Myotonia (myotonia)

MYOTONIA, myotonia (from Greek mys- muscle and tonos-tension), a special condition of muscles which consists in the fact that a muscle that has come into a state of contraction does not relax for a long time, and then relaxation occurs extremely slowly. This phenomenon is more often observed in voluntary, striated musculature, but can also occur in involuntary, smooth musculature. Sanger described the "myotonic reaction of the pupil," which consists in the fact that the constriction of the pupil that occurs during convergence persists for a long time after convergence ceases. The myotonic reaction of the pupil occurs in the following diseases: in tabes, progressive paralysis, Basedow's disease, multiple sclerosis, and in myotonia. The myotonic reaction of the pupil is usually unilateral; only in 15% of cases is it bilateral. M. congenita, Thomsen's disease, m. congenita, m. intermittens. The first indications of this disease date back to 1832 (Bell); in 1866, Leyden returned to it. A detailed description of M. was given by Thomsen (1876), and this disease quite justifiably bears his name. Thomsen observed it in his own family; in 4 generations more than 20 people suffered from it, including the author himself. Thomsen proposed the following name for this disease: tonic spasms in voluntary muscles; this long name was replaced by the shorter "congenital M." at the suggestion of Strümpel, which has been preserved to the present time. This disease is congenital and hereditary, and the hereditary predisposition to it is transmitted according to the type of a monohybrid dominant trait. This disease is observed in both men and women; in the former, however, it is somewhat more common; it manifests in childhood. Patho-anatomical changes were initially found only in the muscles. Individual muscle fibers are markedly hypertrophied; the number of sarcolemma nuclei is increased; on longitudinal sections, blurring of the cross-striation of muscle fibers is noted. Along with this, atrophic changes of muscle fibers are also encountered. In recent years, degenerative changes have been found in the central nervous system, mainly in the extrapyramidal motor and in the central autonomic nervous system (Foix, Nicolesco). The symptomatology of the disease consists almost exclusively of changes in the function of voluntary musculature. Following active tension of a particular muscle, a tonic spasm appears in it, lasting for a longer or shorter time. The spasm is more significant the faster and stronger the movement. After the spasm ceases, the muscle can again be brought into a state of contraction, but this movement is also accompanied by a new spasm, albeit a less prolonged one; subsequent movements gradually become easier due to the decrease in the intensity of the spasm and its shorter duration; finally, movements are performed completely freely and do not differ in any way from normal ones. From this it is clear that for patients with M., the first steps are especially difficult, and often when they try to move quickly right away, they fall like a stick. A hand clenched into a fist can only be opened very slowly and with great difficulty; repeated clenching and unclenching become progressively easier; after 10-12 movements, they finally become completely free. The disease in most cases affects the muscles of the limbs and trunk, but sometimes also the musculature of the face and head, which is accompanied by a characteristic myotonic disorder of speech, facial expression, and chewing. Sometimes myotonic phenomena have also been observed in the external muscles of the eye. Emotional excitement and cold intensify the phenomena of M. The muscular system in myotonics is usually well developed, but at the same time muscular strength is somewhat below normal. In 1/10 of all cases of myotonia, atrophies of individual muscles have been found, but probably these cases belong to the group of "atrophic myotonia" (see below). In M., the mechanical excitability of nerves is reduced, while the mechanical excitability of muscles, on the contrary, is increased. When the muscles are struck with a percussion hammer, tonic tension of the irritated area of the muscle occurs, lasting for some time. The study of electrical excitability of nerves and muscles reveals its characteristic changes, which were carefully and thoroughly studied by Erb and are known under the name of "myotonic reaction." The faradic excitability of nerves with a weak current is generally not impaired; when nerves are irritated with a stronger current, tonic contraction of the muscle occurs, lasting for some time after the current ceases. Direct irritation of muscles with faradic current is accompanied by tonic contraction of the muscle, continuing after the current ceases and with its slight force. Galvanic excitability of nerves is reduced, while that of muscles is increased. When muscles are irritated with galvanic current, contractions occur only with closure; anodal closing contraction predominates over cathodal closing contraction; muscle contractions are weak, tonic. With stable passage of galvanic current through a muscle, rhythmic, wave-like contractions—Erb's waves, going from cathode to anode—are observed. From the side of the sense organs, superficial and deep sensitivity, as well as pelvic organs, no deviations from the norm are usually noted. As for reflexes, it is usually written in all textbooks that they show no deviations from the norm; but this is not so. In 1913, Souques in Paris described changes in skin reflexes, and Kozhevnikov in Moscow described changes in tendon reflexes. These changes consist in that a muscle brought into a state of contraction by reflex pathways does not relax immediately, but remains in a state of tonic spasm for some time and then slowly emerges from it. When eliciting the cremasteric reflex, the elevated testicle remains in that position for some time and then slowly descends; when eliciting the plantar reflex, the flexed fingers do not remain in a state of flexion for long and then slowly straighten. When eliciting the knee reflex, extension of the lower leg quickly occurs; it remains in this position for some time and then slowly descends; this phenomenon is also observed when eliciting other tendon reflexes. This change in reflexes can only be noted in the case that the muscle from which the reflex is elicited was previously in a state of rest for a long time (in the morning in bed).- The psyche of patients with M. usually does not suffer; oligophrenic symptoms have sometimes been noted. As already stated, the disease usually manifests in childhood. Cases have been described in early infancy, and observant parents in whose families such a disease existed noted difficulties in movements during sucking, crying, etc. from the first weeks of life. At first the symptoms of the disease progress, then the progressive character is lost, and the pathological phenomena remain persistent throughout life.- The prognosis for life is favorable, but recovery never occurs. In some cases, trauma, emotional excitement, infectious diseases served as a trigger for the manifestation of the disease.--The characteristic disorders of movement, the myotonic reaction, and the familial nature of the disease make its diagnosis extremely easy. Treatment consists exclusively of symptomatic measures (gymnastics, massage, baths). Drug treatment is pointless. Myotonics should avoid colds, emotional excitement.-The question of the choice of profession is very important for myotonics; they are not suitable for a whole range of professions; they cannot be drivers, pilots, etc., and they are also not suitable for military service. Myotonia atrophica-atrophic M.-a special disease that has only some external similarity with Thomsen's disease; it is characterized by late onset, localization of myotonic phenomena, localization of atrophy typical for myopathy, ataxia, absence of tendon and periosteal reflexes, ptosis, dysarthria. In addition, trophic and endocrine symptoms are usually present: emaciation, cyanosis, atrophy of the testicles, weakening of sexual power, baldness, cataract, etc. Atrophic myotonia is also a hereditary affliction. However, the type of hereditary transmission here has not yet been sufficiently clarified.-Myotonia trepidans; under this name Oppenheim distinguished a variety of traumatic neurosis, mainly of military origin, consisting in a combination of spastic hysterical paralyses with tremor.