MoD Chronic Inflammation Flashcards
How is chronic inflammation different to acute inflammation?
- a long term response
- there is always fibrosis, meaning the tissue never goes back to its original state
- occurs when damage is too severe to be resolved via acute inflammation
- microscopic appearance is much more varied
What is the role of macrophages in chronic inflammation? (Macrophages have lots of granular cytoplasm)
Phagocytosis: destruction of bacteria and debris
Antigen presentation to the immune system
Control of other cells by cytokine release
Synthesis of cytokines, blood clotting factors and proteases
What is the role of lymphocytes in chronic inflammation? (lymphocytes are a normal component of many tissues e.g. gut, airways, lymph nodes)
Immunological functions
B lymphocytes differentiate to produce antibodies
T lymphocytes are involved in control and some cytotoxic functions
The presence of plasma cells (differentiated antibody producing b lymphocytes) implies considerable chronicity.
What is the role of eosinophils in chronic inflammation?
Present in allergic reactions, parasite infestations and some tumours
What is the role of (myo)fibroblasts in chronic inflammation?
They are recruited by macrophages to make collagen
What are giant cells?
Multinucleate cells made by fusion of macrophages
They are formed as a result of ‘frustrated phagocytosis’ where macrophages can’t easily phagocytose something so all group together
What type of giant cells form when tuberculosis is present and what is their microscopic appearance?
Langhans type giant cell (not Langerhans!)
The nuclei form a horse shoe shape around
The cytoplasm appears foamy and pink
What type of giant cells form when there is a foreign body such as a bone fragment, and what is their microscopic appearance?
Foreign body type giant cell
There are clusters of nuclei
What type of giant cells are present in lesions with a high lipid content and what is their microscopic appearance?
Toulon giant cell
Occurs in fat necrosis
There is a circle of nuclei surrounding pink cytoplasm, surrounded by foamy cytoplasm
When does chronic inflammation arise?
- may take over from acute inflammation if the damage is too severe to resolve in a few days
- may work alongside acute inflammation if there is prolonged exposure to toxic agents
- may occur in some autoimmune conditions such as rheumatoid arthritis
- may occur in chronic persistent infections (mostly viral)
List some complications of chronic inflammation
- fibrosis e.g. cirrhosis
- impaired function e.g. inflammatory bowel disease
- rarely increased function e.g. thyrotoxicosis
- atrophy e.g. gastic mucosa
- stimulation on immune response
Chronic Cholecystitis is an example of chronic inflammation. Briefly describe this condition.
Gall stones block the cystic duct leading out from the gall bladder, causing blockage of bile flow which is toxic so damages tissues.
Fibrotic gall bladder wall
Chronic gastritis is an example of chronic inflammation. Briefly describe this condition.
Gastric ulceration (mucosal necrosis) occurs because of an imbalance of acid production. Can lead to scarring and peristalsis interference
Inflammatory bowel disease is an example of chronic inflammation. Briefly describe this condition.
2 types: Crohn’s disease + ulcerative colitis
Patients present with rectal bleeding and diarrhoea.
Ulcerative colitis: affects colon, so diarrhoea and bleeding
Crohn’s disease: affects anywhere from mouth to anus. Can get fistulae (two organs connect)
Cirrhosis disease is an example of chronic inflammation. Briefly describe this condition.
Fibrosis and impaired function of the liver.
Common causes: alcohol, hepatitis, drugs, fatty liver disease
