chronic inflammation Flashcards
what is chronic inflammation?
prolonged inflammation with associated repair
what are the basic principles of chronic inflammation?
- delayed onset
- variable duration
- variable appearances
- limits damage, inititates repair
- can cause deibilitating symptoms
how does chronic inflammation arise?
- takes over from acute inflammation
- can occur alongside acute inflammation
- can arise without any preceeding acute inflammation
what does chronic inflammation look like?
variable appearances
variety of cell types
what are the different cells involved in chronic inflammation?
- macrophages
- Lymphocytes
- Plasma cells
- Eosinophils
- Myo/fibroblasts
- Giant cells
what are the basic principles of macrophages?
- in blood = monocytes
- in tissue = macrophage or histiocyte
- large cells because of abundant foamy cytoplasm
- slipper shaped nucleus
- carry out phagocytosis + then antigen presentation
- control and regulate release of inflammatory mediators
why do macrophages stain difficultly on H+E staining?
vary drastically on appearance based on what they are phagotycosing
what are the basic features of lymphocytes?
- smaller cells (similar in size to RBC)
- contain a large circular nucleus (little cytoplasm)
- 2 types:
1. T cells: variety of types, assist other inflammatory cells and destroy pathogens
2. B cells: mature into plasma cells, produce antibodies, neutralises pathogens
what are the basic features of plasma cells?
- fully differentiated B cell
- nucleus is pushed to periphary
- chromatin clumps in plasma cells + appears like a clock face
- peri-nuclear clearing = slightly paler region of cytoplasm near nucleus
what are the basic features of the eosinophil?
- bilobed nucleus
- cytoplasm stains bright red + is granular
- release lots of mediators
what are the basic features of fibroblasts/myofibrolasts?
regeneration + repair
lay down fibrin
what are the basic features of giant cells?
- multinucleate cells
- fusion of multiple macrophages in “frustrated phagocytosis”
what are the 3 types of giant cells?
foreign body giant cells:
* nuclei arranged randomly
langhans giant cell:
* partial or complete circle of nucleus on rim of cell
* can be seen in tuberculosis
touton giant cell:
* ring of nuclei right in middle of cell sorrounded by cytoplasm
* can be seen in fat necrosis
what are the effects of chronic inflammation?
- fibrosis - deposition of collagen
- impaired function - specialised cells replaced by collagen
- atrophy - decrease in size
- ongoing stimulaton of immune response - antigen presentation by macrophages
what are the impacts of fibrosis in the gall bladder?
- repeated obstruction of bile duct by gall stones
- repeated bouts of acute inflammation results in chronic inflammation
- fibrosis of gall bladder wall (thickened and no longer pink)
what is the impact of impaired function in idiopathic inflammatory bowel disease?
2 main types of idiopathic inflammatory bowel disease:
1. chrons disease
2. ulcerative disease
inflammed bowel will have impaired function so patients present with:
* abdominal pain
* altered bowel function
* weight loss
what are the differences between chrons disease + ulcerative colitis?
Chrons disease:
* can affect all GI tract
* discontinuous patches of inflammation
* inflammation affects full thickness of bowel wall - transmural
* can sometimes find granulomata
* less likely to have rectal bleeding
Ulcerative colitis:
* affects large bowel only
* continous inflammation
* inflammation affects superficial bowel wall only
* no granulomata
* more likely to have rectal bleeding
- what is cirrhosis?
- what is cirrhosis of the liver caused by?
- damage to tissue (seen in end stage damage to the liver) with fibrosis and attempted regeneration
- alcohol, hepatitis, drugs and toxins, fatty liver disease
what is granulomatous inflammation?
chronic inflammation with presence of one or more granulomata
what is a granulomata?
a collection of:
* epitheliod histiocytes (macrophages which look like epithelial cells)
* presence of giant cells
* may be sorrounded by lymphocytes
what are the 2 types of granulomatas?
foreign body:
* destruction and removal of foreign material
* few lymphocytes.
immune mediated:
* destruction + removal of pathogens (arises due to infection)
* can be idiopathic (disease of unknown cause)
* can undergo central (caseous) necrosis
* lots of lymphocytes
what infections are common causes of immune mediated granulomatas?
myobacterium tuberculosis
myobacterium leprae
why do granulomatas arise in response to mycobacterium?
mycobacterium are difficult to destroy since:
* they have a thick cell wall
* mycolic acids
