topic 4.2: chronic inflammation Flashcards
what occurs during chronic inflmmation
invloves active inflammation, tissue injury and healing proces simulatenously
tissue destruction induced by products of inflammatory cells (eg proteases)
tissue repair/healing process: fomration of fibrorus tissue, new vessel proliferation
what causes chronic inflmmation
unresolved accute inflmmation (acute inflammation progressing to chronic inflmation)
-persistent infections (microbes that are difficult to eradicate) (body stuck in a cycle of destruction and repair)
-harmful stimulus that tirggers a chronic inflmmatory response from the onset (eg viral infections, autoimmune disease) (eg straight away go into chronic inflmmation)
prolonged exposure to toxic agents eg. atherosclerosis – chronically elevated plasma lipids (toxic agent) (too long, body have to keep fighting)
what are the two examples of hypersentivity rxns/types we learn about
glomerulonephritis and vasculitis
tell me about the mechanism of glomerulonephritis
what is glomerulonephritis: inflammation of the glomeruli in the kidney
cause: consequence of some other disease, such as infection/cancer. many dogs with glomerulonephritis, the trigger cannot be determined
mechanism: immune complexes (antinody-antigen complex) become trapped in the glomeruli-> activation of the body’s inflmmatory defence system-> damages the glomeruli
immune complex deposition in gomeruli-> basement membrane thicend and stimulates glomerlar cells to proliferate (form new cells) -> form lesions-> this it is called Membranoproliferative glumerulonephritis
any or all of the three glomerular cells populations-epithelail,enodthelial and mesangial cells can proliferate
MPGN lesion are classified into three types (I, II & III) based on histopathology &
pathogenesis. 7
Explain hypersensitivity mechanisms and allergic diseases
impact of glomerulonephritis: protein in the urine during a urine test is the first indication
treatment: 1.treating any underlying disease
2.reducing the amount of protein lost in the urine
3.managing existing kidney disease
4.giving and immunosuppressive drugs to reduce the formation of immune complexes
untreated-> chronic kidney failure
tell me about vasculitis
what is vasculitis: inflmmation of the blood vessles casued by immune complexes (rem immune complex cause other cells to come to clear it-> inflmmation-> hence inflmmation of the blood vessels)
causes: drugs are a frequent cause of vasculitis in dogs
signs: skin abnormalities are seen as purplish red dots, (bleeding under the skin) ulcerations (sores/wonds) and scabs (crust-due to healing)
where: depending on which blood vessles invloved, signs appear on the lower leg, paws, ears, mouth or tongue
diagnosis: The disorder is diagnosed by performing tests on samples removed from the affected areas (biopsies)
treatment: Vasculitis is treated by stopping the offending drug (if implicated as the cause) or by giving drugs that suppress the immune system (reduce the formation of complexes causing the imflammtion)
what cells are invloved in chronic inflammation
macrphage
lymphocytes
eosinophils
charactersitics anddunction of machropage in chronic inflmmation
Dominant cells of chronic inflammation.
- Blood monocytes → (migrate to tissues) →
macrophage
- Phagocytes
- When activated: increased cell size,
lysosomal enzyme content & phagocytic
capacity. - H&E stain: large, flat, pink
- function: Activated macrophages secrete products
that cause tissue injury & inflammation
(eg. proteases, cytokines) and fibrosis (eg.
growth factors) - Can be stimulated by lymphocytes to fuse
into large, multinucleated giant cells
(MNGC)
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function and characteristics of lymphocyte in chronic inflmmation
Macrophages and lymphocytes interact in a
bidirectional way that sustain chronic
inflammation. (keep activating each other)
➢ Macrophage stimulate T cell response
by displaying antigens.
➢ Activated T cells produce cytokines that
activate macrophages
Plasma cells (from activated B cells)
produce antibodies directed against
persistent antigens.
function and characteristic of eosinophils in chronic inflmation
Usually found in parasitic or allergic
inflammatory sites
what are the two main types of chronic inflmmation
non-granulomatous and granulomatous
how does non granulomatous chronic inflmation look like under the microscope
Microscopically: Loose clusters of inflammatory cells with no particular arrangement.
* Macroscopically: Variable background of fibrosis, or reactive hyperplasia or hypertrophy in
surrounding tissues.
* Eg: Chronic inflammation of skin – skin thickens, become greasy because of hyperplasia of skin
glands; chronic inflammation of gut – wall is thicker than normal.
what does granulomatous chronic inflamation look like under the microscope
Distinct arrangements of inflammatory cells – ‘granulomas’
* (Microscopically) Granulomas = central aggregates of macrophages with mononuclear
inflammatory cells clustered around the macrophages, and a rim of fibrous tissue around the
outside.
* May be present (microscopically):
* Multinucleated giant cells = fusion of macrophages
* Neutrophils + macrophages in the centre of granulomas → known as pyogranulomatous (seen
in feline infectious peritonitis, FIP).
what does granulmatous chronic inflmation look lole macrscopically
Single, large, visible lumps
* Numerous, smaller lumps (tissue feels thickened and nodular)
* Formed when: cause of inflammation resists destruction by inflammatory or immune mediated
processes
* Eg. foreign material (suture, splinter); infectious organisms (bacteria with protective capsules eg
tuberculosis, parasites with tough outer walls); hypersensitivity response.
what are harmful effects of chronic inflmmation
1.Long term disease and lasting dysfunction of affected organ/tissue.
* Chronic nephritis → persistent renal disease
* Chronic enteritis → diarrhea, weight loss, inability to absorb nutrients efficiently.
2.Loss of organ/tissue function due to pain, swelling, fibrosis (scarring), discharge
3.Weight loss, persistent fever due to chronic effects of chemical mediators (refer to Acute
inflammation – systemic effects)
- Changes in blood – increased leukocytes, globulins (producing antibodies), decreased RBCs (anaemia)
