Bacterial synergistic gangrene

Introduction to bacterial synergistic gangrene Bacterial synergistic gangrene (also known as Meleneys Synergistic Gangrene), or progressive synergistic necrosis. It is a subcutaneous tissue infection caused by micro-aerobic non-hemolytic streptococcus and anaerobic streptococci. In addition, soft tissue infections of the limbs can also lead to pathological changes in gangrene. Bacterial synergistic gangrene has a slow course and is rare, but soft tissue necrosis is severe. basic knowledge The proportion of sickness: 0.003%-0.005% Susceptible people: no specific population Mode of infection: non-infectious Complications: skin anthrax, gas gangrene, necrotizing fasciitis, cellulitis

Bacterial synergistic gangrene

(1) Causes of the disease

The pathogen is similar to necrotizing fasciitis. It is caused by a variety of pathogens. Micro-aerobic non-hemolytic streptococcus is often found around the infected area, while Staphylococcus aureus, Proteus, Enterobacter, and green are isolated in the central necrotic area. Pseudomonas aeruginosa and Clostridium.

This disease often occurs in the incision after abdominal or thoracic surgery, especially in the indwelling site of the suture, intra-abdominal abscess and empyema drainage incision, colostomy or ileal fistula near the fistula, micro-trauma can also be complicated by the disease, This has a great relationship with the local infection of the wound.

(two) pathogenesis

Bacterial synergistic gangrene is a slow-progressive infection. The development of infection is only 1 to 2 cm in 7 to 10 days, and histopathology is chronic suppurative necrotic inflammation with obvious eosinophilic infiltration.

1. Widely dissolved coagulative necrosis of skin, subcutaneous, fascia and muscle. A large number of Gram-positive cocci and a variety of bacilli can be seen in the necrotic area. Necrosis develops from shallow to deep, skin, subcutaneous, deep fascia, muscle and bone. Membrane, bone can be necrotic.

2. Some small blood vessel walls around the necrotic lesion are invaded by inflammatory cells and repaired and proliferated. Some of the lumens are narrowed or occluded. It can be seen that microvascular stagnation and embolism in a wide range of tissues lead to blood circulation disorders.

3. Mixed inflammatory infiltration: There are dense lymphocytes around the necrotic foci, plasma cells, mononuclear cells infiltration, and a large number of eosinophils can be seen. Inflammatory cells infiltrated in some areas may even be dominant.

Bacterial synergistic gangrene prevention

Contaminated wounds should be cleaned and debrided as much as possible. Postoperative prophylactic use of antibiotics, strengthen the patient's systemic nutrition, improve anti-infective ability, strengthen postoperative wound observation, and timely treat local infection.

Bacterial synergistic gangrene complications Complications Skin anthrax gas gangrene necrotizing fasciitis cellulitis

1. Skin anthracnose: The pathogen is Bacillus anthracis, which is an itchy red spot rash from the beginning of the skin, followed by blisters. The center of the lesion is dark purple, full of blood and pus, ulceration after ulceration, and black dryness. More severe systemic symptoms, drainage of lymph nodes, often complicated by severe sepsis, can die within a few days.

2. Gas gangrene: The pathogenic bacteria are mainly Clostridium perfringens, generally have a history of trauma, and the disease progresses rapidly, mainly due to muscle necrosis, and may also have skin necrosis. There is a sounding pronunciation around the infected area, and the X-ray film can be seen in the soft tissue.

3. Necrotizing fasciitis: It is also a mixed infection of various pathogens. However, the infection mainly invades the fascia. Unless the primary disease involves the muscles, there is usually little muscle necrosis. The symptoms of systemic poisoning appear early and the symptoms are severe.

4. Cellulitis: It is a subcutaneous soft tissue infection caused by purulent bacteria. The surface skin is necrotic due to interruption of blood supply, and there is little necrosis of deep muscle tissue. After adequate drainage and application of antibiotics, infection is often easy to control.

Bacterial Synergistic Gangrene Symptoms Common Symptoms Red Severe Pain Skin Necrosis Subcutaneous Tissue Induration Lower Limb Wet Gangrene Dry Gangrene

1. Red induration: After a few days to several weeks after surgery, a small redness and induration appeared near the wound, and a gray-red inflammatory infiltrating area was formed later, and the central part was purple.

2. Fuchsia gangrene: Intense pain in the purple area with tenderness is a local characteristic of the disease. The induration gradually forms necrosis and ulceration. There is a sneak skin around it. The surrounding tissue of the ulcer is purple-red gangrene and serous secretion.

3. Skin necrotic circle: The ulcer grows slowly, and skin necrosis circle appears around it. Outside the skin necrosis circle, the skin is purple, and then the outer is a red circle. It has scattered satellite-like small ulcers and multiple sinus, tenderness. This specific lesion is called "Meleney ulcer."

4. Systemic symptoms are mild.

Bacterial synergistic gangrene examination

Peripheral blood

(1) The white blood cell count is elevated.

(2) The white blood cell classification count is increased.

2. Bacteriology examination

(1) Smear examination: Gram staining is performed on the secretions or serum around the skin edge to facilitate identification of bacterial species.

(2) Bacterial culture and drug sensitivity test: the secretion or slurry of the lesion is cultured, and the drug sensitivity test is carried out, which has a guiding effect on clinical diagnosis and treatment.

X-ray film: There is air shadow in the local soft tissue, which helps to distinguish from the infection of the bacterium.

Diagnosis and identification of bacterial synergistic gangrene

diagnosis

1. History of surgery: Recently there is sutured contaminated abdominal or chest surgery.

2. Local characteristic performance: severe pain in the wound accompanied by "Meleney ulcer".

3. Bacterological examination: In particular, pay attention to the cultivation of anaerobic bacteria and guide the diagnosis.

Differential diagnosis

1. Skin anthracnose: The pathogen is Bacillus anthracis, which is an itchy red spot rash from the beginning of the skin. After the blisters appear, the center of the lesion is dark purple, full of blood and pus. After ulceration, it forms an ulcer, and the knot is black and dry. Severe systemic symptoms, draining lymph nodes, often complicated by severe sepsis, can die within a few days.

2. Gas gangrene: The pathogenic bacteria are mainly Clostridium perfringens, which generally has a history of trauma, and the disease progresses rapidly. It is mainly caused by muscle necrosis, and there may also be necrosis of the skin. X-ray films can be seen in the soft tissue.

3. Necrotizing fasciitis: It is also a mixed infection of various pathogens, but the infection mainly invades the fascia. Unless the primary disease involves muscles, there is usually little muscle necrosis. The symptoms of systemic poisoning appear early and the symptoms are heavy.

4. Cellulitis: a subcutaneous soft tissue infection caused by purulent bacteria. The surface skin is necrotic due to interruption of blood supply, and there is little necrosis of deep muscle tissue. After adequate drainage, infection is often easily controlled after application of antibiotics.

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