necrosis

NECROSISNECROSIS

Dr. R. Dr. R. GeethaGeetha M.D.M.D.Professor Professor

Department of PathologyDepartment of PathologySMCSMC

DEFINITION OF NECROSISDEFINITION OF NECROSIS

Spectrum of morphologic changes that follows cell death in living tissues.

CAUSES OF NECROSISCAUSES OF NECROSIS

ISCHEMIAISCHEMIAPHYSICAL AGENTSPHYSICAL AGENTSCHEMICAL AGENTSCHEMICAL AGENTSIMMUNOLOGICAL INJURYIMMUNOLOGICAL INJURY

PATHOGENESIS OF NECROSIS

1.Denaturation of intracellular proteins.

2.Enzymatic digestion of the cell.

MORPHOLOGYMORPHOLOGY

Increased Increased eosinophiliaeosinophilia of cytoplasmof cytoplasmGlassy homogeneous appearanceGlassy homogeneous appearanceCytoplasm is Cytoplasm is vacuolated,mothvacuolated,moth eateneatenCalcification of dead cells.Calcification of dead cells.Appearance of myelin figuresAppearance of myelin figuresGeneration of calcium soapsGeneration of calcium soaps

CYTOPLASMIC CHANGES

NUCLEAR CHANGESNUCLEAR CHANGES

1. KARYOLYSIS

Fading of basophilia of chromatin

Due to DNAase activity.

2. PYKNOSIS2. PYKNOSIS

Nuclear shrinkage and increased basophilia

3.KARYORRHEXIS3.KARYORRHEXIS

Fragmentation of pyknotic nucleus

TYPES OF NECROSISTYPES OF NECROSIS

CoagulativeCoagulative necrosisnecrosisLiquefactiveLiquefactive necrosisnecrosisCaseousCaseous necrosisnecrosisFat necrosisFat necrosisFibrinoidFibrinoid necrosisnecrosis

COAGULATIVE NECROSISCOAGULATIVE NECROSIS

Preservation of general tissue Preservation of general tissue architecturearchitecture--tombstone appearance tombstone appearance of the cells.of the cells.Affected tissue is firmAffected tissue is firmDenaturation of structural proteins Denaturation of structural proteins and enzymatic digestion of cells.and enzymatic digestion of cells.Example Example –– Heart, Heart, kidney,spleenkidney,spleen..

NORMAL NORMAL HEARTHEART

COAGULATIVE NECROSIS

COAGULATIVE NECROSIS HEART

COAGULATIVE NECROSISNORMAL KIDNEY

COAGULATION NECROSISNORMAL SPLEEN

LIQUIFACTIVE NECROSISLIQUIFACTIVE NECROSIS

The tissue becomes liquid viscous The tissue becomes liquid viscous massmassMaterial is creamy yellow in colorMaterial is creamy yellow in colorSeen in brain, abscessSeen in brain, abscess..

LIQUEFACTIVE NECROSIS BRAIN

LIQUEFACTIVE NECROSIS BRAIN

LIQUEFACTIVE NECROSISNORMAL BRAIN

LIQUEFACTIVE NECROSIS BRAIN

GANGRENOUS NECROSISGANGRENOUS NECROSIS

Wet gangreneWet gangreneDry gangreneDry gangreneGas gangreneGas gangrene

WET GANGRENEWET GANGRENE

Occurs in moist tissues like mouth, bowel, Occurs in moist tissues like mouth, bowel, lung, cervixlung, cervixDiabetic footDiabetic footBed soresBed sores

WET GANGRENE INTESTINE

WET GANGRENE

DRY GANGRENEDRY GANGRENE

Toes and feet due to arteriosclerosisToes and feet due to arteriosclerosisThromboangitisThromboangitis obliteransobliteransRaynaudRaynaud diseasediseaseTraumaTrauma

DRY GANGRENE

WET GANGRENE DRY GANGRENEWET GANGRENE DRY GANGRENE

BowelBowelVenous obstructionVenous obstructionMoist,swollen,darkMoist,swollen,darkNo clear line of No clear line of demarcationdemarcationBacteria presentBacteria presentPrognosis poorPrognosis poor

LimbLimbArterial obstructionArterial obstructionDry, shrunken, blackDry, shrunken, blackPresence of line of Presence of line of demarcationdemarcationNo bacteriaNo bacteriaPrognosis betterPrognosis better

GAS GANGRENEGAS GANGRENE

Wet gangrene caused by gram Wet gangrene caused by gram positive anaerobic bacteriapositive anaerobic bacteriaSeen in muscle and in colonSeen in muscle and in colon

GAS GANGRENEGAS GANGRENE

CASEOUS NECROSISCASEOUS NECROSIS

Type of Type of coagulativecoagulative necrosisnecrosisSeen in tuberculous infectionsSeen in tuberculous infectionsTissue is cheesy white in appearanceTissue is cheesy white in appearanceThe tissue architecture is preservedThe tissue architecture is preserved

CASEOUS NECROSIS LUNG

CASEOUS NECROSIS LUNG

CASEOUS NECROSIS LYMPHNODECASEOUS NECROSIS LYMPHNODE

CASEOUS NECROSIS LYMPH NODE

CASEOUS NECROSIS

CASEATION NECROSIS LYMPH NODE

FAT NECROSISFAT NECROSIS

Seen in pancreas, breastSeen in pancreas, breastIn acute pancreatitis ,activated In acute pancreatitis ,activated lipase causes fat necrosis.lipase causes fat necrosis.Grossly visible chalky white Grossly visible chalky white areas.areas.Presence of shadowy outlines of Presence of shadowy outlines of necrotic cells.necrotic cells.

FAT NECROSIS

FAT NECROSIS

FIBRINOID NECROSISFIBRINOID NECROSIS

Deposition of fibrin like materialDeposition of fibrin like materialSeen in immunologic cell injury, Seen in immunologic cell injury,

hypertension ,peptic ulcer.hypertension ,peptic ulcer.

FIBRINOID NECROSISFIBRINOID NECROSIS