The causative agent of gas gangrene. Diagnosis and treatment of the disease

Anaerobic gas gangrene is an infectious disease that occurs against the background of reproduction and growth of bacteria of the genus Clostridium in human soft tissues, most often on the limbs. The causative agent enters the body in case of skin disfiguration.

Definition of

Lesion is considered a serious surgical pathology, which is formed due to anaerobic infection in the wound, which leads to significant tissue necrosis. The disease is dangerous by extensive toxic effects on the body, which even leads to death, if not on time to provide medical care. Because of the vital activity of microorganisms, a large amount of gas appears in the wound, which collects in the form of vesicles inside soft tissues.

Pathogens

Gas gangrene may appear due to the entry into the wound of certain microorganisms that affect the limbs and lead to tissue death.

Cl.perfringens are large and immovable polymorphic sticks that cause oval spores to form. They are placed subterminally and form a unique capsule in the body. Microbes have weakly expressed proteolytic properties and produce a large set of saccharolytic enzymes. As a result, fermentation of sugar takes place with the further formation of gas and acid. Pathogenic infection is divided into six serovars( A, B, C, D, E, F), having a variety of necrotic characteristics. Clostridia "A" is the primary causative agent of gas gangrene and form the disease in 70-80% of cases. Spores can withstand the temperature of the lesion at 100 ° C for 1 to 6 hours.

Cl.novyi are large and thick Gram-positive mobile rods that form oval spores, and inside are arranged without capsules and subterminally. They have weak proteolytic characteristics. Saccharolytic properties are less pronounced. There are four serovars( A, B, C, D) that can distinguish various antigenic characteristics of toxins that have hemolytic and necrotic properties. Disputes are resistant to various environmental factors and survive boiling for several hours, in the soil can be 7-8 years in active form.

Cl. Septicum are polymorphic, mobile and Gram-positive rods that form oval spores, do not form capsules and are subterminal. This causative agent of gas gangrene has mildly expressed saccharolytic and proteolytic properties. Possesses six serological types( A, B, C, D, E, F), isolates necrotic, lethal and hemolytic toxins.

Cl. Histolyticum are small, mobile and Gram-positive sticks that form spores without capsules. They have strong proteolytic properties. They are engaged in the production of exotoxin, which leads to necrotic and lethal outcome. These characteristics are formed due to the release of enzymes such as hyaluronidases, collagenases and lecithinases.

Causes of

Gas gangrene is caused by chopsticks of the clostridium family, which often live in the intestines of herbivores and from there enter the soil, clothing and street dust. In some cases, the pathogen can be found on the skin and in the feces of healthy people. Microorganisms multiply only in an oxygen-free environment, but if air gets on them, they remain for a long time in the form of spores, and under favorable circumstances again become active and become dangerous.

Most pathology develops as a result of multiplication, extensive wounds and traumatic limb breaks, less often due to lesions of the large intestine after ingestion of foreign bodies. In some situations, signs of gas gangrene may appear due to small cuts contaminated with soil particles and scraps of clothing.

How the

develops Clostridium is widely dispersed in the external environment, as well as in soil where it exists as a spore and penetrates the human body through abrasions and scratches if not treated in time. The following factors are the main factors of the development of anaerobic infection of gas gangrene:

• Often the situation occurs when the oxygenation is disturbed and the cavity and environment are poorly communicated. Also, the lesion is formed by the long-term wearing of the hemostatic tourniquet on the extremities when the main vessel is injured and in patients with chronic arterial insufficiency.
• Favorable background is the presence of a significant mass of bruised and withered tissues, as well as factors that reduce the body's resistance.
• The causative agent of gas gangrene is activated by the formation of positive anaerobic conditions. Microorganisms begin to vigorously multiply and form toxins that have a damaging effect on tissues, and also contribute to the rapid spread of necrosis.
• Because of the saccharolytic function, glycogen collapses, and the proletarian effect leads to melting and destruction of proteins.
• Clostridia differ in the formation of edema and gases.
• Because of the toxin action, thrombosis of the arteries and veins is formed, paralysis and destruction of the permeability of the vessels occur.
• Enzymatic elements of blood and plasma enter the necrosis zone, which causes the rapid absorption of bacterial toxins, and the decomposition products lead to severe intoxication.
• The incubation period ranges from a couple of hours to 2-3 weeks. On average, this time takes 1-7 days, and the shorter the period, the worse and heavier the current and the forecast.

Clostridia isolates exotoxins consisting of several fractions, possessing local and systemic influence, which include:

• lecithinase C - has a hemolytic and necrotic effect;
• collagenase - blocks protein structures;
• hemolysin - has cardiotoxic and necrotizing effects;
• fibrinosolin;
• hyaluronidase - is a factor of bacteria penetration;
• hemagglutinin - inhibits the formation of phagocytosis;
• neuraminidase - neutralizes immune receptors on erythrocytes.

Symptoms of

A specific feature is crepitation - when palpation you can feel the sounds similar to the crunch of snow. Most often, the onset of the disease is violent with a significant development of severe intoxication. The classic symptoms of gas gangrene are:

• pronounced edema passing without hyperemia;
• blisters in which there are hemorrhagic compositions, and green spots on the skin are also observed;
• significant bursting pain;
• massive necrosis of the muscular and connective tissues;
• temperature reduction;
• formation of a turbid exudate of a non-uniform manifestation, accompanied by an unpleasant odor;
• the accumulation of gases.

