Сухая и влажная гангрена: причины, симптомы и лечение.

Type of tissue death by infection or lack of blood supply

Treatment may involve surgery to remove the dead tissue, antibiotics to treat any infection, and efforts to address the underlying cause. In certain cases, hyperbaric oxygen therapy may be useful.

Symptoms may include a change in skin color to red or black, numbness, pain, skin breakdown, and coolness. It is associated with diabetes and long term tobacco smoking. The term dry is used only when referring to a limb or to the gut (in other locations, this same type of necrosis is called an infarction, such as myocardial infarction). Dry gangrene is often due to peripheral artery disease, but can be due to acute limb ischemia. As a result, people with atherosclerosis, high cholesterol, diabetes and smokers commonly have dry gangrene. Dry gangrene is the result of chronic ischemia without infection. If ischemia is detected early, when ischemic wounds rather than gangrene are present, the process can be treated by revascularization (via vascular bypass or angioplasty). However, once gangrene has developed, the affected tissues are not salvageable. Because dry gangrene is not accompanied by infection, it is not as emergent as gas gangrene or wet gangrene, both of which have a risk of sepsis. Over time, dry gangrene may develop into wet gangrene if an infection develops in the dead tissues. Diabetes mellitus is a risk factor for peripheral vascular disease, thus for dry gangrene, but also a risk factor for wet gangrene, particularly in patients with poorly controlled blood sugar levels, as elevated serum glucose creates a favorable environment for bacterial infection.

Wet, or infected, gangrene is characterized by thriving bacteria and has a poor prognosis (compared to dry gangrene) due to sepsis resulting from the free communication between infected fluid and circulatory fluid. 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 foul odor. Wet gangrene usually develops rapidly due to blockage of venous (mainly) or arterial blood flow.

Gas gangrene is a bacterial infection that produces gas within tissues. It can be caused by Clostridium, most commonly alpha toxin producing C. perfringens, or various nonclostridial species. Infection spreads rapidly as the gases produced by the 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 bacterial exotoxin producing clostridial species, which are mostly found in soil, and other anaerobes such as Bacteroides and anaerobic streptococci. These environmental bacteria may enter the muscle through a wound and subsequently proliferate in necrotic tissue and secrete powerful toxins that 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, gas production, and sepsis. Progression to toxemia and shock is often very rapid.

Necrotizing fasciitis, also known as hemolytic streptococcal gangrene, is a very rare infection that spreads deep into the body along tissue planes. It is characterized by infection with S. pyogenes, a gram positive cocci bacteria. Noma is a gangrene of the face most often found in Africa, Southeast Asia and South America. Fournier gangrene is a type of necrotizing fasciitis that usually affects the genitals and groin. Venous limb gangrene may be caused by heparin induced thrombocytopenia and thrombosis. Severe mesenteric ischemia may result in gangrene of the small intestine. Severe ischemic colitis may result in gangrene of the large intestine.

Treatment varies based on the severity and type of gangrene.

Surgical removal of all dead tissue, however, is the mainstay of treatment for gangrene. Often, gangrene is associated with underlying infection, thus the gangrenous tissue must be debrided to hinder the spread of the associated infection. The extent of surgical debridement needed depends on the extent of the gangrene and may be limited to the removal of a finger, toe, or ear, but in severe cases may involve a limb amputation. Angioplasty should be considered if severe blockage in lower leg vessels (tibial and peroneal artery) leads to gangrene.

Hyperbaric oxygen therapy treatment is used to treat gas gangrene. It increases pressure and oxygen content to allow blood to carry more oxygen to inhibit anaerobic organism growth and reproduction. Regenerative medical treatments and stem cell therapies have successfully altered gangrene and ulcer prognosis.

As early as 1028, flies and 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 to the range of treatments for wounds. In recent times, however, maggot therapy has regained some credibility and is sometimes employed with great efficacy in cases of chronic tissue necrosis. The French Baroque composer Jean Baptiste Lully contracted gangrene in January 1687 when, while conducting a performance of his Te Deum, he stabbed his own toe with his pointed staff (which was used as a baton). The disease spread to his leg, but the composer refused to have his toe amputated, which eventually led to his death in March of that year. French King Louis XIV died of gangrene in his leg on 1 September 1715, four days prior to his 77th birthday. Sebald Justinus Brugmans, Professor at Leyden University, from 1795 on Director of the Medical Bureau of the Batavian Republic, and inspector general of the French Imperial Military Health Service in 1811, became a leading expert in the fight against hospital gangrene and its prevention. He wrote a treatise on gangrene in 1814 in which he meticulously analyzed and explained the causes of this dreadful disease, which he was convinced was contagious. He completed his entry with a thorough evaluation of all possible and well experienced sanitary regulations. His work was very well received and was instrumental in convincing most later authors that gangrene was a contagious disease. John M. Trombold wrote: "Middleton Goldsmith, a surgeon in the Union Army during the American Civil War, meticulously studied hospital gangrene and developed a revolutionary treatment regimen. The cumulative Civil War hospital gangrene mortality was 45%. Goldsmith's method, which he applied to over 330 cases, yielded a mortality under 3%." Goldsmith advocated the use of debridement and topical and injected bromide solutions on infected wounds to reduce the incidence and virulence of "poisoned miasma". Copies of his book were issued to Union surgeons to encourage the use of his methods.

The etymology of gangrene derives from the Latin word gangraena and from the Greek (γάγγραινα), which means "putrefaction of tissues".