Inflammation is the body's response to harmful stimuli and involves increased blood flow, swelling, heat, redness, and pain. The goals of inflammation are to eliminate the initial cause, remove damaged cells, and initiate tissue repair. The cardinal signs of inflammation come from Latin and include pain, heat, redness, swelling, and loss of function. Acute inflammation lasts less than 48 hours and involves neutrophils, while chronic inflammation lasts longer and involves mononuclear cells. Acute inflammation may resolve, progress to chronic, lead to abscess formation, or result in tissue repair through scarring.

1. INFLAMMATION
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2.  Inflammation is part of the complex biological
response of body tissues to harmful stimuli,
such as pathogens, damaged cells or irritants
 The function of inflammation is to eliminate the
initial cause of cell injury, clear out necrotic
cells and tissues damaged from the original
insult and the inflammatory process, and
initiate tissue repair.
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3. Cardinal signs
 The traditional names for signs of inflammation
come from Latin:
 Dolor (pain)
 Calor (heat)
 Rubor (redness)
 Tumor (swelling)
 Functio laesa (loss of function)
 Redness and heat are due to increased blood
flow at body core temperature to the inflamed
site
 Swelling is caused by accumulation of fluid
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4. Stimuli for Acute Inflammation
• Infections (bacterial, viral, fungal, parasitic) &
microbial toxins
• Tissue necrosis: ischemia, trauma, physical
or
chemical injury (e.g., thermal injury;
irradiation; some environmental chemicals)
• Foreign bodies (splinters, dirt, sutures)
• Immune reactions (aka hypersensitivity
reactions)
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5. Acute inflammation
 Main components:
– Vascular changes
• Vasodilation
• Vascular permeability
• Increased adhesion of white blood cells
– Cellular events
• Cellular recruitment and activation of
neutrophils (polymorphonuclear
leukocytes)
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6. Aetiology
 Microbial infections: bacterial, viral, fungal,
etc.
 Physical agents: burns, trauma--like cuts,
radiation
 Chemicals: drugs, toxins, or caustic
substances like battery acid.
 Immunologic reactions: rheumatoid
arthritis.
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8. Acute inflammation
 Time course
 Acute inflammation: Less than 48 hours
 Chronic inflammation: Greater than 48 hours
(weeks, months, years)
 Cell type
 Acute inflammation: Neutrophils
 Chronic inflammation: Mononuclear cells
(Macrophages, Lymphocytes, Plasma cells)
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9. Mechanism of Inflammation
1. Vasodilatation
2. Exudation - Edema
3. Emigration of cells
4. Chemotaxis
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10. Mechanism of Inflammation
 The major local
manifestations of acute
inflammation
(1) Vascular dilation and
increased blood flow
(causing erythema and
warmth).
(2) Extravasation and
deposition of plasma fluid
and proteins (oedema).
(3) Leukocyte emigration and
accumulation in the site of
injury.
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11. Changes in vascular flow
(hemodynamic changes)
 Slowing of the circulation
 outpouring of albumin rich fluid into the
extravascular tissues results in the
concentration of RBCs in small vessels and
increased viscosity of blood.
 Leukocyte margination
 Neutrophils become oriented at the periphery
of vessels and start to stick.
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12.  An ultrafiltrate of
blood plasma
 permeability of
endothelium is
usually normal.
 low protein content
( mostly albumin)
 A filtrate of blood
plasma mixed with
inflammatory cells
and cellular debris.
 permeability of
endothelium is
usually altered
 high protein
content.
Transudate Exudate
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Pus:
A purulent exudate: an inflammatory exudate rich in
leukocytes (mostly neutrophils) and parenchymal cell
debris.

13. Leukocyte exudation
 Divided into 4 steps
 Margination, rolling, and adhesion to
endothelium
 Diapedesis (trans-migration across the
endothelium)
 Migration toward a chemotactic stimuli from the
source of tissue injury
 Phagocytosis
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15. Chemical Mediators
Chemical substances synthesised or released and
mediate the changes in inflammation.
 Histamine by mast cells - vasodilatation
 Prostaglandins - Cause pain & fever
 Bradykinin - Causes pain
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16. Acute inflammation has one of four
outcomes:
 Abscess formation
 Progression to chronic inflammation
 Resolution- tissue goes back to normal
 Repair- healing by scarring or fibrosis
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17. Abscess formation
 "A localised collection of pus (suppurative
inflammation) appearing in an acute or chronic
infection, and associated with tissue destruction,
and swelling.
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18. Carbuncle
 It is an extensive form of abscess in which pus is
present in multiple loci and opens at the surface
by sinuses.
 Occurs in the back of the neck and the scalp.
 Furuncle or boil
 It is a small abscess related to hair follicles or
sebaceous glands
 Could be multiple furunclosis
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20. Cellulitis
 It is an acute diffuse suppurative inflammation
caused by streptococci, which secrete
hyaluronidase & streptokinase enzymes that
dissolve the ground substances and facilitate the
spread of infection.
 Sites:
 Areolar tissue: orbit, pelvis, etc
 Lax subcutaneous tissue
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22. Examples of disorders
associated with inflammation
 Acne vulgaris
 Asthma
 Autoimmune diseases
 Autoinflammatory diseases
 Celiac disease
 Chronic prostatitis
 Colitis
 Diverticulitis
 Glomerulonephritis
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23. Examples of disorders
associated with inflammation
 Hypersensitivities
 Inflammatory bowel diseases
 Otitis
 Pelvic inflammatory disease
 Rheumatic fever
 Rheumatoid arthritis
 Rhinitis
 Sarcoidosis
 Transplant rejection
 Vasculitis
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Acute dermatitis
Acute tonsillitis
Scars present on the skin, evidence of fibrosis and healing of a wound