Inflammation 2

Question 1

What are the possible outcomes of acute inflammation?

Answer 1

Resolution
Suppuration (abscess formation)
Repair, organisation and fibrosis (scar formation)
Chronic inflammation

Question 2

What is resolution?

Answer 2

Complete restoration of tissue to normal after removal of inflammatory components (due to acute inflammatory response)

Question 3

When can resolution occur?

Answer 3

If basement membrane is intact
After little tissue damage
If tissue has capacity to repair:
GI tract frequently replaces epithelien whereas CNS cells cannot be regenerated

If good vascular supply for delivery of wbcs (remove injurious agent)

Question 4

What is suppuration? Different terms

Answer 4

ABSCESS formation occurs when localised collection of pus forms

If space is filled by pus and walled off, called an EMPYEMA, like in gallbladder

Question 5

How can an abscess be removed?

Answer 5

No blood supply in middle so antibiotics do not work
Sometimes, will discharge spontaneously
May have to be removed by surgery

Question 6

What does pus consist of?

Answer 6

Living, dying and dead cells (neutrophils, bacteria, inflammatory debris - called fibrin)

Question 7

When does healing by fibrosis and scar formation occur?

Answer 7

Occurs when damage goes beyond basement (basal) membrane

If injury produces lots of necrosis during acute phase (cell death)
If injury produces lots of fibrin that cannot be cleared
If poor blood supply - wbcs cannot remove fibrin
Some tissue types cannot regenerate (liver can)

Question 8

What does fibrosis and scar formation involve?

Answer 8

Damaged tissues cannot regenerate so replaced by FIBROUS tissue (results in loss of function), e.g: in heart

Question 9

What is granulation tissue?

Answer 9

New connective tissue and blood vessels that form on wound surfaces during healing and appears very red

Question 10

How does granulation tissue form?

Answer 10

Defect is infiltrated by capillaries and then by myofibroblasts
Collagen and smooth muscle cells deposited

Question 11

Describe scarring and fibrosis in liver

Answer 11

Liver has some regenerative capacity but can be overwhelmed
CIRRHOSIS results, causing liver failure (loss of liver function)
Liver cannot remove toxins and cannot make proteins
Vascular disturbances occur as large volume of blood flow occurs

Question 12

Describe how long chronic inflammation lasts and what it involves in relation to acute inflammation

Answer 12

Occurs over a longer period than acute

Less oedema formation; less cellular changes

Major difference is infiltration of tissue by lymphocytes and monocytes (in tissues, called macrophages)

Question 13

When is chronic inflammation favoured?

Answer 13

Persistence of injury/infection, e.g: with Myobacterium tuberculosis or asbestos

If suppuration/walled off pus

In autoimmune diseases/transplant rejection

Question 14

How do macrophages exit the circulation into tissues?

Answer 14

Via chemotaxis

Question 15

What do macrophages do in chronic inflammation?

Answer 15

Capable of phagocytosis and intracellular killing of bacteria

Capable of releasing potent proteolytic enzymes (results in degradation of extracellular matrix and tissue damage)

Question 16

What is granulomatous inflammation and when can it occur?

Answer 16

Specific pattern of chronic inflammation characterised by local aggregation of histiocytes (tissue macrophages) and epithelial cells - called a GRANULOMA (macrophages activate and transform into epithelioid cells)

Occurs due to specific infection, e.g: TB
Parasities
Worms
Eggs
Syphilis

Question 17

What characterises TB?

Answer 17

Tuberculosis granulomas - CASEOUS NECROSIS (appears cheesy)

Also, acid-fast bacilli stain on TB can identify