Chronic Inflammation

Question 1

What is chronic inflammation?

Answer 1

Inflammation;

• where cell population is mostly lymphocytes/plasma cells/macrophages
• which causes tissue/organ damage
• is a long term, insidious process
• which is characterised by granulation and scar tissue

Question 2

What are the main causes of chronic inflammation?

Answer 2

• resistance on infection to phagoctytosis/intracellular killing e.g. TB/leprosy
• endogenous factors e.g. necrotic tissue/bone
  (cannot easily be phagocytosed and can become stuck)
• exogenous tissue e.g. prostheses/sutures
• autoimmune diseases e.g. thyroiditis/rheumatoid arthritis

Question 3

What are the main clinical appearances of chronic inflammation?

Answer 3

• granulomatous inflammation
• fibrosis
• ulceration
• cellular infiltrate of lymphocytes/macrophages
• vague symptoms - malaise/weight loss etc.

Question 4

Describe the process of granulation

Answer 4

• capillaries grow into the inflammatory mass
• plasma proteins/macrophages gain access
• fibroblasts lay down collagen to repair damage and replace exudate
• patches and pulls cells together
• replaces necrotic tissue

Question 5

What are the possible outcomes of chronic inflammation?

Answer 5

• ongoing damage
• destruction
• loss of function
• granulation
• angiogenesis
• scarring
• fibrosis

Question 6

How may acute inflammation give rise to chronic inflammation?

Answer 6

• large volume of damage
• inability to remove debris
• failure to resolve itself

Question 7

How can fibrosis be problematic?

Answer 7

When it adheres loops of the bowl together after peritonitis (inflammation of the peritoneum), the bowl cannot contract as it is made inelastic by the volume of scar tissue it contains

Question 8

What is a fibroblast?

Answer 8

Metabolically active motive cell that makes and assembles structural proteins

Question 9

What is granulomatous inflammation?

Answer 9

• type of chronic inflammatory response
• stimulated by indigestible antigens
• characterised by granuloma presence in tissues/organs

Question 10

What is a granuloma?

Answer 10

• gathering of macrophage

may;
- contain giant cells
- surround areas of dead tissue
- be surrounded by lymphocytes
contain neutrophils and eosinophils

Question 11

Name an example of an infective granulomatous inflammatory condition

Answer 11

Tuberculosis

Leprosy

Question 12

Name an example of a non-infective granulomatous inflammatory condition

Answer 12

Rheumatoid arthritis

Crohn’s disease

Question 13

What are Giant cells?

Answer 13

• masses formed by unions of macrophages

- multinucleate cells with a large cytoplasm

Question 14

Name four types of giant cells

Answer 14

Langhans type
Foreign body type
Silicone associated
Warthin-Finkeldy type

Question 15

What is a caseous necrosis?

Answer 15

• white lumps of dead tissue in the lungs caused by TB

- surrounded by giant cells/macrophages/lymphocytes

Question 16

Describe the process of surgical wound healing

Answer 16

• primary intention
• minimal gap = small blood clot
• small amount of granulation tissue
• small linear scar

Question 17

Describe the process of larger defect healing

Answer 17

• secondary intention
• lots of granulation tissue
• contraction/puckering and scarring

Question 18

Describe the healing process (8 steps)

Answer 18

• injury
• blood clots (fibrin)
• acute inflammation
• granulation tissue formation
• angiogenesis (+ osteoblasts in fracture healing)
• fibrin phagocytosis
• fibrin replacement with collagen by myofibroblasts
• scar contraction and re-epithelialisation

Question 19

How is the healing process improved?

Answer 19

• cleanliness
• sound nutrition
• metabolic normality
• normal inflammation and coagulation

Question 20

How is the healing process impaired?

Answer 20

• dirty/gaping/large haematoma
• poor nutrition
• lack of vitamin A/C
• abnormal metabolism (e.g. diabetes)
• angiogenesis inhibition

Question 21

What is a callus?

Answer 21

bony healing tissue which forms around the ends of broken bones

Question 22

Describe callus formation

Answer 22

• osteoblasts lay down woven bone
• cartilage nodes are present
• followed by bone remodelling

Question 23

Describe the process of bone remodelling?

Answer 23

• removal of dead bone by osteoclasts
• replacement of woven bone with lamellar bone
• reformation of cortical and trabecular bone

Question 24

How do hypoxic cells stimulate angiogenesis?

Answer 24

by releasing Vascular Endothelial Growth Factor (VEGF)