MoD Acute Inflammation

Question 1

What are the characteristic clinical signs of acute inflammation?

Answer 1

Rubor - redness
Tumor - swelling
Calor - heat
Dolor - pain
Loss of function

Question 2

List the causes of acute inflammation

Answer 2

Microbial infections (e.g pyogenic organisms - puss forming)
Hypersensitivity reactions (immunological)
Physical agents (e.g. heat)
Chemicals
Tissue necrosis

Question 3

What is the purpose of acute inflammation?

Answer 3

To limit tissue damage.

It is innate, immediate and stereotyped.

Question 4

List the 3 tissue changes that occur in acute inflammation

Answer 4

• changes in vascular flow
• formation of fluid exudate in tissues
• infiltration of inflammatory cells (neutrophils)

Question 5

Describe the changes that occur in vascular flow and how this presents clinically.

Answer 5

There is vasodilation of arterioles and capillaries causing an increased blood flow to the tissues. RUBOR + CALOR

There is increased permeability of blood vessels so there is exudation of fluid into tissues, and circulation is slowed. TUMOR

Question 6

Describe the formation of fluid exudate and how this presents clinically.

Answer 6

(Fluid flow is determined by hydrostatic pressure (exerted by fluid) and colloid osmotic pressure (exerted by proteins)).

Vasodilation of arterioles leads to increased hydrostatic pressure + increased permeability leads to loss of proteins. Net flow out of tissues = OEDEMA

Question 7

Describe the infiltration of inflammatory cells.

Answer 7

The primary type of cell to infiltrate is neutrophils / polymorphs (poly-nuclei)

1. Margination: neutrophils line up along the endothelium as blood flow slows
2. Rolling: they roll along the endothelium and occasionally stick to it
3. Adhesion: they then stick properly
4. Emigration: through vessel wall

Question 8

How do the changes in vascular flow constitute an effect response to injury?

Answer 8

Increased vascular flow to the tissue increases delivery of all the components needed for effective acute inflammation e.g. plasma proteins such as fibrinogen
inflammatory cells such as neutrophils
oxygen + nutrients
inflammatory mediators

Increased blood flow also increases temperature which aids in combatting pathogens.

Question 9

How does the exudation of fluid constitute an effect response to injury?

Answer 9

Delivers plasma proteins to the area of injury such as inflammatory mediators, fibrinogen which converts to fibrin. Fibrin localises swelling. (important for organs surrounded by serosa).

Dilutes toxins

Question 10

How does the infiltration of inflammatory cells constitute an effect response to injury?

Answer 10

Inflammatory cells remove pathogenic organisms and necrotic debris

Question 11

How does dolor and loss of function constitute an effect response to injury?

Answer 11

Enforces rest which reduces the change of further traumatic damage.