CP2: Chronic inflammation Flashcards
1. Outline features of chronic inflammation 2. Differences between acute and chronic inflammation 3. Examples of chronic inflammation, foreign bodies, infection, autoimmune and hypersensitivity 4. Cell types involved 5. What is granulomatous inflammation 6. Outcome and complications 7. Relationship to healing
What is chronic inflammation
An inflammatory response of prolonged duration whose extended time is provoked by persistence of the causative stimulus
It is the result of a balance between continuing tissue damage caused by the stimulus and eradication of this via healing and scar formation
Give an example of a chronic inflammatory process
Active chronic peptic ulceration of the stomach
- fibrous scarring occurs so that the response remains localised
List aetiological agents producing chronic inflammation
- infectious organisms which avoid rest or resist defences e.g. TB
- infections organisms which are able to persist due to location (pleural abcesses, joint infections)
- irritant, non-living foreign material
- autoimmune diseases (rheumatoid arthritis, crohns)
What is the function of macrophages in chronic inflammation
- digestion and killing of cells
- stimulation of fibroblasts and connective tissue
- stimulates angiogenesis (formation of new blood vessles)
- recruits other inflammatory cells
What is the function of lymphocytes in chronic inflammation
B-cells; humoral response, production of antibodies by plasma cells
T-cells; cytotoxic response - CD8 and CD4 cells
Outline the histological appearance of chronic inflammation
- mixed inflammatory cell infiltrate
- healing by fibrosis, angiogenesis, scar tissue
- granulation tissue = new connective tissue and tiny blood vessels on the surface of the wound
- cell death, necrosis, apoptosis
- abscess formation
What is a granulomatous inflammation
A distinctive chronic inflammatory reaction with activated macrophages (epithelioid appearance)
What is a granuloma
A collection of epithelioid macrophages surrounded by lymphocytes and sometimes plasma cells
These wall off the site of infection and so prevent its growth and spreading
Give examples of granulomatous inflammation
- TB
- Crohn’s disease
- Foreign bodies
- Sarcoidosis
What are autoimmune disorders
These are chronic inflammatory conditions where there is an inability to distinguish self from non-self e.g. rheumatoid arthritis and hashimoto’s thyroiditis
What is rheumatoid arthritis
Chronic inflammatory condition associated with rheumatoid factor which leads to joint destruction and deformity as a result of inflammation within the joint synovium
What is hashimoto’s thyroiditis
An autoimmune disease of thyroid producing goitre (swelling) and hypothyroidism (under activity causing reduction in hormones, weight gain and cold sensitivity)
This is because antibodies for TSH receptors are produced in thyroid glands resulting in chronic inflammatory response where there is glandular destruction and endocrine disturbance
Outline type 1 hypersensitivity
Anaphylactic shock
- mast cell mediated release of IgE antibody in response to the allergen
- histamine and inflammatory mediator release is caused
Outline type 2 hypersensitivity
This is where circulating antibodies attack and bind to specific body tissues leading to inflammatory response; damage is by complement activation/ cytotoxicity e.g. Goodpastures syndrome
Outline type 4 hypersensitivity
NOT mediated by antibodies
- cell mediated reaction
- caused by sensitised T-cells
- stimulates macrophages and other inflammatory cells
- e.g. TB, organ graft rejections
