Acute inflammation Flashcards
Define acute inflammation
Acute inflammation is a series of protective changes in living tissue as a response to injury.
What are the cardinal signs of inflammation ?
- Redness
- Heat
- Swelling
- Pain
What are the causes of acute inflammation ? (6)
- Micro-organisms
- Mechanical trauma to tissue
- Chemical changes
- Extreme physical conditions
- Dead tissue
- Hypersensitivity
Describe the local changes in vessel radius in relation to blood flow
- Transient arteriolar constriction
- Local arteriolar dilation
- Relation of vessel smooth muscle
Describe the change in vessel permeability
- Localised vascular response
- Endothelial leak produced by local chemical mediators
- Exudation of plasma and proteins such as fibrinogen and immunoglobulin
What are the effects of exudation ?
- An oedema is formed.
- This is the accumulation of fluid in the extra vascular space.
- This causes swelling which causes pain
Explain the phases of emigration of neutrophils
- Margination : Neutrophils move to endothelial aspect of lumen
- Pavementing :Neutrophils adhere to endothelia -Emigration : Neutrophils squeeze between endothelia to outside tissue
What are the benefits of acute inflammation ?
- 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
Describe the mechanism of attack by neutrophils
- 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
What are the roles of plasma proteins in inflammation ?
Fibrinogen - Forms fibrin and clots exudate. It localises the inflammatory process
Immunoglobulins in the plasma for the specific antigen
Explain the effects of the main mediators
Histamine - cause vasodilation and increased permeability
Prostaglandins - many of these promote histamine effects and inhibit inflammatory cells
What are the 4 enzyme cascades in the plasma ?
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
What are the collective effects or mediators ? (4)
- vasodilation
- increased permeability
- neutrophil adhesion
- chemotaxis
What are the immediate systematic effects of inflammation ?
- Pyrexia
- Malaise
- Neutrophilia
What is suppuration ?
This is pus formation.
This contains dead tissue, fibrin, dead neutrophils, exudate, RBCs
A pyogenic membrane made of fibrin surrounds the pus
What is an abscess ?
This is when suppuration comes under pressure
Describe the 2 types of discharge with an abscess
Single locule - the pus discharges at one point through the epithelial surface
Multiloculated abscess - pus bursts through pyogenic membrane and forms new cavities
What are the outcomes of acute inflammation ?
- 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
What are the detrimental potentials of acute inflammation ?
Sepsis - presence of bacteria in tissues
Bacteraemia - bacteria in the blood
Septicaemia - growth of bacteria in blood
Toxaemia - toxic products in blood
The increased heart rate is insufficient to maintain cardiac output during septic shock, what is the effect of this?
Blood pressure drops due to reduced SVR There is a reduced perfusion of tissues, hypoxia and loss of cell tissue and organ function
What is the outcome of septic shock
- Rapidly fatal
- Tissue hypoxia
- Haemorrhage Requires immediate intervention and support
What are the outcomes of acute inflammation?
- Resolution
- Suppuration
- Organisation
- Dissemination
- Chronic inflammation
