L53: Chronic Inflammation

Question 1

2 types of chronic inflammation

Answer 1

1. Following acute inflammation: chronic suppurative inflammation
2. As a distinct process:
   - persistent infection by intracellular microorganisms (e.g. tubercle bacillus, leprosy)
   - insoluble particles (e.g. silica, asbestos)
   - persistent hypersensitivity (e.g. allergic contact dermatitis, rheumatoid arthritis)
   - unknown etiology

Question 2

General features of chronic inflammation

Answer 2

1. Infiltration by mononuclear cells (macrophage, neutrophils, lymphocytes and plasma cells)
2. Granulation tissue (fibroblast + endothelial cells) —> pyogenic membrane
3. Fibrosis and tissue destruction
4. Regeneration (can lead to epithelial overgrowth)

Question 3

Function of macrophage

Answer 3

1. Tissue damage
2. Chemotactic factors (IL-1, TNF) to attract other inflammatory cells
3. Fibroblast proliferation (collagen deposition)
4. Vascular proliferation

—> Fibrosis

Question 4

General effects of chronic inflammation

Answer 4

1. Hyperplasia of the lymphoid system

2. Long-continued antibody production —> amyloid disease

Question 5

What is granuloma

Answer 5

A collections of modified macrophage called “epitheloid cells”, having abundant, pale pink plump cytoplasm, less phagocytic than macrophage

Question 6

Factors that affect the presence of granuloma

Answer 6

1. Presence of indigestible organism/material: sequestration within macrophages
2. Presence of cell-mediated immunity: activated T cells enhance transformation of monocytes to epitheloid cells and multinucleate giant cells (fusion of epitheloid cells)

Question 7

3 types of multinucleated giant cells

Answer 7

1. Langhans giant cells: horseshoe shape nucleus (Tuberculosis lesion)
2. Foreign-body giant cells: haphazardly scattered nuclei
3. Touton giant cells: in Xanthomata, foamy lipid-rich peripheral cytoplasm, ring of nuclei, central clear eosinophilic cytoplasm

Question 8

Acute vs Chronic inflammation

Answer 8

1. Etiological onset: 
Brief and Intense VS Persistent and Indolent
2. Duration:
Days VS Weeks to months
3. Nature:
Exudative VS Proliferative
4. Consequence:
Resolution VS Destruction and Fibrosis