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The necrosis is provided by process which is characterized by local necrosis of a site of fabric of a live organism. This process begins to develop as under the influence of endogenous, and exogenous factors (that is internal or external). It is possible to refer disturbances of blood circulation and a trophicity of fabrics because of various reasons to the first, injuries most often concern to the second. The factors causing a necrosis:
- Mechanical from which the gap and other disturbances of integrity of fabric result
- Thermal, temperatures are below 15 degrees Celsius and above 60 can specify to frostbites, and as a result to necroses of fabrics
- Electric factors work with image, similar thermal: in places of passing of a current there is a high temperature, and fabrics burn through
- Chemicals, such as strong alkalis and acids, can lead to a necrosis, causing its dry or wet form
- Beam factors also lead to necrosis of fabrics, the penetrating radiation can lead to necroses of the most severe forms
- Toxins of microbes which also can belong to toxic factors becomes the reason of development of a necrosis
- The circulatory disturbances leading to development of necroses can be a consequence of misoperation of cardiovascular system, a long vasospasm, wound or a prelum of vessels, changes of chemism of blood, etc. Even insignificant disturbance of a trophicity can lead to necrosis of fabrics. For example, at injuries of a spinal cord decubituses develop during which period.
The speed of development and penetration depth of a necrosis are influenced by many factors: features of external environment, existence or lack of microflora in the center, physiological features of an organism, state of health, etc. Coolings of area of potential necrosis, its warming, presence of microbes can aggravate process of a necrosis of fabrics considerably.
On an emergence etiology the necrosis is subdivided on:
- Ischemic – in other words a heart attack. Arises owing to an embolism, thrombosis, a spasm of arteries, an overstrain of body because of air hunger (hypoxia). The term a heart attack can be applicable to a kidney, a spleen, a brain, a myocardium site.
- The traumatic necrosis arises owing to direct impact of various factors on fabric. Radiation, high and low temperatures, electric traumas lead to this type of necrosis of fabrics.
- The trophoneurotic necrosis can be caused by disturbances or diseases of a peripheral or central nervous system.
- Toksigenna the necrosis can develop as a result of hit of toxins of not bacterial and bacterial origin. In the pre-natal period cases of a toxic necrosis occasionally result from action of bacteria or medicines.
- Direct: traumatic, toxic
- Indirect: trophoneurotic, ischemic, allergic
On morphological features:
- Dry necrosis. Develops in case of delay of hydrolytic processes, the increased content of proteins. The dry and dense consistence of devitalized fabric is characteristic of this type of a necrosis. The necrosis of muscles at typhus can serve as an example, a fibrinoid necrosis at autoimmune and allergic diseases. The tyromatosis belongs to this version, it develops at such diseases as syphilis, tuberculosis, limfogrunelemotoz. As a result of the chemical analysis of such devitalized sites of skin a large number of lipids comes to light.
- Wet necrosis. The flabby fabric containing a large amount of moisture is characteristic of this type of a necrosis. The wet necrosis can develop in fabrics which are rich with liquid and of which activity of hydrolytic enzymes is characteristic. The brain can be an example of such center.
- Gangrene. It represents a necrosis of fabrics of very dark or black color which develops fabrics via anatomic channels or directly. Such color is caused by substance which turned out from compound of hemoglobin and hydrosulphuric air. Gangrene happens dry and wet. The first usually mentions extremities, the long current is characteristic of it. Wet gangrene can develop very quickly, presence of an infection is characteristic of it.
- Decubituses. Understand their death as a result of disturbance of a trophicity, blood circulation, constant pressure as this type of necrosis of fabrics. As a rule decubituses arise at bed patients on shovels, heels, in the field of kresets, elbow joints, an ischium, etc. In world medical practice the most unexpected places of formation of decubituses are known: even denture pressure can give not a gingiva in this type of a necrosis.
For treatment of necroses both local, and general drugs are used, at the same time the special treatment is characteristic of each type of a necrosis. In general treatment means processing dezenfetsiruyushchy raster, opening – for wet forms, excision of dead fabrics, imposing of bandages, carrying out vascular and antibacterial therapy.