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Inflammation
DR .HALA BADAWI
LECTURER OF PATHOLOGY
INFLAMMATION
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DEFINITION:
Inflammation is the reaction of vascularized living
tissue to local injury. It is a series of vascular and
cellular reactions aiming to protect the body against
the injurious agent .
TYPES:
-Acute: sudden onset and short duration ( hours days)
-Chronic: gradual onset and long duration ( days years)
INFLAMMATION
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CAUSES:
Living irritants
Bacteria, viruses, parasites and fungi
Non-living irritants
Physical, chemical and mechanical
Antigens
ACUTE INFLAMMATION
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Caused by an irritant of short duration of
action
The tissue response is rapid i.e. sudden onset
Inflammation lasts for days or weeks
Characterized by presence of fluid exudate
and cellular exudate mainly polymorphnuclear leucocytes
CARDINAL SIGNS AND SYMPTOMS OF
ACUTE INFLAMMATION
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REDNESS
HOTNESS
SWELLING
PAIN
LOSS OF
FUNCTION
Major events in inflammation
Vascular events
•Vasodilatation of arterioles
and capillaries
•Increased blood flow
•Slowing of blood stream
•Increased capillary
permeability
Formation of
Inflammatory
Fluid exudate
Cellular events
• Margination of leucocytes
• Emigration of leucocytes
• Emigration of monocytes
• Chemotaxis:
(directed movement towards
area of inflammation)
• Phagocytosis:
(engulfment of bacteria and
necrotic tissue)
Vascular Events
in inflammation
•Vasodilatation of arterioles
and capillaries
•Increased blood flow
•Slowing of blood stream
•Increased capillary
permeability
Cellular Events in inflammation
• Margination , Emigration of neutrophils & monocytes
• Chemotaxis & phagocytosis
Phagocytosis,
Killing &
degradation
Chemical Mediator of Inflammation
CHEMICAL MEDIATORS
ACTIONS
Bind to specific receptors on the cells
Histamine
Vasodilatation
Prostaglandins
C3a & C5a
Increase vascular permeability
Histamine, kinins, leukotriens
Chemotaxis
Leukotriens & lysosomal components
The Inflammatory Fluid Exudate
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Function:
It dilutes bacterial toxins and chemical irritants.
It brings antibodies to the area of inflammation.
It brings the chemical mediators derived from plasma to the
area.
It contains fibrinogen which changes to fibrin by activation
of clotting system. Fibrin helps in localization of
inflammation by surrounding the area .
Fate:
Fluid exudate is absorbed by lymphatics.
Fate of Acute inflammation
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Complete resolution
Healing by scarring
Progression and spread:
(direct, lymphatic & blood spread)
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Chronicity
TYPES OF ACUTE INFLAMMATION
SUPPURATIVE
INFLAMMATION
NON-SUPPURATIVE
INFLAMMATION
I- SUPPURATIVE INFLAMMATION
Types:
II- Diffuse Supp. Inflamm.
I-Localized
Supp. Inflamm.
Abscess,
furuncle,
carbuncle
Cellulitis,
Suppurative appendicitis,
Suppurative cholecystitis,
Suppurative peritonitis,
Suppurative meningitis
…etc.
I- LOCALIZED SUPPURATIVE INFLAMMATION
Abscess
furuncle
carbuncle
Abscess
Definition:
 Cavity containing
pus
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(pus is formed of
fluid exudate,
fibrin,pus cells,
polymprph,
macrophages,
necrotic tissue and
bacteria)
Abscess
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Fate of abscess:
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Small abscess:
Pus may be absorbed followed by healing
Large abscess:
Should be evacuated, spontaneous or surgical
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Abscess
Complication of abscess:
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Ulcer (local defect on
the surface)
Sinus (blind end tract)
& Fistula (tract with
two openings)
Hemorrhage &
gangrene
Spread of infection
Ulcer
Sinus
Gangrene
II- DIFFUSE SUPPURATIVE INFLAMMATION
Acute supp. appendicitis
Diffuse sup.cholecystitis
Suppurative meningitis
Cellulitis
Cellulitis
NON-SUPPURATIVE INFLAMMATION
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Catarrhal inflammation: e.g.common cold
Pseudo-membranous inflam.: e.g.diphtheria
Fibrinous inflammation: e.g. fibrinous pericarditis,
fibrinous pleurisy, fibrinous peritonitis.
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Serous inflammation: e.g. burns
Haemorrhagic inflammation
Gangrenous (necrotizing) inflammation
Allergic inflammation
NON-SUPPURATIVE INFLAMMATION
Fibrinous pleurisy
Gangrenous inflammation
Fibrinous
pericarditis
Haemorhagic
pericarditis.
Fibrinous
pericarditis
Fibrinous peritonitis
CHRONIC INFLAMMATION
Characterized by:
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Mild irritant with a prolonged action
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Tissue response is gradual and prolonged
(mild vascular dilatation and congestion)
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Tissue destruction is progressive and
gradually replaced by fibrous tissue with
thickening and narrowing of blood vessels
(endarteritis obliterans)
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Scanty fluid exudate
Chronic Inflammatory Cellular
Exudate
Composed of:
 Lymphocytes
 Plasma cells
 Macrophages
 Giant cells
 Esinophils in parasitic and allergic
inflammation.
Types of Chronic Inflammation
1- Chronic non-specific inflammation
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Different irritants produce inflammatory
reaction of the same microscopic picture
2- Chronic specific inflammation
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Each irritant produces inflammation of a
characteristic microscopic picture
Chronic non-specific
inflammation
Granuloma
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Definition:
A type of chronic inflammation
characterized by focal accumulation of large
number of macrophages together with
lymphocytes, plasma cells, giant cells and
fibroblasts forming tiny granules
Types of Granulomas
1-Infective granuloma
 a. Bacterial e.g.TB, leprosy & syphilis
 b. Parasitic e.g. Bilharziasis
 c. Fungal e.g. madura foot
2-Non-infective granuloma
 a. Silicosis and asbestosis
 b. Foreign body granuloma
3-Granuloma of unknown cause
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Sarcoidosis
Tuberculous granuloma
of the lung
Granuloma