Dry gangrene is the death of tissues under the influence of destructive factors or due to the cessation of blood supply. It is accompanied by darkening, a decrease in the volume of the segment, wrinkling and loss of moisture. It can develop as a result of temperature, radiation and chemical influences, atherosclerosis, as well as gradual disruption or cessation of blood supply due to other reasons. It is accompanied by sharp pain with subsequent loss of sensitivity. The diagnosis is made on the basis of symptoms, to find out the causes of dry gangrene, Dopplerography, angiography, phlebography, MRI, CT and other studies may be required. Surgical treatment – necrectomy or amputation.
ICD 10
R02 Gangrene, not classified elsewhere
Meaning
Dry gangrene is tissue necrosis that has arisen under the influence of external destructive influences or blood supply disorders. Characteristic features are the mummification of tissues and the advancement of the necrosis zone from the periphery to the center. Unlike wet gangrene, it is not accompanied by a large amount of toxins entering the body and is not prone to spreading to healthy tissues. When an infection is attached, it can turn into a wet gangrene.
Usually occurs in the extremities, but can develop in the internal organs. In the first case, the outcome is the rejection of the dead area, in the second – the replacement of the necrosis zone with connective tissue. It does not belong to the category of independent diseases, it is always the result of an injury or some kind of pathological process. Treatment of this pathology, depending on the cause of its occurrence, can be carried out by traumatologists-orthopedists, combustiologists (doctors providing assistance in the field of burn medicine), phlebologists, vascular surgeons and other specialists.
Causes
The direct cause of dry gangrene is the impact on the tissues of various thermal, mechanical, chemical, electrical, radiation, toxic and other factors. As a result of this exposure, cells or organs are destroyed and rejected. A predisposing factor for the occurrence of dry gangrene is a small amount of fluid in the tissues of the affected area, which creates unfavorable conditions for the development of infection and provides prerequisites for mummification.
Most often, dry gangrene develops with frostbite (exposure to tissue temperatures below -15 degrees), but with such an injury, wet gangrene can also form – the nature of necrosis in each case depends on the amount of moisture in the tissues and the presence or absence of infection. Tissue mummification can also be observed after exposure to high voltage electric current. In this case, areas of necrosis are formed at the points of entry and exit of the current, in the area of burned tissues.
Another possible reason for the development of dry necrosis is the effect of strong acids, leading to the coagulation of cell proteins and the formation of a zone of dry coagulation necrosis. In addition, dry gangrene can occur as a result of gradual blood supply disorders in diabetes mellitus, atherosclerosis or obliterating endarteritis. For thrombosis, embolism or damage to the main vessel, wet gangrene is more characteristic, however, in emaciated patients, in some cases, the formation of dry necrosis may be observed.
The factors contributing to the development of dry gangrene include general and local anatomical and physiological features, environmental parameters (physical influences) and the absence of infection in the affected area. General anatomical and physiological features that contribute to the development of any gangrene (both dry and wet) – deterioration of the general condition of the body due to intoxication, acute or chronic infection, disorders of blood composition and metabolism, hunger, cold, heart weakness or anemia. At the same time, the likelihood of dry rather than wet gangrene increases with dehydration and general exhaustion of the patient.
Local predisposing factors are the features of the vascular system (loose or main type of artery branching), the degree of development of collaterals and vascular anastomoses, the absence or presence of a hematoma squeezing vessels, the condition of the vascular wall (endarteritis, sclerosis) and the rate of development of circulatory disorders. With sudden circulatory disorders, wet gangrene develops more often, with gradual – dry. Highly differentiated tissues with dry necrosis die faster than less differentiated ones.
External factors that provoke the development of dry necrosis are temperature changes. Cooling of the damaged area contributes to increased vascular spasm, and, consequently, further worsens blood circulation conditions. Excessive warming of the lesion causes an acceleration of metabolism, which, against the background of insufficient supply of tissues with blood, in some cases also leads to the formation of necrotic foci. At the same time, a prerequisite for the development of dry, not wet gangrene is the absence of infection, since after infection, dry necrosis quickly turns into wet.
Dry gangrene symptoms
This pathology is based on coagulation necrosis of tissues with the disintegration of the shaped elements of blood and coagulation of plasma proteins. At the initial stage, there are sharp ischemic pains in the affected segment. The skin turns pale, and then acquires a marble color. The patient complains of a feeling of numbness. On examination, the limb is cold, the pulse on the arteries is not palpable. There are violations of function. The degree of sensitivity disorders depends on the characteristics and degree of damage, as well as on the nature of the traumatic impact. Both a slight decrease in sensitivity and its complete absence are possible.
The tissues gradually shrink, dry out and mummify. They decrease in volume and thicken, become dark brown or black with a bluish tinge, due to the breakdown of blood pigment. This stage is accompanied by a complete loss of sensitivity with prolonged preservation of pain (the latter is explained by the presence of “living” nerve cells in an array of dead tissues and reactive edema above the necrosis zone). Regardless of the stage of the process, necrotic tissues do not emit an unpleasant odor. A characteristic feature is the spread of necrosis from the periphery to the center, to the place of blockage of the vessel or to the level at which there are sufficiently developed collateral arteries.
A demarcation shaft is gradually forming on the border between dead and healthy tissues. Dry dead tissues are an unfavorable environment for the development of infection, therefore, the greatest probability of infection and the transition of dry necrosis to wet exists in the initial stages of gangrene, when the tissues are not yet dry enough. The disintegration of dead tissues with dry gangrene is weakly pronounced, the absorption of toxic products practically does not occur, therefore the patient’s condition remains satisfactory or close to satisfactory.
Diagnostics
The diagnosis of dry gangrene is made on the basis of anamnesis and characteristic clinical manifestations. In some cases, additional studies are needed to clarify the cause of necrosis, assess the condition of the vessels of the affected area and determine treatment tactics. The patient may be prescribed phlebography, angiography, Dopplerography, CT arteriography, MRA, etc.
Dry gangrene treatment
The absence of pronounced intoxication and a tendency to spread the process to healthy tissues makes it possible not to carry out urgent removal of necrosis foci. At the initial stages, the patient is hospitalized in the department of traumatology and orthopedics, vascular or purulent surgery, rest of the limb is ensured and bandages are carried out with careful observance of the rules of asepsis in order to exclude infection of the affected area and the transition of dry gangrene to wet. To eliminate reflex spasm of collateral vessels, circular novocaine blockades of the limb are performed.
Apply means that help to improve the nutrition of tissues. After the formation of the demarcation shaft, the dead areas are removed. Independent rejection of necrotic tissues is not expected, since this process can take several months. Subsequently, according to the indications, plastic and reconstructive operations are performed to restore the appearance and function of the affected limb.
Prognosis and prevention
The prognosis for dry gangrene is favorable for life, but unfavorable for the preservation of the damaged segment. With the transition of dry necrosis to wet, the prognosis for life deteriorates sharply, immediate amputation or necrectomy is necessary. The main means of prevention is the prevention of injuries (primarily frostbite), as well as early diagnosis and adequate treatment of diseases, the consequence or complication of which may be dry tissue necrosis.
Literature
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