Chronic Inflammation Flashcards
What are the 4 main cell types in chronic inflammation?
Lymphocytes
macrophages
Plasma cells (differentiated B cells)
Fibroblasts
When does chronic inflammation arise from acute inflammation?
When theres:
- A larg evolume of damage
- Debris that cant be removed
- When it fails to resolve (e.g. repeated infection)
When does chronic inflammation arise as a primary legion?
As a result of:
- An Autoimmune Disorder
- A material resistant to digestion
- An exogenous substance
- An endoenus substance where it shouldnt be
Examples of exogeneous substances that cause chronic inflammation?
Glass
Sutures
Plastic/metal joint replacements
Examples of endogenous substances that cause chronic inflammatoin?
Hair
Keratin
Necrotic Tissue
What are the clinical presentations of chronic inflammation?
Malaise
Weight loss
Loss of function e.g. hypothyroidism in autoimmune thyroiditis
How does granulation occur
Angiogenesis occurs so capillaries grow into inflammatory mass
New capilalries give acces for plasma proteins
Macrophages form blood/tissue arrive and clear debris
Granulation tissue made from plasma proteins, macrophages & capillaries fills wound
How does fibrosis occur?
Fibroblasts replace inflammatory exudate with collagen
Collagen cross links & contracts or greater strength
Scar forms
Examples of organisms resisitant to destruction that cause chronic inflammation?
Mycobacteria
Brucella
Viruses
Why do endogenous substances int he wrong place cause CI?
They cant be easily phagocytosed
Function of B cells in chronic inflammation?
They form plasma cells which produce antibodies &
present antigens,. The also form memory B cells
Function of T cells in chronic inflammation?
Produce cytokine that attract leukocytes & increase vascular permeability
Produce Interferons which are antiviral and attract immune cells
Lysis of pathogenic cells
Function of macrophages in CI:
Remove debris
Epithelioid macrophages form granulomas
Antigen presenting
Fibroblasts in CI:
Assemble structures most notably collagen for scarring & wound repair
What is granulomatous inflammation?
Chronic inflammation involving a granuloma.
Occurs in many serious infections & idiopathic diseases
Why does a granuloma form?
To block off an indigestible piece of material that cant be removed from the body
What is a granuloma?
An agregate of epithelioid macrophages in tissue.
Also contains neutrphils, eosinophils & lymphocytes
What unusual cell type may be found in a granuloma?
Giant Cells
What type of hypersensitiivity reaction canc ause granulomas?
Type 4 hypersensitivity
What is Giant cell?
An immune cell with a large cytoplasm & multiple nuclei.
There are many types
Define Langhans type giant cell
Often found in TB
Peripheral rim of nuclei
Large eosinophilic cytoplasm.
What are the 4 phases of wound healing?
- Acute inflammation
- Grandulation tissue formation
- Local angiogenesis
- Fibrosis & scar formation
What is fibrin and how is it involved in cloting?
Fibrin is a derivative of Fibrinogen
It forms the edge of a blood clot
What is the sequence of events in wound healing?
- Acute inflammation & clotting
- granulation tissue grows along with angiogenesis
- Fibrin is phagocytosed
- Fibroblasts lay down collagen
- Contraction of collagen
- re-epithelialisation
What is another name for surgial wound healing?
Healing by primary intention
How does surgical wound healin occur?
Sututes are used to give a minimal gap (apposition of edges)
- small amount of granulation tissue forms
- small linear scar forms
What is another name for healing a larger defect?
Healing by secondary intention
Whats different about healing by secondary intention?
the gap of the wound is large
So lots of granulation tissue grows in
The tissue contracts and a large messy scar forms
List the 6 factors favouring healing?
- Cleanliness
- Apposition of edges
- Good nutrition
Metabolic normality/stability - Normal inflammatory & coagulatory mechanisms
- Normal local mediators
List the 5 factors that impair wound healing:
- Dirty, large wounds
- Large Haematomas (clots)
- Poor nutrition (mainly low Vitamin C & A)
- Abnormal metabolism
- Inhibition of angiogenesis
Example of abnormal metabolism that effects healing?
- Abnormal CHO metabolism
- Cortiocosteroid therapy
- Diabetes
How is angiogenesis stimulated?
Hypoxic cells release VEGF
VEGF stimulates formation of new capillary buds
What is VEGF?
Vascular Endothelial Growth Factor
What else aids aniogenesis?
Enzyme secretion from hypoxic cells
Why would you want to inhibit VEGF?
To block angiogeneis in tumours as a therapeutic control of tumour growth.
Sumarise the sequence of events in fracture healing?
- Trauma, fracture, haematoma
- Acute inflammation
- Organisation
- Callus formation
Whats different about granulation tissue in fracture healing?
It contains both fibroblasts to lay down collagen and Osteoblasts to lay down and calcify Hydroxy Apatite crystals.
What are the steps of Callus formation?
- Osteoblasts lay down woven bone
- Osteoclasts remove dead bone
- Woven bone progressively replaced by lamellar bone
- Cotrical/trabecular bone reformed.
How is angiogenesis involved with malignant tumour?
Angiogenesis occurs as the tumor grows.
Potential for therapeutic control by inhibiting VEGF.
How is atherosclerosis similar to chronic inflammation?
They both involve fibrosis & scarring.
What is thrombosis?
Local clotting in the circulatory system
How are angiogenesis & organisation important in stoppin thrombosis?
They limit thrombus propagation & reinstate flow by breaking clots.
