Miotoniya — the hereditary disease relating to kanalopatiya (the disease connected with pathology of ion channels). It is shown by the slowed-down relaxation of muscles. Characteristic signs of a miotoniya — the miotonichesky categories revealed by needle EMG and miotonichesky phenomena which come to light at clinical inspection. The congenital miotoniya is followed by a muscular hypertrophy, the dystrophic miotoniya, on the contrary, is followed by muscular atrophies. Diagnostics of a miotoniya is performed by means of EMG, ENG and a research of the caused potentials. So far radical medicamentous therapy of a miotoniya is not developed. To patients symptomatic and metabolic treatment, massage, LFK, electrostimulation is carried out.
Miotoniya — the hereditary disease relating to kanalopatiya (the disease connected with pathology of ion channels). It is shown by the slowed-down relaxation of muscles. Characteristic signs of a miotoniya — the miotonichesky categories revealed by needle EMG and miotonichesky phenomena which come to light at clinical inspection.
Etiology and pathogenesis of a miotoniya
Among two types of a dystrophic miotoniya there is type 1 which gene is mapped in a locus 19q13, meets most often (98%). As well as all types of a dystrophic miotoniya it is descended on autosomno-prepotent type. The major etiologichesky factor of a dystrophic miotoniya of 1 type — increase in number of trinukleotidny repetitions of CTG (to several thousand). Miotonin-proteinkinaza coded by DMPK gene is present not only in skeletal, but also a myocardium, and also TsNS. The main clinical manifestations of a dystrophic miotoniya are also explained by it.
The congenital paramiotoniya of Eylenburga connected with pathology of sodium channels is transferred on autosomno-prepotent type. The gene of SCN4A is mapped in a locus 17q23.1-q25.3. Paramiotonichesky manifestations develop in connection with hypererethism of a membrane of muscle fibers and violation of functioning of sokratitelny elements of a muscle.
Unlike the majority of the neyromiotoniya which are acquired diseases, the idiopathic neyromiotoniya (Isaaks's syndrome) is descended and meets most often. Efficiency of introduction of a curare for knocking over of muscular spasms speaks about the nevrogenny nature of a neyromiotoniya, however finally the pathogenesis of a disease is not clear and today. With identification of the raised caption of antibodies to potential - to dependent potassium channels the neyromiotoniya began to be considered an autoimmune disease. The efficiency of a plasma exchange which is also observed in some cases speaks about the autoimmune nature of a disease.
Classification of a miotoniya
The most common forms of a miotoniya:
- dystrophic (two types)
- kongenitalny autosomno-prepotent
- kongenitalny autosomno-recessive
- paramiotoniya of Eylenburga
Clinical picture of a miotoniya
Symptom of "fist" — the main clinical test for identification of a miotoniya: the patient cannot quickly unclench a fist, for this purpose it needs time and certain efforts. In repeated attempts such miotonichesky phenomenon dies away except for a miotoniya of Eylenburga when constraint, on the contrary, amplifies with each repeated attempt. Constraint is also observed when unclamping of the compressed jaws, to quickly open the narrowed eyes, to rise quickly from a chair. On a needle electromyography reveal one of the phenomena, most characteristic of a miotoniya — the miotonichesky categories which are followed by a sound of "the diving bomber", arising at introduction and movement of a needle electrode.
Distinctive clinical feature of a congenital miotoniya is the hypertrophy of separate muscular groups which makes an impression about an athletic constitution of the patient. In most cases muscular force is kept, but sometimes reduced in disteel muscles of hands. A dystrophic miotoniya — a multisystem disease. In most cases neurologic symptoms are combined with cardiac pathology (a hypertrophy of the left ventricle, arrhythmia), cerebral symptoms (a gipersomniya, the reduced I.Q.), endocrine frustration (violation of a menstrual cycle at women; a gipogonadizm and impotence at men). The so-called "holodovy miotoniya" — emergence of a muscular spasm and paresis on cold is typical for a paramiotoniya; such attacks can last of several minutes till several o'clock. Clinical manifestations of neyromiotoniya are muscular constraint, spasms (painless) and constant muscular activity on EMG.
Diagnostics of a miotoniya
The debut of a dystrophic miotoniya is the share, as a rule, of youthful or adult age, extent of progressing of a disease depends on genetic defect therefore careful collecting the family anamnesis is of great importance in diagnosing of a dystrophic miotoniya. Debuts Miotoniya Becker in 5-12 years and it is characterized by a slow current, and Tomsen's miotoniya can debut both in children's, and at mature age and proceeds, as a rule, hard and with complications. Fizikalny inspection at a dystrophic miotoniya reveals an atrophy of muscles and decrease in their force. For a dystrophic miotoniya of type 1 muscular weakness in disteel departments of extremities, is characteristic of a dystrophic miotoniya of type 2 — in proximal.
By means of laboratory researches at a neyromiotoniya reveal antibodies to potential - to dependent potassium channels, and the dystrophic miotoniya differs in slight increase of activity of KFK in blood.
The main tool by method of diagnostics of a miotoniya is the needle electromyography (EMG) on which define miotonichesky categories — a patognomonichny sign of a miotoniya. The research by means of the caused potentials and an elektroneyrografiya is conducted. At a paramiotoniya on EMG register normal PDE and rare miotonichesky categories. For a congenital miotoniya preservation of the parameters within norm, is typical for a dystrophic miotoniya — a combination of neuropathic and miopatichesky lines. For diagnostics of a paramiotoniya carry out holodovy test: insignificant cooling causes miotonichesky categories, at further cooling there comes "bioelectric silence" (both miotonichesky phenomena, and PDE disappear). DNA diagnostics of a dystrophic miotoniya is based on identification of the increased number of CTG repetitions in DMPK gene.
As a rule, the neurologist manages to differentiate a congenital miotoniya from a dystrophic miotoniya on clinical signs. However in some cases a congenital miotoniya define easy weakness of disteel muscles of hands and weak activity at EMG — the signs typical for a dystrophic miotoniya. Constant muscular activity — a clinical sign of a neyromiotoniya — is a part of a syndrome of "the rigidny person" (stiff-man syndrome), however unlike a neyromiotoniya muscular activity at a syndrome of "the rigidny person" decreases after diazepam introduction, and also during sleep.
Treatment of a miotoniya
The purpose of treatment of a neyromiotoniya is elimination of constant muscular activity and achievement of possible remission, the purpose of treatment of a miotoniya — decrease in expressiveness of miotonichesky manifestations. Non-drug treatment of a miotoniya consists of a diet with restriction of salts of potassium, LFK, massage, an elektromiostimulyation, and also the prevention of overcoolings as at cold all miotonichesky reactions amplify. Radical drug treatment of a miotoniya does not exist therefore for reduction of expressiveness of miotonichesky manifestations apply , and for decrease in level of potassium — diuretics. In certain cases it is possible to reach remission by means of immunosupressivny therapy: intravenous administration of immunoglobulin of the person, Prednisolonum, .
The forecast at a miotoniya
The forecast for life at a miotoniya in general favorable except for exceptional cases of a dystrophic miotoniya of type 1 when approach of sudden warm death because of kardialny pathology is possible. The forecast with congenital myopathies is also favorable for working ability of patients (at rational employment).