Chronic Inflammation

Question 1

What is chronic inflammation?

Answer 1

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.

Question 2

How does chronic inflammation present itself clinically?

Answer 2

No specific sore bit.
Malaise and weight loss
loss of function
tired

Question 3

When do we see chronic inflammation?

Answer 3

Arising from acute inflammation -
large volume of damage
inability to remove debris
fails to resolve – ongoing acute insult

Arising as a primary lesion.

Question 4

What is the role of granulation tissue?

Answer 4

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

Question 5

Describe the granulation tissue mechanism?

Answer 5

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

Question 6

What happens to scars overtime?

Answer 6

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.

Question 7

When does fibrosis become a problem?

Answer 7

When is happens when you don’t want it to e.g adhesion between the loops of the bowel following peritonitis.

Question 8

What is osteomyelitis?

Answer 8

Acute inflammatory process effecting the bone. It can become chronic.

Question 9

What are some causes of primary chronic inflammation?

Answer 9

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

Question 10

What are the main types of lymphocytes?

Answer 10

T cells (immune response) cellular
B cells (immune memory) humoural

Question 11

What is a plasma cell and what is its role?

Answer 11

A differentiated B cell.

Secrete antibodies.

Question 12

What are some B cell mechanisms?

Answer 12

Differentiate to plasma cells - antibodies
Facilitate immune response
Act with macrophages - antigen presenting capacity
Immune memory

Question 13

What are the T cell mechanisms?

Answer 13

Produce cytokines
Produce interferons
Damage and lyse other cells and destroy their antigen.

Question 14

What is the function of the cytokines released by T cells?

Answer 14

Molecular messengers that:
Attract and hold macrophages
Activate macrophages and other cells eg lymphocytes
Increase permeability so other molecules can come to help.

Question 15

What is the function of interferons released by T cells?

Answer 15

Antiviral effects

Attract and stimulate other cells

Question 16

What is the function of macrophages?

Answer 16

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

Question 17

What are the different names for macrophages in the following locations;

1. blood
2. epithelium
3. Connective tissue

Answer 17

1. Monocyte
2. Epithelioid cell
3. Histiocyte

Question 18

What are some properties of fibroblasts?

Answer 18

Motile cells
Metabolically active
Make and assemble structural proteins e.g collagens

Question 19

What does idiopathic mean?

Answer 19

There is no known cause.

Question 20

What are granulomas?

Answer 20

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.

Question 21

What are giant cells?

Answer 21

The fusion of many macrophages together into one whole mass or the proliferation of macrophages. They have a large cytoplasm and are multi nucleated.

Question 22

Describe what Langhan’s type giant cells are like?

Answer 22

Classically found in TB
Peripheral rim of nuclei
Large eosinophilic cytoplasm.

Question 23

Describe what foreign body giant cells are like?

Answer 23

Often associated with pyogenic granulation tissue
Acutely inflamed
Neutrophils, pus
Organisation

Question 24

Give some examples of infectious granulomatous diseases?

Answer 24

Tuberculosis – Mycobacterium tuberculosis
Leprosy – Mycobacterium leprae
Syphilis – Treponema pallidum

Question 25

What is caseous necrosis?

Answer 25

Dead tissue surrounded by macrophages, giant cells and lymphocytes.

Question 26

What is leprosy?

Answer 26

Infection that attacks peripheral nerve endings, causing disfigurement by granulation response.

Question 27

Give some examples of non-infectious granulomatous diseases?

Answer 27

Rheumatoid disease - tissue specific auto-immune disease
Sarcoidosis – classical clinical picture
Crohn’s disease – chronic inflammatory bowel disease

Question 28

Describe the process of wound healing?

Answer 28

Process of repair of tissue damage
Phase of acute inflammation
Granulation tissue formation
Local angiogenesis – new vessels grow
Fibrosis and scar formation

Question 29

What type of wound heals by primary intention?

Answer 29

Surgical wound of a minimal gap.

Small amount of granulation tissue and scarring(linear)

Question 30

What type of wound heals by secondary intention?

Answer 30

Larger defects with lots of granulation tissue formation and contraction with scarring.

Question 31

What are the sequence of events regarding scar tissue formation?

Answer 31

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

Question 32

Name some factors that favour wound healing?

Answer 32

Cleaniness
Apposition of edges (no haematoma)
Sound nutrition
Metabolic stability and normality
Normal inflammatory and coagulation mechanisms

Question 33

Name some factors that impair wound healing?

Answer 33

Dirty, gaping wound, large haematoma
Poorly nourished, lack of vitamins C, A
Abnormal CHO metabolism, diabetes, corticosteroid therapy
Inhibition of angiogenesis

Question 34

What is callus formation?

Answer 34

A piece of bone that is healing and undergoing bone remodelling.

Question 35

What are the stages of callus formation?

Answer 35

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

Question 36

What are the stages of angiogenesis?

Answer 36

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