Wet gangrene of lower extremities

Introduction After tissue necrosis, due to the infection of secondary spoilage bacteria and other factors, it shows a special morphological change such as black and dark green, called gangrene. The necrotic tissue is decomposed by spoilage bacteria to produce hydrogen sulfide, which combines with the iron decomposed in hemoglobin to form iron sulfide, making the necrotic tissue black. The gangrene is divided into the following three types: dry gangrene (Dry gangrene) is mostly found at the extremities of the extremities, such as atherosclerosis, thromboangiitis obliterans and frostbite. At this time, the artery is blocked and the venous return is smooth, so the necrotic tissue has less water, and the surface water is easy to evaporate, causing the lesion to dry and shrink, showing a dark brown color, and there is a clear boundary line with the surrounding healthy tissue. Since necrotic tissue is relatively dry, spoilage infections are generally mild. Wet gangrene (wet gangrene) Most of the wet gangrene occurs in the internal organs (intestines, uterus, lungs, etc.) that are connected to the outside world, and can also be seen in the limbs (when accompanied by congestion and edema). At this time, due to the high water content of the necrotic tissue, the spoilage bacteria are seriously infected, and the local area is obviously swollen, and it is dark green or dirty black. The spoilage bacteria break down proteins, produce sputum, skatole, etc., causing bad odor. Because the lesions develop faster and the inflammation is more diffuse, there is no obvious dividing line between the necrotic tissue and the healthy tissue. At the same time, the toxic products and bacterial toxins produced by tissue necrosis can be absorbed, which can cause symptoms of systemic poisoning and even death due to toxic shock. Common wet gangrene have gangrenous appendicitis, intestinal gangrene, lung gangrene and postpartum gangrenous endometritis. Gas gangrene is a special type of wet gangrene, mainly found in severe open muscle wounds and combined with anaerobic infections such as Clostridium perfringens. When the bacteria break down the necrotic tissue, a large amount of gas is generated, so that the necrotic tissue contains a large amount of air bubbles, and there is a "burst" sound. Gastric gangrene lesions develop rapidly, the symptoms of poisoning are obvious, and the consequences are serious, requiring urgent treatment. Wet gangrene of the lower extremities refers to wet gangrene that occurs in the lower extremities. Infectious "wet" gangrene is a toxin produced by bacteria called Clostridium that multiplies on necrotic muscles, killing muscles and upper skin in an area. Gun wounds, car accidents, and other wounds that are deprived of muscle or skin blood supply are contaminated and may infect the bacteria. Surgeons can often prevent this infectious "wet" gangrene by carefully cleaning the wound. The doctor will remove all the poor circulation and contaminated tissue. Sometimes, in order to prevent gangrene, doctors must inevitably remove some of their limbs.

Cause

1) The blood sugar is too high for a long time, and there is no external factor to ulcer itself;

2) improper treatment of athlete's foot infection;

3) Improper handling of cockroaches, corns, and splits;

4) The toenail is too short, and the nail bed is infected twice;

5) Itching of the skin and infection caused by mosquito bites;

6) Inadvertent burns and burns during winter heating;

7) traumatic infection;

8) infection after surgery;

9) Infected by improper dry and dry treatment of the foot;

10) Inappropriate footwear and friction cause infection. Diabetic ulcers can also occur in other areas.

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.

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. 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. 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.

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.

an examination

Related inspection

X-ray lipiodol imaging bacteria bacteriological test for antibiotic susceptibility test

Mainly based on clinical manifestations, wound secretion examination and X-ray examination, such as 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 acceleration. Irritability, 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 An 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

Talus necrosis: ischemic necrosis is more common. The talus is the only bone in the whole body that has no muscles to stop and attach. When the ankle joint is severely damaged, the blood supply to the talus is completely destroyed and ischemic necrosis occurs. Eventually, the talus body collapses and deforms, causing ankle joint osteoarthritis. Therefore, prevention and early treatment of avascular necrosis of the talus have an important role in its function. The talus fracture is the main cause of talus necrosis. The other causes of talus necrosis account for only about 10%. Osteoclast necrosis should be actively treated according to the cause, glucocorticoids (which can cause osteonecrosis).

Lower extremity arterial ischemia: Common diseases include arteriosclerotic occlusive disease, thromboangiitis obliterans, vasculitis, arterial injury, arterial distress and aneurysmal cystic disease, of which the former two are the most common. Lower extremity arterial ischemia can be divided into three phases: early, middle and late. In the early stage of ischemia, the main manifestations are the cold, numbness and acupuncture of the affected limb. During the examination, there may be a plaque-like change in the back of the foot. The toe tip and the toenail are obviously thickened and pale, and the skin temperature of the affected limb is lowered. The dorsal artery pulsation weakens or even disappears. It is followed by difficulty in walking, that is, the patient's walking speed is slowed down, the walking distance is shortened, and limp is present. The patient usually walks within 100 meters and feels numbness and pain in the affected limb. He must stop for a while before continuing to walk. Therefore, this symptom is also called "intermittent claudication", and this period can also be called "intermittent claudication".

If the disease develops further, it will enter the mid-term. On the basis of the above-mentioned symptoms gradually increasing, the main feature of the mid-term is pain. The patient is painful while walking, and also pains during rest, and the more the night is quiet, the more severe the pain, so this period is also called the resting pain period. Late stage is also called "necrosis period", which is mainly manifested by the blackening and necrosis of the toe, the external hemorrhoids, the heel and other peripheral parts, and the infection occurs on the basis of necrosis, forming ulceration. The patient was unable to sleep all night and the pain was unbearable.

Pigmentation in the lower part of the lower leg, desquamation, and eczema: one of the symptoms of varicose veins in the lower extremities. The varicose veins of the lower extremities refer to the superficial veins of the lower extremities only. Because of the insufficiency of the valve and the weak vein wall, it affects the blood return, causing the vein to prolong, bend and expand. Most occur in the saphenous vein, a small number of small saphenous veins or a small saphenous vein.

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