7 Chronic inflammation

Question 1

What is the purpose of inflammation?

Answer 1

Remove the cause of injury.
Remove necrosis.
Initiate repair.

Question 2

Contrast acute vs chronic inflammation.

Answer 2

Fast onset vs slow.
Prominent vs subtle signs.
Mild and self limiting vs severe and progressive.
Neutrophils based vs macrophage and lymphocyte based.

Question 3

Five sources of primary chronic inflammation.

Answer 3

Primary granulomatous diseases.
Exogenous material.
Auto-immune.
Endogenous material.
Infections.

Question 4

Describe 2 ways acute inflammation may become secondary chronic inflammation.

Answer 4

Supportive acute inflammation can forms abscess, walls thicken. Granulation and fibrous tissue forms.
OR
Recurrent acute to chronic.

Question 5

What is the macroscopic feature of chronic inflammation?

Answer 5

Fibrosis - more prominent when inflammatory infiltrate has stopped.
Dependant on disease.

Question 6

What are the microscopic features of chronic inflammation? (3).

Answer 6

Cellular infiltrate of lymphocyte, plasma cells and macrophages.
Exudation fluid is not prominent.
Production of new fibrous tissue from granulation tissue.

Question 7

What do cytokines do in chronic inflammation? (4).

Answer 7

Attract macrophages.
Attract neutrophils and histamine - increasing permeability.
Cause perforins to kill cells.
Produce interferons to activate NK cells and macrophages.

Question 8

What is the role of macrophages in chronic inflammation?

Answer 8

Increase inflammation.
Release cytokines to signal monocytes which enter tissue via leukocyte extraversion (recruitment).
Proliferate.
Trapped in tissue by inhibiting factor.

Question 9

How do macrophages change the structure of tissue around them in chronic inflammation?

Answer 9

Low O2 content makes them produce angiogenesis inducing factors.
Induce cells to re-epitheliase wound and create granulation tissue.

Question 10

What does granulation tissue formation involve and what is its aim?

Answer 10

To repair injured tissue by fibrosis.

Angiogenesis. Fibroblasts deposit collagen. Inflammatory cells.

Question 11

What is fibrosis?

Fibroma?

Answer 11

Formation of excess fibrous connective tissue during repair (scarring).

Fibroma = arise form 1 cell line.

Question 12

What is a granuloma?

Answer 12

Aggregate of epithelioid histiocytes, lymphocytes and histolytic giant cells.

Question 13

What are histolytic giant cells?

How and where do they form?

Answer 13

Multinucleate (>100) giant cells. Develop when two macrophage try to engulf one particle. Not phagocytic anymore.

Form where material is indigestible - tubercle bacilli with resistant cell walls.

Question 14

List 4 infectious causes of granulomatous diseases:

1 mineral cause:

Answer 14

TB.
Leprosy.
Schistosomiasis.
Cryptococcus.

Silicosis.

Question 15

Describe the stages granuloma in TB. (4)

Answer 15

1. Inhale MTB. Invades alveolar macrophage via mannose receptor. Multiplies. 1wk.
2. 2-3wks. Proliferation.
3. Proliferation and phagocytosis are balanced. 90% stay here. Not contagious.
4. Reactivation 1-2yr later. 5%. Proliferation, cavity formed. Active, symptomatic infection. Contagious. >Immunocompromised.

Question 16

What is a round complex in TB stage 3?

Answer 16

Tb and infected macrophages in centre with normal macrophages surrounding it.

Question 17

Describe the layers in a caseous granuloma.

Answer 17

Caseous necrosis -> langerhans type cells +epithelioid macrophages -> lymphocytes and plasma cells -> fibroblasts producing collagen.