Chronic inflammation

Question 1

what is chronic inflammation ?

Answer 1

inflammatory process in which lymphocytes, plasma cells and macrophages predominate

• It is usually accompanied by the formation of granulation tissue resulting in fibrosis
• few eosinophils may be present but neutrophil polymorphs are scarce

Question 2

In what ways can chronic inflammation arise?

Answer 2

I) Chronic inflammation developing from acute inflammation
Or more commonly,
II) Primary chronic inflammation

Question 3

what are factors favouring progression from acute to chronic inflammation?

Answer 3

1)Indigestible substances such as glass and suture material may result in chronic suppuration (foreign body reaction)

2. Deep seated suppurative inflammation in which drainage is delayed or inadequate will result in a thick abscess wall composed of fibrous/granulation tissue -
   The rigid walls fail to come together after drainage, pus within the cavity becomes organised and eventually results in a fibrous scar
3. Recurrent episodes of acute inflammation and healing may eventually result in the clinicopathological entity of
   chronic inflammation

Question 4

what are macroscopic appearances of chronic inflammation?

Answer 4

-Chronic ulcer- mucosa is breached, the base is lined by granulation tissue, fibrous tissue extends through the muscle layers
- Chronic abscess cavity eg osteomyelitis
-Thickening of the wall of a hollow viscus by fibrous tissue,
eg intestine
-Granulomatous inflammation eg tuberculosis

Question 5

what is the most prominent feature of chronic inflammatory reaction?

Answer 5

fibrosis

Question 6

what role does macrophages play in chronic inflammation?

Answer 6

• Possess considerable phagocytic capabilities
• Capable of ingesting a wide range of materials
• Relatively large cells
• Can harbour viable organisms resistant to lysosomal enzymes

Question 7

what does stimuli of macrophages result in?

Answer 7

• Increased cell size
• Increased lysosomal enzyme levels
• Increased metabolic activity -Increased phagocytic abilities

Question 8

what is granulomatous inflammation?

Answer 8

• A pattern of chronic inflammation
• A granuloma is an aggregate of epithelioid histiocytes
• A histiocyte is a macrophage present in connective tissue
• Little phagocytic activity
• Secretory function

Question 9

what are the causes of granulomatous inflammation?

Answer 9

• Specific infections
• Foreign bodies i) endogenous ii) exogenous
• Specific chemicals
• Drugs

Question 10

Describe mycobacteria.

Answer 10

1. Slowgrowinginculture–causesubacute&chronicinfection
2. Acid/Alcoholfastonmicroscopicstaining–akeyfeature
3. Resistant to many antimicrobials eg penicillins
4. Induce granulomatous reactions in tissue
5. Intracellular pathogens able to survive and replicate within neutrophils and macrophages