Gas fire

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Gas fire is a serious bacterial infectious disease. Synonyms for the disease are gas edema or malignant edema. The gas fire pathogen comes from the group of so-called clostridia and usually causes wound infections. A characteristic of gas burn is the increased formation of gas in the infected wound. Gas fire is one of the most serious wound infections known and is often fatal. Here you will find out how you can recognize gas fire and how you can prevent the infection.

Gas fire: description

Gas fire is a serious wound infection with certain bacteria, the so-called clostridia of the gas fire group. These bacteria, which are found almost everywhere in the environment, thrive exclusively under anaerobic conditions, i.e. with the exclusion of oxygen. Doctors differentiate between two forms of gas burn, a more common exogenous form, in which the bacteria get into the wound from outside, and an endogenous form. Here the clostridia enter the bloodstream via the intestine and from there into soft tissue such as the muscles. The endogenous gas fire is less common and primarily affects people whose immune system is weakened by another underlying disease.

Gas fire develops quickly - the clinical picture appears after five to 48 hours. The bacteria produce gases (especially carbon dioxide) in the absence of oxygen. As a result, characteristic bubbles form in the infected wound, which give the gas fire its name. Another property of gas fire bacteria is the production of bacterial toxins, so-called exotoxins (especially phospholipase C and cytolysin). Among other things, these cause blood clotting disorders and can trigger septic shock. Several organs fail at the same time (multiple organ failure) - without timely treatment, the septic shock can be fatal.

In earlier times gas fires were relatively common and were feared because of their serious, often fatal course. It is not uncommon for the pathogens to get into the body during medical interventions with unclean instruments. Since sterilization and disinfection have become standard in medicine, gas fire infections have become rare. The discovery of antibiotics was a milestone in the fight against bacteria such as gas burn pathogens.

Gas fire: symptoms

The symptoms of a gas fire develop quickly - on average after about two days. In some cases, the first signs of illness can appear after five hours, but characteristic gas fire symptoms appear on the third day at the latest. The following symptoms indicate a wound infection with gas burn bacteria:

The wound pain suddenly increases significantly.
The area around the wound swells up a lot and wound edema forms.
The infected area turns brownish-yellow, sometimes blue-black.
The wound exudes cloudy brown, foul-smelling secretion.
Dark blue, fluid-filled bubbles form under the skin.
If you touch the affected area, a noticeable crackling sound (crepitation) can be heard, which is due to the gas formation of the bacteria.
The bacterial toxins break down the muscles and tissues of the affected area, causing it to die.

If the disease persists, a so-called septic shock can occur. In this life-threatening condition, the blood pressure suddenly drops drastically, while the heart rate is greatly accelerated. The bacterial toxins that the gas fire germs secrete also disrupt blood clotting. The coagulation in the small blood vessels is initially greatly increased, so that small blood clots (thrombi) form. After a while, however, the coagulation factors are used up, so that normal blood clotting no longer works. Bleeding in the skin and mucous membranes and also within organs is the result. In this condition, several organs can fail at the same time, doctors speak of multi-organ failure.

Gas fire: causes and risk factors

The cause of a gas fire is an infection with bacteria from the clostridial group. Up to 80 percent of the gas fire cases are caused by the pathogen Clostridium perfringens of type A, infections with C. novyi, C. septicum, C. hystolyticum and other bacteria from the so-called gas fire group are more rare.

Clostridia look like rods under the microscope; Due to the structure of their bacterial wall, they are one of the gram-positive bacteria. The pathogens only multiply in the absence of oxygen (anaerobically).

They also have the peculiarity of forming so-called spores. These represent a kind of permanent form of the bacterium and are particularly resistant to heat and disinfectants. They cannot be inactivated, for example, by simply washing your hands. In contrast, the active form of bacteria is normally sensitive to disinfectants.

Clostridium perfringens occurs practically everywhere in the environment, but the gas fire pathogen is particularly common in the soil and in the intestines of mammals. An infection can occur when wounds come into contact with the bacteria, for example when working with dirt or soil (e.g. gardening). Faecal matter from animals can also accommodate Clostridium perfringens, and enter the body either through injuries (e.g. during stable work) or through contaminated food.

