Gangrene

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, which makes the necrotic tissue black, and the necrotic tissue has less water, and the surface water is easy to evaporate, causing the lesion to dry. Solid shrinkage, dark brown, and a clear dividing line between the surrounding healthy tissue.

Cause

Dry gangrene: 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 occurs mostly 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: A special type of wet gangrene, mainly found in severe deep muscle wounds 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.

an examination

Gangrene grading

Grade 0: no open lesions, obvious insufficient blood supply.

Grade I: superficial ulcers. May be caused by blisters or other damage, or spontaneously.

Grade II: ulcers deep into tendons, ligaments, bones and joints.

Grade III: deep ulceration infection, and osteomyelitis and abscess sinus formation.

Grade IV: There are toes and/or partial foot gangrene.

Class V: All-round gangrene.

Differential diagnosis

No special illness is identified.

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