Irreversible Cell Injury 3 - Necrosis Flashcards
5 types of necrosis
- Coagulative necrosis
- Liquefactive necrosis
- Caseous necrosis
- Gangrenous necrosis
- Enzymatic necrosis
-Coagulative necrosis
-_________ induced in what organs
-basic tissue preserved or not?
Ischaemia/toxin in liver, heart, kidney, skeletal muscle
Preserved temporarily
Liquefactive necrosis
____________ induced in CNS
Ischaemia/toxin
Caseous necrosis
Caused by…
Causes…
Mycobacteria infections like Tuberculosis
Causes tissues to become “cheese-like” in appearance
What changes do we recognise with cell death under the microscope?
—cytoplasmic changes
—nuclear changes
Cytoplasmic changes in the morphology of cell death
—early phase
Early phase:
-Cytoplasm becomes homogeneous pink in H&E section
Increased eosinophilia due to: loss of RNA which is responsible for cytoplasmic basophilia so basophilia lost
-condensed cytoplasm
-degradation of cytoplasmic proteins causes ghost-like appearance
-necrotic cells become “ individualised” i.e lose adherence/attachment to basement membranes and adjacent cells
Cytoplasmic changes in the morphology of cell death
—late phase
Cell membrane rupture with loss of integrity and release of cell contents into extracellular space
Name the 4 Nucleur changes in morphology of cell death
-Pyknosis
-Karyorrhexis
-Karyolysis
-Absence
Describe nuclear change of Pyknosis in cell
Shrunken, dark, homogenous, round, basophilic nuclei
Describe nuclear change of Karyorrhexis of cell
Fragmentation of nucleus
-rupture of nuclear membrane and chromatin
-dark nuclear remnants released into cytoplasm
Describe nuclear change of Karyolysis of cell
Nucleus becomes very pale
-due to dissolution of chromatin by DNAses
Describe the nuclear change of Absence of cells nucleus
Completely dissolved or lysed nucleus
Diagram of the different nuclear changes of cell during cell death
https://www.google.co.uk/url?sa=i&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FKaryolysis&psig=AOvVaw01aar9gkKfkmEcpPTUQp2I&ust=1674673524348000&source=images&cd=vfe&ved=0CA8QjRxqFwoTCMDljpbz4PwCFQAAAAAdAAAAABAg
https://www.google.co.uk/imgres?imgurl=https%3A%2F%2Fi0.wp.com%2Fwww.pathologystudent.com%2Fwp-content%2Fuploads%2F2022%2F08%2FNuclear-changes.png%3Fresize%3D655%252C212%26ssl%3D1&imgrefurl=https%3A%2F%2Fwww.pathologystudent.com%2Fdoes-pyknosis-occur-in-necrosis-or-apoptosis%2F&tbnid=x82gbgAnzZirHM&vet=12ahUKEwiWgc7R8-D8AhWOsCcCHZDuBgIQMygDegUIARDBAQ..i&docid=6Lgk51fnFeGPWM&w=655&h=212&q=pyknosis%2C%20karyohsis%20and%20karyolitic%20cell%20diagrams&hl=en-gb&client=safari&ved=2ahUKEwiWgc7R8-D8AhWOsCcCHZDuBgIQMygDegUIARDBAQ
Common causes of Coagulative necrosis
Hypoxia- local loss of blood supply
Ischaemia
Bacterial or chemical toxins
Local actin of irritating substances
Causes for renal necrosis (kidney)
Plants—>
—Cattle: -oak, acorn
-Oxalate (rhubarb, sorrel, dock)
—Cats:- Easter lily
—Pigs:- redroot pigweed phenolic compounds)
—Dogs:- raisins/grapes
Heavy metals—> mercury, lead
Chemicals—> ethylene glycol
Therapeutic drugs—-> antibiotics & chemotherapeutics
Necrosis relating to infectious disease
-viral infections
-bacterial infections
Viral infections
Infectious Bovine Rhinotracheitis (IBR)
-Bovine Herpesvirus 1 (BHV-1)
Canine parvoviral enteritis
-Canine Parvovirus 2 (CPV-2)
Canine infectious hepatitis
-Canine Adenovirus 1 (CAV-1)
Bacterial infections
Tuberculosis (Mycobacteria)
-Mycobacterium tuberculosis, M. bovis, other
Salmonellosis (S. enterica, serotypes S. typhimurium, S. choleraesuis, S. dublin etc.)
Clostridial infections (Cl. perfringens, Cl. difficile, Cl. chauvoei, Cl. septicum, other…)
Infectious Bovine Rhinotracheitis
-caused by…
-causes what?
-may also cause secondary bacterial infection which results in…
-Bovine Herpesvirus 1
-causes transient acute febrile illness with respiratory signs
-causes severe hyperaemia and focal necrosis of: trachea, larynx, nasal cavity pharynx and mucosae
-also may cause secondary bacterial infection which results in thick plaques of fibrinonecrotic exudate
Canine parvovirus enteritis
-caused by what
-causes what
-caused by canine parvovirus-2
-causes segmental necrosis and haemorrhage of small intestine (with this might also see variable dilation of intestinal loops &
granular texture of serosal surface)
Canine infectious hepatitis
-caused by what
-causes what
Caused by CAV1
Causes liver to be enlarged and friable; will see fibrin on capsular surface and over liver lobes. Liver has granular appearance on serosal surface. Gallbladder walls thickened by oedema
Caseous necrosis
-what does dead tissue look like
-microscopic appearance;
-contains what
-examples
Dead tissue converted into a glandular, friable mass
-Resembles cottage cheese
● Microscopic appearance
– accumulation of fragmented / lysed cells with an amorphous granular appearance
– tissue architecture obliterated, no cell outlines visible
– dystrophic calcification often seen centrally
● Chronic lesions
– often associated with poorly degradable bacterial lipids
Classic examples
– TUBERCULOSIS
– Corynebacterium pseudotuberculosis in sheep
Caseous lymphadenitis (CLA)
-in which animals
-causes
-caused by
-spread by…
-incubation period
Sheep/goats
-causes chronic suppurative lymphadenitis
-caused by Corynebacterium pseudotuberculosis
-spread by;
● Shearing wounds
– arthropod bites or contaminated dips
● Spread by ruptured abscesses, oral and nasal secretions
Incubation period; 3 months
Liquefactive necrosis
-Specific for CNS
-caused by hypoxia or toxin induced by neuronal necrosis which causes liquefaction
What is liquefaction?
partial or complete dissolution of dead tissue and transformation into a liquid, viscous mass
Describe the process of Liquefactive necrosis occurring due to pyogenic bacteria
1.Recruitment of inflammatory cells (mainly neutrophils)
2.Release of lytic enzymes
3.Destruction of bacteria
+ degeneration & necrosis of neutrophils
4.ABSCESS (pus-filled cavity)
can be considered a type of liquefactive necrosis
