Indicators of Liver Damage:

1. Liver Enzymes in Blood

• Liver enzymes (e.g., ALT, AST) are normally contained within hepatocytes (liver cells).
• When liver cells rupture or die:
  • Enzymes leak into the bloodstream.
  • Elevated enzyme levels indicate cell damage or hepatocyte rupture.
• Blood tests measuring these enzymes can assess the extent of liver injury.

2.  Impact on Liver Function

• Protein synthesis:
  • Damaged hepatocytes can’t produce normal levels of plasma proteins and clotting factors.
  • Result: Reduced plasma proteins in blood, affecting clotting and fluid balance.
• Bilirubin metabolism:
  • Damage causes build-up of unconjugated bilirubin in the blood, leading to jaundice.

3.  Hepatitis: Inflammation of the Liver

• Hepatitis literally means liver inflammation.
• Causes:
  • Injury or irritation (e.g., alcohol, toxins).
  • Infections: Hepatitis viruses (at least 5 types).
  • Idiopathic (unknown causes).

Pathophysiology

• Severe inflammation damages hepatocytes.
• Structural damage:
  • Loss of normal liver architecture.
  • Scarring (fibrosis) and biliary stasis (bile flow impairment).
  • Bile may back up into the liver, causing further damage.

Signs of Liver Damage

• Edema in inflamed tissues.
• Pain and tenderness due to nerve irritation.
• Biliary stasis may reduce bile secretion or cause bile duct blockage, exacerbating liver injury.

Liver Structure & Function

• ** hepatocytes **:
  • Main functional cells.
  • Take in blood, screen nutrients.
  • Store glucose as glycogen, lipids, and amino acids.
  • Produce bile and send it through bile ducts.
• Damage to hepatocytes impacts:
  • Blood protein and clotting factor synthesis.
  • Bilirubin processing.
  • Overall metabolic processes.

Causes of Liver Injury

• Alcoholic liver disease.
• Some causes: idiopathic.
• Viruses (including Hepatitis Virus types A, B, C, D, E):
  • Cause viral hepatitis, varying severity.
• Drugs and toxins
• Reye syndrome
• Chronic inflammation can lead to cirrhosis and liver failure.

Summary

• Elevated liver enzymes, decreased protein synthesis, and bilirubin build-up signal liver damage.
• Hepatitis involves inflammation from multiple causes and can vary from mild to severe.
• Protecting the liver involves limiting alcohol, managing viral hepatitis infection, and avoiding toxins.