Necrosis

Overview

• Exogenous cell injury resulting in uncontrolled cell degradation 
  • normal cellular enzymes responsible for controlled cell death (apoptosis) are inactivated
• Key principles
  • release of intracellular components
  • presence of inflammation
• Several types
  • coagulative 
    • solid organs which allow preservation of cell shape by coagulation of cell proteins
      • e.g.) heart, liver, kidney
  • liquefactive 
    • soft organs which allow lysis of cells and surrounding proteins
      • e.g.) brain
  • caseous 
    • presence of fatty cell walled organisms creates a cheese-like consistency
      • e.g.) tuberculosis, fungi
  • fat 
    • damage to fat as result of trauma or presence of activated lipase
      • e.g.) pancreas
  • fibrinoid
    • result of protein leaking from vessel wall 
      • e.g.) blood vessels
  • gangrenous 
    • dry
      • ischemic necrosis without concomitant bacterial infection
    • wet
      • liquefactive necrosis with concomitant bacterial infection