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| ==Pathophysiology== | | ==Pathophysiology== |
| ===Dry Gangrene=== | | ===Dry Gangrene=== |
| If the blood flow is interrupted for a reason other than severe bacterial infection, the result is a case of dry gangrene. People with impaired peripheral blood flow, such as diabetics, are at greater risk of contracting dry gangrene.The dark coloration is due to liberation of [[hemoglobin]] from hemolyzed red blood cells which is acted upon by [[hydrogen sulfide]] (H<sub>2</sub>S) produced by the bacteria, resulting in formation of black iron sulfide that remains in the tissues<ref>[http://compepid.tuskegee.edu/syllabi/pathobiology/pathology/genpath/chapter3.html chapter 3.html<!-- Bot generated title -->]</ref>.
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| ===Wet Gangrene=== | | ===Wet Gangrene=== |
| In wet gangrene, the tissue is infected by saprogenic microorganisms (Bac.perfringes, fusiformis, putrificans, etc.), which cause tissue to swell and emit a fetid smell. Wet gangrene usually develops rapidly due to blockage of venous and/or arterial blood flow. The affected part is saturated with stagnant blood which promotes the rapid growth of bacteria. The toxic products formed by bacteria are absorbed causing systemic manifestation of [[septicemia]] and finally death.
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| ===Gas Gangrene=== | | ===Gas Gangrene=== |
| Gas gangrene is caused by a bacterial [[exotoxin]]-producing clostridial species, which are mostly found in soil and other anaerobes (e.g. ''[[Bacteroides]]'' and anaerobic [[Streptococcus|streptococci]]). These environmental bacteria may enter the muscle through a wound and subsequently proliferate in necrotic tissue and secrete powerful toxins. These toxins destroy nearby tissue, generating gas at the same time. A gas composition of 5.9% hydrogen, 3.4% carbon dioxide, 74.5% nitrogen and 16.1% oxygen was reported in one clinical case.<ref>{{cite journal |author=Chi CH, Chen KW, Huang JJ, Chuang YC, Wu MH |title=Gas composition in Clostridium septicum gas gangrene |journal=J. Formos. Med. Assoc. |volume=94 |issue=12 |pages=757–9 |year=1995 |month=December |pmid=8541740 |doi= |url=}}</ref>
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| ==References== | | ==References== |