Gangrene
Overview
Gangrene is a serious and potentially life-threatening condition that arises when a considerable mass of body tissue dies (necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...

). This may occur after an injury or infection, or in people suffering from any chronic health problem affecting blood circulation. The primary cause of gangrene is reduced blood supply to the affected tissues, which results in cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

 death. Diabetes and long-term smoking increase the risk of suffering from gangrene.

There are different types of gangrene with different symptoms, such as dry gangrene, wet gangrene, gas gangrene
Gas gangrene
Gas gangrene is a bacterial infection that produces gas tissues in gangrene. It is a deadly form of gangrene usually caused by Clostridium perfringens bacteria. It is a medical emergency....

, internal gangrene and necrotising fasciitis.
Encyclopedia
Gangrene is a serious and potentially life-threatening condition that arises when a considerable mass of body tissue dies (necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...

). This may occur after an injury or infection, or in people suffering from any chronic health problem affecting blood circulation. The primary cause of gangrene is reduced blood supply to the affected tissues, which results in cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

 death. Diabetes and long-term smoking increase the risk of suffering from gangrene.

There are different types of gangrene with different symptoms, such as dry gangrene, wet gangrene, gas gangrene
Gas gangrene
Gas gangrene is a bacterial infection that produces gas tissues in gangrene. It is a deadly form of gangrene usually caused by Clostridium perfringens bacteria. It is a medical emergency....

, internal gangrene and necrotising fasciitis. Treatment options include debridement
Debridement
Debridement is the medical removal of a patient's dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue...

 (or, in severe cases, amputation
Amputation
Amputation is the removal of a body extremity by trauma, prolonged constriction, or surgery. As a surgical measure, it is used to control pain or a disease process in the affected limb, such as malignancy or gangrene. In some cases, it is carried out on individuals as a preventative surgery for...

) of the affected body parts, antibiotics, vascular surgery
Vascular surgery
Vascular surgery is a specialty of surgery in which diseases of the vascular system, or arteries and veins, are managed by medical therapy, minimally-invasive catheter procedures, and surgical reconstruction. The specialty evolved from general and cardiac surgery...

, maggot therapy
Maggot therapy
Maggot therapy is a type of biotherapy involving the intentional introduction of live, disinfected maggots into the non-healing skin and soft tissue wound of a human or animal for the purpose of cleaning out the...

 or hyperbaric oxygen therapy
Hyperbaric oxygen therapy
Hyperbaric medicine, also known as hyperbaric oxygen therapy , is the medical use of oxygen at a level higher than atmospheric pressure. The equipment required consists of a pressure chamber, which may be of rigid or flexible construction, and a means of delivering 100% oxygen...

.

Etymology

The etymology
Etymology
Etymology is the study of the history of words, their origins, and how their form and meaning have changed over time.For languages with a long written history, etymologists make use of texts in these languages and texts about the languages to gather knowledge about how words were used during...

 of gangrene derives from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 word gangraena and from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 gangraina (γάγγραινα), which means "putrefaction
Putrefaction
Putrefaction is one of seven stages in the decomposition of the body of a dead animal. It can be viewed, in broad terms, as the decomposition of proteins, in a process that results in the eventual breakdown of cohesion between tissues and the liquefaction of most organs.-Description:In terms of...

 of tissues". It has no etymological connection with the word green
Green
Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...

, despite the affected areas turning black and/or green and/or yellowish brown. It is coincidence that, in Lowland Scots
Scots language
Scots is the Germanic language variety spoken in Lowland Scotland and parts of Ulster . It is sometimes called Lowland Scots to distinguish it from Scottish Gaelic, the Celtic language variety spoken in most of the western Highlands and in the Hebrides.Since there are no universally accepted...

 the words "gang green" (going green) can be said to be an eggcorn
Eggcorn
In linguistics, an eggcorn is an idiosyncratic substitution of a word or phrase for a word or words that sound similar or identical in the speaker's dialect. The new phrase introduces a meaning that is different from the original, but plausible in the same context, such as "old-timers' disease" for...

 for gangrene, as it describes the symptoms of the affliction.

Causes

Gangrene is caused by infection
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

 or ischemia
Ischemia
In medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...

