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What is inflammation?

Inflammation

Inflammation is a complex reaction in tissues that

consists mainly of responses of blood vessels and

leukocytes

Protectiveresponse intended to eliminate the initial

cause of cell injury and the necrotic cells and tissues

arising from the injury

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Egyptian papyrus - 3000 B.C.

Celsus(Roman in 1st century A.D.)

Rubor - Tumor - Calor - Dolor

redness - swelling - heatpain

Rudolf Virchowadded loss of function later

Elie Metchnikoff -Phagocytosis

History

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Acute

Rapid in onset, lasting for min/hrs/days

Exudation of fluid and plasma proteins (edema)

Emigration of leukocytes predominantly

neutrophils

Chronic

Longer duration Lymphocytes and macrophages

Proliferation of blood vessels, fibrosis and tissue

necrosis

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Etiologies

Microbial infections: bacterial, viral, fungal,parasiticetc.-Toll like receptors

Physical agents: burns, trauma--like cuts, radiation

Chemicals: drugs, toxins, or caustic substances likebattery acids

Immunologic reactions: rheumatoid arthritis

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Microbial infections

One of the commonest causes of inflammation

Bacteria release specific exotoxins or endotoxins

In parasitic infections hypersensitivity plays an

important role

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Physical agents

Tissue damage leading to inflammation may occurthrough physical trauma, ultraviolet or other ionizingradiation, burns or excessive cooling

Irritant and corrosive chemicals

Corrosive chemicals (acids, alkalis, oxidizing agents)provoke inflammation through tissue damage

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Five classic local signs of acute

inflammation

Heat

Redness

Swelling

Pain

Loss of function

Calorvasodilatation

Ruborvasodilatation

Tumorvascular permeability

Dolormediator release

Functio laesa

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Components of Inflammation

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Acute inflammation is a rapid response to an injuriousagent that serves to deliver mediators of host defense-leukocytes and plasma proteins- to the site of injury

Alterations in vascular caliber

Structural changes in microvasculature

Emigration and activation of leukocytes

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Vascular changes

Transient vasoconstriction

Vasodilation

Exudation of protein rich fluid

Blood stasis

Margination

Transmigration

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LeukocyteAdhesionTransmigration

ChemotaxisPhagocytosis

Termination

Stasis

Vascular

permeability

Vasodilatation

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Vasodilation Earliest manifestation

First involves arterioles

Important mediators- Histamine and NO

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Histamine

Causes dilatation of arterioles first Increases the permeability of the venules

Principal mediator of the immediate transient phase

of increased vascular permeability, causing venulargaps

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Swelling (tumor)

Swelling result from edema, the accumulation of

fluid(exudate) in the extra vascular space

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Exudate Transudate

vascular permeability

High protein & cell

debris

Specific gravity >

1.020

Normal vascularpermeability

Low protein (mostly

albumin) Specific gravity