pattern of inflammation

Pathology

Pattern of inflammmation

muhammad koksh sidiqB.Sc. In pharmacy

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Inflammation

• Inflammation is defined as the physiological response of living tissue to injury

• Inflammation is the body's attempt at self-protection; the aim being to remove harmful stimuli, including damaged cells, irritants, or pathogens - and begin the healing process.

• Inflammation does not mean infection, even when an infection causes inflammation. Infection is caused by a bacterium, virus or fungus, while inflammation is the body's response to it.

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Types of inflammation

1. Acute inflammation.

2. Chronic inflammation.

Inflammation is divided into acute inflammation, which occurs over seconds, minutes, hours, and days, and chronic inflammation, which occurs over longer times.

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• Acute inflammation - starts rapidly (rapid onset) and quickly becomes severe. Signs and symptoms are only present for a few days, but in some cases may persist for a few weeks.

• Chronic inflammation - this means long-term inflammation, which can last for several months and even years. It can result from:Failure to eliminate whatever was causing an acute inflammation

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Morphologic Patterns of

Inflammation (exudate)

• Serous Inflammation

• Fibrinous Inflammation

• Suppurative Inflammation

• Ulceration

• pseudomembranous inflammation

• Catarrhal inflammation

• Granulomatous inflammation

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Patterns of inflammation

• 1. Serous inflammation

• abundant watery effusion of fluid (exudate).

• This is characterized by outpouring of thin fluid that is either derived from the blood (serum) or secretions of serous mesothelialcells of pleura, peritoneum, and pericardium or joints spaces. Serous inflammation is seen for example in tuberculous pleurisy.

• Examples: peritonitis, pericarditis, pleuritis, skin burn, viral infections.

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Serous pleural inflammation

Excessive accumulation of clear, thin fluid within pleural cavity. It is

transparent but note the reflection of light in the upper part of the

photograph and lung collapse due to pressure induced by the fluid. 7

BLISTER, “Watery”, i.e., SEROUS8

2. Fibrinous inflammation In this type there is exudation of large amounts of plasma

proteins including fibrinogen with subsequent precipitation of masses of fibrin e.g. in rheumatic pericarditis the pericardial space may become filled with large masses of fibrin; when the epicardium is stripped from the pericardium, the rubbery adherent fibrin coats both surfaces and simulating the appearance of bread & butter . Organization of fibrinous exudates by formation of fibroblasts & capillaries obliterate the cavity. Alternatively there is fibrinolysis & resolution.

Example: trauma, bacterial infections.

may lead to fibrous adhesions. Example: restrictive pericarditis, fibrous adhesion in the peritoneum.

fibrinolysis resolution; organization fibrosis scar

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Fibrinous exudate-pericardium (G)

there is a lot of fibrin

the visceral and parietal

surfaces become stuck

together (by fibrin).

Separation of the two layers

imparts rough irregular

appearance (the so called

bread and butter).

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FIBRINOUS

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3. Suppurative inflammation:

• This is characterized by the production of large amounts of pus or purulent exudates.

• pus accumulation (neutrophils, exudate fluid and cellular debris)

• Staphylococci produce localized suppuration. In suppurative appendicitis, there is pus within the lumen with an intense infiltration of polymorph neutrophils that are present in the mucosa, submucosa, muscularis & serosa.

• Abscess is a localized collection of pus caused by suppurative inflammation.

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Abscess

Furuncle

(boil)

Abscess that involves

the skin is called “Boil”

or “furuncle”.

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PUS

=

PURULENT

ABSCESS

=

POCKET

OF

PUS

=

NEUTROPHILS15

PURULENT, FIBRINOPURULENT16

4.Ulcer

• it is loss in the continuity of an epithelial surface of the skin, the lining of a viscous organ or tissue (gastrointestinal, respiratory or genitor-urinary tracts), which is produced by sloughing of inflammatory necrotic tissue.

• Ulcer can be acute or chronic.

• Peptic ulcer is a typical example.

• Ulcer may result from physical or chemical injury, or ischemic necrosis.

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Ulceration, larynx, gross

Below the vocal cords in this

larynx are large ulcerations.

Such subglottic ulcers are

produced with prolonged

endotracheal intubation in

which the cuff of the

endotracheal tube fits too

tight. Thus, ulcerations can

be produce by mechanical

forces. In fact, so-called

"pressure ulcers" or

"decubitus ulcers" can form

in the skin over bony

prominences in persons who

are bedridden for an

extended time. 18

ULCERATIVE 19

Appendix: acute suppurative inflammation

ulceration and undermining

by an extensive neutrophilic

exudate

Upper half of excised appendix.

Lt: fibrino-purulent serosal

exudate

Rt: lumen filled with pus

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5. pseudomembranous inflammation

is characterized by the formation of a pseudomembrane,which is usually made up of precipitated fibrin, necrotic epithelium & together with polymorphs, red cells; bacteria produce a false membrane over the inflamed surfaces. This occurs when the inflammation is so severe as to cause epithelial necrosis. An example of this pattern is seen with Diphtheria affecting the larynx & pharynx. It may also affect the large bowel causing pseudomembranous colitis . The latter is caused by Clostridium difficile or Staph. aureus infections.

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Pseudomembranous inflammation

of mucous membranes

• Severe injury extensive epithelial necrosis

large shallow ulcers sloughing

• Fibrin, dead epithelium, neutrophils, red cells

and bacteria mix together false (pseudo-)

membrane (white or cream-colored layer)

• Diphtheria and psudomembranous colitis are

typical examples

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pseudomembrane

Pseudomembranous entercolitis (G)

This yellow-green exudate on the surface of an inflamed, hyperemic

(erythematous) bowel mucosa consists of many neutrophils along with

fibrin and amorphous debris from dying cells.23

6. Catarrhal inflammation:

• This is a mild inflammation of mucosal membranes as is seen in common cold, bacillary dysentery, and food poisoning

• most frequently seen in the respiratory tract, but may occur in any mucous membrane, and is characterized by hyperemia of the mucosal vessels, edema of the interstitial tissue, enlargement of the secretory epithelial cells , as exudation progresses, variable numbers of neutrophils migrate into the affected tissue and are included in the exudate, along with fragments of degenerated and necrotic epithelial cells; such an inflammation may frequently become muco purulent.

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Granulomatous inflammation

• distinctive chronic inflammation type

• cell mediated immune reaction (delayed)

• aggregates of activated macrophages epithelioid cell multinucleated giant cells (of Langhans type x of foreign body type)

• NO agent elimination but walling off

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Granulomatous inflammation

• 1. Bacteria– leprosy

– syphilis

• 2. Parasites + Fungi

• 3. Inorganic metals or dust– silicosis

• 4. Foreign body

- talc powder

• 5. Unknown - sarcoidosis

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Diagram of typical TB granuloma

Caseation

Epithelioid cells

Multinucleated GC

Lymphocytes

fibroblasts

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TB granulomas lung

This is a low power view

showing two, adjacent,

well-defined, rounded

granulomas . From this

power the presence of

multinucleated giant cells

is obvious (arrow).

This is a high power view

showing a portion of

typical TB granuloma.

Note the amorphous,

pinkish central caseation,

which is surrounded by a

rim of epithelioid cells.

caseation

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Langhan’s Vs FB giant cells

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Thank you

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