6. Chronic Inflammation Flashcards Preview

EMS - Mechanisms of Disease > 6. Chronic Inflammation > Flashcards

Flashcards in 6. Chronic Inflammation Deck (17):

what is the purpose of inflammation?

1. remove the cause of injury
2. initiate repair
3. prevent necrosis


what are the dominant cells in chronic inflammation?

lymphocytes, macrophages and plasma cells
granulation and scar tissue is more abundant


does chronic inflammation have a primary or secondary onset?

usually primary, but can be sequential from acute inflammation


what are the factors precipitating chronic inflammation?

1. infection - TB, leprosy, viruses
2. endogenous materials - uric acid crystals
3. exogenous materials - asbestos, sutures, implants
4. autoimmune - RA, SLE
5. primary granulomatous diseases - crohn's, sarcoidosis


when does chronic inflammation have a secondary onset?

most common in suppurative acute inflammation
if the abscess is deep enough, the walls thicken, cause granulation and fibrous tissue.
recurrent acute inflammations also lead to chronic


what are the morphological features of chronic inflammation?

infiltration with mononuclear cells
tissue destruction
healing by fibrosis


what is a granuloma?

mass of immune cells that forms at sites of infection or inflammation


what are the macroscopic features of chronic inflammation?

dependent on the actual disease
chronic abscess cavity
granulomatous in some cases


what are the microscopic features of chronic inflammation?

1. cellular infiltrate of lymphocytes, plasma cells and macrophages
2. exudation if fluid is not prominent
3. production of new fibrous tissue from granulation tissue


what is the function of macrophages?

phagocytosis of bacteria and damaged tissue


what are the 3 processes involved in wound healing?

1. angiogenesis
2. deposition of collagen by fibroblasts
3. inflammatory cells


what is the aim of wound healing?

to replace injured tissue with fibrous tissue


what is fibrosis?

macrophage induced laying down of connective tissue including collagen during repair of damaged tissue


what are histiocytic cells?

multinuclear giant cells which develop when 2 or more macrophages try to engulf the same particle
no known function


what are the histological contents of a granuloma?

langerhans giant cells + epithelioid histiocytes + caseous necrosis


examples of granulomatous diseases

1. bacterial - TB, leprosy
2. parasitic - schistosomiasis
3. fungal - cryptococcus
4. synthetic materials - silicosis
5. unknown - sarcoidosis, crohn's


what are the clinical outcomes of chronic inflammation?

1. persistence of infection
2. prolonged exposure to toxic agents
3. autoimmune diseases eg. RA