acute inflammation Flashcards
Definition of acute inflammation
fundamental response maintaining integrity of organism
dynamic homeostatic mechanism
higher organisms
series of protective changes occurring in living tissue as a response to injury
Cardinal signs of inflammation
rubor - redness calor - heat tumor - swelling dolor - pain loss of function all of these explained by the sequence of Pathological events taking place
Causes - aetiology -
of acute inflammation
micro-organisms - bacteria, fungi, viruses, parasites
pathogenic organisms cause infection
mechanical - trauma - injury to tissue
all injuries even sterile (eg surgery)
Process 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
extracellular “space” and fluid and molecules within it
lymphatic channels and drainage
Starling forces control flow (fluid flux) across membrane
Q = LpS{(Pc - Pi) - (p - i)}
dynamic balance
hydrostatic and colloid osmotic pressures
compartments and physical constants
Steps - pathogenesis -
in acute inflammation
changes in vessel radius - flow
change in the permeability of the vessel wall - exudation
movement of neutrophils from the vessel to the extravascular space
Effects 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
Resolution of acute inflammation - ideal outcome
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
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
Outcomes of acute inflammation
resolution
suppuration
organisation
chronic inflammation
what is inflammation called in the periotoneal cavity
peritonitis
what is inflammation called in the meninges
meningitis
what is inflammation called in the appendix
appendicitis
what is inflammation called in the lungs
pneumonia
what is inflammation called in the pleural cavity
pleurisy
whats the function of neutrophils
mobile phagocytes
- recognise foreign antigen
- move towards it - chemotaxis
- adhere to organism
granules possess oxidants (eg H2O2) and enzymes (eg proteases)
release granule contents
phagocytose & destroy foreign antigen
what happens when neutrophils die
they die when granule contents are released, it produces a soup fluid (pus) and can extend to tissues
whats 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
what are the Mediators of acute inflammation
molecules on endothelial cell surface membrane
molecules released from cells
molecules in the plasma
molecules inside cells
whats the effects of mediators
vasodilatation increased permeability neutrophil adhesion chemotaxis itch and pain
where do adhesion molecules appear on?
endothelial cells
when are 5- hydroxytryptamine released?
when platelets degranulate in coagulation
why is histamine released
as a result of local injury
does histamine or 5-hydroxytryptamine cause vasodilation
histamine causes vasidilation and 5 hydro causes vasoconstriction
whats the function of prostglandins
many promote histamine effects and inhibit inflammatory cells
what are cytokines and chemokines and how are they produced?
small molecules produced by macrophages, lymphocytes, endothelium in response to inflammatory stimuli
are cytokines and chemokinespro inflammatry or anti?
both
whata the function of nitrogn oxide when its been released
smooth muscle relaxation, anti-platelet and regulated leukocyte recruitment to inflammatry focus
what releases oxygen free radicals (H2O2, OH-, O2-)
and what is there function
released by neutrophils on phagocytosis
amplify other mediator effects
what are the three intracellular inflammatory pathways
NF-κB (nuclear factor kappa-B) pathway
MAPK (mitoger-activated protein kinase0
JAK-STAT (Janus kinase – signal transducer and activator to transcription) pathway
whats the function of the MAPK (mitoger-activated protein kinase0 pathway?
and NF-κB (nuclear factor kappa-B) pathway
Regulates pro-inflammatory cytokine production and inflammatory cell recruitment
whats the function of JAK-STAT (Janus kinase – signal transducer and activator to transcription) pathway
Direct translation of extracellular signal to molecular expression
what are the four enzyme cascades in the plasma
blood coagulation pathways
fibrinolysis
kinin system
complement cascade
whats the function of blood coagulation pathways
clots fibrinogen in exudate
interacts widely with other systems
whats the function of fibrinolysis
breaks down fibrin, helps maintain blood supply
fibrin breakdown products vasoactive
whats the function of kinin system
bradykinin: pain
whats the function of complement cascade
ties inflammation with immune system
active components stimulate increased permeability, chemotaxis, phagocytosis, cell breakdown
what is pyrexia and what is it a side effect of
raised temperature endogenous pyrogens from white cells act centrally
side effect of inflammation
whats three side effects of inflammation
pyrexia
feel unwell
neutrophilia - raised white cell count
what are outcomes of acute inflammation
pus formation
pyogenic membrane surrounds pus
what is multiloculated abscess
pus that bursts through pyogenic membrane and forms new cavities
what is empyema
gathering of pus in pleural cavity
what is pyaemia
discharge to bloodstream
what are granulation tissue formed of?
new capillaries - angiogenesis
fibroblasts and collagen
macrophages
what is dissemination in an outcome of acute inflammation
its spread
define the terms septic
spread to bloodsteam
define the terms bacteraemia
bacteria in blood
define the terms septicaemia
growth of bacteria in blood
define the terms 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
whats the pathogenisis of septic shock
bacterial endotoxin released
activation of coagulation
whats the function of bacterial endotoxin being released released in the tratment of septic shock
interleukin-1 released
acts on hypothalamus - pyrexia
whats the function of activation of coagulation in the tratment of septic shock
disseminated intravascular coagulation
vasoactive chemical - vasodilatation
haemorrhagic skin rash
what happens when compensation fails?
raised HR insufficient to maintain cardiac output
SVR low; so BP falls
reduced perfusion of tissues
what are the outcomes of septic shock
rapidly fatal
tissue hypoxia - cell death
haemorrhage
requires urgent intervention and support
