Gangrene
Presented by
Salma Ahmed Walid Anwar Morad
Supervision by
Dr/ Sara Nabil
Pathology Department
First Year
Fourth Module
2019-2020
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Gangrene
Gangrene
Definition: A form of tissue necrosis with superadded putrefaction.
Causes:
1 - Necrosis is due to: a - Acute ischemia
b - Bacterial infection
c- Traumatic injuries e.g., gunshot wounds or crushing injuries
2 - Putrefaction is due to saprophytic bacteria with increased activity in necrotic
tissue. They digest necrotic tissue liberating hydrogen sulphide (H2S) which gives
tissue an odor. Hydrogen sulphide PLUS iron of Haemoglobin produced iron sulphide
which stain the gangrenous tissue black.
Types of gangrene: according to the amount of blood & tissue fluids (nutritive to
saprophytic bacteria) in the affected part.
1 - Dry gangrene
Site
Mechanism
Cause
Putrefaction
Macroscopic picture
Line of demarcation
Line of separation
Self-amputation
Spread
Toxemia
Prognosis
Exposed limb
Gradual arterial occlusion
Atherosclerosis &
thromboangitis obliterans
Limited due to very little
blood supply (Slow)
Organ dry , shrunken & dry
Marked at the junction
between healthy and
gangrenous parts
Present
May occur
Slow
Mild
Senile gangrene of lower limb
Diabetic gangrene.
Better due to little
septicemia (not fatal)
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2 - Moist gangrene
Internal organ as intestine
Sudden occlusion of Both
artery and vein (mainly
venous)
Emboli& trauma
Marked due to congestion
of organ with blood (Rapid)
Part moist, soft, swollen&
dark.
Not clear cut-line
Absent
Not occur
Rapid
Sever
Moist gangrene of intestine.
Moist gangrene of the limb
Subtypes:
Gas (war) gangrene
Infective gangrene.
Poor due to profound
toxemia (Fata)
Gangrene
3. Gas gangrene

Site: Gas gangrene typically affects deep muscle tissue.

Cause: Gas gangrene is most commonly caused by infection with the
bacterium Clostridium perfringens, which develops in an injury or surgical
wound that's depleted of blood supply. The bacterial infection produces
toxins that release gas, hence the name "gas" gangrene and cause tissue
death. Like wet gangrene, gas gangrene can be life-threatening.

Manifestations: If you have gas gangrene, the surface of your skin may
initially appear normal. As the condition progresses, your skin may become
pale and then evolve to a gray or purplish red color. A bubbly appearance to
your skin may become apparent, and the affected skin may make a crackling
sound when you press on it because of the gas within the tissue.
4. Internal gangrene.

Site: Gangrene that affects one or more of your organs, such as your
intestines, gallbladder or appendix, is called internal gangrene.

Cause: this type of gangrene occurs when blood flow to an internal organ is
blocked — for example, when your intestines bulge through a weakened
area of muscle in your abdomen (hernia) and become twisted.

Manifestations: Internal gangrene may cause fever and severe pain. Left
untreated, internal gangrene can be fatal.
5. Fournier's gangrene.

Site: Fournier's gangrene involves the genital organs. Men are more often
affected, but women can develop this type of gangrene as well.

Cause & Manifestations:: Fournier's gangrene usually arises due to an
infection in the genital area or urinary tract and causes genital pain,
tenderness, redness and swelling.
6. Progressive bacterial synergistic gangrene (Meleney's gangrene). This rare
type of gangrene typically occurs after an operation, with painful skin lesions
developing one to two weeks after surgery.
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