.