gas gangrene

Gas fire: description

Gas gangrene refers to a serious wound infection with certain bacteria, the so-called clostridia of the gas gangrene group. These bacteria, which occur almost everywhere in the environment, thrive exclusively under anaerobic conditions, that is, to the exclusion of oxygen. Doctors distinguish two forms of gas gangrene, a more common one exogenous formin which the bacteria get into the wound from the outside, as well as a endogenous form, Here the clostridia enter the bloodstream via the intestine and from there into soft tissue such as the musculature. The endogenous gas gangrene is rarer and affects primarily people whose immune system is weakened by another underlying disease.

Gas gangrene develops rapidly – after five to 48 hours, the disease appears. The bacteria produce gases (especially carbon dioxide) in the absence of oxygen. As a result, characteristic bubbles form in the infected wound, giving the gas fire its name. Another characteristic of gas gangrene bacteria is the production of bacterial poisons, so-called exotoxins (mainly phospholipase C and cytolysin). These cause, among other disorders of blood clotting and can trigger a septic shock. Multiple organs fail at the same time (multiple organ failure) – without timely treatment, the septic shock can end fatally.

In earlier times, gas blight was relatively common and was much feared for its serious, often fatal course. It is not unusual for the pathogens to enter the body during medical procedures with unclean instruments. Since sterilization and disinfection are standard in medicine, gas gangrene has become rare. Another milestone in the fight against bacteria such as the gas gangrene was the discovery of antibiotics.

Gas gangrene: symptoms

The symptoms of gas gangrene develop quickly – on average about two days. In some cases, the first signs of the disease may appear even after five hours, at the latest, however, characteristic symptoms of gas gangrene appear on the third day. The following symptoms indicate a wound infection with gas gangrene:

• The wound pain suddenly increases significantly.
• The area around the wound swells strongly, forming a wound edema.
• The infected area turns brownish-yellow, sometimes blue-black.
• The wound secretes cloudy-brown, foul-smelling secretions.
• Dark blue, fluid-filled bubbles form under the skin.
• If one touches the affected area, a noticeable crackling (crepitation) can be heard, which is due to the gas formation of the bacteria.
• The bacterial toxins decompose muscles and tissues of the affected area, causing it to die.

If the disease persists, a so-called septic shock may occur. In this life-threatening condition, the blood pressure suddenly drops drastically, while the heart rate is greatly accelerated. The bacterial toxins that secrete the gas burners also interfere with blood clotting. In the small blood vessels, the coagulation is initially greatly increased, so that small clots (thrombi) form. After a while, however, the coagulation factors consume so that normal blood clotting stops working. Bleeding in skin and mucous membranes and also within organs are the result. In this condition, multiple organs can fail at the same time, doctors speak of a multi-organ failure.

Gas gangrene: causes and risk factors

The cause of gas gangrene is an infection with bacteria from the group Clostridia. Up to 80 percent of gas gangrene cases are the causative agent Clostridium perfringens type A, rarer are infections with C. novyi, C. septicum, C. hystolyticum and other bacteria from the so-called gas gangrene group.

Clostridia look like a rod under the microscope; Due to the structure of their bacterial wall, they are among the Gram-positive bacteria. The pathogens multiply exclusively under exclusion of oxygen (anaerobic).

They also have the peculiarity to form so-called spores. These are a kind of permanent form of the bacterium and are particularly resistant to heat and disinfectants. For example, they can not be deactivated by simply washing their hands. In contrast, the active bacterial form is usually sensitive to disinfectants.

Clostridium perfringens is found in the environment virtually everywhere, but it is particularly common that the gas gangrene is found in the soil and in the intestines of mammals. Infection can occur when wounds come in contact with the bacteria, such as when working with dirt or soil (e.g., gardening). Fecal matter from animals can also harbor Clostridium perfringens, either through injury (such as in stable work) or through contaminated food into the body.

In earlier times, gas gangrene infections were often caused by unsterile surgical instruments – fortunately, this path of infection plays fortunately no longer a role. Occasionally, gas gangrene also occurs in drug addicts who use contaminated needles.

