Diathermy: mechanism of action, methodology, indications and contraindications

Diathermy [from the Greek diatfiermaino - I warm up (dia - through, across and therme - heat, warmth); syn.: endothermy, thermolenetration] is one of the methods of electrotherapy, consisting of local or general exposure of the patient's body to alternating electric current of high frequency and great strength, leading to an increase in temperature in organs and tissues.

The method was introduced into medical practice in 1905 by the Czech doctor R. Zeinek, the term "diathermy" was proposed by the German doctor F. Nagelipmidt, who was working on the method at the same time. It is usually prescribed in combination with other methods of treatment. Diathermy is not currently used as an independent method. Diathermy is based on the effect of alternating current of high frequency (up to 2 MHz), with a strength of 0.5-3 A, and relatively low voltage (hundreds of volts).

The amount of heat generated in the body is proportional to the square of the current passing through the conductor (body tissue), the electrical resistance of the tissues and the time of current passage. Therefore, if intensive tissue heating is required, a high-power current is required. But a strong direct or low-frequency current irritates sensitive nerves (pain). With an increase in frequency, the irritating effect of a strong current decreases and practically disappears for a current of 3 A at a frequency of 1 MHz. Tissues and organs of the body have different electrical conductivity. Thus, the skin, fat, bones, muscles have the highest resistance, they heat up more strongly, the organs rich in blood or lymph have the lowest resistance - the lungs, liver, lymph nodes and others, they heat up less strongly.

High-frequency currents also cause non-thermal (so-called specific) processes in the body, the nature of which is not clear. It is assumed that under the influence of the current, cellular ions move to the cell boundaries. At a certain maximum concentration at the boundaries, the cell colloids precipitate and the cell passes into an excited state. Specific effects are more pronounced at a comparatively lower current frequency; at a higher frequency, the thermal effect is more pronounced. The effect of diathermy is manifested by physiological reactions - the activity of the autonomic nervous system increases, which is expressed in increased lymph, blood circulation and metabolism (while the body temperature can increase by 0.1-0.2 ° C). Especially in the area subjected to diathermy, the activity of leukocytes increases. Under the influence of diathermy, skeletal muscles and muscles of internal organs relax, the threshold of excitability of sensory nerves increases. Therefore, diathermy is used in the treatment of diseases based on spasms of blood vessels, ureters, bile ducts, gall bladder and other hollow organs, as well as chronic non-purulent inflammatory diseases, inflammation of nerves and their roots, neuralgia, muscle, joint and other pain.

Mechanism of action of diathermy:

• vasodilation, which leads to improved blood and lymph circulation, and consequently, tissue trophism, improved removal of metabolic products;
• stimulation of metabolism;
• increased permeability of vascular walls:
• stimulation of phagocytosis;
• decreased excitability of nerve cells, and consequently, decreased pain;
• reflex decrease in the tone of striated and smooth muscles, which leads to a decrease in pain associated with their spasm;
• stimulation of the evacuation function of the stomach, increase in the acidity of gastric juice, decrease in the content of pepsin;
• increased secretion of bile;
• stimulation of the secretory function of the salivary glands;
• increased diuresis;
• lowering blood sugar levels, increasing glucose tolerance.

Indications for diathermy:

• diseases of the respiratory system (croupous and catarrhal pneumonia, bronchial asthma, dry and exudative pleurisy);
• heart disease (coronary artery spasm);
• diseases of the gastrointestinal tract (chronic gastritis, chronic cholecystitis, chronic colitis);
• kidney disease (acute nephritis);
• diseases of the musculoskeletal system (gonorrheal, rheumatic, traumatic arthritis, myositis, tendovaginitis);
• diseases of the peripheral and central nervous system (neuritis, radiculitis, encephalitis, myelitis);
• alopecia.

Methods of appointment

Treatment of alopecia: two electrodes measuring 5-8 cm are placed in the area of the cervical vertebrae along the sternocleidomastoid muscles. Using a double wire, these two electrodes are connected to the positive terminal of the equipment. The third electrode, 80 cm3 in area ^, is placed on the back of the neck. Duration of the procedure is 10-20 minutes. Duration of the course is 10-20 procedures. Diathermy is performed daily or every other day. Usually, the treatment consists of 2-3 courses with breaks of 1-1.5 months. Active hair growth is observed 2-5 months after the end of the treatment.

The principle of diathermy is also used in various surgical instruments. For example, a diathermy knife is used to coagulate tissue. The knife itself is one electrode, and the other electrode is a large, moistened pad placed on the patient's body. Since the blood immediately coagulates (coagulates) and small blood vessels are sealed when using a diathermy knife, the doctor can make a virtually bloodless tissue incision in the patient. Diathermy snares and needles can be used to destroy tissue and remove small superficial growths.

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