WEEK 5 infl--6.pptx

8/10/2019 WEEK 5 infl--6.pptx

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CHRONIC INFLAMMATION


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Chronic Inflammation

An immune reaction to "mild" but

persistent antigen producing a

proliferation of lymphocytes and plasma

cells.

There is usually no pain, redness,

swelling, or warmth. Scarr ing and persistence of et io logic

agent is common .


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Causes of chronic inflammation Prolonged exposure to non-degradable:

Partially toxic substances are either endogenous lipidcomponents which result in atherosclerosis or

exogenoussubstances such as silica, asbestos.

Progression from acute inflammation:

Persistent suppuration is result from un-collapsed

abscess cavities, foreign body materials (dirt, cloth,

wool, etc), sequesterum in osteomylitis, or a

sinus/fistulafrom chronic abscesses.

Autoimmuniy:

Autoimmune diseases such as rheumatoid arthritis and

systemic lupus erythematosis are chronic

inflammations


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Chronic Inflammation

Time course:

Greater than 48 hours (weeks, months, years)

Cell type

Mononuclear cells (Primarily Macrophages,

Lymphocytes, Plasma cells), giant cells &fibroblast.

Chronic inflammation classified into:

Diffuse

Focal (granuloma)

Other cells in chronic inflammation:

Lymphocytes: Plasma cells: Eosinophils:


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Cells of chronic inflammation

(1) Monocytes and Macrophages

Monocytes and Macrophages are the prima Dona

(primary cells) in chronic inflammation.

Macrophages are phagocytic Cs, derived from

circulating blood monocytes or tissue histocyte).

Macrophagesarise from the common precursor cells in

the bone marrow, which give rise to blood monocytes.

These cells are then diffusely scattered in various parts

of the body, in the liver (Kupffer cells), spleen, lymph

nodes (sinus histiocytes), lungs (alveolar macrophages),

brain (microglia), skin (Langerhanscells), etc.

Macrophages are scavenger cells of the body.

(2) i


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(2) giant cell Inflammatory giant cells are

multinucleated cells that result from:

1- The fusion of macrophages.

2-Giant cells may form by mitotic

division of the macrophages nuclei

without division of the cytoplasm. i -Langhansgiant cell type: it is large

cells with multiple nuclei (arranged

peripherally). It is situated specially

in tuberculous lesions.

ii- Foreign body giant cell type:

large cells with multiple nuclei are

placed centrally or scattered in thec to lasm as F.B ranulomas


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(3) Other cells in chronic inflammation

1. T-Lymphocytes are primarily involved in cellular

immunity with lymphokine production, and they arethe key regulator and effector cells of the immune

system.

2. B-lymphocytes and Plasma cells produce antibody

directed either against persistent antigen in the

inflammatory site or against altered tissue components.

3.Mast cells and eosinophils appear predominantly in

response to parasitic infestations & allergic reactions.

4. Fibroblast is cell of connective tissue origin synthesis

the collagen fibers in case of fibrosis or cirrhosis


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Classification of chronic inflammation

Chronic inflammation can be classified into the following

two types based on histologic features:

1) Non specific chronic inflammation:

This involves a diffuse accumulation of macrophages and

lymphocytesat site of injury that is usually productive withnew fibrous tissue formations. E.g. Chronic cholecystitis.

2) Specific inflammation (granulomatous inflammation):.

Granulomatous inflammation is characterized by the

presence of granuloma. A granuloma is a microscopic

aggregate of epithelioid cells.


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1- non specific chronic inflammation Different irritants can produce inflammatory

reactions of the same microscopic picture. So

etiology cantbe identified from reaction. Follows acute inflammation e.g. chronic abscess

Gross

Decrease of organ size

Pale in color .Hard inconsistency

Microscopic picture

Lymphocytes, plasma cells, and macrophagesinfiltration

Proliferation of fibroblasts collagen fibers

Thickening of blood vessels wall

Tissue necrosis

Complications of Chronic Inflammation Fibrosis and scarrin .Persistence of etiolo ic


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2- Specific inflammation

(granulomatous inflammation)

Foreign body Tuberculosis (Tb)

Fungal infections

Schitosomiasis

Granulomas

Each irritant produces a specific inflammatory reaction& so etiologycan be identified from reaction e.g.

tuberculosis, bilharziasis


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Granulomatous Inflammation

Factors necessary for granuloma formation:

Presence of indigestible organisms or particles(T.B, mineral oil, etc)

Cell mediated immunity (T cells)

Microscopic Features of granulomatousinflammation

Lymphocytes

Fibroblasts

Collagen

Macrophages

Plasma cells, giant cells, eosinophils


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Foreign Body Granuloma Tuberculosis (Tubercle)


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WEEK 5 infl--6.pptx

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