Chronic Inflammation Flashcards
Which of the 4 clinical signs of acute inflammation persist in chronic inflammation?
- Swelling and pain persist
- Redness and heat resolve
What is the dominant cell type involved in chronic inflammation?
Macrophages
Define chronic inflammation
Chronic response to injury with associated fibrosis
What are the 3 situations in which chronic inflammation can arise?
- When it takes over from acute inflammation (most common)
- Begins without preceding acute inflammation e.g TB, RA, prolonged expose to toxic agents e.g silica
- Develops alongside acute inflammation e.g ongoing bacterial infection
What does chronic inflammation look like under the microscope?
macrophages and lymphocytes predominant cell type (granulation tissue)
What are macrophages called when they are circulating in blood?
Monocytes
Give some of the functions of macrophages?
- Phagocytosis
- Secretion of substances that activate other cells
- Present antigens to immune system to initiate immune response
- Stimulate angiogenesis
- Induce fibrosis
- Induce fever, acute phase reaction and cachexia
What are the functions of T and B lymphocytes?
- process antigens
- secrete antibodies (B cells differentiated to plasma cells)
- secrete cytokines (T cells)
- kill cells (NK cells attack virally infected cells)
What is the function of Eosinophils?
Attack large parasite (worms) and present in allergic reactions
How do Eosinophils look under the microscope?
tomato with sunglasses
What is the function of fibroblasts and myofibroblasts?
- recruited by macrophages
- make collagen, elastin and glycosaminoglycans
What are giant cells?
Multinucleated cells made by fusion of macrophages when certain bacteria are present
Name the 3 types of giant cell and describe the circumstances you would see them in
- Langerhans cell- seen mainly in TB
- Foreign body giant cells- when a foreign body is hard to digest
- Touton cell- seen in fat necrosis
Describe the appearance of Langerhan cells
Nuclei line up around the edge of the cell in a horse-shoe/ semi-circle
Describe the appearance of foreign body giant cells
Nuclei arranged randomly in the cell
Describe the appearance of Touton cells
Ring of nuclei surrounding a foamy cytoplasm of foam cells
How does fibrosis occur from chronic inflammation?
- Excess fibrous tissue laid down when fibroblasts are stimulated
- If inappropriate, collagen can replace normal parenchymal tissue and impair organ function
What is granulomatous inflammation
Type of chronic inflammation where granulomas are seen
In what circumstances would granulomas develop?
When particles are poorly soluble or difficult to eliminate
Define granuloma
A focus of chronic inflammation consisting of macrophage accumulated transferred into epithelial histiocytes
What is an epitheloid macrophage?
Macrophages that behave as epithelial cells that form in a sheet and become secretory
What are the 2 general types of granuloma?
1. Foreign body granuloma
- macrophages, forming body giant cells, epitheloid cells but FEW lymphocytes
- develop around any material that is NOT antigenic
2. Hypersensitivity/ immune type granuloma
- macrophages, giant cells, epitheloid cells, fibroblasts and lymphocytes
- can undergo central necrosis (seen in TB)
- develop around insoluble, antigenic particles
What is Sarcoidosis?
A granulomatous disease of unknown origin
- non-caseating granulomas involving lymph node
- looks naked (doesn’t have rim of lymphocytes around edge)
- mainly seen in young adult women
What is Crohn’s Disease?
A granulomatous disease of unknown origin
- patchy, full thickness inflammation throughout the bowel (different to Ulcerative collitis, no granuloma)
What is Wegener’s granulomatosis?
A granulomatous disease of unknown origin -inflammation of lung and kidneys with vasculitis
What are the 4 complications of chronic inflammation?
- Tissue destruction
- Excessive fibrosis
- Impaired function
- Atrophy
Apart from fat, what else can accumulate in the liver of alcoholics?
Mallory’s Hyaline
Describe the appearance of liver cirrhosis
1) bands of fibrosis
2) surrounded by nodules of regenerating hepatocytes
