Chronic Inflammation Flashcards
What are 5 examples of macroscopic features associated with this process?
Chronic ulcer - e.g. Chronic peptic ulcers with a base lined by granulation tissue
Chronic abscess cavity
Thickening of wall of hollow viscus by fibrous tissue e.g. In Crohn’s
Granulomatous inflammation perhaps with caseous necrosis
Fibrosis when infiltrate subsides
What is the basic definition of chronic inflammation?
A chronic (long lasting) response to injury with associated fibrosis and scarring
What are macrophages like?
Characterized by granular cytoplasm, large size and large bean-shaped nuclei
Derived from blood monocytes which become macrophages in tissues
Varying levels of activation
Key cell in chronic inflammation
What are lymphocytes like?
Very large nuclei and scarce cytoplasm
Link between immune and chronic inflammatory responses
B lymphocytes produce antibodies
T cells are involved in control and come cytotoxic functions
What are plasma cells and eosinophils?
Plasma cells - differentiated antibody-producing B cells synthesised 2 weeks after infection starts (sign of chronic)
Eosinophils are mainly involved in allergic reactions and parasitic infestations
What are giant cells? What are the 3 types?
Multi nucleate cells made by fusion of macrophages during frustrated phagocytosis - formed accidentally by head butting macrophages
Little phagocytic activity and no real known function
Langhans - TB, horse shoe arrangement of peripheral nuclei
Foreign body type - multiple nuclei disorganised, may seen the foreign material in a specimen
Toulon type - found where fat necrosis and Xanthomas, foamy cytoplasm and organised central nuclei in a ring structure
Using 3 examples how can cell proportions vary in chronic inflammation?
Rheumatoid - mainly plasma cells
Chronic gastritis - mainly lymphocytes
Protozoan infection - mainly macrophages, granulomatous because Protozoa are difficult to deal with
What are cytokines from activated T cells responsible for?
Recruitment of macrophages
Production of inflammatory mediators
Recruitment of other lymphocytes
Destruction of target cells (perforins destroy membranes)
Interferon production (antiviral and activates macrophages)
What are the 4 key functions of macrophages?
Phagocytosis and destruction
Processing and antigen presentation
Synthesis of cytokines and TNF as well as complement, clotting factors and proteases
Controls other cells via cytokines
What do macrophages produce?
Potent proteolytic enzymes important to defend against bacterial infection and also for causing tissue damage
Extensive degradation of ECM resulting in characteristic tissue damage
How can macrophages contribute to the repair process?
Produce growth factors such as PDGF, EGF, FGF and transforming growth factor beta.
Secret pro-inflammatory cytokines and plasma proteins
What are some examples of de novo chronic inflammation?
Resistance of an infective agent to phagocytosis e.g. TB and leprosy
Chronic low level irritation from Endogenous material e.g. Necrotic adipose
Exogenous material e.g. Asbestos, sutures
Autoimmune - hashimoto’s (organ specific), rheumatoid (non-specific)
When could chronic lead on from acute inflammation?
Damage caused is more than can be solved by immediate resolution
Example is abscesses
Could be indigestible material present which resist action of lysosomal enzymes
Foreign bodies that provoke granulomatous inflammation
When can chronic develop directly alongside acute inflammation?
In severe persistent or repeated irritation which leads to tissue destruction
What are 4 possible consequences of chronic inflammation?
Fibrosis and scarring e.g. Chronic cholocystitis and gallstones
Loss of function e.g, chronic inflammatory bowel disease
Atrophy
Stimulation of immune response by macrophage-lymphocyte interactions
