Diathermy: mechanism of action, technique, indications and contraindications

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

The method was introduced into medical practice in 1905 by the Czech physician R. Zeineck, the term "diathermy" was proposed by the German physician F. Nagelippidt, who worked on the method at the same time. It is usually prescribed in combination with other methods of treatment. As an independent method, diathermy is not currently used. At the heart of diathermy is the effect of alternating current of high frequency (up to 2 MHz), force 0.5-3 A, relatively small voltage (hundreds of volts).

The amount of heat generated in the body is proportional to the square of the current flowing through the conductor (tissue of the body), the electrical resistance of the tissues and the time of passage of the current. Therefore, if intensive tissue heating is necessary, a current of great strength is required. But a strong constant or low-frequency current causes irritation of the sensory nerves (pain sensations). As the frequency increases, the stimulus of the strong current decreases and practically disappears for a current of 3 A at a current frequency of 1 MHz. Tissues and organs of the body have different electrical conductivity. So, skin, fat, bones, muscles have the greatest resistance, they heat up more, the least - organs that are rich in blood or lymph - light, liver, lymph nodes and others, they heat up more weakly.

High-frequency currents cause in the body also non-thermal (so-called specific) processes, the essence of which is not clear. It is assumed that under the influence of current, the cellular ions move to the cell boundaries. At a certain limiting concentration at the boundaries, the colloids of the cell drop out and it passes into an excited state. Specific effects are more pronounced at a relatively 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 manifested in the intensification of lympho-, blood circulation and metabolism (the body temperature can be increased by 0.1-0.2 ° C). Especially in the area undergoing diathermy, leukocyte activity increases. Under the influence of diathermy, skeletal muscle and muscles of the internal organs relax, the threshold of excitability of the sensitive nerves increases. Therefore, diathermy is used in the treatment of diseases that are based on spasms of blood vessels, ureter, bile ducts, gall bladder and other hollow organs, as well as chronic inflammatory diseases of inflammation of the nerves and their roots, neuralgia, muscle, joint and other pain.

Mechanism of action of diathermy:

• vasodilation, which leads to an improvement in blood and lymph circulation, and consequently trophism of tissues, improvement of excretion of metabolic products;
• stimulation of metabolism;
• increase in permeability of vessel walls:
• stimulation of phagocytosis;
• a decrease in the excitability of nerve cells, and consequently, a reduction in pain;
• reflex reduction in the tone of the striated and smooth musculature, which leads to a reduction in the pain associated with their spasm;
• stimulation of the evacuation function of the stomach, increasing the acidity of the gastric juice, reducing the content of pepsin;
• increased bile secretion;
• stimulation of the secretory function of the salivary glands;
• increased diuresis;
• decrease in the level of sugar in the blood, increase in glucose tolerance.

Indications for diathermy:

• diseases of the respiratory system (croup and catarrhal pneumonia, bronchial asthma, dry and exudate pleurisy);
• heart disease (spasm of the coronary vessels);
• diseases of the gastrointestinal tract (chronic gastritis, chronic cholecystitis, chronic colitis);
• kidney disease (acute nephritis);
• diseases of organs of the musculoskeletal system (gonorrhea, 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 5-8 cm in size are located in the region of the cervical vertebrae along the sternocleidomastoid muscles. With the help of a double wire, these two electrodes are connected to the plus of the equipment. The third electrode, an area of 80 cm ³, is placed on the posterior surface of the neck. The duration of the procedure is 10-20 min. The duration of the course is 10-20 procedures. Diathermy is performed daily or every other day. Usually treatment is 2-3 courses with interruptions of 1 - 1.5 months. Active hair growth is observed after 2-5 months after the end of treatment.

The principle of diathermy is also used in various surgical instruments. For example, a diathermy knife (diathermy knife) is used to coagulate tissues. The knife itself is one electrode, the other electrode is a large moistened gasket applied to the patient's body. Since with the use of a diathermic knife, blood coagulates immediately (coagulates), and small blood vessels are clogged, the doctor can make the patient a virtually bloodless section of tissues. Diathermy snares and diathermy needles can be used to destroy tissues and remove small superficial tumors.

[1], [2], [3], [4], [5], [6]