Necrosis through wounds

Various mechanisms can lead to necrosis in wounds. Overall, however, this happens only rarely.One possibility is that the injury to the skin leads to a defect in the blood supply and thus to an undersupply of oxygen. A necrosis, which is caused by the immigration of pathogens, for example bacteria, is also possible.

Bacteria cause thrombosis (formation of blood clots) of the blood vessels and reduced blood flow. Another option is that the mechanical action that caused the wound has already caused a small number of cell necroses. This releases inflammatory mediators and causes the death of further cells, which in turn allows the necrosis to spread. People with a weakened or suppressed immune system are particularly at risk.

Necrosis of the skin

Necroses of the skin are significantly more frequent than necroses of bones or organs. They occur mainly in the form of a decubitus, circulatory disorders or frostbite. What all these forms have in common is an undersupply of oxygen to the tissue.

The cells become sour, die and finally burst. Necroses only become visible to humans when entire cell groups within the tissue die. Externally, necroses appear yellowish-greyish-black discolored and usually very dry and sunken (leathery).

In addition, inflammation of the surrounding tissue often occurs, which then reddens, swells, becomes warm and hurts. The necrosis itself hurts mainly because of the undersupply of oxygen. Often, however, the patient does not notice this because the necrosis progresses very slowly or there is a reduced sensation.

Necrosis of the skin is treated by surgical removal of the skin and a classic wound treatment. This is usually supplemented by antibiotic therapy and the administration of anti-inflammatory drugs. A special form of skin necrosis is necrotizing fasciitis, which is caused by bacteria. If this occurs in the genital region, it is called Fournier gangrene.

Femoral head necrosis

In femoral head necrosis, also known as femoral head necrosis, bone tissue in the head of the femur dies. Femoral head necrosis is usually a circulatory disorder. The reason is that the femoral head is very complicated and is supplied by various small blood vessels.

Necrosis usually occurs sporadically (by chance), but can also be caused by traumatic events (accidents) or as a result of circulatory influences such as diabetes, alcoholism or smoking. A necrosis of the femoral head manifests itself by load-dependent pain in the groin, which, however, also occurs at rest. Femoral head necrosis is usually diagnosed by MRI (magnetic resonance imaging).

The therapy depends mainly on the patient’s age and everyday demands. Often the hip joint is replaced by a prosthesis, a so-called hip TEP, which completely eliminates the necrosis but is not quite as strong as an original hip and has to be replaced again after about 15 to 20 years. In younger patients there are other options, such as drilling the necrosis or replacing the necrosis with stem cells from the femur. In less advanced cases of femoral head necrosis, drug therapy with blood flow-enhancing drugs is also possible. Femoral head necrosis can also occur in the context of Perthes disease, which should not be confused.