Gas gangrene can only occur if the bacteria are in the wound with the exclusion of air. For example, if the injured area is poorly supplied with blood, for example, when the blood vessels contract in shock, this may favor a gas gangrene infection. Also, diseases associated with reduced blood flow and thus reduced oxygenation of the tissue (e.g., diabetes mellitus or arteriosclerosis) may increase the risk of gas gangrene.

Often, in addition to the Clostridia also get more bacteria in the wound, doctors then speak of a mixed infection. These involved pathogens can additionally change the environment in the infected tissue so that gas gangrene can occur more easily.

In addition to the exogenous gas gangrene, in which the pathogen has entered the body from the outside, endogenous gas gangrene diseases also occur. Serious diseases that severely weaken the immune system usually form the starting point of the infection. The bacteria, which also occur in the intestine, pass through the intestinal barrier and pass through the blood to the surrounding tissues (such as the musculature), where they then cause gas gangrene.

Gas fire: examinations and diagnosis

Most gas burns are preceded by an injury, which usually requires medical treatment. If the doctor observes that the wound suddenly swells and hurts, the suspected wound infection is close. The doctor already makes the diagnosis of gas gangrene due to characteristic symptoms, such as blistering or crackling noises in the wound area.

In order to unequivocally identify the pathogen, it takes a sample of the wound secretion, possibly also of the affected muscles. The samples are then usually examined in a special laboratory (for example, the Konsiliarlaboratorium for anaerobic bacteria of the University of Leipzig). In addition, an X-ray examination can sometimes also indicate the gas gangrene if, for example, an increased accumulation of gas in the tissue can be seen on the X-ray image. Since gas gangrene quickly takes a life-threatening course, the quickest possible diagnosis is required. Doctors have to report both illness and death by gas gangrene at the health department (obligation to register).

Gas gangrene: treatment

If there is a suspicion of gas gangrene, the medical team immediately initiates the treatment – even if not all laboratory results are available yet. Since the disease is one of the most serious known wound infections and progresses rapidly, there is no valuable time to lose in therapy. The treatment of the gas fire is basically based on two pillars:

• wound treatment: The wound is cleaned and disinfected, dead tissue must be removed, if necessary, an amputation of the affected limb may be required. The aim is to bring the wound as possible in contact with oxygen in order to stop further propagation of the gas gangrene.
• Antibiotic therapy: To kill the bacteria, doctors place antibiotics, e.g. Penicillin G, often combined with clindamycin, or cephalosporins with metronidazole.

In some cases, a so-called hyperbaric oxygen therapy is used. The patient breathes oxygen in a room where there is an increased air pressure (pressure chamber). This should increase the oxygen content in the tissue. Also in the air surrounding the wound, the oxygen content is increased. In professional circles, however, one disagrees on whether hyperbaric oxygen therapy is useful for gas gangrene.

In case of shock intensive care is required. For shock treatment, for example, doctors administer infusions and medications that stabilize the circulation. If it comes to organ failure, the organ function – if possible – must be temporarily replaced, in kidney failure, for example, by a blood wash (dialysis).

Gas fire: Prevent

There are some measures by which wound infections such as gas gangrene avoid:

• If you have a small injury, clean it with plenty of water and then disinfect the wound.
• The treatment of large or deep wounds and bite injuries are always in the hands of a doctor.
• Heavily soiled wounds (such as with soil, fecal matter or bites) should be treated as preventative antibiotic.
• Diseases such as diabetes mellitus are often associated with decreased tissue perfusion, and as a diabetic always allow wounds to be examined by a doctor.

Gas gangrene: disease course and prognosis

Gas gangrene is a relatively rare but dreaded disease. Mortality is high at 30 to 50 percent. In endogenous gas gangrene affecting predominantly immunocompromised individuals, the risk of dying from the disease is even higher. Becomes gas gangrene Recognized in time and takes the therapy, however, a cure is possible.