Gas fire

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Classification according to ICD-10
A48.0 Gas fire (gas edema)
ICD-10 online (WHO version 2019)
Clostridium perfringens , the causative agent of the gas fire, in a smear preparation stained according to Gram

When gas gangrene (Syn .: gas gangrene , Gasödem , Gasphlegmone , Clostridium myositis , clostridial cellulitis , clostridial myonecrosis , malignant edema ) is, to a rapidly arising, infectious-toxic syndrome (infectious disease) of extreme danger. The cause is a local soft tissue infection with gas-forming, anaerobic clostridia (esp. C. perfringens ), which occur everywhere (ubiquitously) in the form of spores in the soil and the rest of the environment.

Nowadays, swift surgical and antibiotic treatment of wounds can avoid an anaerobic wound environment that is absolutely necessary for infection, and thus prevent gas fires. After natural disasters, however, late wound care still leads to very high numbers of infections.

Purulent mixed infections, which can also sometimes form gas (for example necrotizing fasciitis or cellulitis not caused by clostridia ), but primarily and mainly do not decompose the muscles, have different symptoms and also have a better prognosis, are to be distinguished from the typical gas fire .

Pathogen

The clostridial species of importance here ( Clostridium perfringens (90% of cases), Clostridium septicum , Cl. Histolyticum , Cl. Novyi , Cl. Fallax , Cl. Bifermentans , Cl. Sordellii ) occur everywhere ( ubiquitously ) in nature . They are obligatory anaerobic gram-positive spore - formers, which can also be found in the human intestine, but where they are not pathogenic (pathogenic) under normal conditions.

The pathogenicity arises only with the change of the environmental conditions to an anaerobic environment (lack of oxygen), as it exists in destroyed soft tissue with reduced oxygen partial pressure .

Pathogenesis

In most cases, heavily soiled, destroyed and fissured areas of tissue due to injury are the place where the clostridia acquire their pathogenicity, i.e. where bacteria develop from spores and then multiply.

Oxygen deficiency is fundamental ( clostridia are anaerobic pathogens). Reduced blood flow through squeezing the soft tissue, tissue destruction ( necrosis ), shock , concomitant diseases such as diabetes mellitus and malignant tumors are beneficial . In addition, the contamination of the wound brings with it an infection with aerobic (oxygen-consuming) pathogens, which promotes the lack of oxygen in the infected tissue and improves the living conditions for the clostridia.

In addition to CO 2, clostridia form various exotoxins that cause cell membrane destruction and edema formation in the surrounding tissue and thus provide further breeding ground for the pathogen in the sense of a vicious circle ( vicious circle ). In addition, exotoxins from clostridia have a function-inhibiting or even killing effect on white blood cells ( leukocytes ). They also promote the closure of small blood vessels through thrombosis, which further increases the oxygen deficiency in the affected tissue due to a circulatory disorder and promotes the optimal growth environment for the clostridia.

Symptoms

Gas burn of right thigh and pelvis, including visualized skin crepitation

After an incubation period of 5 to 48 hours after operations or soft tissue injuries, a rapidly spreading wound infection (reddening, heat in the wound area) that is extremely painful is noticed.

In most cases, when you touch (palpate) the area around the wound, you can hear and feel a noticeable crackling sound: skin emphysema caused by CO 2 formation ( skin crepitation ).

A bloody-blackish, foamy, sweetish-putrid smelling secretion is often emptied from drains . The affected muscles are gray-red in color and look compared to cooked beef.

The general condition of the patient is characterized by a rapidly progressing septic clinical picture with tachycardia , consumption coagulopathy (blood coagulation disorder), circulatory disorder, respiratory disorders and hemolytic anemia due to the decomposition of red blood cells by means of toxins from the clostridia. In addition, there are acute kidney failure and liver dysfunction ( multi-organ failure ).

diagnosis

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Due to the rapid and fatal course of the untreated disease and the need for immediate but at the same time interventional therapy up to the amputation of extremities, the diagnosis must be made immediately and reliably. For the clinical picture of a gas fire, all 3 of the following criteria must be met:

  • severe wound pain
  • Rapidly increasing soft tissue swelling, possibly signs of gas accumulation in the tissue
  • fast heartbeat ( tachycardia )

The gas formation in the tissue typically appears as "feathered" muscles in the X-ray structure. If all criteria are met, the next step should be to determine the cause of the infection. An exogenous gas fire must be distinguished from an endogenous one.

