3. Acute Inflammation Flashcards
what is an inflammatory exudate?
a fluid rich in protein and cellular elements that oozes out of blood vessels due to inflammation and is deposited in nearby tissues
what is fibrosis?
the thickening and scarring of connective tissue, usually as a result of injury
what is suppuration?
the formation of pus
what is an abscess?
a swollen area within body tissue, containing an accumulation of pus
what is pyrexia?
high temperature/fever
what is an acute phase reaction?
a general term attributed to a group of systemic and metabolic changes that occur within hours of an inflammatory stimulus
what is acute inflammation?
a non specific initial reaction to tissue damage
what are the 2 main causes of acute inflammation?
infection
tissue death
what are the causes of tissue death?
ischaemia trauma toxins chemical insults thermal injury radiation
what is the prognosis after acute inflammation?
- if cells can regrow - healing by regeneration
- if cells cannot regrow - healing by repair
- if damaging agent persists - chronic inflammation
what is the purpose of acute inflammation?
- clear away dead tissues
- locally protect from infection
- allow access of immune system components
what are the 4 cardinal signs of infection?
- calor - heat
- rumour - redness
- dolor - pain
- tumour - swelling
what determines the manifestation of the cardinal signs?
anatomical considerations and which stage of the process is most prominent. this varies with cause or with time
what are the manifestations of inflammation in different organs?
serous
fibrinous
purulent
what are the components of an acute inflammatory response?
- vascular reaction
- exudative reaction
- cellular reaction
what happens in the vascular reaction?
microvascular dilatation leading to increased flow
flow then decreases
permeability of blood vessels increases
what chemicals act as mediators of the vascular reaction?
histamine bradykinin NO leukotriene B4 complement components
what is an exudative reaction?
formation of inflammatory exudate
what are the contents of an acute inflammatory exudate?
proteins
immunoglobulins
fibrinogen
why is there a constant turnover of inflammatory exudate?
dilution of noxious agents transport of noxious agents to lymph nodes supply of nutrients spread of inflammatory mediators spread of antibodies spread of drugs
what is involved in the cellular reaction?
migration of inflammatory cells out of vessels, and accumulation of neutrophils in extracellular space
when is pus formed?
when, in severe cases, neutrophils, cellular debris and bacteria accumulate in an extracellular space
what are the biomarkers of an acute phase reaction?
CRP
ESR
which is the commonest white cell in the blood?
neutrophils
how do neutrophils move into tissues?
directional chemotaxis
what is the lifespan of a neutrophil?
low. as low as a few hours when they are in tissues
how do neutrophils move into tissues?
from axial stream to margination on injury
rolling and adhesion to mediators (pavementing)
migrating outside capillary
due to chemotaxis
what are the cell derived mediators of acute inflammation?
prostaglandins leukotrienes PAF cytokines NO chemokine histamine
what are the plasma derived mediators of acute inflammation?
kinin system
clotting pathway
thrombolytic pathway
complement pathway
what are the consequences of acute inflammation?
if minimal tissue damage - resolution
if some tissue damage - fibrosis
if marked neutrophil reaction with tissue damage - suppuration
if damaging agent persists - chronic inflammation
