Chronic Inflammation & Repair 1

Question 1

Describe how inflammation gets resolved.

Answer 1

-macrophage can lymphatic vessels remove the exudate
-inciting agent or substance is eliminated
-CT of affected tissue can still support epi cells
-damaged epi can regen on intact BM

Question 2

Describe abscess formation.

Answer 2

-localized collection of pus in a cavity formed by disintegration of tissue
-caused by bacteria or other inf agents/foreign body
-surrounded by fibrous capsule
>ex of chronic inflam
-consists of purulent/suppurative exudate
>ex of liquefaction necrosis
>fluid collection of necrotic & inflam cells
-occurs when acute inflam resp FAILS to rapidly elim inciting stim
-enzymes & inflam mediators LIQUIFY affected tissue & neutrophils to make pus
-form within FEW DAYS
-thick fibrous capsule can wall off exudate (weeks-months)
*antibiotics dont penetrate -> lance

Question 3

Describe chronic inflammation.

Answer 3

-weeks, months, yrs
-chronic inflam cells
-tissue destruction
-attempts at healing
-occurs when acute inflam resp fails to elim stim
-repeated episodes of acute inflam
-resp to unique biochem characteristics/virulence factors in stim or microbe

Question 4

Describe chronic inflammation examples of causes.

Answer 4

1. Systemic mycoses
   -crypto, histo, blasto
2. Intracellular bacteria
   -mycobacteria, Rhodococcus
3. Protozoa
   -toxoplasma, leishmania
4. Parasites
   -Toxocara, Habronema
5. Foreign body
   -grass seeds, splinters, suture, inj
6. Autoimmune disease
   -allergic dermatitis (FAD)

Question 5

Describe how chronic inflammation is characterized by.

Answer 5

persistence of inciting stim
1. Bacteria, mycoses, parasites *
-avoid/resist phagocytosis
-prevent fusion of lysosomes
-isolation (hide from IR) in pus [ex. Strep, staph]
2. Unresponsiveness to phagocytosis or enzymatic breakdown *
-ex: plants, suture
3. Altered immune resp
-autoimmune disease = altered adaptive IR to self aG w chronic inflam
-unidentified mech
4. Infiltration by mononuclear cells
-macrophages & lymphocytes (inflam & IR)
-other inflam cells: plasma, neutrophils, eosinophils
5. Extensive tissue injury & necrosis
6. CT replacement followed by fibrosis (attempt to repair)

Question 6

Describe macrophages in inflammation.

Answer 6

-stimuli cont induce release of cytokines, chemokines, inflam mediators
-macrophage infiltration & activation
-cytokines made by macrophages & T cells amplify & prolong inflam
-activated macrophages in tissue are large w clear cytoplasm, eccentric nuclei ‘epitheliod’

Question 7

Describe macrophages roles.

Answer 7

1. Respond & migrate to inflam stim
2. Remove injurious agents & cell debris (phagocytosis)
3. Stim adaptive IR (lymphocyte)
4. Cause further tissue damage
5. Secrete growth factors to begin repair
   >fibroplasia, angiogenesis

Question 8

Describe multinucleate giant cells.

Answer 8

macrophage differentiate w time
-Collection of fused macrophages
-Langhans (peripheral nuclei) or foreign body type (central nuclei) *
>seen in granulomatous inflam esp when diff to elim cause of inflam (mycobacteria, fungi, foreign body)

Question 9

Pictures of macrophages.

MNGC

Answer 9

Question 10

Describe monocytes in tissue macrophages.

Answer 10

-leave blood under physiologic conditions to pop tissues
-CT (histiocytes)
-liver (kupffer cells)
-lung (alveolar macs)
-LN
-spleen
-BM (osteoclasts)
-brain (microglial cells)
-skin (histiocytes)

Question 11

Describe monocytes in infiltrating macrophages.

Answer 11

1. M1 macs
   -receptors that resp to inflam stim to cause migration, chemotaxis, phagocytosis
   -stim to resp to & secrete cytokines
   -resp for acute phase protein resp via cytokines (IL1/TNFa)
   -present antigen/interact w TLC (link to adaptive IR)
2. M2 macs
   -CT repair & fibroplasia *

Question 12

Describe the different types of chronic inflammation.

Answer 12

1. Granulomatous inflammation - diffuse & nodular
2. Eosinophilic granuloma
3. pyogranulomatous
4. Lymphocytic
   *can have mixture of cell types

Question 13

Describe granulomatous inflammation.

Answer 13

-chronic inflam
-predominant cell = macrophage
>contains MNGC, lymphocytes, eosinophils, fibroblasts, fibrous tissue (collagen), necrosis
-due to persistence of foreign injurious agents
>tuberculosis (mycobacterium), fungi, myocardia, foreign body
-special stains to ID cause:
>mycobacterium spp = ziehl neelson stain acid fast
>fungi = periodic acid schiff stain - silver stains

Question 14

Describe the two morphological forms of granulomatous inflammation.

Diffuse form

Answer 14

1. Diffuse (lepromatous) form (th2)
   -diffuse accumulation of macrophages in tissue
   -ex. Johnes disease
2. Nodular (tuberculoid) form (th1)
   -tissue forms into nodular masses of inflam tissue
   -nodules called ‘granulomas’
   -ex. Tuberculosis

Granulomatous

Question 15

Describe more examples of granulomatous inflammation.

Answer 15

Question 16

Describe chronic eosinophilic inflammation & eosinophilic granuloma.

Answer 16

-eosinophils can form a lg portion of inflam cells & macrophages
-inflam secondary to migrating parasites, fungal inf, allergic conditions
-3 allergic examples:
>feline eosinophilic complex
>canine eosinophilic granuloma
>equine nodular collagenolytic granuloma

Question 17

Describe feline eosinophilic granuloma.

Answer 17

Question 18

Describe equine nodular collagenolytic granuloma.

Answer 18

Question 19

Describe chronic pyogranulomatous inflammation.

Answer 19

-combo of neutrophil & macrophages

Question 20

Describe chronic lymphocytic inflammation.

Answer 20

Question 21

Describe summary.

Answer 21

1. Causes of chronic inflam: failure to elim stim, repeated acute inflam, unique virulence factors of microbes
2. Morphologic features: mononuclear cells (macrophages, lymphocytes) attempt at repair = angiogenesis, fibrosis
3. Macrophages: tissue injury, phagocytosis, stim adaptive immunity, initiate repair & fibrosis
4. Granulomatous inflam: predom cell is macrophage, MNGC, lymphocytes, eosinophils, fibroblasts, fibrous tissue, necrosis (diffuse VS nodular)
5. Other forms of chronic inflam: eosinophilic, pyogranulomatous, lymphocytic