Chronic Inflammation Flashcards
What is the purpose of inflammation in general?
Remove cause of injury
Remove necrosis
Initiate repair
What are the following points characteristic of?
Slow onset
Macrophages/Lymphocytes/Plasma cells
Severe, progressive
Subtle signs
Chronic Inflammation
What are the following points characteristic of?
Fast onset
Neutrophils
Mild, self limiting
Prominent signs
Acute inflammation
What are the possible outcomes of acute inflammation?
Resolution
Suppuration
Organisation
Progression to chronic inflammation
What are the dominant cells in chronic inflammation?
Lymphocytes
Plasma cells
Macrophages
When does acute to chronic inflammation occur most commonly?
In suppurative acute inflammation
Granulation and fibrous tissue form and recurrent acute inflammations can lead to chronic conditions
What does ‘caseating’ mean?
Necrosis with conversion of damaged tissue into a soft substance
The macroscopic view of chronic inflammation is dependant on the disease. What are features of the microscopic view?
Cellular infiltrate of lymphs/plasma cells and macros
Exudation if fluid is not prominent
Production of new fibrous tissue
What is the general role of macrophages in chronic inflammation?
They increase inflammation and stimulate the immune system
What is the more specific role of macrophages in chronic inflammation?
Release cytokines which signal monocytes
What is leucocyte extravasion?
Monocytes enter damaged tissue from endothelium of blood vessel
What are some other roles of macrophages?
Release proteases after they decried damaged tissue
Induce cells to re-epithelialise the sound and create granulation tissue
Can hold and contain viable organisms if they cannot kill them
Produce factors that induce angiogenesis in granulation tissue
Which cell type deposits collagen in the formation of granulation tissue?
Fibroblasts
What is fibrosis?
Formation of excess fibrous connective tissue during repair of damaged tissue
What is a fibroma?
The same as fibrosis but only arises from 1 cell line
What is a granuloma?
a mass of granulation tissue, typically produced in response to infection, inflammation, or the presence of a foreign substance. Primary cell type is epitheloid histiocytes
What are two examples of granulomatous disease?
TB
Leprosy
What is granulomatous inflammation?
Granulomatous inflammation is a cell-mediated hypersensitivity-type reaction to persistent and nondegradable microbial agents.
What is the basic pathology of granulomatous inflammation?
Histiocytic giant cells form where material is indigestible to macrophages
They develop when 2 or more macrophages try to engulf the same particle
What is the key feature required for a mass of cells to be a granuloma?
The presence of epitheloid histiocytes
What is the bacterium responsible for TB?
Mycobacterium tuberculosis
What is the bacterium responsible for Leprosy?
Mycobacterium leprae
What is silicosis?
Occupational lung disease from inhaling silica dust
What is sarcoidosis?
Granulomas form in multiple organs. Usually self limiting
What are the following diseases examples of?
TB
Leprosy
Silicosis
Sarcoidosis
Granulomatous disease
What is the mechanism of TB?
- Alveolar macrophages release cytokines to recruit more macrophages
- ) Dendritic cells present antigens to T cells in lymph nodes to mount a T cell response
Events 1 and 2 lead to granuloma formation for the purpose of containing infection and eliminating bacteria
3.) Granuloma contains macrophages, epithelioid cells and langerhand giant cells surrounded by T cells
