acute inflammation Flashcards
define inflammation
the local physiological response to tissue injury (a reaction to injury involving cells such as neutrophils and macrophages - from lec)
give examples of cells involved in inflammation
neutrophils, macrophages, lymphocytes, endothelial cells, fibroblasts
give features of neutrophils
short-lived
first inflammatory cells in acute inflammation
cytoplasmic granules with enzymes that kill bacteria
dise at the scene of inflammation
release chemokine (that attract other inflammatory cells e.g. macrophages)
give features of acute inflammation
sudden onset short duration usually resolves neutrophils dilation of vessels exudate- vascular leakage of protein rich fluid
give features of chronic inflammation
slow onset/sequel to acute
long duration
may never resolve/slow resolution
lymphocytes, plasma cells and macrophages
neutrophils do not carry out phagocytosis? T or F
False
what do endothelial cells do in inflammation?
become sticky to allow inflammatory cells to adhere to them
become porous to allow inflammatory cells to pass into tissues
grow into areas of damage to form new capillaries
what happens to capillaries in inflammation and why
they fill with blood as there is vasodilation of arterioles and opening of pre-capillary sphincters
why is there oedema?
as the endothelial lining becomes more porous, plasma protein leaves the vessels and fluid leaves the vessels by osmosis, as the oncotic pressure is greater outside the vessels
What are the steps of migration of neutrophils?
- margination of neutrophils
- pavemetation of neutrophils
- pass between endothelial cells
- pass through basal lamina and migrate into adventitia
What systems are interlinked in inflammation?
Four plasma enzymatic cascade systems:
coagulation, fibrinolytic, kinin and complement
give an example of acute inflammation and info about it
acute appendicitis unknown cause neutrophils dilation of blood vessels inflammation of serial surfaces pain result: 1. appendix surgically removed 2. inflammation resolves 3. appendix bursts giving generalised peritonitis and possible death
give examples of the stages of acute peritonitis
- oedema and swelling with dilated blood vessels
- pus
- rupture of contents
what is the difference between exudate and transudate?
exudate has a high protein content because they result from increased vascular permeability
transudates have a low protein content as the vessels have normal permeability characteristics
give an example of a drug use for inflammation
ibuprofen (NSAIDs)
what are the beneficial effects of inflammation?
destruction of invading microorganisms
walling off of an abscess cavity, preventing spread of infection
What are the harmful effects of inflammation?
- may produce disease
e. g. an abscess in the brain may act as a space-occupying lesion, compressing vital surrounding structures - fibrosis from chronic inflammation may distort the tissues and permanently alter their function
- digestion of normal tissues
- swelling
- inappropriate inflammatory response
define acute inflammation
initial and often transient series of tissue reactions to injury
chronic inflammation
subsequent and prolonged tissue reactions following the initial response (beware though not always following acute inflammation)
causes of acute inflammation
microbial infections -pyogenic bacteria and viruses
hypersensitivity reactions - parasites, tubercle bacilli
physical agents - trauma, ionising radiation, heat, cold
chemicals - corrosives, acids, alkalis, reducing agents
tissue necrosis - ischaemic infarction (due to peptides released from dead tissue)
bacterial toxins that lead directly to inflammation
define hypersensitivity reaction
occurs when an altered state of immune responsiveness causes an inappropriate or excessive immune reaction that damages tissues
what are the essential macroscopic appearances of acute inflammation?
Rubor Calor Tumor Dolor loss of function
explain rubor
dilation of small blood vessels within the damaged area
explain calor
hyperaemia in periphery due to vasodilation
systemic fever due to chemical mediators of inflammation
explain tumor
this is selling of the area due to oedema - the accumulation of fluid in the extravascular space due to fluid exudate
also from the physical mss of inflammatory cells migrating to the area
formation of connective tissue contributes to swelling in later stages
explain dolor
pain
- from stretching and situation of tissues due to oedema and pus under pressure in an abscess cavity
- chemical mediators e.g. bradykinin, prostaglandins and serotonin cause pain
explain loss of function
- movement inhibited by pain
2. severe swelling may physically immobilise the tissues
what three processes are important in acute inflammation?
- change in vessel calibre and flow
- increased vascular permeability and formation of the fluid exudate
- formation of the cellular exudate - neutrophils
what are the three causes of increased vascular permeability?
- immediate transient chemical mediators e.g. histamine, bradykinin, NO, C5a, leukotriene, PAF
- immediate sustained severe direct vascular injury e.g. trauma
- delayed prolonged endothelial cell injury - x-rays, bacterial toxins
What causes neutrophil adhesion to the endothelial surface?
histamine and thrombin, interleukins, C5a, leukotriene and PAF
cause up-regulation of adhesion molecules on the surface of endothelial cells
What do endogenous chemical mediators cause?
vasodilation emigration of neutrophils chemotaxis increased vascular permeability itching and pain
Name some endogenous chemical mediators that cause vasodilation
histamine VIP NO PAF prostaglandins
Name some endogenous chemical mediators that cause increased vascular permeability
histamine bradykinin NO C5a leukotriene B4 PAF
name some endogenous chemical mediators that cause neutrophil chemotaxis
leukotriene B4
Il-8
name special macroscopic appearances of acute inflammation
serous suppurative membranous pseudomembranous necrotising (gangrenous) So Special Macroscopic Parts Now
what are the outcomes of acute inflammation?
resolution
suppuration
organisation
progression to chronic inflammation
what are the systemic effects of acute inflammation?
pyrexia constitutional symptoms weight loss reactive hyperplasia of the RES haematological changes amyloidosis
what is resolution?
complete restoration of tissue to normal
what is suppuration?
formation of pus - living and dead neutrophils, bacteria, cell debris, e.g. abscess
What is organisation?
replacement of tissue by granulation tissue as part of repair (granulation tissue consists of small blood vessels in a connective tissue matrix with myofibroblasts)
why does acute inflammation sometimes progress to chronic?
causative agent not removed
