CIRCULUS VITIOSUS

From Big Medical Encyclopedia

CIRCULUS VITIOSUS in medicine e (Latin circulus a circle; vitiosus spoiled, vicious; a synonym a vicious circle) — one of mechanisms of a pathogeny which is characterized by the fact that the structurally functional disturbances which arose in an organism become the reason of further aggravation of these disturbances as lead to development of the new pathological phenomena to-rye promote weighting (progressing) of initially arisen structurally functional disturbances. Such vicious circle is observed, e.g., at patients with heart diseases. Developments of stagnation in a small and big circle of blood circulation cause in them hypostases, disbolism, patol. changes in easy and other bodies. These changes, in turn, are the reason of further dysfunctions of blood circulation and even more burden a current of a basic disease. Other example — hron. the starvation leading to disorders of function of digestion and secretory processes, digestion and nutritive absorption are broken that aggravates disorders of function of digestion and the exhaustion which is originally caused by starvation.

The Page v is frequent. arises only in a certain stage of a disease or patol. process, at considerable expressiveness of the available disturbances. So, the developing hypoxia (see) any origins usually serves in the beginning as the signal mobilizing adaptive reactions of an organism (see Adaptation, adaptive reactions). However its deepening leads to further disturbances in systems of transport and utilization of oxygen: to frustration of the central pneumotaxis and blood circulation, patol. to changes of microcompasses - an even bed, to damage biol. membranes, including mitochondrial, etc. Such potentiation of primary frustration inevitably is followed by progressing of a hypoxia and can lead to gross irreversible violations of life activity up to death of an organism.

Various forms of frustration, a pathogeny to-rykh

the Page v is the cornerstone., can arise at disturbance of negative feed-backs in system of nervous control. Heavy pain syndromes, convulsive states concern to them (see Tetanus., pathophysiological aspects of development of tetanus, t. 25, additional materials), nek-ry types of hyperkinesias, etc., at to-rykh form generators patholologically of the strengthened excitement in different departments of a head and spinal cord (see. Nervous system).

In nek-ry cases at the heart of Page v. lie adaptive on the biol. entities of reaction. E.g., fiziol. the phenomenon of adaptation of baroreceptors at tranzitorny hypertensive states promotes stabilization of a high level of the ABP that, in turn, can lead to aggravation of frustration of system of regulation of the ABP and his further increase.

However not always Page v. leads to the progressing disorders of life activity. Sometimes Page v. represents naturally arising temporary component patol. process, in Krom premises to its elimination are put. The secondary alteration at an inflammation (see) aggravating primary damages, however at the same time promoting elimination of the reason which caused an inflammation and the most inflammatory process can be an example. In other cases more or less bystry «disintegration» of Page v. results from the accruing mobilization of protective and adaptive reactions of the different levels leading to elimination of nodal mechanisms of a vicious circle.

In all cases it is important to define timely danger of formation of a vicious circle both to accept the corresponding precautionary and to lay down. measures.

Sometimes the term «circulus vitiosus» designate the mechanical frustration arising in an organism after operative measures — gastroenterostomies (see) or gastroduodenostomies (see). They are that food from a stomach comes to a duodenum, from there back to a stomach through an artificial opening, then again to a duodenum etc. Such vicious circle becomes a severe form of «a disease of an anastomosis», often threatens life of the patient and results in need of repeated operative measures.

From Page v. it is necessary to distinguish the processes which are constantly proceeding in an organism, at to-rykh the shift which is originally a consequence then becomes the reason. So, at height of gastric digestion the mucous membrane of a stomach excretes in his cavity a secret, and in blood and a lymph — hormone gastrin. Circulating with a blood flow, it till a certain moment activates gastric secretion and by that process of digestion. In this case are absent patol. the phenomena, it is also about natural mechanisms fiziol. regulation when after achievement of the «programmed» result normally functioning negative feed-backs stop the corresponding function. N I. Losev.

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