Chronic inflammation 1

Question 1

Define chronic inflammation.

Answer 1

Chronic inflammation is a prolonged immune response that can persist for months or even years.
It is inflammation in which the cell population is especially;
- Lymphocytes
- Plasma cells
- Macrophages

Question 2

Discuss the clinical findings of chronic inflammation.

Answer 2

Chronic inflammation is characterised (clinically) by tissue or organ damage, which could potentially lead to loss of function of the tissue or organ.

• Malaise and weight loss - systemic effect
• Loss of function

Question 3

Describe the causes of chronic inflammation

Answer 3

Chronic inflammation can arise as a result of:
- Acute inflammation (from an inability to remove debris, and an ultimate failure to resolve)
- Primary lesion (no preceding acute phase & only chronic changes seen)

Question 4

Describe the components of chronic inflammation

Answer 4

The key components of chronic inflammation, that are required for it to occur.
- Chemical mediators
- Angiogenesis (enabling blood supply to enter damaged tissue)
- A persistent stimulus
- Immune cells
- Fibrous scar formation

Question 5

Describe fibrosis as an outcome of chronic inflammation.

Answer 5

The process of fibrosis is mediated by granulation tissue.
Fibrosis results in the ‘patching up’ of the tissue defects. It replaces the dead (or necrotic tissue) and contracts and pulls the edges of damaged tissue together.

Question 6

Describe the mechanism of granulation tissue

Answer 6

Capillaries grow into inflammatory mass allowing:
- Access of plasma proteins
- Macrophages from blood and tissue

The fibroblasts lay down collagen (*structural protein):
- Repairs damaged tissue
& the collagen replaces the inflammatory exudate.

Question 7

Describe disease as an outcome of chronic inflammation

Answer 7

Autoimmune disease:
- Autoantibodies are directed against own cell and tissue components - they destroy organs, tissues, cells and cell components.
Thyroiditis, rheumatoid disease, pernicious anaemia, etc.

(lymphocytes, plasma cells, macrophages, fibrosis)

Question 8

Describe the role of angiogenesis in granulation tissue formation.

Answer 8

The new blood vessels bud from existing capillaries.
VEGF - vascular endothelial growth factor is released by hypoxic cells - this stimulates proliferation.
This leads to new growth of epithelial cells (enzyme secretion aids this process)

Overall:
This enables blood supply to enter the damaged tissue