Chronic inflammation

Question 1

What is Chronic Inflammation?

Answer 1

Inflammation of a prolonged duration

Question 2

When does chronic inflammation occur?

Answer 2

1. When the acute inflammatory response fails to remove the stimulus
2. When there are repeated episodes of acute inflammation
3. The stimulus or microbe has unique biochemical characteristics or virulence factors which incite chronic inflammation

Question 3

What are some mechanisms of chronic inflammation?

Answer 3

Persistent or resistant infections
unresponsiveness to phagocytosis or enzymatic breakdown
autoimmunity

Question 4

What maintains the chronic inflammatory response?

Answer 4

infiltration and activation of lymphocytes, macrophages, plasma cells and multinucleated giant cells
Tissue destruction
proliferation of fibroblasts and deposition of collagen
Initiation of wound healing

Question 5

What are the benefits of chronic inflammation?

Answer 5

walling off/ getting rid of the inciting substance

Question 6

What are the harmful aspects of chronic inflammation?

Answer 6

The space occupying lesions can be formed resulting in
* displacement of the original tissue
* Loss of function
* Clinical sigficance that is determined by the size, tissue and the position

Question 7

What is granulomatous inflammation?

Answer 7

a distinct type of chronic inflammation dominated by cells of the monocyte-macrophage system and multinucleated giant cells

Question 8

Why do birds and reptiles struggle to convert neutrophils into pus?

Answer 8

Because they lack myeloperoxidase in their neutrophils

Question 9

How are the macrophages of granulomatous inflammation dispersed?

Answer 9

either dispersed as sheets at random within the tissue
or arranged in discrete masses/nodules

Question 10

How do nodular/tuberculoid granulomas develop?

Answer 10

they develop with a T helper lymphocyte type 1 response

Question 11

What is the difference between caseating and non-caseating granulomas?

Answer 11

Caseating means they have a central core of necrotic debris

Question 12

What is the general appearance of tuberculoid granulomas?

Answer 12

Round/Oval
May form a fibrous capsule

Question 13

What are some of the causes of tuberculoid granulomas?

Answer 13

Myobacterium bovis/ Myobacterium tuberculosis
Deep fungal infections

Question 14

How do lepromatous granulomas develop?

Answer 14

they develop with a T helper lymphocyte type 2 response

Question 15

What do lepromatous granulomas look like?

Answer 15

they are poorly delineated, forming sheets within the tissue
composed of numerous macrophages and few lymphocytes/plasma cells

Question 16

What are some of the causes of lepromatous granulomas?

Answer 16

Mycobacterium avium
Mycobacterium lapraemurium

Question 17

What are eosinophillic granulomas characterised by?

Answer 17

dense infiltration of eosinophils, macrophages and varying numbers of lymphocytes/palsma

Question 18

When does pyogranulomatous inflammation occur?

Answer 18

When the inciting stimulus continues to elicit an acute inflammatory response

Question 19

What are the cellular constituents of a pyogranulomatous inflammation?

Answer 19

same as teh granulomatous inflammation but with neutrophils, plasma proteins and fibrin

Question 20

What is a pyogranuloma?

Answer 20

a ndoular granuloma with a central area of neutrophils

Question 21

What is a Lymphoplasmacytic inflammation?

Answer 21

Common type of inflammation often seen at the early stages of chronic inflammation
also seen in response to specific microbes or in response to antigenic inflammation

Question 22

What occurs to the macrophages once they enter the tissues?

Answer 22

They become activated by cytokines (e.g IL-4 or IFN-7 from T lymphocytes)

Question 23

What two roles do activated macrophages have?

Answer 23

• Inflammation/ tissue injury (e.g removing NO, ROS, Proteases, Cytokines…)
• Repair (Growth factors, Remodelling)

Question 24

What are the two different classes of activated macrophage?

Answer 24

• Classically activated macrophage
• Alternatively activated macrophage

Question 25

What are the 4 types of granulomatous inflammtion?

Answer 25

• Diffuse or lepromatous (dispersed as sheets at random within the tissue)
• Tuberculoid or nodular (discrete masses)

Question 26

What is the difference between lymphoplasmacytic and lymphohistiocytic inflammation

Answer 26

lymphoplasmacytic- composed of lymphocytes and plasma cells
lymphohistiocytic- when the lymphocytes and macrophages predominate over plasma cells

Question 27

When is lymphoplasmacytic inflammation most commonly seen?

Answer 27

In the early stages of chronic inflammation

Question 28

What are the functions of classically activated macrophages?

Answer 28

• Microbicidial actions
• phagocytosis
• pathological inflammation

Question 29

What activates classically-activated macrophages?

Answer 29

pro-inflammatory signals
microbial products

Question 30

What is the function of alternatively activated macrophages?

Answer 30

• Anti-inflammatory effects
• Wound repair

Question 31

What stimulates alternatively activated macrophages?

Answer 31

Induced by anti-inflammatory signals

Question 32

What are eosinophillic granulomas secondary to?

Answer 32

They are secondary to parasitic infections