Acute inflamation mw % XXXXXXXXXXXXXXXXXXXXXXXXXXXX Flashcards Preview

ME2308 Principles of Disease > Acute inflamation mw % XXXXXXXXXXXXXXXXXXXXXXXXXXXX > Flashcards

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 What is the Definition of acute inflammation?

•Series of protective changes occurring in living tissue as a response to injury.




What are the important signs of inflammation?

•Rubor   - redness

•Calor   - heat

•Tumor   - swelling

•Dolor   - pain

•Loss of function


 What are the Causes - aetiology -
of acute inflammation?


•Mechanical  - trauma - injury to tissue.

•Chemical - upset stable environment

•Physical - extreme conditions

•Dead tissue




Outline some feutures of acute inflammation?

•Series of microscopic events

•Localised to affected tissue

•Take place in the microcirculation

•Result in the clinical symptoms and signs of acute inflammation - the cardinal signs


 What is the microcirculation?

•Capillary beds, fed by arterioles and drained by venules. 


What are the overall steps in acute inflamation?

•Changes in vessel radius - flow

•Change in the permeability of the vessel wall - exudation

•Movement of neutrophils from the vessel to the extravascular space


Explain the changes in vessel radius in acute inflamation?

1. Transient arteriolar constriction.

2.Local arteriolar dilatation- causes increased local tissue blood flow

3. Relaxation of vessel smooth muscle



What is the advantage of increased permeability in acute inflamation?

•Locally produced chemical mediators cause an endothelial leak followed by the net movement of plasma from capillaries to extravascular space( Exudation). 


What is the effect of exudation?

•Oedema formed

•Oedema is accumulation of fluid in the extravascular space

•Explains swelling of tissue in acute inflammation

•Swelling causes pain - reduce function


Describe the phases of emigration of neutraphils?

•Margination - neutrophils move to endothelial aspect of lumen

•Pavementing - neutrophils adhere to endothelium

•Emigration - neutrophils squeeze between endothelial cells - active process - to extravascular tissues. 


What is the resolution of acute inflammation?

•Inciting agent isolated & destroyed

•Macrophages move in from blood and phagocytose debris; then leave

•Epithelial surfaces regenerate

•Inflammatory exudate filters away

•Vascular changes return to normal

•Inflammation resolves


What are the benefits of acute inflammation?

•Rapid response to non-specific insult

•Cardinal signs and loss of function

–transient protection of inflamed area

•Neutrophils destroy organisms and denature antigen for macrophages

•Plasma proteins localise process

  • Resolution and return to normal


What are the outcomes of acute inflamation?


•Suppuration-formation of pus.


•Chronic inflammation


Inflammation at various anatomical locations


  • appendix   -appendicitis

•Lungs   -pneumonia

•Pleural cavity   -pleurisy


What do neutrophils do?

•Mobile phagocytes

–recognise foreign antigen

–move towards it - chemotaxis

–adhere to organism

•Release granule contents

•Phagocytose & destroy foreign antigen


What are the Consequences of neutrophil action?

•Neutophils die when granule contents released.

•Produce a “soup” of fluid, bits of cell, organisms- pus.

•Might extend into other tissues, progressing the inflammation


What is the role of plasma proteins in inflammation?

•Fibrinogen - coagulation factor - forms fibrin and clots exudate - localises inflammatory process

•Immunoglobulins in plasma specific for antigen - humoural immune response 


Where do mediators of acute inflmation come from?

• Endothelial cell surface membrane

• Released from cells

• In the plasma


 What are the collective effects of mediators?


•Increased permeability

•Neutrophil adhesion


•Itch and pain

•Mediators had positive and negative effects

•Result is a dynamic balance

•Favours and inhibits acute inflammation

•relative to need


What are the immediate systemic effects of inflammation?

•Pyrexia - raised temperature

•Feel unwell.

•Neutrophilia - raised white cell count

–bone marrow releases/produces.


What are the longer term effects?

  • Lymphadenopathy which is a regional lymph node enlargement–immune response
  • Weight loss - catabolic process
  • Anaemia


 Explain suppuration as an outcome to acute inflamation?

•Pus formation

–dead tissue, organisms, exudate, neutrophils, fibrin.

•pyogenic membrane(fibrin) surrounds pus

–capillary sprouts, neutrophils, fibroblasts

–Walls off pus


What is an abscess?

•Collection of pus (suppuration) under pressure

•Single locule, multiloculated

•“points” and discharges

•Collapses - healing and repair


Explain organisation as an outcome to acute inflamation?

•Granulation tissue characteristic

•Healing and repair

•Leads to fibrosis and formation of a scar


What is granulation tissue?

•“universal patch” – repair kit – for all damage

•Formed of:

–new capillaries - angiogenesis

–fibroblasts and collagen



Explain dissemination as an outcome of acute inflammation ?

•Spread to bloodsteam - patient “septic”

•Bacteraemia - bacteria in blood

•Septicaemia - growth of bacteria in blood

•Toxaemia - toxic products in blood


What are the effects of systemic infection?

•Shock - inability to perfuse tissues

•Clinical picture of early septic shock

–peripheral vasodilatation

–tachycardia - high heart rate

–hypotension - low blood pressure

–often pyrexia

–sometimes haemorrhagic skin rash


 What are the outcomes of septic shock?

•Rapidly fatal

•Tissue hypoxia - cell death


•Requires urgent intervention and support

–awareness and early recognition

–ability of young people to compensate

 - admit to hospital and intensive care