From Big Medical Encyclopedia

ADYNAMIA (Greek adynamia — powerlessness) — reduction or complete cessation of a physical activity as a result of disturbances of the neuromuscular device. The ADYNAMIA can be a consequence of an atrophy of the muscular system arising in connection with a long immovability, starvation, the exhausting infectious diseases, chronic intoxications, a cachexia at a heavy hyperthyroidism, Simmonds's disease (see. Pituitary cachexia ), and also at regeneration of muscles because of pathological processes in a spinal cord, multiple neuritis and at some inborn myopathies.

The ADYNAMIA can develop owing to disturbance of specific mechanisms of reduction of muscle fibers. Lead rough shifts of electrolytic balance to the ADYNAMIA (gl.obr. ions of K, Na, Ca, Mg), what occurs, e.g., at Addison's disease, Conn's syndrome and some other endocrine diseases.

Disturbances of sokratitelny process can be connected with system acetylcholine — holinoretseptivny structures of muscles — cholinesterase, e.g. at a myasthenia, the neuromuscular block called by botulinovy toxin and at other acute intoxications.

Disturbances of exchange processes in neuromuscular educations at disorders of functions of the autonomic nervous system quite often lead to the ADYNAMIA

the ADYNAMIA can arise at frustration of the central departments of a motor innervation: damages of a cerebellum, motive zones of bark of big hemispheres, conduction paths.

The ADYNAMIA accompanies deep hypoxia (see), to whom (see) and other serious morbid conditions of various origin. Quite often the ADYNAMIA is caused by action of several pathogenic factors.

Along with the general ADYNAMIA the ADYNAMIA of separate bodies arising as a result of their functional exhaustion because of hyperfunction or disturbance of regulatory mechanisms, e.g. is noted. An adynamia of heart at a myxedema or at dystrophic changes of a myocardium, the ADYNAMIA of a gall bladder at reduction of products in a duodenum cholecystokinin (see).

Biophysical mechanisms of an adynamia. It is known that muscular contraction represents difficult reversible complex (biochemical and physical and chemical) the process proceeding in separate elements of muscular tissue. Therefore the ADYNAMIA from the point of view of the mechanism of development can depend on many reasons leading to disturbance of structure and function of muscular tissue and its separate elements. It is possible to refer changes of permeability of membranes of fiber and an endoplasmic reticulum for various substances to them, first of all for potassium ions and calcium; balance upset of electrolytes in muscle fiber and in the intercellular environment (first of all change of a normal ratio between quantity of potassium ions and calcium); disturbances of biosynthesis of the sokratitelny proteins and enzymes necessary for reduction and relaxation of muscles; changes of activity of enzymes.

At an adynamia first of all the triad system of muscle fiber suffers (see. Muscular contraction ), i.e. dissociation of functions of carrying out, excitement and reduction is observed. Disturbance of process of energy conversion of phosphoric connections in mechanical work is of great importance. All listed disturbances can act at the same time. The sequence of approach of these or those disturbances is connected with the nature of a disease, a consequence to-rogo the ADYNAMIA is. At certain stages of development of the ADYNAMIA is reversible process and it can be completely eliminated. At an irreversible ADYNAMIA in muscular tissue structural disturbances up to an atrophy of muscle fibers are observed.

See also Mechano-chemical processes .

N. I. Losev; O. R. Necklace (biophysical).