Chronic Inflamation Flashcards
Explain the sequelae of acute inflammation?
diagram
What factors favour resolution?
- minimal cell death and tissue damage
- occurrence in an organ/tissue with regenerative capacity (eg. liver)
- rapid destruction of the casual agent
- rapid removal of fluid and debris by good local vascular drainage
What is resolution?
- active process aimed at restoration of tissue and function
- it involves apoptosis and subsequent clearance of activated inflammatory cells
What is a casual agent?
biological pathogen that causes disease
What happens is resolution cannot occur?
organisation
What is organisation?
replacement of destroyed tissue by granulation tissue
What is granulation tissue?
new connective tissue and microscopic blood vessels that form on the surfaces of wounds during the healing process
- light red/pink colour, soft, moist, pulseful, bumpy, painless when healthy
How is granulation tissue formed?
Inflammatory exudate replaced by: - capillaries - macrophages - fibroblasts - collagen Regulated by growth factors: -TNF - EGF - FGF
What factors favour organisation?
- large amounts of fibrin
- substancial necrosis
- exudate and debris cannot be removed or discharged
What causes chronic inflammation?
- primary causes - does not have an acute response (eg. arthritis)
- progression from acute inflammation
- recurrent episodes of acute inflammation
What are the factors favouring progression from acute to chronic inflammation?
- indigestible substances eg. glass, suture material - foreign body reaction
- deep seated suppurative inflammation where drainage is delayed or inadequate - (thick abscess wall - fibrous/granulation tissue - pus becomes organised - forms fibrous scar) - deep seated bone abscesses
- recurrent episodes of acute inflammation and healing may eventually result in chronic inflamation - macrophages and lymphocytes used instead of neutrophils
What is osteomyelitis
chronic bone abscess which is difficult to treat
What are the primary cells of chronic inflammation?
macrophages
lymphocytes
plasma cells (activated by lymphocyte)
What are the primary cells of acute inflammation?
neutrophils
What does chronic inflammation look like?
- chronic ulcer (mucosa breached, base lined by granulation tissue, fibrous tissue throughout muscle layers)
- chronic abscess cavity
- thickening of the wall of a hollow viscus
- granulomatous inflamation (TB)
- fibrosis
What does the formation of granulation tissue result in?
fibrosis
What is special about macrophages?
they can communicate with other immune response cells
What are the properties of macrophages?
- phagocytic
- can ingest a wide range of materials
- relatively large cells
- ingest viable organisms resistant to lysomal enzymes
- produce a range of cytokines
- activated on migration to area of inflamation (by macrophage activation/inhibition factors MAF, MIF)
What are lysosomes?
membrane-bound vesicles that contain digestiveenzymes,
What are cytokines?
chemicals that activate other immune cells
What is the production/life cycle of a macrophage like?
diagram
Where do macrophages originate from?
haemopoietic stem cell in bone marrow
What are macrophages released into the blood as?
monocytes
What is a granuloma?
an aggregate of epithelia histiocytes
What is a histiocyte?
a macrophage in connective tissue
What are the properties of granulomatous inflammation?
- little phagocytic activity
- secretory function
- necrotic material in centre of granuloma
- surrounded by epithelium histiocytes
- peripheral rim of activated lymphocytes
- central giant cells
What are the causes of granulomatous disease?
- specific infections
- foreign bodies - endogenous/exogenous
- specific chemicals
- drugs
- unknown
How are (Langhans) giant cells formed?
histiocytes fuse to form multinucleate giant cells
What is the difference between granuloma and granulation?
granuloma - aggregate of macrophage like cells
granulation - important healing process with small vessels and connective tissue
What is the difference between fibrin and fibrous/
fibrin - deposited in acute inflammation
fibrous - typical scar with collagen
