NECROSIS, GANGRENE.

I. practical training

2rd year Dentistry

Signs of death

• Cardiac arrest (no pulse)

• Pallor mortis, paleness which happens in the 15–120 minutes after

death

• Livor mortis, a settling of the blood in the lower (dependent) portion

of the body

• Algor mortis, the reduction in body temperature following death. This

is generally a steady decline until matching ambient temperature

• Rigor mortis, the limbs of the corpse become stiff (Latin rigor) and

difficult to move or manipulate

• Decomposition, the reduction into simpler forms of matter,

accompanied by a strong, unpleasant odor.

• Diffusion of the liquid and gasses from the intestine –

pseudomelanosis, verdohemoglobin

• Cell Autolysis – destruction of lysosomes

Vital reaction

• Inflamation –

(redness, white blood cells - polymorfonuclears,

lymfocytes, plazmocytes, macrofages)

• Demarcation

• Reparation

Regresive changes

• Deth, necrosis, apopthosis, dystrophy

• Apoptosis – is the process of programmed cell death

that may occure in multicellular organism and leads to

characteristic cell changes and death of the cell

- the programmed destruction of cells during

embryogenesis

- cell death injury – DNA demage, drug injury

(cytostatics), cell death in tumours

Morfology – cell shrinkage, chromatin condensation,

formation of the cytoplasmatic blebs and apoptotic

bodies

Regresive changes

• Necrosis – cell death in living tissue, results form

the progressive degenerative reaction of

enzymes on the lethaly injured cell

Morfology – increased eozinophilia, nuclear

changes (karyolysis, pyknosis (nuclear

shrinkage and increased basophilia)

Ethiology – microorganisms, chemicals, physical

factors,

Necrosis

• Coagulative - is a type of accidental cell death typically caused by

ischemia or infarction. Injury denatures structural proteins as well as

lysosomal enzymes thus blocking the proteolysis of the damaged

cells. (In tissues rich for proteins – typicaly infarction of myocardium)

• Liquefactive - In liquefactive necrosis, the affected cell is

completely digested by hydrolytic enzymes, resulting in a soft,

circumscribed lesion consisting of pus and the fluid remains of

necrotic tissue. Sometimes it is associated with focal bacterial or

fungal infections. Typical for tissues poor for proteins – ischemic

brain nekrosis

• Gangrenous - this term is used in clinical surgical practice. Usually

aplied for limbs, mumiffication (dry gangrene), modiffication by

microorganisms (wet gangrene)

Necrosis

• Caseous – in foci of tuberculous infection, name form white gross

appearance of the area of necrosis. Microscopicly – acellular pink

areas of necrosis surrounded by a granulomatous inflammatory

process. In necrosis – amorphous granular debris composed of

fragmented coagulated cells

• Zenker´s necrosis – muscles, influensa infection

• Fat necrosis (Balzer´s) – in which the neutral fats in adipose tissue

are split into fatty acids and glycerol, usually affecting the pancreas

and peripancreatic fat in acute hemorrhagic pancreatitis.

• Fibrinoid - accumulation of amorphous, basic, proteinaceous

material in the tissue matrix with a staining pattern reminiscent of

fibrin. (vasculitis, gastric ulcer)

Recent myocardial infarction

Recent myocardial infarction

Coagulative necrosis– myocardial

infarcrion

Older myocardial infarction

Older myocardial infarction

Postinfarction scar of the myocard

Postinfarction scar of the myocard

Renal infarct

Caseous tbc lymphadenitis

Cerebral infarct (encephalomalacia)

Cerebral infarct (encephalomalacia)

Lung tromboembolism and haemorrhagic infarct

Fibrinoid necrosis

gastric ulcer revmatoid artritis

Liquefactive necrosis – brain

Gangrena

Secondary modified necrosis

Dry (mumification) – drying up of necrotic parts – diabetes

patient´s legs (hematin), fetus papyraceus

Wet (sfaceus, humida) – modified by bacterias

Emphysematous (emfyzematóza) – anearobic bacterias –

Clostridia, toxins

Gangrene of foot