Mechanisms of Chronic Inflammation Flashcards
When does chronic inflammation occur
24-72hrs after acute
How long does chronic inflammation last for
weeks->months->years
Cell types involved in chronic inflammation
Macrophages
M1 cells or M2 Cells
Role of M1 cells in chronic inflammation
Convert arginine to nitric oxide (pro-inflammatory and Highly toxic to phagocytosed organisms)
Role of M2 cells in chronic inflammation
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
Role of a granuloma
Body’s attempt to wall off initiator of inflammation
Walls off a persistent stimulus such as an inert irritant
Can cause severe tissue necrosis
Examples of types of chronic inflammation without a clear pathogen (3)
Atopic Dermatitis
Inflammatory Bowel Disease- idiopathic
Toxic Agent
What are pyogranulomatous lesions
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
Examples of pyogranulomatous lesions (2)
Feline infectious peritonitis
johnes disease in cattle- contagious, chronic and often fatal
Effects of caseous granuloma
Affects organ function
Breakdown can lead to bacterial dissemination throughout the body
What is chronic granulomatous disease
Inherited disorder
phagocytes don’t work properly
increased susceptibility to repeated bacterial or fungal infection
Examples of bacterial causes of chronic inflammation (2)
Chronic mastitis in cow
Tuberculosis - mycobacterium bovis
What is immune mediated arteritis
Inflammation of blood vessels
causes swelling of heart muscle
Aren’t many symptoms until severe
what are giant cells
fused macrophages
Chronic Pyelonephritis in dogs
Chronic pyogenic inflammation in the kidney
Pyogenic granulomas are small raised red bumps
Hydronephrosis occurs- kidneys become swollen and stretched
Actinobacillosis in cow
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
Chronic hepatitis
Aetiology unknown- acute hepatic failure can lead to chronic active hepatitis
Might be seen as weight loss, lethargy and depression
Lung pyogranuloma (dog)
grey nodules which vary in size throughout the lung parenchyma can be seen
lung lobes would fail to collapse
