From Big Medical Encyclopedia

SPASM (Greek spasmos a spasm) — involuntary tonic contraction of cross-striped or unstriated muscles. Accurate clinical criteria of difference of S. from various options tonic spasms (see) are absent. The Page of muscles (myospasmus)

is the cornerstone increase in a myotatic reflex owing to disturbance of supraspinal influences on a segmented reflex arc (see. Reflex ). Besides, S. of muscles can result from disturbances in a neuromuscular synapse, changes of electrolytic and ion potential of membranes of muscle cells and fibers or biochemism of sokratitelny elements of muscles.

S. at damages first of all belongs to the myospasmuses connected with defeat of supraspinal systems pyramidal system (see), the having character of constant spastic tension of certain groups of cross-striped muscles owing to what the central paralysis is called spastic paralysis (see. Paralyses, paresis ). The page on the party of paralysis or paresis remains at rest; at the passive and active movements there is additional reflex strengthening of a tone of nek-ry muscular groups (see. Hemiplegia ). Selective S. of muscles at defeats of pyramidal system is followed by increase in tendon jerks and emergence of pathological hand and-foot signs (see. Reflexes pathological ).

The page of cross-striped muscles at nek-ry defeats of extrapyramidal system, napr, at parkinsonism, also has constant character, however it covers all skeletal muscles, creating the general constraint, rigidity (see. Parkinsonism ). Depending on localization and prevalence of process in to extrapyramidal system (see) various develop hyperkinesias (see) with variability of a tone of muscles from a hypertension to hypotonia (dystonia), spasms of separate groups of muscles, napr, muscles of one half of a neck — spastic wryneck (see), a peculiar torsion spasm (see. the Torsion dystonia ), involving muscles of a trunk and proximal departments of extremities, athetosis (see), followed by tonic spasms of muscles of distal departments of extremities (spasmus mobilis). Difficult genesis has writer's cramp (see) — a peculiar disorder of motility, at Krom becomes impossible the act of the letter. Bilateral symmetric S. of mimic muscles — a front paraspasm — can begin with S. of circular muscles of eyes (see. Nictitating spasm ), to extend to muscles of a forehead, cheeks, a circular muscle of a mouth, a muscle of a chin and even a neck. More short-term front paraspasm is observed at stutter. In the residual period of neuritis of a facial nerve occasionally on the party of defeat there is S. of mimic muscles (see. Hemispasm ). At an epileptiform neuralgia and tetanus S. of masseters is observed — lockjaw (see), complicating opening of a mouth. At meningitis (see) note a characteristic spasm — a stiff neck and muscles of a neck, at inflammatory processes in an abdominal cavity — protective, reflex S. of muscles of a front abdominal wall (see. Muscular protection symptom ), etc.

At a hemorrhagic stroke with break of blood in cerebral cavities attacks of tonic S. group of extensor muscles of extremities and a trunk are observed — gormetoniya (see) — the disturbances of cerebral circulation which are observed more often in the early period. A specific place is held by the spasms of skeletal muscles connected with damage of a peripheral part of the nervous system — reflex and dystonic syndromes (see. Scalene syndrome , Piriformis-sindrom , Tunnel syndromes ), S. of separate muscles at spondilogenny disturbances of a radicular innervation (see. Osteochondrosis, neurologic manifestations ).

Involuntary tonic S. of cross-striped muscles can arise at myatonias (see).

The page of skeletal muscles happens manifestation of difficult disturbances of a homeostasis, ion-electrolytic balance, hormonal disturbances. Tonic S. of muscles of a brush (a so-called obstetrical hand) and feet are known at hypoparathyrosis (see), tetanus (see), spasmophilias (see), S. of face muscles at the patients with a chronic renal failure who are exposed to a hemodialysis, etc.

At disturbances of a vegetative innervation spasms of smooth muscles of vessels, bronchial tubes, throats, a gullet, intestines, bilious channels, ureters, etc. can be observed (see. Vasomotor spasm , Bronchospasm , Laryngospasm , Pylorospasm ). The peculiar combination of S. of many muscles of a trunk, extremities and internals at children developing pristupoobrazno are spasmophilia (see) and tetany (see).

S.'s identification muscles at a wedge, survey demands a complex neurologic, biochemical, elektromiografichesky research.

Treatment The page is directed first of all to a basic disease. Depending on an etiology and S.'s pathogeny appoint various muscle relaxants (see), antispasmodics (see), carry out acupuncture (see), etc.

Forecast depends on a basic disease.

See also Tone .

Bibliography: Boldyrev A. A. Biochemical aspects of electromechanical interface, M., 1977; D and in and d e N - to about in S. N. Clinical lectures on nervous diseases, century 2, page 5, D., 1956; JI and-ponogov O. A. and Tsymba-l yu to V. I. Dinamika of hyperkinesias and disturbances of a muscle tone after stereotaxic operations depending on an etiology of a disease and the period of damage of a brain, the Doctor, business, No. 12, page 97, 1980; JI e d not in V. V. Some aspects of regulation of muscular contraction, in book: Structural bases and regulation biol. activities, under the editorship of G. R. Ivanitsky, page 221, M., 1980; Malkin V. A. The selection cooling of a spinal cord and roots of spinal nerves at patients with spastic and pain syndromes, Vopr. neyrokhir., No. 3, page 46, 1978; Safronov V. A., Vasin N. Ya. and to Talambuma. And. Features of a muscle tone at rigidity and spasticity, in the same place, No. 5, page 27, 1978; Auger R. G. and. lake of Microvas-cular decompression of the facial nerve for hemifacial spasm, clinical and electrophy-siologic observations, Neurology, v. 31, p. 346,1981; Goers C., Telerman-T about p p e t N. Durdu J. Neurogenic benign fasciculations, pseudomyotonia and pseudotetany, Arch. Neurol. (Chic.), v. 38, p. 282, 1981; Concu A., D e-c a n d i and M. e. About r a n i G. P. Com-portamento della scarica degli organi ten-dinei del Golgi durante la contrazione sub-tetanica muscolare, Boll. Soc. ital. Biol, sper., v. 56, p. 82, 1980; Green C. A., Mediacion of myoclonic seizures by dopamine and clonic seizures by acetylcholine an GABA, Life Sci., v. 21, p. 385, 1977; Iyer V. G., Ranish N. A. a. Penichel G. M. Ionic conductance and experimentally induced myotonia, J., neurol. Sci., v. 49, p. 159, 1981; To about t-s i a s B. A. Miotonias, Medicina (V. Aires), v. 40, p. 593, 1980; Lanari A. Miotonas, ibid, p. 613.

D. K. Bogorodinsky, A. A. Skoromets.