From Big Medical Encyclopedia

CYANOSIS (Greek kyanos dark blue - f - osis) — the cyanotic coloring of skin and mucous membranes caused by high content in blood of the recovered hemoglobin. Unlike C. discolorations of skin owing to adjournment in it alien substances, napr, silver (argyrosis) or gold (hriziaz), call false cyanosis.

C. appears at concentration in capillary blood of the recovered hemoglobin more than 50 g! the l (at norm less than 30 g/l) can also be a symptom of various diseases. Most often C. observe at respiratory insufficiency (see) and heart diseases. It meets also at inborn patol. forms of hemoglobin (see Hemoglobinopathies) as a result of education in blood of sulfhemoglobin at poisoning with aniline derivatives, nitrites, sulphamides or owing to absorption of a large amount of endogenous nitrites from intestines at food toxicoinfection, cholera.

Sharply arising C. (for several seconds or minutes) it is observed at asphyxia (see), a cardiac tamponade (see), thromboembolisms of pulmonary arteries (see); developed subacutely (in terms from several tens minutes about one days) — at the heavy not stopped attack of bronchial asthma (see), acute inflammatory extensive processes in lungs (see), poisoning with methemoglobin formers of an exogenous and endogenous origin, at crises at patients with carcinoid (see), etc. At hron. heart diseases and easy C. develops gradually, gradually. Inborn C. it is observed at inborn heart diseases (see Heart diseases inborn) and a hereditary methemoglobinemia (see).

To true C. always the anoxemia owing to decrease in oxygen capacity of blood accompanies. At a long anoxemia and a fabric hypoxia (see) accessory signs appear: secondary erythrocytes (see), increase in a hematocrit and concentration of hemoglobin of blood, develops capillary staz (see). Quite often at hron. the diseases which are followed by C., at the same time observe changes of fingers in the form of drum sticks (see. Drum fingers) and a shape of nails in the form of clock glasses (see Hippocrates a nail).

C. is more noticeable on body parts with thin skin — lips, a face, fingers of hands, and also on nails. Expressiveness of C. depends on quantity of erythrocytes in blood and contents of hemoglobin in them: at a polycythemia (see). C. it is noticeable on reaching concentration of the recovered hemoglobin 50 g! l, and at the respiratory insufficiency which is combined with anemia (see) it appears late when already more than a half of hemoglobin becomes recovered.

By origin and to manifestations it is accepted to distinguish the central and peripheral cyanosis. To the central C. give three groups patol. processes. 1. Disturbance of oxygenation of blood in lungs at acute and hron. bronchopulmonary diseases, pathology of a pleura (see), a thorax (see) and other departments of system of external respiration (see) when respiratory insufficiency develops, and also at primary pulmonary hypertensia (see. And yer-sa syndrome). 2. An obstacle to inflow of a venous blood to lungs that is observed at a stenosis of a pulmonary trunk, Fallo's tetrad (see Fallo a tetrad), thromboembolisms of pulmonary arteries (see) 3. Mixing of an arterial and venous blood in a left ventricle of heart or in arteries of a big circle of blood circulation with the inborn or acquired defects of partitions of heart or large arteriovenous soustiya (the defects of interventricular and interatrial partitions complicated by a circulatory unefficiency, Lyutambashe's syndrome, etc.) - Thus, at the central C. strengthening of the recovered hemoglobin not only in capillary, but also in an arterial blood takes place.

Peripheral C. arises at delay of a blood-groove in fabrics owing to what the amount of the recovered hemoglobin increases only in capillary blood of those fabrics where the blood stream is slowed down. Peripheral C. — a frequent symptom of right ventricular heart failure (see); it is observed also owing to local disturbances of venous outflow at a varicosity (see), thrombophlebitis (see), a prelum of veins by a tumor, frustration of a tone of peripheral vessels, disturbances of microcirculation (a polyglobulia, increase in a caption of cold agglutinins, metastasises of carcinoid of a small bowel, a local inflammation), sometimes at insufficient inflow of an arterial blood (atherosclerosis, arteritis).

Differentiation pulmonary (central) and cordial (peripheral) forms of cyanosis is clinically important. To the central C. diffusion, an ash-gray shade of skin are inherent, owing to the accelerated blood-groove it is warm to the touch. Peripheral C. owing to the slowed-down blood-groove has character of a Crocq's disease (see); it is often expressed on brushes and feet, on lobes of ears, quite often has a reddish shade; skin is to the touch cold. After massage of a lobe of an ear before emergence of «capillary pulse» at peripheral C. cyanosis of a lobe disappears, and at central — remains. At difficulties in diagnosis it is necessary to consider that to peripheral C. such symptoms as swelling of cervical veins accompany, often swelled (see); besides, C. pulmonary origin (central C.) unlike a Crocq's disease disappears or decreases after 5 — 12-minute inhalation of pure oxygen. At a number of diseases the central and peripheral mechanism C. can be combined (e.g., at a mitral stenosis, a dekompensirovanny pulmonary heart, etc.). For confirmation of an arterial anoxemia also use an oksigemometriya (see).

Predictive value C. unequally at different diseases; the expressed and resistant C. at pulmonary diseases or hearts points to high degree of respiratory or heart failure, to-rye have the adverse forecast.

To special treatment of C. is not subject, but its existence can be the indication to an oxygenotherapy (see. Oxygen therapy), intensification of treatment of a basic disease. Reduction of C. is one of criteria of efficiency of the carried-out treatment.

Bibliography: Berezhnitskiym. N and

Vakalyukp. M. Znacheniye of a vascular tone of a big circle of blood circulation for developing of cyanosis, the Doctor, business, No. 7, page 7, 1971; E r sh about in A. I. Correlations of an anoxemia and cyanosis at bronchial asthma, Works Kazansk. medical in-that, t. 41, page 106, 1971; Y about N and sh B. Private cardiology, the lane from Czeches., t. 1, page 56, Prague, 1963; Hegglinr. Differential diagnosis of internal diseases, the lane with it., page 297, M., 1965.

V. I. Falcons; H. M. Plotnikova.