Necrosis (necrosis)

Local death of cells, tissues or organs in a living body, death can occur from direct destruction by a traumatizing agent, from a circulatory disorder or trophic disorder. Factors leading to necrosis are: mechanical, thermal, electrical, chemical, toxic, radiation, etc.
Exposure to cells, tissues and organs of mechanical force exceeding the resistance of the shells leads to their crushing, rupture, etc. Temperature above + 60 ± C or lower - 15 ± C causes burns, frostbite. In places of entry and exit from the body of high-voltage electrocution (see Electric trauma) a very high temperature develops, "signs of current" - burned in these places of tissue appear on the body.
Chemical action. Strong acids, coagulating the cell proteins, cause dry necrosis. Strong alkalis, dissolving proteins and saponifying fats, lead to the development of colliquated tissue necrosis (both - chemical burns). Microbial toxins can also lead to necrosis of cells, tissues (for example, anaerobic gangrene of the limb, etc.).
Circulatory disorders, causing necrosis of tissues or organs, are caused by the following reasons: a) violation of cardiac activity, its weakening (decompensation, embolism); B) prolonged spasm or obliteration of vessels (sclerosis of vessels with senile gangrene, obliterating endarteritis and atherosclerosis, gangrene in case of ergot poisoning, etc.); C) Stiffened or wounded vessel (necrosis of the intestine with strangulated hernia, gangrene of the limb with a timeless not removed tourniquet or an excessively tight plaster bandage); D) violation of blood chemistry, leading to thrombosis of the main vessel in the absence of sufficiently developed collaterals (thrombosis, embolism).
Circulatory disorders and subsequent necrosis often determine the course of surgical and other diseases. Thus, tissue necrosis plays an important role in the development of the clinic of anaerobic gangrene, obliterating endarteritis, gangrenous appendicitis, cholecystitis, acute pancreatitis, intestinal obstruction, strangulated hernia, perforated stomach ulcers, etc.
Violations of trophic tissue can also lead to necrosis, even with the most minor external influences. An example is the rapid development of pressure ulcers on the body with spinal cord injuries.
Conditions that affect the speed and extent of the occurrence of necrosis can be divided into three groups: 1) apatomo-physiological characteristics; 2) the presence or absence of microflora in the locus of the disease; and 3) physical phenomena (especially the environment).
1. Anatomico-physiological features are divided into general, relating to the whole patient's body, and local, characterizing the area of ​​the body in which the pathological process develops. Disturbances in the general state of the body caused by acute or chronic infection, intoxication, exhaustion, avitaminosis, varying degrees of anemia, cardiac weakness, cold, hunger, metabolic disorders and blood composition contribute to the development and spread of necrotic processes.
Local conditions include the structure of the vascular system (main, loose type of branching of the arteries), the presence or absence of vascular anastomoses, collaterals in the lesion, the rapid development of circulatory disorders, the state of the vascular wall (sclerosis, endarteritis), the presence or absence of the blood vessel compressing hematoma, etc. .
2. The presence of microbes and their toxins in the area with impaired blood circulation accelerates the development and increases the spread of tissue necrosis (gas gangrene, gangrenous appendicitis, cholecystitis, gangrene of the lung, etc.).
3. Cooling the area with impaired blood circulation, strengthening the spasm of blood vessels, further disturbs blood circulation and promotes the development of necrosis.
4. Excessive warming of this area increases the metabolism of tissues in conditions of insufficient blood circulation and can also lead to necrosis necrosis.
Various causes and conditions that promote the development of necrosis, cause a variety of clinical manifestations in this type of pathology.
5. Severe types of necrosis are observed when tissues are affected by penetrating radiation. The mechanism of action of this factor is very complex and consists of local effects on tissues and general disorders characteristic of radiation sickness.
Intestinal obstruction. There are two types: mechanical and dynamic. Mechanical obstruction occurs as a result of a bowel turn, knot formation, adhesion, invagination (insertion of one intestine into another), with an injured hernia, blockage of the intestine by food or calves, foreign bodies, ascarids, tumors. Dynamic intestinal obstruction can be a result of severe disruption (paresis) of the motor function of the intestine (peristalsis).
With mechanical obstruction there is bloating, sometimes asymmetrical, spastic pain, lack of stool; With small intestinal obstruction, vomiting occurs, which eventually becomes stinking feces. When invagination, bloody diarrhea occurs. There are signs of intoxication, dehydration. In the diagnosis can help X-ray. Treatment of mechanical intestinal obstruction surgical.
With dynamic intestinal obstruction symptoms are almost the same, but there is no peristalsis. Treatment conservative: stimulation of peristalsis, purifying, hypertensive and siphon enemas, control of intoxication and dehydration.
The nail is ingrown. The disease primarily affects the first toe of the foot. It is caused by constant pressure of the edge of the nail on the peri-oral roller. Predisposing factor is wearing tight shoes, wrong nail cutting (too far in the direction to the base cut off the side edges).
Patients note pain in the region of the nail roller when walking, swelling of the tissues. Then there are granulations, pus is released. It should be checked whether there are concomitant diseases: diabetes, obliterating endarteritis.
In the early cases, conservative: warm baths, noggy toilet, wearing large shoes, furatsilin treatment, manganese-acid potassium. With a deep ingrowth of the nail, removal of the entire nail plate or part of it is indicated. If the disease recurs, then the bed of the nail plate is dissected from the diseased side.