Acute Inflammation 2 Flashcards
What is the suffix for inflammation and exception to it?
“-itis”
- Pneumonia (lungs)
- Pleurisy (pleural cavity)
What are neutrophils?
Mobile phagocyte which recognise and move to antigen (chemotaxis) and adhere to it
Mechanism of neutrophils
Release granule contents into phagosome (non-specific)
What do neutrophil granules contain?
Oxidants and digestive enzymes
Consequences of neutrophil action
- Neutrophils die (digests itself)
- Suppuration - forms fluid of digested cells, organisms & endogenous proteins
What is the role of fibrinogen?
It’s coagulation factors - forms fibrin which clots the exudate and localises it by stopping inflammation from spreading
What are two important plasma proteins involved in acute inflammation?
Fibrinogen and immunoglobulins
What is the mechanism of immunoglobulins (antibodies)?
- Neutralisation - prevent binding
- Opsonisation - attract phagocyte
- Complement activation
What are 3 mediators?
- Molecules on endothelial cell surface membrane
- Molecules released from cells
- Molecules in the plasma
Effects of mediators
- Vasodilatation
- Increased permeability - leaky vessels
- Neutrophil chemotaxis & adhesion
- Itch and pain
What mediators cause neutrophils adhesions?
Cell surface adhesion molecules
- ICAM-1 helps pavementing
- P-selectin helps adhesion to antigen
What inflammatory mediator is released from mast cells and what activates its release?
Histamine - due to local injury; IgE mediated reaction (allergic)
What does histamine cause?
Vasodilatation and increased permeability - acts on H1 receptors on endothelial cells
What is 5-hydrocytryptamine and where is it produced?
Serotonin and produced in platelets
What activates serotonin’s released?
When platelets degranulate in coagulation
What does serotonin cause and why?
Vasoconstriction to prevent leakage from damaged vessel
What does antihistamine do?
Prevents the mast cells releasing histamine
What are cytokines and chemokine?
Inflammatory mediators which are produced by macrophages, lymphocytes, endothelium in response to inflammatory stimuli
What do cytokines and chemokine do?
Attract inflammatory cells - pro-inflammatory
What are the immediate systemic effects of inflammation?
- Pyrexia
- Feeling unwell (malaise)
- Neutophilia
What is pyrexia?
Raised temperature
What is neutrophilia?
Raised white cell count
What are long term effects of acute inflammation?
- Lymphadenopathy - lymph node enlargement
- Weight loss
- Anaemia
What does pus contain?
Dead tissue, organisms, exudate, neutrophils, fibrin, red cells, debris
What is suppuration?
Pus formation
What surrounds pus?
Pyogenic membrane - helps localisation
What is an abscess?
Collection of pus (suppuration) under pressure from ingrowth of granulation tissue and when it collapses it leads to healing and repair
What forms multiloculated abscesses?
Pus bursts through pyogenic membrane and forms new cavities
What is empyema?
Collection of pus in a hollow viscus
- Gall bladder
- Pleural cavity
What is pyaemia?
Discharge of pus to bloodstream
What is organisation?
Granulation tissue formation - fibrosis and formation os a scar
What is granulation tissue?
Repair of damage
What is granulation tissue formed of?
- Angiogenesis
- Fibroblasts and collagen
- Macrophages
What is dissemination?
Spread of substances to the blood stream - patient “septic”
What are examples of dissemination?
- Bacteraemia - bacteria in blood
- Septicaemia - growth of bacteria in blood
- Toxaemia - toxic products in blood
What are the signs of early septic shock?
- Peripheral vasodilatation
- Tachycardia - high heart rate
- Hypotension - low BP
- Pyrexia (temp)
- Skin rash
Effects of systemic infection
Shock - inability to perfuse tissues
Describe pathogenesis of septic shock?
Systemic release of chemical mediators from cells into plasma - catecholamine release
What is the action of catecholamine?
Chemical mediators which cause vasodilatation, tachycardia
Outcome of septic shock
- Tissue hypoxia - cell death
- Haemorrhae - vessel abnormality
