Chronic inflammation is inflammation that lasts for weeks or months, where inflammation, tissue damage, and attempts at repair occur simultaneously. It can be caused by persistent infections, autoimmune diseases, or prolonged exposure to toxic agents. Chronic inflammation is characterized by infiltration of mononuclear cells like macrophages, lymphocytes, and plasma cells. It also involves ongoing tissue destruction and attempts at healing through fibrosis and new blood vessel formation. Macrophages and lymphocytes play major roles, and granulomatous inflammation forms distinctive clusters of immune cells around certain infectious agents or foreign materials.

1. CHRONIC INFLAMMATION
DR PREETI AGRAWAL

2. DEFINITION
Chronic inflammation is inflammation of
prolonged duration (weeks or months) in which
inflammation, tissue injury, and attempts at
repair coexist, in varying combinations.

3. CAUSES OF CHRONIC INFLAMMATION
• Persistent infections by microorganisms that are
difficult to eradicate, such as mycobacteria, and
certain viruses, fungi, and parasites.
• Immune-mediated inflammatory diseases -
autoimmune diseases
• Prolonged exposure to potentially toxic agents,
either exogenous or endogenous.egs. silicosis ,
Atherosclerosis

4. MORPHOLOGIC FEATURES
chronic inflammation is characterized by:
• Infiltration with mononuclear cells, which include
macrophages, lymphocytes, and plasma cells
• Tissue destruction, induced by the persistent
offending agent or by the inflammatory cells
• Attempts at healing by connective tissue
replacement of damaged tissue, accomplished by
proliferation of small blood vessels (angiogenesis)
and, in particular, fibrosis

6. ROLE OF MACROPHAGES IN CHRONIC INFLAMMATION

7. OTHER CELLS IN CHRONIC INFLAMMATION-
• Lymphocytes
• Plasma cells
• Eosinophils
• Mast cells
• Giant cells

8. GRANULOMATOUS INFLAMMATION
Granulomatous inflammation is a distinctive pattern
of chronic inflammation that is encountered in a
limited number of infectious and some noninfectious
conditions.

9. Disease Cause Tissue Reaction
Tuberculosis Mycobacterium tuberculosis Caseating granuloma (tuberc
focus of activated macropha
(epithelioid cells), rimmed by
fibroblasts, lymphocytes,
histiocytes, occasional Langh
giant cells; central necrosis w
amorphous granular debris;
fast bacilli
Leprosy Mycobacterium leprae Acid-fast bacilli in macrophag
noncaseating granulomas
Syphilis Treponema pallidum Gumma: microscopic to gros
visible lesion, enclosing wall
histiocytes; plasma cell infiltr
central cells necrotic without
of cellular outline
Cat-scratch disease Gram-negative bacillus Rounded or stellate granulom
containing central granular d
and recognizable neutrophils
giant cells uncommon
Sarcoidosis Unknown etiology Noncaseating granulomas wi
abundant activated macroph
Crohn disease (inflammatory
bowel disease)
Immune reaction against
intestinal bacteria, self-antigens
Occasional noncaseating
granulomas in the wall of the

10. A granuloma is a focus of chronic inflammation
consisting of a microscopic aggregation of
macrophages that are transformed into epithelium-
like cells, surrounded by a collar of mononuclear
leukocytes, principally lymphocytes and occasionally
plasma cells

11. Epithelioid cells fuse to form giant cells in the periphery or
sometimes in the center of granulomas. These giant cells may
attain diameters of 40 to 50 μm. They have a large mass of
cytoplasm containing 20 or more small nuclei arranged either
peripherally (Langhans-type giant cell) or haphazardly (foreign
body–type giant cell). There is no known functional difference
between these two types of giant cells