MoD S4 - Chronic Inflammation Flashcards
What is chronic inflammation?
Chronic response to injury with associated fibrosis
How does chronic inflammation arise?
Give examples for each ‘mechanism’
May take over from acute inflammation:
- If damage is too severe to be resolved quickly
May arise de novo:
- Some autoimmune conditions (Rheumatoid arthritis)
- Some chronic infections (Viral hepatitis)
- Chronic low level irritation
May develop alongside acute inflammation:
- If severe persistent or repeated irritation
How is chronic inflammation characterised?
What is the most important characteristic?
Characterised by the microscopic appearance (which is much more variable then acute inflammation)
Most important characteristic is the cell type present
What cell types might be involved with chronic inflammation?
Macrophages Lymphocytes Plasma cells Eosinophils Fibroblasts/myofibroblasts
What is frustrated phagocytosis?
When macrophages encounter a large foreign body that they cannot internalise (E.g. an implant) they experience frustrated phagocytosis where they attach to the foreign body and secrete superoxides, free radicals and lysosomal contents to damage it.
Inability to internalise foreign body may also result in giant cell formation
What is a giant cell?
A multinucleate cell made by fusion of macrophages
What types of giant cells are there?
Langhans
Foreign body type
Touton
Give a few examples of chronic inflammation and the major inflammatory cell type present in these conditions
Rheumatoid arthritis - Plasma cells
Chronic gastritis - Lymphocytes
Leishmaniasis - Macrophages
Langhans Giant cells appear in what conditions?
Granulomatous conditions (E.g. Tuberculosis)
Touton giant cells appear in what conditions?
Appear during fat necrosis
When do foreign body type giant cells appear?
When the body is exposed to foreign substances (E.g. Sutures, implants or bone fragments)
Why is looking at giant cell type useful?
Can aid diagnoses (Different types appear in different conditions)
List the major effects of chronic inflammation
Fibrosis
Impaired or increased function
Atrophy
Stimulation of immune response
What causes chronic cholecystitis?
What is the major effect of chronic inflammation on the gallbladder?
Repeated obstruction of the cystic duct by gall stones from the gall bladder
Repeated acute inflammation leads to chronic inflammation
Leads to fibrosis of the gallbladder wall
How does gastric ulceration occur?
What is the end result?
Acute gastritis - Alcohol, drugs
Chronic gastritis - Helicobacter pylori
Ulceration occurs due to the imbalance between acid production and mucosal defence that these condition result in
The affected gastric wall will become fibrotic