In the past, gas fire infections often occurred through non-sterile surgical instruments - fortunately, this route of infection no longer plays a role today. Occasionally, gas burn also occurs in drug addicts who use contaminated needles.

Gas fire can only occur if the bacteria are in the wound with exclusion of air. If the injured area is poorly supplied with blood, for example, if the blood vessels contract in shock, this can lead to a gas fire infection. Diseases that are associated with reduced blood flow and thus a lower oxygen supply to the tissue (e.g. diabetes mellitus or arteriosclerosis) can increase the risk of gas fire.

Often, in addition to the clostridia, other bacteria also get into the wound; doctors then speak of a mixed infection. The pathogens involved can also change the environment in the infected tissue in such a way that gas fires can occur more easily.

In addition to the exogenous gas fire, in which the pathogen has entered the body from outside, endogenous gas fire diseases also occur. Serious illnesses that severely weaken the immune system are usually the starting point for the infection. The bacteria, which are also found in the intestine, pass the intestinal barrier and reach the surrounding tissue (e.g. into the muscles) via the blood, where they then cause the gas burn.

Gas fire: examinations and diagnosis

The gas fire is usually preceded by an injury that usually requires medical treatment. If the doctor observes that the wound suddenly swells and hurts, a wound infection is suspected. The doctor makes the diagnosis of the gas fire based on characteristic symptoms such as blistering or crackling noises in the wound area.

In order to unequivocally identify the pathogen, he takes a sample of the wound secretion and, if necessary, the affected muscles. The samples are then usually examined in a special laboratory (e.g. the consulting laboratory for anaerobic bacteria at the University of Leipzig). Sometimes an additional X-ray examination can also point out the gas fire if, for example, an increased accumulation of gas in the tissue can be seen on the X-ray image. Since gas fires can quickly become life-threatening, diagnosis must be made as quickly as possible. Doctors must report both illnesses and deaths from gas fires to the health department (mandatory notification).

Gas fire: treatment

If a gas fire is suspected, the medical team immediately initiates treatment - even if all laboratory results are not yet available. Since the disease is one of the most serious wound infections known and progresses quickly, there is no valuable time to be lost in therapy. The treatment of gas fires is based in principle 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 necessary. The aim is to bring the wound into contact with oxygen as much as possible in order to stop the gas fire pathogen from multiplying further.
Antibiotic therapy: To kill the bacteria, doctors use antibiotics, e.g. penicillin G, often combined with clindamycin, or cephalosporins together with metronidazole.

In some cases, so-called hyperbaric oxygen therapy is also used. The patient inhales oxygen in a room in which there is increased air pressure (pressure chamber). This should increase the oxygen content in the tissue. The oxygen content is also increased in the air surrounding the wound. In specialist circles, however, there are different opinions as to whether hyperbaric oxygen therapy is useful for gas fires.

Intensive medical care is required in the event of shock. For shock treatment, doctors give infusions and medication, for example, that stabilize the circulation. If organ failure occurs, the organ function - as far as possible - must be temporarily replaced, in the case of kidney failure, for example, by blood washing (dialysis).

Gas fire: prevent it

There are a few measures that can be taken to prevent wound infections such as gas fire:

If you have sustained a small injury, clean it with plenty of water and then disinfect the wound.
The treatment of large or deep wounds as well as bite injuries basically belong in the hands of a doctor.
Heavily soiled wounds (e.g. with soil, faeces or bite wounds) should be treated with antibiotics as a preventive measure.
Diseases such as diabetes mellitus are often associated with reduced blood flow to the tissue. As a diabetic, always have wounds examined by a doctor.

Gas fire: disease course and prognosis

Gas fire is a relatively rare but dreaded disease. The mortality rate is high at 30 to 50 percent. In the case of an endogenous gas fire that predominantly affects people with weakened immune systems, the risk of dying from the disease is even higher. However, if a gas fire is detected in good time and the therapy takes effect, a cure is possible.

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