|
|
| Line 10: |
Line 10: |
|
| |
|
|
| |
|
| Gangrene is a complication of [[necrosis]] (i.e., [[Cell (biology)|cell]] death) characterized by the decay of [[biological tissue|body tissue]]s, which become black and malodorous. It is caused by [[infection]] or [[ischemia]], such as from [[thrombosis]] (blocked [[blood vessel]]). It is usually the result of critically insufficient [[blood]] supply (e.g., [[peripheral vascular disease]]) and is often associated with [[diabetes]] and long-term smoking. This condition is most common in the lower [[extremities]]. The best treatment for gangrene is [[revascularization]] (i.e., restoration of blood flow) of the affected organ, which can reverse some of the effects of necrosis and allow healing. Other treatments include [[debridement]] and surgical [[amputation]]. The method of treatment is generally determined depending on location of affected tissue and extent of tissue loss. Gangrene may appear as one effect of foot binding.
| |
|
| |
|
| (Images courtesy of Charlie Goldberg, M.D., UCSD School of Medicine and VA Medical Center, San Diego, CA)
| |
|
| |
|
| <div align="left">
| |
| <gallery heights="175" widths="175">
| |
| Image:extremities_toe_gangrene2.jpg|Patient with peripheral vascular disease that has lead to infarct of several toes.
| |
| Image:extremities_toe_no_gangrene2.jpg|Same patient. Normal left foot for comparison.
| |
| </gallery>
| |
| </div>
| |
|
| |
|
| ==Etymology== | | ==Etymology== |
| Line 25: |
Line 17: |
| The [[etymology]] of gangrene derives from the [[Latin]] word "gangraena" and from the [[Greek language|Greek]] gangraina (γάγγραινα), which means "[[putrefaction]] of tissues". | | The [[etymology]] of gangrene derives from the [[Latin]] word "gangraena" and from the [[Greek language|Greek]] gangraina (γάγγραινα), which means "[[putrefaction]] of tissues". |
|
| |
|
| ==Types of gangrene==
| |
|
| |
| ===Dry gangrene===
| |
|
| |
| Dry gangrene begins at the distal part of the limb due to [[ischemia]] and often occurs in the toes and feet of elderly patients due to arteriosclerosis. Dry gangrene spreads slowly until it reaches the point where the blood supply is inadequate to keep tissue viable. Macroscopically, the affected part is dry, shrunken and dark black, resembling [[mummy|mummified]] flesh. 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>. The line of separation usually brings about complete separation with eventual falling off of the gangrenous tissue if it is not removed surgically.
| |
|
| |
| 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 early signs of dry gangrene are a dull ache and sensation of coldness in the affected area along with [[pallor]] of the flesh. If caught early, the process can sometimes be reversed by vascular surgery. However, if necrosis sets in, the affected tissue must be removed just as with wet gangrene.
| |
|
| |
| <div align="left">
| |
| <gallery heights="175" widths="175">
| |
| Image:ULCERCELLULITIS1.JPG|Diabetic [[ulcer]]ation with central "dry" gangrene and toward the edges wet gangrene with some ascending [[cellulitis]] <br> (Image courtesy of Charlie Goldberg, M.D., UCSD School of Medicine and VA Medical Center, San Diego, CA)
| |
| </gallery>
| |
| </div>
| |
|
| |
| ===Wet gangrene===
| |
|
| |
| Wet gangrene occurs in naturally moist tissue and organs such as the mouth, bowel, lungs, cervix, and vulva. [[Bedsores]] occurring on body parts such as the sacrum, buttocks and heels—although not necessarily moist areas—are also categorized as wet gangrene infections. 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. Macroscopically, the affected part is edematous, soft, putrid, rotten and dark. The darkness in wet gangrene occurs due to the same mechanism as in dry gangrene.
| |
|
| |
| <div align="left">
| |
| <gallery heights="175" widths="175">
| |
| Image:AUTOAMPUTATE1.JPG|Diabetic with severe infection and loss of toes - wet gangrene in center. <br> (Image courtesy of Charlie Goldberg, M.D., UCSD School of Medicine and VA Medical Center, San Diego, CA)
| |
| </gallery>
| |
| </div>
| |
|
| |
| ===Gas gangrene===
| |
| {{main|Gas gangrene}}
| |
| Gas gangrene is a bacterial infection that produces gas within tissues. It is a deadly form of gangrene usually caused by ''[[Clostridium perfringens]]'' bacteria. Infection spreads rapidly as the gases produced by bacteria expand and infiltrate healthy tissue in the vicinity. Because of its ability to quickly spread to surrounding tissues, gas gangrene should be treated as a medical emergency.
| |
|
| |
| 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>
| |
|
| |
| Gas gangrene can cause [[necrosis]], gas production, and [[sepsis]]. Progression to [[bacteremia|toxemia]] and [[septic shock|shock]] is often very rapid.
| |
|
| |
| ==Specific gangrenes==
| |
| *[[Noma (disease)|Noma]] is a gangrene of the face.
| |
| *[[Necrotizing fasciitis]] affects the deeper layers of the skin.
| |
| *[[Fournier gangrene]] usually affects the male genitals.
| |
|
| |
|
| ==Treatment== | | ==Treatment== |
