What is acute inflammation?
Usually a rapid, transient process involving vascular changes and neutrophil accumulation.
What is chronic inflammation?
A persistent form of inflammation in which there is ongoing tissue destruction and attempted repair.
What are the three factors of acute inflammation?
- Cell injury
- Vascular changes
- Neutrophil leucocytosis
What are the steps of acute inflammation?
- Dilation of blood vessels
- Endothelial cell activation - increased capillary permeability, leakage of fluid + fibrinogen.
- Activation of coagulation cascade makes thrombin (then fibrinogen to fibrin).
- Increased neutrophil production in bone marrow - neutrophil leucocytosis.
- End result is acute inflammatory exudate at area of damage (fluid, fibrin, neutrophils).
What are the local effects of acute inflammation?
Warmth, redness, swelling, pain, loss of function.
What are the systemic effects of acute inflammation?
Fever, CRP, increased ADH, cortisol, adrenaline - malaise, weakness, appetite loss (due to IL-1b, IL-6, TNFa).
What is CRP and what causes it to rise?
- Acute phase protein produced by liver in response to IL-6 produced by macrophages.
- Bacterial infections, burns, trauma, polymyalgia rheumatica, giant cell arteritis.
What are the outcomes of acute inflammation?
- Regeneration - damaged cells replaced by same cell type
- Repair - granulation tissue, then scar formation (collagen) - loss of specialised function)
- Chronic inflammation
What mediates the outcome of acute inflammation?
- Severity of injury
2. Type of cell damaged - how often they divide
What is an abscess?
Localised collection of pus within a newly-formed cavity in the tissue.
What is pus?
Necrotic tissue with dead and dying neutrophils, fibrin and oedema fluid
What are the features of chronic inflammation?
- Persistent injury
- Chronic inflammatory cells (macrophages, lymphocytes)
- Scarring
What are the consequences of chronic inflammation?
- Scarring = fibrosis
- Tissue destruction
- Development of cancer
- Diversion of nutrients
- Amyloidosis
What is a granuloma and what causes it?
- Aggregate of activated (epithelioid) macrophages.
2. Infections (mycobacteria), sarcoidosis, Crohn’s disease.
