DR SHWE SIN

M.Med.Sc

FMHS

OVERVIEW OF INFLAMMATION INFLAMMATION : is a protective response involving host cells, blood vessels, and proteins and other mediators that is intended to eliminate the initial cause of cell injury as well as the necrotic cells and tissues resulting from the original insult and to initiate the process of repair.

PURPOSE OF INFLAMMATION To bring phagocytic cells to the injured area

to engulf invading bacteria

To bring in factors from the serum to neutralize the infectious agents

To serve to destroy, dilute, wall of the injurious agent and tissue cells that it may have destroyed

Although inflammation clear infections, noxious stimuli & initiate repair cause harm (capable of injuring normal tissue)

Inflammation is induced by chemical mediators in response to injurious stimuli that are produced by host cells

The main components are vascular reaction and cellular response

CLASSIFICATION OF INFLAMMATION I. Based on duration: i) Acute inflammation ii) Chronic inflammation II. Based on characteristic of exudates: i) Serous inflammation ii) Fibrinous inflammation iii) Suppurative or Purulent inflammation iv) Haemorrhagic inflammation v) Mixed III. Based on location: i) Abscess ii) Ulcer iii) Membranous inflammation iv) Catarrhal inflammation v) Cellulitis

Features of Acute and Chronic Inflammation***

Feature Acute Chronic

Onset Fast: minutes or hour Slow: days

Cellular infiltrate Mainly neutrophils Monocytes/ macrophages & lymphocytes

Tissue injury, Fibrosis Usually mild and self-limited

Often severe and progressive

Local & Systemic signs Prominent Less prominent; may be subtle

Local Cardinal Signs of Inflammation

Heat (calor)

Redness (rubor)

Swelling (tumor)

Pain (dolor)

Loss of function (functio laesa)

CHEMICAL MEDIATORS

May be produced by cells or may be circulating in the plasma.

Cell-derived mediators are sequestered in intracellular granules (histamine, prostaglandins and cytokines)

Plasma-protein-derived mediators (complement proteins and kinins)

Cell-Derived Mediators 1. Vasoactive amines

2. AA metabolites

3. Platelet activating factors

4. Cytokines

5. Chemokines

6. Reactive oxygen species

7. Nitric oxide

8. Lysosomal Enzymes of Leukocytes

9. Neuropeptides

Plasma Protein-Derived Mediators

1. Complements

2. Coagulation and Kinin System

General Principles of Chemical Mediators * Mediators originate either from plasma

or cells

* Most mediators perform their biologic

activity by initially to binding to

specific receptors on target cells

* A chemical mediator can stimulate the

release of mediators by target cells

themselves

* Mediators can act on one or few target

cell types

* Once activated and released from the

cell, most of these mediators are short-

lived

* Most mediators have the potential to

cause harmful effects

Systemic Effects of

Inflammation I. Acute Phase Response

i) Fever (Prostaglandin PG)

ii) Elevated levels of acute-phase

proteins (C-reactive protein CRP,

fibrinogen and serum amyloid A (SAA)

iii) Leucocytosis (rise in number of

immature neutrophils in the blood (shift

to left)

II. In Chronic Inflammation:

i) Disseminated intravascular

coagulation (DIC)

ii) Hypoglycemia

iii) Hypotensive shock

REFERENCE Robbins Basic Pathology, 8th Edition

Robbins Basic Pathology, 9th Edition