Chronic Inflammation Flashcards
What is the definition of chronic inflammation
This is an inflammatory response of prolonged duration that is provoked by the persistence of the inflammatory stimulus to the tissue
Give an example of the chronic inflammatory process and explain how this is chronic inflammation
Active chronic peptic ulcers of the stomach = result of a balance between continuing tissue damage and eradication of the damaging stimulus versus healing and scar formation
What etiological agents produce chronic inflammation
- Infectious organisms that avoid or resist host defences e.g. TB
- Infectious organisms that have the ability to persist due to location, pleural abscess or joint infections
- ## Autoimmune diseases
What are some of the key effector cells for the immune/inflammatory response
- Lymphocytes
- Plasma cells
- Macrophages (Histiocytes, monocytes)
- Fibroblasts - Often referred to as “Chronic inflammatory cells”
What are macrophages derived from
Blood monocytes
What are macrophages sitimulated by
Stimulated by chemokines and chemotactic agents released by T- lymphocytes
What are the functions of macrophages
- Digestion/killing of cells
- Digestion of ECM
- Stimulation of fibroblasts and CT
- Angiogenesis
- Recruitment of other inflammatory cells
What is the cellular infiltrate of acute and chronic inflammation
Acute = Mainly neutrophils Chronic = Monocytes/macrophages and lymphocytes
What histological appearances can you see in chronic inflammation
- Mixed inflammatory cell infiltrate = lymphocytes, plasma cells and macrophages
- Healing by fibrosis, granulation tissue, angiogenesis, scar tissue
- Cell death, necrosis, apoptosis, abscess formation
What is a granuloma
This is a small area of inflammation that is a collection of epithelioid macrophages surrounded by lymphocytes and occasionally plasma cells
Describe granulomatous inflammation responses
- Distinctive chronic inflammatory reaction with a predominant cell type, which is the activated macrophage that has an epithelioid appearance
Give examples of granulomatous inflammation
- TB
- Sarcoidosis
- Crohn’s disease
- Foreign Body
Which bacteria causes tuberculosis
Mycobacterium Tuberculosis
What does tuberculosis cause to cells
Caseous Necrosis
Also causes langerhan’s cells to form by the fusion of epithelioid cells (macrophages).
Name some bacterial granulomatous diseases
Leprosy
Syphilis
Cat-scratch disease
Name a parasitic granulomatous disease
Schistosomiasis
Name a fungal granulomatous disease
Cryptococcus
Name a granulomatous disease that can be caused by inorganic dusts
Silicosis
What is tolerance
The ability for the body to distinguish self from non-self
Give examples of inflammatory autoimmune disorders
Rheumatoid arthiritis
Hashimoto’s thyroiditis
What is rheumatoid arthritis and what does it cause
- This is a chronic inflammatory condition that is associated with rheumatoid factor
- Leads to joint destruction and deformity as a result of chronic inflammatory process taking place within joint synovium
What stain is used to identify the presence of tuberculosis
The Ziehl Nielsen stain
What is Hashimoto’s thyroiditis and what does it cause
- This is an autoimmune disease of the thyroid that produces goitre and hypothyroidism
- Caused by antibodies attaching to TSH receptors in the thyroid gland
- Causes massive chronic inflammatory cell response within thyroid with glandular destruction and endocrine disturbance
Describe what type 1 sensitivity is (chronic inflammation)
Anaphylactic - Mast cell mediated release of IgE antibody in response to an allergen, leads to release of histamine and inflammatory mediators and subsequent inflammation
Describe what type 2 hypersensitivity is
Results from circulating antibodies attacking and binding to specific body tissues leading to inflammatory response. Damage by complement activation or cytotoxicity, may stimulate/block a receptor
What is an example of Type 2 hypersensitivity disorder and describe it
Goodpastures syndrome - reaction between an antibody and the basement membrane and endothelium of capillaries in the glomerulus in the kidney and lungs. Results in chronic inflammation and subsequent damage to kidneys and lungs
Describe what type 3 hypersensitivity is
Due to the deposition of antigen-antibody complexes within vessel walls and tissues resulting in inflammation and tissue damage
Give an example of type 3 hypersensitivity
SLE glomerulopathy due to deposition of immune complexes within the glomerulus, leading to inflammation and damage
Describe what type 4 hypersensitivity is
- Cell mediated reaction
- Caused by sensitized T-lymphocytes
- Stimulate macrophages and other chronic inflammatory cells
Give and example of type 4 hypersensitivity
- TB
- Rejection of organ grafts
What is the outcome of chronic inflammation
- Healing by scarring
- Perforation
- Chronicity
- Depends on local factors, host immune response, persistent disease
