2. DEFINITION
• Chronic inflammation is defined as prolonged
process in which tissue destruction and
inflammation occur at the same time.
INFLAMMATION
TISSUE DESTRUCTION
CHRONIC INFLAMMATION
3. CAUSES:
• May occur by one of the following 3 ways:
1. Chronic inflammation following acute
inflammation.
2. Recurrent attacks of acute inflammation.
3. Chronic inflammation starting de novo.
6. 2. Recurrent attacks of Acute Inflammation:
Repeated bouts/Attacks of Acute Inflammation
Chronicity of the process
CHRONIC INFLAMMATION
7. E.g: Recurrent Urinary Tract Infection leading to
Chronic Pyelonephritis
Recurrent Urinary Tract Infection/Pyelonephritis Chronic Pyelonephritis
8. 3. Chronic inflammation starting de novo.
ORGANISMS OF LOW PATHOGENICITY
Eg: Mycobacterium tuberculosis
CHRONIC INFLAMMATION STARTING DE NOVO
9. GENERAL FEATURES OF CHRONIC INFLAMMATION
• Following general features characterise any chronic
inflammation:
CHRONIC
INFLAMMATION
1.MONONUCLEAR
INFILTRATION.
2.TISSUE
DESTRUCTION
OR
NECROSIS
3. PROLIFERATIVE
CHANGES
10. TYPES OF CHRONIC INFLAMMATION:
Chronic inflammation is subdivided into 2 types:
1. Chronic Non-Specific Inflammation
2. Chronic Granulomatous Inflammation
11. 1. Chronic Non-Specific Inflammation
• When the irritant substance produces a non-
specific chronic inflammatory reaction with
formation of granulation tissue and healing by
fibrosis, it is called chronic non-specific
inflammation.
E.g. Chronic Osteomyelitis, Chronic Ulcer,
Lung Abscess
12. 2. Chronic Granulomatous Inflammation
• In this, the injurious agent causes a
characteristic histologic tissue response by
formation of granulomas e.g. tuberculosis,
leprosy, syphilis, actinomycosis, sarcoidosis
etc.
13. GRANULOMATOUS INFLAMMATION
Definition:
• Granuloma is defined as a circumscribed, tiny
lesion, about 1 mm in diameter, composed
predominantly of collection of modified
macrophages called epithelioid cells, and
rimmed at the periphery by lymphoid cells.
14.
15. PATHOGENESIS OF GRANULOMA:
Persistence of the poorly digestible antigen e.g.
Mycobacterium tuberculosis, M. leprae.
TYPE IV GRANULOMATOUS HYPERSENSITIVITY REACTION
Formation of Granuloma
16. Sequence in evolution of Granuloma:
Antigen engulfment by Macrophages
Since antigen is poorly degradable
Macrophages present antigen to CD4+T lymphocytes
Activated lymphocytes release lymphokines.
IL-1, IL-2, Interferon-γ TNF-α
PROLIFERATION OF
MORE T CELLS ACTIVATES MACROPHAGES FIBROBLAST PROLIFERATION
ACTIVATED MACROPHAGES TRANSFORM TO
EPITHELIOID CELLS, -> MULTINUCLEATED GAINT CELLS
17. • Thus, a granuloma is formed having:
Macrophages modified as epithelioid cells
in the centre.
With some interspersed multinucleate giant
cells.
Surrounded peripherally by lymphocytes
(mainly T cells).
Healing by fibroblasts or collagen
depending upon the age of granuloma.