Introduction |
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Introduction:
In contrast to the characteristics of acute inflammation
ie. vascular changes, oedema and a neutrophil dominated response, chronic
inflammation is characterised by:
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Infiltration of macrophages - often with
lymphocytes and plasma cells
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Tissue destruction - which may be due to
the actions of the inflammatory cells
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Repair - scar tissue formed by the development
of fibrosis and angiogenesis (new vessel proliferation)
The proliferation of fibroblastic cells and new capillary
buds in regions of healing is known as GRANULATION TISSUE, and must
not be confused with a form of chronic inflammation known as GRANULOMATOUS
INFLAMMATION. Granulomatous inflammation is recognised by the accumulation
of macrophages, and may also contain giant cells, epithelioid macrophages,
lymphocytes and plasma cells.
Generally chronic inflammation follows a period of acute
inflammation which cannot be resolved (ie the injurious agent persists).
Chronic inflammation can be any duration greater than 5-7 days and may
persist for years, with active inflammation, tissue injury, granulation
tissue formation and healing occurring simultaneously.
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