, such as by the bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

 Clostridium perfringens
Clostridium perfringens
Clostridium perfringens is a Gram-positive, rod-shaped, anaerobic, spore-forming bacterium of the genus Clostridium. C. perfringens is ever present in nature and can be found as a normal component of decaying vegetation, marine sediment, the intestinal tract of humans and other vertebrates,...

or by thrombosis
Thrombosis
Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets and fibrin to form a blood clot to prevent blood loss...

 (blocked blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...

). It is usually the result of critically insufficient blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....

 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
Limb (anatomy)
A limb is a jointed, or prehensile , appendage of the human or other animal body....

. The best treatment for gangrene is revascularization
Revascularization
Revascularization is "a surgical procedure for the provision of a new, additional, or augmented blood supply to a body part or organ." The term derives from the prefix re-, in this case meaning "restoration" and vasculature, which refers to the circulatory structures of an organ.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
Debridement
Debridement is the medical removal of a patient's dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue...

 and surgical amputation
Amputation
Amputation is the removal of a body extremity by trauma, prolonged constriction, or surgery. As a surgical measure, it is used to control pain or a disease process in the affected limb, such as malignancy or gangrene. In some cases, it is carried out on individuals as a preventative surgery for...

. The method of treatment is, in general, determined depending on location of affected tissue and extent of tissue loss. Gangrene may appear as one effect of foot binding
Foot binding
Foot binding was the custom of binding the feet of young girls painfully tight to prevent further growth. The practice probably originated among court dancers in the early Song dynasty, but spread to upper class families and eventually became common among all classes. The tiny narrow feet were...

.

Dry

Dry gangrene begins at the distal part of the limb due to ischemia
Ischemia
In medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...

, and often occurs in the toes and feet of elderly patients due to arteriosclerosis
Arteriosclerosis
Arteriosclerosis refers to a stiffening of arteries.Arteriosclerosis is a general term describing any hardening of medium or large arteries It should not be confused with "arteriolosclerosis" or "atherosclerosis".Also known by the name "myoconditis" which is...

. Dry gangrene is mainly due to arterial occlusion. There is limited putrefaction and bacteria fail to survive. Dry gangrene spreads slowly until it reaches the point where the blood supply is adequate to keep tissue viable. The affected part is dry, shrunken and dark reddish-black, resembling mummified
Mummy
A mummy is a body, human or animal, whose skin and organs have been preserved by either intentional or incidental exposure to chemicals, extreme coldness , very low humidity, or lack of air when bodies are submerged in bogs, so that the recovered body will not decay further if kept in cool and dry...

 flesh. The dark coloration is due to liberation of hemoglobin
Hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...

 from hemolyzed red blood cells, which is acted upon by hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...

 (H2S) 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, also called autoamputation
Autoamputation
Autoamputation is the spontaneous detachment of an appendage from the body. This is not to be confused with self-amputation....

.

Dry gangrene is actually a form of coagulative necrosis
Coagulative necrosis
Coagulative necrosis is a type of accidental cell death typically caused by ischemia or infarction.It is characterised by the 'ghostly' appearance of cells under light microscopy in the affected area of tissue. In coagulative necrosis the architecture of dead tissue is preserved for at least a...

. 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 developing dry gangrene.

The early signs of dry gangrene are a dull ache and sensation of coldness in the affected area along with pallor
Pallor
Pallor is a reduced amount of oxyhaemoglobin in skin or mucous membrane, a pale color which can be caused by illness, emotional shock or stress, stimulant use, lack of exposure to sunlight, anaemia or genetics....

 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.

Wet

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. It is characterized by numerous bacteria and has a poor prognosis (compared to dry gangrene) due to septicemia. In wet gangrene, the tissue is infected by saprogenic microorganisms (Clostridium perfringens or Bacillus fusiformis, for example), which cause tissue to swell and emit a fetid smell. Wet gangrene usually develops rapidly due to blockage of venous (mainly) 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. 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. Wet gangrene is coagulative necrosis progressing to liquefactive necrosis
Liquefactive necrosis
Liquefactive necrosis is a type of necrosis which results in a transformation of the tissue into a liquid viscous mass. Often it is associated with focal bacterial or fungal infections...

.

Gas

Gas gangrene is a bacterial infection that produces gas within tissues. It is a deadly form of gangrene usually caused by Clostridium perfringens
Clostridium perfringens
Clostridium perfringens is a Gram-positive, rod-shaped, anaerobic, spore-forming bacterium of the genus Clostridium. C. perfringens is ever present in nature and can be found as a normal component of decaying vegetation, marine sediment, the intestinal tract of humans and other vertebrates,...

