2. Chronic Inflammation
Chronic inflammation is inflammation of
prolonged duration (weeks to years) in which
continuing inflammation, tissue destruction, and
healing (often by fibrosis), proceed
simultaneously
3. Chronic Inflammation
May follow acute inflammation
eg. Pneumonia chronic lung abscess
Repeated bouts of acute inflammation
eg. cholecystitis , pyelonephritis
Begin insidiously as a low grade smoldering
response - Tuberculosis
4. Causes
Persistent infections by microbes that are difficult to
eradicate.
Mycobacterium tuberculosis
Treponema pallidum
Immune-mediated inflammatory diseases
Autoimmune diseases rheumatoid arthritis,
inflammatory bowel disease, and psoriasis
Allergic diseases, such as bronchial asthma
Prolonged exposure to potentially toxic agents.
Silicosis (silica)
5. General Features of Chronic
Inflammation
Mononuclear Cell Infiltration
Macrophages, Lymphocytes and Plasma cells
Tissue destruction or necrosis
Proliferative Changes
Attempts at healing by connective tissue replacement of
damaged tissue – angiogenesis (proliferation of small
blood vessels) and by fibrosis
10. Chronic granulomatous
inflammation
GRANULOMA
Form of chronic inflammation characterised by
collections of activated macrophages, T-
lymphocytes and sometimes associated with
central necrosis
Cellular attempt to contain an offending agent
that is difficult to eliminate
11. Chronic granulomatous
inflammation
Strong macrophage and lymphocyte activation – injure
normal tissues
EPITHELIOID CELLS – Activated macrophages develop
abundant cytoplasm and resemble epithelial cells
Some activated macrophages fuse forming multinucleate
GIANT CELLS
Older granulomas develop an enclosing rim of
FIBROBLASTS AND CONNECTIVE TISSUE
12. Giant cells
40 to 50 µ in diameter
abundant cytoplasm
Langhans‘ giant cell
20 or more nuclei in periphery
( horse shoe pattern)
Foreign body giant cell
nuclei scattered in cytoplasm
13. EPITHELIOID CELLS
Activated macrophages with epithelial – cell like
appearance
Cells with indistinct cell boundaries
Abundant pale staining granular cytoplasm
Elongated/ oval, slipper shaped nuclei
14. CASEOUS NECROSIS
Grossly
This has a granular, cheesy appearance
Microscopically
Appears as amorphous, structureless, granular
debris, with complete loss of cellular details
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20. Macroscopic appearance
Fibrosis - The most prominent feature of the chronic
inflammatory reaction when most of the chronic inflammatory
cell infiltrate has subsided. This is commonly seen in chronic
cholecystitis
'Hour-glass contracture' of the stomach - lead to acquired
pyloric stenosis
Strictures - as in Crohn's disease