12 - Inflammation and Healing Flashcards
Relevant examinations for inflammation
1)
2)
3)
1) Full blood examination
2) C-reactive protein
3) Erythrocyte sedimentation rate (ESR)
Inflammation
Protective response of vascularised tissue to injury.
Closely associated with healing process.
Acute inflammation
1)
2)
3)
1) Rapid onset
2) Short duration - Several days, sometimes longer
3) Features neutrophils, fluid and protein exudate, vasodilation, macrophages
Chronic inflammation
1)
2)
3)
1) Later response
2) Lasts weeks/months/years
3) Macrophages, lymphocytes, plasma cells, fibrosis/scarring
Aims of acute inflammation
1)
2)
3)
1) Mediate local defences
2) Destroy any infective agents
3) Remove debris
Possible causes of acute inflammation 1) 2) 3) 4) 5)
1) Certain infections
2) Trauma
3) Foreign material
4) Burns
5) Infarction
Initiation of acute inflammatory response
1)
2)
1) Release of preformed mediators from E: mast cells, platelets (could be disrupted though trauma)
2) PRR on DCs, macrophages, epithelial cells lead to release of cytokines, which initiate inflammatory reponse
Vascular response in acute inflammation 1) 2) 3) 4) 5) 6)
1) Transient arteriolar constriction
2) Arteriolar, then capillary and
venular dilation
3) Increased vascular permeability
4) Vasocongestion
5) +/- vascular injury
6) Vascular responses involve
endothelial activation
Factors released by normal endothelium to prevent blood clotting
Nitric oxide, prostacyclin
Ability of leukocytes to adhere to normal endothelium
Poor. Normal endothelium is resistant to leukocyte adherence
Molecules that mediate leukocyte rolling (margination)
P- and E-selectin on endothelial wall, sialyl-lewis X-modified glycoprotein and low-affinity-form integrin on leukocyte
Molecules that mediate adhesion and diapedesis of leukocytes to endothelial cells
P-, E-selectin, ICAM-1, PECAM-1 on endothelial cells, activated integrin on leukocyte.
Difference of histology of normal and acutely inflamed lung
Normal lung has air-filled alveoli, which don’t stain.
Inflamed lung has exudate in alveoli, which stains with eosin (full of proteins)
Factors secreted by macrophages that promote tissue repair
TGF-beta, PDGF, FGF
What creates ROS in phagocytes?
NADPH oxidase (phagocyte oxidase) in cell membrane converts NADPH to NADP+ and O2 to O2-.
Three main types of inflammatory exudate
1) Serous
2) Purulent
3) Fibrinous
Examples of purulent exudate
1)
2)
3)
1) Lobar pneumonia
2) Bacterial meningitis
3) Abscess
Examples of fibrinous exudate
1)
2)
3)
1) Fibrinous pleuritis
2) Fibrinous pericarditis
3) Acute appendicitis
Abscess
A localised collection of necrosis in an organ.
Fibrinous inflammation
1) Occurs on serosal surfaces.
2) Heals via scarring.
Serous inflammation
Mostly fluid
Transudate
Oedema with normal vascular permeability, but increased hydrostatic pressure and/or reduced plasma oncotic pressure (to do with plasma proteins)
Exudate
Oedema with impaired vascular permeability
Types of oedema
1)
2)
3)
1) Transudate (normal vasc permeability)
2) Exudate (impaired vasc permeability)
3) Impaired lymphatic drainage
Difference in composition between transudate and exudate
Transudate has less protein in it than exudate (as vascular permeability is normal so proteins can’t extravasate as easily)
