Inflammation-Sequel to Acute Inflammation Flashcards
What determines the sequelae to acute inflammtory reactions?
Extent of damage caused to tissue cells
Whether causal agent is eliminated or persists to cause further damage and more responses
What are the main sequelae?
- Resolution or organizaton
- Organization or repair
- Progression to chronic inflammation
What is resolution?
complete return to normal architecture, removal of dead cellular debris
What happens when cellular damage is mild?
reversal of inflammatory change, no appreciable necrosis, activation of resolution program
What are the processes involved in the resolution program?
- Switch from production of inflammatory mediators (prostaglandins, leukotrienes, etc) to lipoxins, resolvins, and protectins
- Antagonization of neutrophil infiltration, promotion of neutrophil apoptosis, and stimulation to regenerate damaged tissue (actions of anti-inflammatory mediators)
- Phagocytosis of apoptotic neutrophils by macrophages
- Induction of macrophage switch from pro-inflammatory to pro-resolution (action of neutrophil phagocytosis)
- Macrophage coordination of healing process
What do macrophages do in the healing process?
remove dead cells, cell debris, fibrin, lipids, hoemosiderin, bacteria, and foreign material
What is the demolition phase?
Removal of dead cells and cell debris by action of macrophages or fibrinolysis, exudate moves out through lymphatics, reinstatement of normal permeability and blood flow within vessels
What do lipoxins do?
switch off many pro-inflammatory pathways
What do resolvins and protectins do?
inhibit inflammation
promote resolution of inflammation
What is organization or repair?
scar formation with loss of original architecture
What denotes suppuration?
- -intense and prolonged neutrophil emigration leading to accumulation of cells at site of damage
- -neutrophils die due to impaired circulation and release lysosomal enzymes that digest and liquefy dead cells and tissue framework
What contributes to movement of fluid into the abscess?
Accumulation of dead cells, digested cell and tissue debris, and plasma proteins within the cavity raises the osmotic pressure
What happens when pointing and discharge of an abscess is gravitational?
drainage and elimination is usually prompt and effective, clearing the way for repair processes to fill cavity
What happens when pointing and discharge of abscess are anti-gravitational?
Only portion of abscess contents may be discharged over sinus track opening, persistence of infection within cavity
What is an abscess?
localized collections of purulent inflammatory tissue caused by suppuration buried in a tissue, organ, or confined space
central region of necrotic leukocytes and tissue cells, zone of preserved neutrophils and outside region of vessels and fibroblastic proliferation
