IV. Table of contents of teaching Structurally logical scheme of the theme

Necrosis and gangrene: determination – circumstances of origin

Classification – features of clinic – features of treatment

Flow of a necrotizing process – characteristic of separate kinds – their symptomatology – the treatment

Symptomatology of necrosis's and gangrenes – general and local manifestations

Methods of the treatment – a choice on soil of determination of the type of necrosis and tempo of development of the process

Ulcer: determination – circumstances of origin

Classification – features of the structure – features of clinic – features of the treatment

Flow of ulcer-necrotic process – Symptomatology – the treatment

Symptomatology of ulcers – general and local manifestations

Methods of the treatment – a choice on soil of determination of character of origin, phase of process and features of the structure of a ulcer

Bedsore – the special type of trophic ulcer

Fistula: determination – circumstances of origin

Classification – features of the structure – features of clinic – features of the treatment

Symptomatology of fistulas – general and local manifestations

Specific methods of the diagnostic: fistulography, test with a colouring material

Methods of the treatment – a choice on soil of determination of the structure and origin

Foreign bodies: determination – circumstances of origin – classification

A reaction of organism – features of clinic – features of the treatment

Symptomatology of foreign bodies – general and local manifestations

Methods of the treatment – a choice on soil of determination of localization, origin, possible consequences

V. Reference basis of an action

BASIC CONCEPTS

Necrosis is a loss of cells (necrocytosis), tissues or organs in a living organism.

Necrobiosis is irreversible dystrophic changes which precede to necrosis.

Patobioz is necrobiosis which is stretched in time.

Gangrene is loss of part of a body (organ) which contacts with an external environment.

Infarct is circulatory ischemic necrosis of internals which do not contact with an external environment.

Detritus is the state of a tissue which was affected by necrosis and disintegration.

A sequestrum is an area of necrotic tissue which is freely locates among living tissues.

Paranecrosis is an aggregate of morphological manifestations of return changes of cells which characterize local widespread excitation: increase of closeness of colloids of cytoplasm and nucleus, changes of electrolyte composition, strengthening of sorption properties of cytoplasm. Paranecrosis is morphological manifestation of parabiosis.

Reasons of a necrosis

1. Factors which draw a necrosis directly (a direct necrosis):

• Mechanical (brute mechanical force which exceeds resistance of tissues, for example at breaking up or squashing of tissues);

• physical (high (>60оC) and low (<15оC) temperature, which causes a burn or frostbite, electric current of high voltage which causes necrosis of tissues in the places of entrance and exit, penetrable radiation);

• chemical (acids which coagulate proteins with subsequent formation of a coagulate necrosis, alkalis which dissolve proteins and saponify lipids with the subsequent formation a moist necrosis; Mustard gas, Calcium chloride at a hypodermic introduction);

• biological (microbial toxins, specific infection (tuberculosis, lepra, syphilis), proteolytic enzymes which digest a mucus membrane at ulcerous illness of a duodenum and stomach, acute pancreatitis).

2. Factors which assist to development of a necrosis (an indirect necrosis)

• It's critical decrease of circulation of blood in arteries at a thrombosis, an embolism, a protracted spasm, an endarteritis, an atherosclerosis, a diabetic macroangiopathy, a trauma of artery, an external compression (a tourniquet, a constricted hernia, a twisted of a mobile viscus) and insufficiency of circulation of blood. Examples: a cardiac infarction, a gangrene of lower on soil of an atherosclerosis, necrosis of bowel at a constricted hernia.

• It's a critical violation of outflow of blood on veins at varicose veins, a thrombosis of deep veins, a syndrome after thrombosis, a thrombophlebitis. An example is a venous gangrene.

• It's an acute decrease and deceleration of circulation of blood in shallow terminal arteries and microvasculature at Reyno's disease, a diabetic microangiopathy, infectious and inflammatory processes, an external or internal compression (it is bedsore).

• It's a change of a vascular wall at an endarteritis, an atherosclerosis (Mortarel's sclerosis) and diabetes mellitus.

• It's a disorder of a trophic innervation (a neurogenic necrosis). An example is an ulcers at the damage of peripheral nerves, an ulcer of a foot which perforates (a malum perforans pedis) on a heel or in the area of the 1th or 5th metatarsus bones.

• It's a violation of metabolism (an avitaminosis, diabetes mellitus, anaemia).

• It's a formation of an ulcer in the area of a tumour (it is their disintegration).

genesis OF NECROTIZING CHANGES

Critical parameters of microcirculation for develop necrosis of tissues are (А.А. Polynskiy, 1985):

• The pulse volume of tissues is < 20,6±2,7 ml/min on 100 cm³ of a tissue;

• The volumetric velocity of circulation of blood is < 2,4±0,2 ml/min on 100 cm³;

• The pressure in capillaries is < 18,5±3,1 mm Hg.

At hypoxia an activity of oxidizing enzymes goes down in tissues and capillaries; a composition of isoenzymic spectrum of LDG changes toward advantage of factions which function in anaerobic conditions. The disintegration of lysosomes and the liberation of hydrolyzing enzymes which lyse cells and tissues arise as a result of the decrease of redox reactions and activity of enzymes. The content of Histamines, Serotonins, kinins, prostaglandins which render a membrane attack action is increased in them.

The necrosis of tissues arises. Proteases which assist in distribution of necrotizing changes| accumulate. A sensitization to products of disintegration of proteins can call autoimmune processes which deepen disorders of blood circulation and hypoxia of tissues and progress of necrotizing changes.

There are conditions which determine a speed and degree of distribution of a necrosis and its kinds.

1. General:

• Acute and chronic infections

• Intoxication

• Exhaustion

• Avitaminosis (scurvy)

• Anaemia

• Cardiac insufficiency

• Cold

• Hunger

• Disorder of metabolism

• Disorder of composition of blood