Necrosis Flashcards
Necrosis
Death Of cells and tissues in the living animal
Necrosis is localised area of death of tissues followed later by degradation of tissue by hydrologic enzymes liberated from death cells
Inflammatory reaction will be there
Always pathological and occurs in the group of cells
What the Types of necrosis
CCCFF
Coagulation necrosis
Colliquative /liquefaction
Caseous
Fat
Fibrinoid
Coagulative necrosis
Architectural details are there but cytoplasmic and nuclear features are absent
Tissues can be recognised
Denaturation of structural and enzymatic proteins block proteolysis
Causes of the
Ishchemia except brain all organs will undergo this coagulative necrosis
Mild burns
Zenkers degeneration necrosis
Grossly how the coagulative necrosis
Early: pale ,firm,slightly swollen
With progressing more yellowish ,softer,shrunken
Microscopic features of the coagulative necrosis
Thomb stones.
Necrotic cells are swollen and more eosinophilic
Pyknosis, karyohexisis,karylosis
Inflammatory cells
Coagulative necrosis
Most common
Architectural details are present but nuclear and cytoplasmic details
Causes are ischemic
Zenkers diverticulum
Thermal injury
Grossly pale ,firm ,swollen,yellow
Microscopically = thomb stones
Pyknosis, karyolysis, karyohexisis,
Inflammatory cells
Liqufactive necrosis
Here the hydrologic enzymes are more so these,I fluid material is formed
No architectural and cytoplasmic and nuclear features are present
Causes of liquefaction necrosis
Pyogenic bacterial infections attract neutrophils
Bacterial and leukocytes enzymes liquefy dead cells amd tissues
Ischemic necrosis of brain
Gross appearance of liquefactive necrosis
Affected area is
Soft and liquefied central containing necrotic debris
Later cyst wall is formed
Liqufactive necrosis
Semi solid
Architectural details are are lost and nuclear details are also lost
Causes
pyogenic infections
Brain
Caseous necrosis
Cheese like dead tissue is converted into
Homogeneous granular mass resembles the cottage cheese
No archetectural details as well as cytoplasmic and nuclear details are lost
Accumulation of amorphous debris within an area of necrosis
Causes of caseous necrosis
Mycobacterium tuberculosis
Sphylis
Fungi(histoplasmosis and coccidomucosis)
Gross appearance of caseous
Dry cheese and are soft,granular and yellowish
Fat necrosis
Occurs in the fat laid anatomical places
Breast,pancreas,(mesentric fat necrosis) omentum
Breast ( fat and pendulous breast)
Grossly appearance of fat necrosis
Yellowish white and firm deposits
Due to the formation calcium soaps chalky white appearance it makes the necrosis foci firmer
How calcium soaps are formed
Acute pancreatitis lo due to damage of pancreas liberation of lipases are done from the damaged tissues
This causes the necrosis of pancreas and fat
Then the adipocytes gets ruptures and glycerol and fatty acids are released these react with calcium and form calcium soaps
Microscopic view of the fat necrosis
Necrosis cell have-cloudy appearance
Surrounded by inflammatory reaction
Calcium soaps appear as amorphous granular and basophils material
Fibrinoid necrosis
Deposition of fibrin like material
It has same staining properties like the fibrinogen with phosphate tungsten acid haemotoxlin staining
IIT occurs mostly in the blood vessels
Causes of the fibrinoid necrosis
Occurs mostly in the immune diseases
Vasculitis ,Arthur’s reaction, nuclear
Arterioles in Hypertension , peptic ulcers
Microscopic features of fibrinoid necrosis
Identified by the eosinophilic hyaline like material deposits on the vessels walls
Necrotic focus is surrounded by the nuclear debris of neutrophils
Local haemorrhage may be causesd due to the rupture
Caseous necrosis
Dead tissue converted to homogeneous granular mass resembling cottage cheese
Architectural details are not present
Accumulation of amorphous debris with in an area of necrosis
Cause of caseous necrosis
Mycobacterium tuberculosis
Syphilis
Fungi
Gross appearance of caseous necrosis
Dry cheese and soft granular yellowish
Partly attributed to the histotoxic effects of liposaccarided present in the capsule of mycobacterium tuberculosis
Microscopic features of caseous necrosis
Centre of necrosis foci contain
Structureless eosinophilic material having scattered granular debris and disintegrated nuclei
Surrounded tissue show granulomatous inflammatory reaction