An exogenous gas fire can occur after:

An endogenous gas fire must be considered in the case of:

The clinical suspicion must now be proven. This happens either with a direct pathogen detection or the histological detection of characteristic changes in tissue samples of muscles. Three methods are possible for direct pathogen detection:

  • Bacterioscopy (microscopic detection of the bacteria in the muscle squeeze specimen)
  • Microbiology: Cultivation of pathogens from suspicious wound areas, infected muscles or blood culture
  • PCR (nucleic acid detection)

Typical features of muscles infected with gas burns are lumpy decay, leukocyte-poor edema and gas inclusions.

therapy

Performed hemipelvectomy indicated by gas fire, visible necrosis in the lumbar muscles

The therapy of gas fire is based on four pillars:

Therapy must begin when it is suspected.

Surgical intervention

Goals of the surgical procedure:

  • Reducing the toxin burden by eliminating all infected tissue. Although it is fundamentally desirable to preserve the body without permanent damage as far as possible, a limb amputation must also be seriously considered in order to save the patient's life.
  • Eliminating the lack of oxygen in the infected tissue in order to deprive the pathogens of their livelihood by changing the wound environment. Especially on the trunk of the body, where amputation is technically impossible, but also on extremities that one does not want to sacrifice, debridement and tissue splitting are carried out, which lead to pressure relief with improved blood circulation.

Due to the drama and danger of the course of the disease, life support must take precedence over the cosmetic and even the functional result.

Antibiotic therapy

Antibiotic therapy must be initiated before the result of an antibiogram is known. Due to the mostly present mixed infections, combinations of high-dose broad-spectrum antibiotics and antibiotics with effectiveness against anaerobes are used. An example combination based on this is penicillin G and metronidazole .

Hyperbaric oxygenation

Gas fire is a standard indication for the use of oxygen overpressure chambers .

This therapy aims to increase the O 2 partial pressure in the infected tissue by means of extremely high oxygen partial pressures in the surrounding atmosphere by means of diffusion . In this way, one deprives the obligatory anaerobic germ of the basis of life and hopes that this elegant, but logistically demanding treatment will save life and preserve extremities.

One problem with this is the time factor. Seriously ill people can hardly be transported and hyperbaric chambers are rare, even with the inclusion of cooperating military facilities. There are 30 of these chambers across Germany, but only 5 are on call for intensive care 24 hours a day. Initially, there is often only an aggressive surgical measure.

Intensive care

Multi-organ failure occurs as a result of the effects of the exotoxins of the pathogen. For stabilizing treatment of the patient, ventilation , therapy with catecholamines and other intensive medical therapy and monitoring methods are often necessary.

Individual evidence

  1. ↑ Yue Wang, Bo Lu, Peng Hao, Meng-ning Yan, Ke-rong Dai: Comprehensive treatment for gas gangrene of the limbs in earthquakes . In: Chinese Medical Journal . tape 126 , no. October 20 , 2013, ISSN  0366-6999 , p. 3833-3839 , PMID 24157141 .
  2. ^ Benjamin Sommer, Stefan Eggstein: Clinical snapshot: gas fire of the gallbladder. In: Deutsches Ärzteblatt. Volume 117, Issue 3, January 17, 2020, p. 38.
  3. ^ Robert Koch Institute : Case definitions for the health authorities of the countries in which, in addition to the IfSG, there is an obligation to report other diseases. 2009, accessed March 8, 2019 .
  4. ^ Marianne Abele-Horn: Antimicrobial Therapy. Decision support for the treatment and prophylaxis of infectious diseases. With the collaboration of Werner Heinz, Hartwig Klinker, Johann Schurz and August Stich, 2nd, revised and expanded edition. Peter Wiehl, Marburg 2009, ISBN 978-3-927219-14-4 , p. 159.
  5. ↑ Regensburg has a pressure chamber again. Mittelbayerische Zeitung , accessed on November 10, 2015 .
  6. ↑ Emergency centers for diving accidents and other (emergency) indications for HBOT. Society for diving and hyperbaric medicine , accessed November 10, 2015 .