Acute inflammation

Question 1

Define acute inflammation

Answer 1

Acute inflammation is a series of protective changes in living tissue as a response to injury.

Question 2

What are the cardinal signs of inflammation ?

Answer 2

• Redness
• Heat
• Swelling
• Pain

Question 3

What are the causes of acute inflammation ? (6)

Answer 3

• Micro-organisms
• Mechanical trauma to tissue
• Chemical changes
• Extreme physical conditions
• Dead tissue
• Hypersensitivity

Question 4

Describe the local changes in vessel radius in relation to blood flow

Answer 4

• Transient arteriolar constriction
• Local arteriolar dilation
• Relation of vessel smooth muscle

Question 5

Describe the change in vessel permeability

Answer 5

• Localised vascular response
• Endothelial leak produced by local chemical mediators
• Exudation of plasma and proteins such as fibrinogen and immunoglobulin

Question 6

What are the effects of exudation ?

Answer 6

• An oedema is formed.
• This is the accumulation of fluid in the extra vascular space.
• This causes swelling which causes pain

Question 7

Explain the phases of emigration of neutrophils

Answer 7

• Margination : Neutrophils move to endothelial aspect of lumen
• Pavementing :Neutrophils adhere to endothelia -Emigration : Neutrophils squeeze between endothelia to outside tissue

Question 8

What are the benefits of acute inflammation ?

Answer 8

• Rapid-response to non-specific insult
• Cardinal signs and loss of function to protect site
• Neutrophils destroy pathogens and denature antigens for macrophages
• Plasma proteins localise process
• Resolution and return to normal

Question 9

Describe the mechanism of attack by neutrophils

Answer 9

• They recognise a foreign antigen. They move towards it through chemotaxis. They adhere to the organism
• They release their granule contents
• Then phagocytose and destroy foreign antigen

Question 10

What are the roles of plasma proteins in inflammation ?

Answer 10

Fibrinogen - Forms fibrin and clots exudate. It localises the inflammatory process
Immunoglobulins in the plasma for the specific antigen

Question 11

Explain the effects of the main mediators

Answer 11

Histamine - cause vasodilation and increased permeability

Prostaglandins - many of these promote histamine effects and inhibit inflammatory cells

Question 12

What are the 4 enzyme cascades in the plasma ?

Answer 12

Blood coagulation pathways - clots fibrinogen in exudate
Fibrinolysis - breaks down fibrin, helps maintain blood supply
Kinin system - bradykinin, causes pain
Complement cascade - ties inflammation with the immune system

Question 13

What are the collective effects or mediators ? (4)

Answer 13

• vasodilation
• increased permeability
• neutrophil adhesion
• chemotaxis

Question 14

What are the immediate systematic effects of inflammation ?

Answer 14

• Pyrexia
• Malaise
• Neutrophilia

Question 15

What is suppuration ?

Answer 15

This is pus formation.
This contains dead tissue, fibrin, dead neutrophils, exudate, RBCs
A pyogenic membrane made of fibrin surrounds the pus

Question 16

What is an abscess ?

Answer 16

This is when suppuration comes under pressure

Question 17

Describe the 2 types of discharge with an abscess

Answer 17

Single locule - the pus discharges at one point through the epithelial surface
Multiloculated abscess - pus bursts through pyogenic membrane and forms new cavities

Question 18

What are the outcomes of acute inflammation ?

Answer 18

• Granulation Tissue : Occurs after a large amount of damage, or an inability to remove dirt from wound. Capillaries grow into the inflammatory mass
  This allows access of plasma proteins, macrophages and fibroblasts which lay down collagen to repair the damage
• Healing and Repair
• Scar formation

Question 19

What are the detrimental potentials of acute inflammation ?

Answer 19

Sepsis - presence of bacteria in tissues
Bacteraemia - bacteria in the blood
Septicaemia - growth of bacteria in blood
Toxaemia - toxic products in blood

Question 20

The increased heart rate is insufficient to maintain cardiac output during septic shock, what is the effect of this?

Answer 20

Blood pressure drops due to reduced SVR There is a reduced perfusion of tissues, hypoxia and loss of cell tissue and organ function

Question 21

What is the outcome of septic shock

Answer 21

• Rapidly fatal
• Tissue hypoxia
• Haemorrhage Requires immediate intervention and support

Question 22

What are the outcomes of acute inflammation?

Answer 22

• Resolution
• Suppuration
• Organisation
• Dissemination
• Chronic inflammation