For anaerobic infection, a typical rapid increase in local symptoms of gas gangrene, as well as widespread processes throughout the limb region. After a few days, as a rule, begins to join and aerobic microflora, accompanied by a purulent infection.

Stages of

• Early. During this period, patients complain of pain. The wound looks dry with a dirty gray coating appeared. Necrosis passes practically without a detachable or insignificant amount of brownish exudation. There is a small swelling near the wound, the skin is pale with a slight jaundice tint.
• The stage of distribution. With it, the process of gassing and edema progresses. Pain acquires its expanding properties. The causative agent of gas gangrene begins to kill tissues, they get lifeless and dry appearance, the muscles look fragile, dull and bloodless. The icteric color of the epidermis extends far from the wound.
• At this stage, the limb becomes cold, it does not show peripheral pulsation, its sensitivity is disturbed, and pain stops. The integument acquires pallor, and the place of defeat considerably increases in size. Gases and swelling spread to the trunk, there are blisters with hemorrhagic or brown exudate. The wound is not alive, and the muscles in it look like boiled meat. From the depth of the lesion, blood-purulent discharge is possible.
• Sepsis. In the problem zone, pus is collected, marked intoxication and metastatic foci are observed.

Classification

There are three main forms:

• clostridial myositis - characterized by local muscle damage;
• clostridial cellulitis - mainly subcutaneous fatty tissue and connective tissues are destroyed;
• mixed form.

Diagnosis

First of all, a clinical examination and history of the disease should be performed:

• in the wound there is practically no pus;
• there is black color and crepitation of the affected area;
• under pressure gas bubbles are formed;
• muscles look like boiled meat;
• despite such a severe course of pathology, there is practically no increase in temperature.

When carrying an X-ray, there is a characteristic porous musculature. Diagnosis of gas gangrene also involves laboratory tests. The material is the elements of necrotic tissue, scraps of clothing, edematous fluid, blood and particles of earth. The bacteriological method consists of sowing on Wilson-Blair blood agar, on Kitt-Tarozzi medium and identification of the distributed cultures.

Treatment

For therapy, the patient must be isolated in a separate room with hygiene maintenance. In the room it is necessary to exclude the possibility of contact spread of the causative agent of gas gangrene. It is required to produce adequate and timely disinfection of medical equipment, dressings and toiletries.

The complex of measures includes the following items:

• timely and permanent surgical sanitation of the wound;
• the prevention of distribution and reproduction of bacteria is made by means of oxygenation, antibacterial agents and specific serums are applied;
• corrected changes in the functions of organs and all systems with the use of anticoagulant and infusion therapy, immunostimulation and immunocorrection;
• transmission routes of gas gangrene are blocked by neutralizing the circulating toxin due to the introduction of specific toxins and the use of extracorporeal detoxification methods.

Surgical intervention can be shown in three cases.

• If there was a wide separation of the affected tissues, namely "lamp-like" incisions with the opening of the fascial vagina to the bone and aponeuroses. All measures are performed for adequate aeration of the wound and elimination of edematous fluid, since it contains a large number of toxins.
• If there is an excision of muscle damage.
• When amputation of extremities is performed above the level of visually located viable tissues without using the procedure of imposition of primary sutures.

In order to improve the oxygenation process that is so necessary for the treatment of the disease, procedures are given in the pressure chamber, where oxygen is supplied under strong and targeted pressure, so that it penetrates better into the tissues. Intravenous it is required to introduce anti-gangrenous serum. It is pre-bred in half with the warmed-up physiological solution. Antibiotic therapy is performed with clostridial infection only with significant doses of penicillin( 20-30 million units per day intravenously).

The duration of treatment depends on the medical picture of the patient's recovery. If there is a rapidly developing necrosis with a sharp deterioration of the condition, then a timely amputation is required. The operation is carried out only to save life, as the infection spreads quickly, and a person can die.

It is already known how gas gangrene is transmitted and how quickly it spreads, so its surgical treatment is so important. Many doctors recommend using a comprehensive methodology. A more effective method is the use of a combination of aminoglycosides and penicillins, aminoglycosides and cephalosporins. Widely used drugs that selectively act on anaerobes, namely "Chloramphenicol", "Metronidazole", "Clindamycin", "Rifampicin", "Carbenicillin."

The use of serotherapy is the introduction of anti-gangrenous sera. One ampoule contains anatoxins against the main types of pathogens, which are actively neutralized, thereby restoring the initiative to the tissues. If there are cases of extensive damage or severe contamination of the wound, then mandatory introduction of multivalent serum at an average maintenance dose of 30,000 IU is required.

Prevention of gas gangrene

For various lesions, the main action to prevent the disease is the timely disinfection of the wound, and the application of a dressing to prevent secondary contamination of the surface.

It is also recommended in the first few hours to introduce anti-tetanus and anti-gangrenous serum if there is a chopped, deep, cut or contaminated wound. When a tourniquet is applied, it is necessary to indicate the time of the procedure next to it, and also, if there is a need for a patient to be transported to the hospital for a long time, relax the bandage every two hours to resume the blood supply to the distal part of the limb. The note needs to be updated after each procedure. Next, you need to conduct timely full-scale surgical treatment of soft tissues and bones.