Gas gangrene

Introduction to gas gangrene Gastric gangrene (Cytoplasmic muscle necrosis) is a serious infection caused by Clostridium exotoxin. It is characterized by muscle necrosis and systemic toxicity. It has an acute onset and rapid progress. The main pathogen is Clostridium perfringens (80%). about). Others include Clostridium botulinum, Novosporium, Clostridium difficile, Clostridium difficile and Clostridium clostridium. More than one kind of Clostridium or other bacterial infections may be combined. The infected bacteria are mostly from the soil, and the endogenous people are mostly from the intestines or biliary tract. Clostridium produces at least 12 exotoxins, which can be caused by intraperitoneal injection of 7 toxins. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific population Mode of infection: non-infectious Complications: hemolytic anemia, shock, bacteremia

Cause of gas gangrene

Bacterial infection (60%):

Clostridium is a Gram-positive anaerobic bacterium, which is mainly caused by Clostridium perfringens (Wei bacillus), edema and bacillus, followed by Bacillus bacillus and lytic bacilli. Gangrene, often a mixed infection of two or more pathogens.

Immunity factor (30%):

The occurrence of gas gangrene is not solely determined by the presence of dysentery bacilli, but is determined by the body's resistance and wounds, that is, an anoxic environment that is conducive to the growth and reproduction of dystrophic gastrobacter. Clostridium is widely found in soil and human and animal feces, so it is easy to enter the wound, but it does not necessarily cause disease. Therefore, water loss, massive blood loss or shock, but also a large area of tissue necrosis, deep muscle damage, especially thigh and buttock damage, shrapnel retention, open fracture or associated with major vascular injury, the use of tourniquet time is too long, etc. It is prone to gas gangrene.

Pathogenesis:

The pathogens of gas gangrene mainly grow and reproduce in the wound, and rarely invade the blood circulation to cause sepsis. The gas-producing bacteria produce alpha toxin, collagenase, hyaluronidase, lytic enzyme and deoxyribonuclease, etc., red blood cell destruction causes hemolysis, hemoglobinuria, oliguria, renal tissue necrosis, edema, liquefaction, and large muscle necrosis. The lesion spreads rapidly and deteriorates. The decomposition of sugar produces a large amount of gas, which causes the tissue to swell; the decomposition of protein and the liquefaction of gelatin produce hydrogen sulfide, which causes the wound to stink. Due to ischemia, plasma exudation, and the action of various toxins, the tissues and muscles in the wound are further necrotic and corrosive, which is more conducive to the reproduction of bacteria and worsens the lesions. A large amount of tissue necrosis and exotoxin absorption can cause severe toxemia. Certain toxins can directly invade the heart, liver and kidneys, causing focal necrosis, causing dysfunction of these organs.

Gas gangrene prevention

Thorough debridement is the most reliable way to prevent gas gangrene after trauma. Debridement within 6 hours after injury can almost completely prevent the occurrence of gas gangrene. Even if the injury has been more than 6 hours, debridement can still play a good preventive role in the use of a large number of antibiotics. Therefore, for all open wounds, especially those with soil pollution and serious damage and lack of viability, thorough debridement should be carried out in time to injure wounds. After debridement, drainage should be opened and not sutured.

For wounds suspected of having gas gangrene, rinse or wet with 3% hydrogen peroxide or 1:1000 potassium permanganate solution; for sutured wounds, the suture should be removed and the wound opened.

Penicillin and tetracycline antibiotics have a good effect in preventing gas gangrene, and can be applied before and after debridement according to the traumatic condition. But it is not a substitute for debridement.

The patient should be isolated and all the clothes, dressings and equipment used by the patient should be collected separately for disinfection. Boiling disinfection should be more than 1h, preferably sterilized by high pressure steam, and the replaced dressing should be destroyed to prevent cross infection.

Gas gangrene complications Complications hemolytic anemia shock bacteremia

Common complications are hemolytic anemia, shock, renal failure, etc., about 15% with bacteremia.

Gastric gangrene symptoms Common symptoms Finger toe necrotic necrotizing fasciitis Lower extremity wet gangrene painful granulocyte reduction edema hypothermia pale pale disillusionment

The incubation period can be as short as 6 to 8 hours, but generally 1 to 4 days.

Partial manifestations of the patient's conscious part of the affected area, there is a tight feeling of dressing. In the future, there was a sudden pain in the affected area, which could not be relieved with a general analgesic. The affected part is swollen and the tenderness is severe. The skin around the wound is edematous, tense, pale, shiny, and quickly turns purple, and then turns purple-black, and blisters of varying sizes appear. The muscles in the wound are dark red or earthy gray due to necrosis, lose elasticity, and do not shrink when the knife is cut, nor bleeding, just like cooked meat. The sputum is often pronounced around the wound, indicating the presence of gas between the tissues. Gently squeeze the affected part, often bubbles escape from the wound, and there is a thin, foul-smelling serous bloody secretion.

Early symptoms of patients with systemic symptoms are indifferent, dizziness, headache, nausea, vomiting, cold sweat, irritability, high fever, rapid pulse (100 ~ 120 times / min), respiratory urge, and progressive anemia. In the late stage, there were severe symptoms of poisoning, blood pressure decreased, and finally jaundice, convulsions and coma.

Gas gangrene check

Direct smear staining of exudate showed Gram-positive Bacillus megaterium, which was arranged alone or in pairs. At the same time, white blood cells were rarely deformed or broken, and could be rapidly identified by fluorescent antibody, enzyme-labeled antibody and enzyme-labeled SPA. It is worth noting that, from a bacteriological point of view, Cp is a Gram-positive bacillus; however, Cp detected from the infected site may be Gram-negative or positive after staining.

Regular X-ray examinations help to detect gas gangrene early.

Diagnosis and identification of gas gangrene

diagnosis

Early diagnosis and timely treatment are the key to saving the injured limb and saving lives. Therefore, make a diagnosis as soon as possible. The diagnosis is mainly based on clinical manifestations, wound secretion examination and X-ray examination. For example, after injury or surgery, the wound has unusual pain, local swelling is rapidly increased, the skin around the wound is sputum, and there are severe symptoms of systemic poisoning such as pulse. Accelerated, irritated and progressive anemia, that is, the possibility of gas gangrene should be considered; the secretion smears in the wound are examined with a large number of Gram-positive bacilli, X-ray examination of the gas between the wound muscles, is the diagnosis of gas gangrene Three important basis. Anaerobic bacterial culture and pathological biopsy can confirm the diagnosis, but it takes a certain time, so you can not wait for the results, so as not to delay treatment.

Differential diagnosis

1. Bacillus cellulitis infection is confined to the subcutaneous tissue, spreading rapidly along the fascia gap, but does not invade the muscle. Generally, the onset is slow, and the incubation period is 3 to 5 days. Although it also begins with wound pain, there are also sputum sounds around the wound, but local pain and systemic symptoms are mild, skin is rarely discolored, and edema is very light.

2. The incidence of anaerobic streptococcal cellulitis is slow, and symptoms usually appear 3 days after injury. Toxemia, pain, local swelling and skin changes are mild. There are emphysema and sputum sounds, but emphysema is limited to subcutaneous tissue and fascia. There is general inflammatory performance around the wound. The exudate was serous and the smear was checked for streptococci.

3. E. coli cellulitis may have interstitial emphysema, and there are symptoms of toxic blood such as high fever and phlegm. However, local swelling develops slowly, and the pus has the characteristic of pus infected by E. coli, that is, the pus is thin and serous. A pus smear test can be found in Gram-negative bacilli.

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