Mechanisms of Chronic Inflammation

Question 1

When does chronic inflammation occur

Answer 1

24-72hrs after acute

Question 2

How long does chronic inflammation last for

Answer 2

weeks->months->years

Question 3

Cell types involved in chronic inflammation

Answer 3

Macrophages
M1 cells or M2 Cells

Question 4

Role of M1 cells in chronic inflammation

Answer 4

Convert arginine to nitric oxide (pro-inflammatory and Highly toxic to phagocytosed organisms)

Question 5

Role of M2 cells in chronic inflammation

Answer 5

Non-inflammatory
Convert arginine -> ornithine
Ornithine= proline in extra cellular fluid
Proline= precursor for collagen synthesis
wound healing requires large amounts of collagen
Also produce TGF-B which promotes collagen deposition

Question 6

Role of a granuloma

Answer 6

Body’s attempt to wall off initiator of inflammation
Walls off a persistent stimulus such as an inert irritant
Can cause severe tissue necrosis

Question 7

Examples of types of chronic inflammation without a clear pathogen (3)

Answer 7

Atopic Dermatitis
Inflammatory Bowel Disease- idiopathic
Toxic Agent

Question 8

What are pyogranulomatous lesions

Answer 8

Chronic inflammatory lesion
Characterised by predominance of macrophages and neutrophils
Large granuloma
Slow growth despite aggressive clinical signs
T cell: macrophage interactions important
Clinicals signs are usually monitored/treated and immunosuppressive therapy can be used, particularly if idiopathic

Question 9

Examples of pyogranulomatous lesions (2)

Answer 9

Feline infectious peritonitis
johnes disease in cattle- contagious, chronic and often fatal

Question 10

Effects of caseous granuloma

Answer 10

Affects organ function
Breakdown can lead to bacterial dissemination throughout the body

Question 11

What is chronic granulomatous disease

Answer 11

Inherited disorder
phagocytes don’t work properly
increased susceptibility to repeated bacterial or fungal infection

Question 12

Examples of bacterial causes of chronic inflammation (2)

Answer 12

Chronic mastitis in cow
Tuberculosis - mycobacterium bovis

Question 13

What is immune mediated arteritis

Answer 13

Inflammation of blood vessels
causes swelling of heart muscle
Aren’t many symptoms until severe

Question 14

what are giant cells

Answer 14

fused macrophages

Question 15

Chronic Pyelonephritis in dogs

Answer 15

Chronic pyogenic inflammation in the kidney
Pyogenic granulomas are small raised red bumps
Hydronephrosis occurs- kidneys become swollen and stretched

Question 16

Actinobacillosis in cow

Answer 16

Bacterial cause
Typically acute presentation
Proliferative and ulcerative chronic-active inflammatory lesions (can last 6 months+)
Contains neutrophils mixed with mononuclear inflammatory cells (lymphocytes, macrophages, plasma cells)
Fibrous tissue present in the tongue
Chronic inflammation-> loss of muscle of the tongue which is replaced by fibrous tissue during healing

Question 17

Chronic hepatitis

Answer 17

Aetiology unknown- acute hepatic failure can lead to chronic active hepatitis
Might be seen as weight loss, lethargy and depression

Question 18

Lung pyogranuloma (dog)

Answer 18

grey nodules which vary in size throughout the lung parenchyma can be seen
lung lobes would fail to collapse