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
Medical emergency
A medical emergency is an injury or illness that is acute and poses an immediate risk to a person's life or long term health. These emergencies may require assistance from another person, who should ideally be suitably qualified to do so, although some of these emergencies can be dealt with by the...

.

Gas gangrene is caused by a bacterial exotoxin
Exotoxin
An exotoxin is a toxin excreted by a microorganism, like bacteria, fungi, algae, and protozoa. An exotoxin can cause damage to the host by destroying cells or disrupting normal cellular metabolism. They are highly potent and can cause major damage to the host...

-producing clostridial species, which are mostly found in soil and other anaerobes (e.g., Bacteroides
Bacteroides
Bacteroides is a genus of Gram-negative, bacillus bacteria. Bacteroides species are non-endospore-forming, anaerobes, and may be either motile or non-motile, depending on the species. The DNA base composition is 40-48% GC. Unusual in bacterial organisms, Bacteroides membranes contain sphingolipids...

and anaerobic streptococci
Streptococcus
Streptococcus is a genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the lactic acid bacteria group. Cellular division occurs along a single axis in these bacteria, and thus they grow in chains or pairs, hence the name — from Greek στρεπτος streptos, meaning...

). 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.

Gas gangrene can cause necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...

, gas production, and sepsis
Sepsis
Sepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...

. Progression to toxemia
Bacteremia
Bacteremia is the presence of bacteria in the blood. The blood is normally a sterile environment, so the detection of bacteria in the blood is always abnormal....

 and shock
Septic shock
Septic shock is a medical emergency caused by decreased tissue perfusion and oxygen delivery as a result of severe infection and sepsis, though the microbe may be systemic or localized to a particular site. It can cause multiple organ dysfunction syndrome and death...

 is often very rapid.

Other

  • Necrotizing fasciitis
    Necrotizing fasciitis
    Necrotizing fasciitis , commonly known as flesh-eating disease or Flesh-eating bacteria syndrome, is a rare infection of the deeper layers of skin and subcutaneous tissues, easily spreading across the fascial plane within the subcutaneous tissue.Necrotizing fasciitis is a quickly progressing and...

     affects the deeper layers of the skin.
  • Noma
    Noma (disease)
    Noma also known as cancrum oris or gangrenous stomatitis, is a gangrenous disease leading to tissue destruction of the face, especially the mouth and cheek.-Causes:...

     is a gangrene of the face.
  • Fournier gangrene
    Fournier gangrene
    Fournier's gangrene is a type of necrotizing infection or gangrene usually affecting the perineum.It was first described by Baurienne in 1764 and is named after a French venereologist, Jean-Alfred Fournier following five cases he presented in clinical lectures in 1883.-Cause:In the majority of...

     usually affects the male genitals and groin.

Treatment

Treatment is usually surgical debridement
Debridement
Debridement is the medical removal of a patient's dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue...

, with amputation necessary in many cases. Antibiotics alone are not effective because they do not penetrate infected muscles sufficiently.

History

As early as 1028, when antibiotics had not yet been discovered, fly
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...

 maggot
Maggot
In everyday speech the word maggot means the larva of a fly ; it is applied in particular to the larvae of Brachyceran flies, such as houseflies, cheese flies, and blowflies, rather than larvae of the Nematocera, such as mosquitoes and Crane flies...

s were commonly used to treat chronic wounds or ulcers to prevent or arrest necrotic spread, as some species of maggot
Maggot
In everyday speech the word maggot means the larva of a fly ; it is applied in particular to the larvae of Brachyceran flies, such as houseflies, cheese flies, and blowflies, rather than larvae of the Nematocera, such as mosquitoes and Crane flies...

s consume only dead flesh, leaving nearby living tissue unaffected. This practice largely died out after the introduction of antibiotics, acetonitrile
Acetonitrile
Acetonitrile is the chemical compound with formula . This colourless liquid is the simplest organic nitrile. It is produced mainly as a byproduct of acrylonitrile manufacture...

and enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 to the range of treatments for wounds. In recent times, however, maggot therapy
Maggot therapy
Maggot therapy is a type of biotherapy involving the intentional introduction of live, disinfected maggots into the non-healing skin and soft tissue wound of a human or animal for the purpose of cleaning out the...

has regained some credibility and is sometimes employed with great efficacy in cases of chronic tissue necrosis.
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