Wet gangrene of lower limbs

After tissue necrosis, due to secondary infection of spoilage bacteria and other factors, it presents special morphological changes such as black and dark green, which is called gangrene. Necrotic tissue is decomposed by spoilage bacteria to produce hydrogen sulfide, which combines with iron decomposed from hemoglobin to form iron sulfide, which makes the necrotic tissue black. Gangrene is divided into the following three types: dry gangrene (dry gangrene) is mostly found in the extremities, such as atherosclerosis, thromboocclusive vasculitis and frostbite. At this time, the arteries are blocked and the venous return flow is unobstructed. Therefore, there is less water in the necrotic tissue. In addition, the body surface water is easy to evaporate, which causes the lesion to dry and shrink. Because necrotic tissue is relatively dry, spoilage infections are generally mild. Wet gangrene Wet gangrene mostly occurs in the internal organs (intestines, uterus, lungs, etc.) communicating with the outside world, and can also be seen in the limbs (with congestion and edema). At this time, because the necrotic tissue contains more water, the spoilage bacteria are seriously infected, and the local swelling is obvious, which is dark green or dirty black. The spoilage bacteria decompose the protein, produce indole, skatole, etc., and cause malodor. Due to the rapid development of lesions and diffuse inflammation, there is no clear dividing line between necrotic tissue and healthy tissue. At the same time, after the toxic products and bacterial toxins produced by tissue necrosis are absorbed, they can cause symptoms of systemic poisoning, and even toxic shock can lead to death. Common wet gangrene include gangrene appendicitis, intestinal gangrene, pulmonary gangrene, and postpartum gangrene endometritis. Gas gangrene (gas gangrene) is a special type of wet gangrene, mainly seen in severe open wounds deep into the muscle and combined with anaerobic infections such as perfringens. When the bacteria break down the necrotic tissue, a large amount of gas is generated, so that the necrotic tissue contains a lot of air bubbles, and there is a "twist" sound. Gas gangrene lesions develop rapidly, the symptoms of poisoning are obvious, and the consequences are serious, requiring urgent treatment. Wet gangrene of the lower limbs refers to wet gangrene that occurs in the lower limbs. Infectious "wet" gangrene is caused by a toxin produced by a bacteria called Clostridium spp. That multiplies on necrotic muscles, killing the muscles and upper skin in an area. Contaminated wounds from gunshot wounds, car accidents, and other trauma that deprives blood from the muscles or skin are at risk of contracting the bacteria. Surgeons can usually prevent this infectious "wet" gangrene by carefully cleaning the wound. The doctor will remove all poorly circulated and contaminated tissue. Sometimes, in order to prevent gangrene, doctors inevitably have to cut off some limbs.