Chronic Inflammation Flashcards
What is chronic inflammation?
Inflammation in which the cell population is especially lymphocytes, macrophages and plasma cells. It features tissue or organ damage as well as loss of function. Tends to be long term.
How does chronic inflammation present itself clinically?
No specific sore bit.
Malaise and weight loss
loss of function
tired
When do we see chronic inflammation?
Arising from acute inflammation -
large volume of damage
inability to remove debris
fails to resolve – ongoing acute insult
Arising as a primary lesion.
What is the role of granulation tissue?
Universal polyfiller Results in healing and repair Leads to scar formation and fibrosis Patches tissue defects Replaces dead or necrotic tissue Contracts and pulls together
Describe the granulation tissue mechanism?
capillaries grow into inflammatory mass
access of plasma proteins (used to make collagen)
macrophages from blood and tissue
fibroblasts lay down collagen to repair damaged tissue
collagen forms scaffold of matrix
collagen replaces inflammatory exudate
What happens to scars overtime?
Scars get smaller and fade overtime as the cross linked collagen fibres become tighter and lose their elasticity. Only collagen is present in scar tissue as all other cells move out.
When does fibrosis become a problem?
When is happens when you don’t want it to e.g adhesion between the loops of the bowel following peritonitis.
What is osteomyelitis?
Acute inflammatory process effecting the bone. It can become chronic.
What are some causes of primary chronic inflammation?
Autoimmune diseases - rheumatoid arthritis, thyroiditis
Lymphocytes, macrophages, fibrosis, plasma cells
Material resistant to digestion
Exogenous substances - sutures, metal and plastic eg joint replacements, mineral crystals, glass.
Endogenous substances - necrotic tissue, keratin, hair
What are the main types of lymphocytes?
T cells (immune response) cellular B cells (immune memory) humoural
What is a plasma cell and what is its role?
A differentiated B cell.
Secrete antibodies.
What are some B cell mechanisms?
Differentiate to plasma cells - antibodies
Facilitate immune response
Act with macrophages - antigen presenting capacity
Immune memory
What are the T cell mechanisms?
Produce cytokines
Produce interferons
Damage and lyse other cells and destroy their antigen.
What is the function of the cytokines released by T cells?
Molecular messengers that:
Attract and hold macrophages
Activate macrophages and other cells eg lymphocytes
Increase permeability so other molecules can come to help.
What is the function of interferons released by T cells?
Antiviral effects
Attract and stimulate other cells
What is the function of macrophages?
Removes debris
Role in immune system - antigen presenting cell
Contain enzymes (lysozymes) that destroy foreign cells.
monocyte, histiocyte, activated macrophage, epithelioid cell, giant cell
Found in bone marrow, blood tissues
What are the different names for macrophages in the following locations;
- blood
- epithelium
- Connective tissue
- Monocyte
- Epithelioid cell
- Histiocyte
What are some properties of fibroblasts?
Motile cells
Metabolically active
Make and assemble structural proteins e.g collagens
What does idiopathic mean?
There is no known cause.
What are granulomas?
Granulomas are aggregates of epithelioid macrophages in tissue. They contain many different types of immune cells e.g giant cells, neutrophils, eosinophils, lymphocytes. They respond to indigestible antigens and are related to type 4 hypersensitivity.
What are giant cells?
The fusion of many macrophages together into one whole mass or the proliferation of macrophages. They have a large cytoplasm and are multi nucleated.
Describe what Langhan’s type giant cells are like?
Classically found in TB
Peripheral rim of nuclei
Large eosinophilic cytoplasm.
Describe what foreign body giant cells are like?
Often associated with pyogenic granulation tissue
Acutely inflamed
Neutrophils, pus
Organisation
Give some examples of infectious granulomatous diseases?
Tuberculosis – Mycobacterium tuberculosis
Leprosy – Mycobacterium leprae
Syphilis – Treponema pallidum
What is caseous necrosis?
Dead tissue surrounded by macrophages, giant cells and lymphocytes.
What is leprosy?
Infection that attacks peripheral nerve endings, causing disfigurement by granulation response.
Give some examples of non-infectious granulomatous diseases?
Rheumatoid disease - tissue specific auto-immune disease
Sarcoidosis – classical clinical picture
Crohn’s disease – chronic inflammatory bowel disease
Describe the process of wound healing?
Process of repair of tissue damage Phase of acute inflammation Granulation tissue formation Local angiogenesis – new vessels grow Fibrosis and scar formation
What type of wound heals by primary intention?
Surgical wound of a minimal gap.
Small amount of granulation tissue and scarring(linear)
What type of wound heals by secondary intention?
Larger defects with lots of granulation tissue formation and contraction with scarring.
What are the sequence of events regarding scar tissue formation?
Injury, blood clot, acute inflammation, fibrin
Many growth factors and cytokines involved
Granulation tissue growth - angiogenesis
Phagocytosis of fibrin
Myofibroblasts move in and lay down collagen
Contraction of scar
Re-epithelialisation
Name some factors that favour wound healing?
Cleaniness Apposition of edges (no haematoma) Sound nutrition Metabolic stability and normality Normal inflammatory and coagulation mechanisms
Name some factors that impair wound healing?
Dirty, gaping wound, large haematoma
Poorly nourished, lack of vitamins C, A
Abnormal CHO metabolism, diabetes, corticosteroid therapy
Inhibition of angiogenesis
What is callus formation?
A piece of bone that is healing and undergoing bone remodelling.
What are the stages of callus formation?
Osteoblasts lay down woven bone
Nodules of cartilage present
Followed by bone remodelling
Osteoclasts remove dead bone
Progressive replacement of woven bone by lamellar bone
Reformation of cortical and trabecular bone
What are the stages of angiogenesis?
New vessels form- capillary buds
Vascular Endothelial Growth Factor (VEGF) released by hypoxic cells stimulates proliferation
Enzyme secretion aids process
Enable blood supply to enter damaged tissue
