Inflammation

Question 1

What is acute inflammation?

Answer 1

Usually a rapid, transient process involving vascular changes and neutrophil accumulation.

Question 2

What is chronic inflammation?

Answer 2

A persistent form of inflammation in which there is ongoing tissue destruction and attempted repair.

Question 3

What are the three factors of acute inflammation?

Answer 3

1. Cell injury
2. Vascular changes
3. Neutrophil leucocytosis

Question 4

What are the steps of acute inflammation?

Answer 4

1. Dilation of blood vessels
2. Endothelial cell activation - increased capillary permeability, leakage of fluid + fibrinogen.
3. Activation of coagulation cascade makes thrombin (then fibrinogen to fibrin).
4. Increased neutrophil production in bone marrow - neutrophil leucocytosis.
5. End result is acute inflammatory exudate at area of damage (fluid, fibrin, neutrophils).

Question 5

What are the local effects of acute inflammation?

Answer 5

Warmth, redness, swelling, pain, loss of function.

Question 6

What are the systemic effects of acute inflammation?

Answer 6

Fever, CRP, increased ADH, cortisol, adrenaline - malaise, weakness, appetite loss (due to IL-1b, IL-6, TNFa).

Question 7

What is CRP and what causes it to rise?

Answer 7

1. Acute phase protein produced by liver in response to IL-6 produced by macrophages.
2. Bacterial infections, burns, trauma, polymyalgia rheumatica, giant cell arteritis.

Question 8

What are the outcomes of acute inflammation?

Answer 8

1. Regeneration - damaged cells replaced by same cell type
2. Repair - granulation tissue, then scar formation (collagen) - loss of specialised function)
3. Chronic inflammation

Question 9

What mediates the outcome of acute inflammation?

Answer 9

1. Severity of injury

2. Type of cell damaged - how often they divide

Question 10

What is an abscess?

Answer 10

Localised collection of pus within a newly-formed cavity in the tissue.

Question 11

What is pus?

Answer 11

Necrotic tissue with dead and dying neutrophils, fibrin and oedema fluid

Question 12

What are the features of chronic inflammation?

Answer 12

1. Persistent injury
2. Chronic inflammatory cells (macrophages, lymphocytes)
3. Scarring

Question 13

What are the consequences of chronic inflammation?

Answer 13

1. Scarring = fibrosis
2. Tissue destruction
3. Development of cancer
4. Diversion of nutrients
5. Amyloidosis

Question 14

What is a granuloma and what causes it?

Answer 14

1. Aggregate of activated (epithelioid) macrophages.

2. Infections (mycobacteria), sarcoidosis, Crohn’s disease.