Gangrene
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| Gangrene Classification and external resources | |
| ICD-10 | R02., I70.2, E10.2, I73.9 |
|---|---|
| ICD-9 | 040.0, 785.4 |
Gangrene is the necrosis and subsequent decay of body tissues caused by infection or thrombosis. It is usually the result of critically insufficient blood supply sometimes caused by injury and subsequent contamination with bacteria. This condition is most common in the extremities. The best treatment for gangrene is revascularization (restoration of blood flow) of the affected organ, which can reverse some of the effects of necrosis and allow healing. Depending on the extent of tissue loss and location, treatment other than revascularization may range from allowing digits to auto-amputate (fall off), debridement and local care, to amputation, the removal of infected necrotic tissues.
Etymology
It comes from the Latin word "gangraena" and from the Greek gangraina (γάγγραινα), which means "putrefaction of tissues".
History
As early as 1028, when antibiotics had not yet been invented, fly maggots were commonly used to treat chronic wounds or ulcers to prevent or arrest necrotic spread, as some species of maggots consume only dead flesh, leaving nearby living tissue unaffected. This practice largely died out after the introduction of antibiotics and enzyme to the range of treatments for wounds. Recently, however, maggot therapy has regained some credibility and is sometimes employed with great efficacy in cases of chronic tissue necrosis.
Types of gangrene
Dry gangrene
Dry gangrene begins at the distal part of the limb due to ischaemia. Dry gangrene often occurs in the toes and feet of elderly patients due to arteriosclerosis. Gangrene spreads slowly until it reaches the point where the blood supply is adequate enough to keep tissue viable. Macroscopically, the affected part is dry, shrunken and dark black, resembling the foot of a mummy. The dark colouration is due to liberation of hemoglobin from hemolysed red blood cells which is acted upon by hydrogendisulfide(HG) produced by the bacteria, resulting in formation of black iron sulfide that remains in the tissues. 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 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.
Internal gangrene
Template:Section-stub In this gangrene the tissues become white. The site of gangrene is located inside the body, and is usually contracted after surgery or trauma. Also called "white gangrene".
Wet gangrene
Wet gangrene occurs in naturally moist tissue and organs such as the mouth, bowel, lungs, cervix, vulva, etc. 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 effected part is edematous, soft, putrid, rotten and dark. The darkness in wet gangrene occurs due to the same mechanism as in dry gangrene.
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 infiltrates 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 exotoxin-producing clostridial species, which is mostly found in soil, and other anaerobes (e.g. Bacteroides and anaerobic streptococci). These environmental bacteria may enter the muscle through a wound and go on to 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.
Gas gangrene can cause myonecrosis, gas production, and sepsis. Progression to toxemia and shock is often very rapid.
Specific gangrenes
- 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 is usually surgical debridement and excision with amputation necessary in many cases. Antibiotics alone are not effective because they do not penetrate ischemic muscles sufficiently. However, penicillin is given as an adjuvant treatment to surgery. In addition to surgery and antibiotics, Hyperbaric oxygen therapy (HBOT) is used to inhibit the growth of and kill the anaerobic C. perfringens.
See also
ca:Gangrena cs:Gangréna da:Gangræn de:Gangräneo:Gangreno fr:Gangrène io:Gangreno it:Cancrena he:נמק nl:Gangreenqu:Kawsaykuq tantalli ismusqafi:Kuolio sv:Kallbrandwa:Grangrin
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
