MYOPATHY

From Big Medical Encyclopedia

MYOPATHY (grech, mys, my[os] a muscle + pathos suffering, a disease) — group of hereditary diseases of muscles, the main clinical manifestations to-rykh are muscular weakness, an atrophy, decrease in a muscle tone, decrease or lack of tendon jerks, change of bioelectric activity of muscles.

The first kliniko-morfol, descriptions of diseases of this group belong to G. Dyushenn, Zh. Kryuvelye (1853), V. Erbu (1883 — 1884), V. K. Roth (1876, 1895). Pathology wind - is hoped worldwide. Frequency of various forms makes 2 — 6 on 100 000 population.

Classification

Questions of classification of M. are developed in various directions. M classify but to a mode of inheritance: autosomal and recessive autosomal and dominant, recessive and dominant, linked to X-chromosome. Depending on time of emergence of the first symptoms and character of a current of M. subdivide into the inborn not progressing M. and the progressing muscular dystrophy (the early nursery, children's, youthful and late forms). The progressing muscular dystrophy is also subdivided into forms depending on preferential localization of miodistrofichesky process (e.g., a shoulder - a scapular and front myodystrophy of Landuzi — Dezherina, tazoplechevy Miopatiya Erba — Roth, bulbar and ophthalmoplegic M., distal M.), a distributional pattern of process (the ascending and descending options). In separate group allocate M. with the expressed pseudo-myopachynsis (a psudohypertrophic Myopathy of Dyushenn, a high-quality psudohypertrophic Myopathy of Becker, etc.).

The etiology and a pathogeny

are the Reason of diseases genetically determined defects of metabolism of muscular tissue or structure of muscle cells. As primary molecular defect is not known for one of forms M., the pathogeny is in detail not studied. Apparently, it is not unambiguous for all forms M. It is known, however, that at all diseases of this group are to a greater or lesser extent expressed the strengthened disintegration of myoproteoses prevailing over their accelerated, but defective synthesis, changes of vessels, disturbances of permeability of their walls, disturbances of structure and permeability of cellular membranes, shift of exchange of cations, changes in connecting fabric, etc. Assume that at nek-ry forms primary molecular defect is localized not in the most muscular tissue (and, e.g.) and serves only as a starting factor of the specified changes in nervous. It is possible also that at nek-ry forms M. the effect of a mutant gene is more generalized and extends on muscular, nervous and other fabrics.

Pathological anatomy

Morfol, changes at M. are characterized by the accruing atrophy of skeletal muscles, to-rye decrease in volume and become dense,




brown color owing to growth of connecting fabric or, on the contrary, increase in volume at the expense of a fatty tissue.

Fig. 1. Microdrug of a muscle (cross section) at Dyushenn's myopathy in a stage of partial safety of motive function: a chaotic arrangement of mixed muscle fibers — atrophied (1), normal diameter (2), single hypertrophied (3); dystrophic changes in a part of muscle fibers (4); growth of connecting fabric in an endomiziya (5); hematoxylin-eosine; X 200.
Fig. 2. Microdrug of a muscle (longitudinal section) at Dyushenn's myopathy in a stage of an obezdvizhennost: single atrophied muscle fibers (1) among fibrous and fatty tissue; lymphoid and histiocytic infiltration (2); hematoxylin-eosine; X 200.

At various forms of muscular dystrophies (psudohypertrophic, a shoulder - scapular and front, tazoplechevy, ophthalmoplegic, bulbar and ophthalmoplegic) changes (fig. 1) are defined generally same gistol: reduction of amount of muscle fibers in bunches, a sharp diffusion raznokalibernost of the remained fibers with dominance among them atrophied, hyaline and vacuolar dystrophy regarding muscle fibers, a diskoidny and coagulative necrosis of separate fibers, splitting of hypertrophied fibers, growth of connecting and fatty tissue in endo-and perimysiums. Find sarcoplasmic little bodies, sarcoplasmic masses, ring-shaped myofibrils in nek-ry muscle fibers. Occasionally the regenerating fibers meet round juicy kernels and a sarcoplasm rich with ribonucleoproteins. Muscle spindles a long time remain not changed. Regarding observations perivascular lymphoid and histiocytic infiltrates come to light. In process of increase of motive disturbances gradual reduction of amount of muscle fibers and leveling of their diameter due to sharp reduction of quantity and caliber of hypertrophied fibers is noted. Most quickly these changes develop at Dyushenn's myopathy — malignant option psudohypertrophic M. The combination of the expressed processes of a lipomatoz of N of a sclerosis to a sharp hypertrophy of a part of muscle fibers is characteristic of high-quality option — Becker's myopathy —. Connect long compensation of motive disturbances at such patients with the last feature. In far come M.'s stage small islands from atrophied muscle fibers against the background of a sharp sclerosis and a lipomatoz endo-are defined and a perimysium (fig. 2), at the same time histologically it is not possible to differentiate M. with a neuromuscular atrophy. At probands at a biopsy of muscles find single atrophied muscle fibers preferential the I type, proliferation of kernels with their transition to the center of fiber and insignificant increase in connecting fabric to endomiziya.

The earliest ultrastructural changes in muscles at M. are characterized by a thickening and splitting of Z-lines with the subsequent destruction of myofibrils of muscle fiber. Thanks to phase and contrast and a submicroscopy defects in membrane systems of muscle fiber are revealed. Gistofermento is chemically marked out weakening of the reciprocal relations between glycolytic and oxidizing enzymes in muscle fibers of various type.

In the central and peripheral nervous system of changes it is not revealed. The cardiosclerosis is characteristic.

Clinical picture

Fig. 3. A sick myopathy with the expressed pseudo-hypertrophy of gastrocnemius muscles.
Fig. 4. A sick myopathy with a symptom of alate shovels: sharp vystoyaniye of both shovels.
Fig. 5. A sick myopathy with a symptom of «free nadplechiya»: lifting of the patient under mice leads to a raising of nadplechiya, resistance of muscles of a shoulder girdle is absent.
Fig. 6. A sick myopathy with a symptom of «ladder»: and, in — a number of consecutive movements to which the patient during the change of horizontal position with vertical is forced to resort.

The leading symptoms of diseases of this group are increased fatigue and weakness of muscles, symmetric muscular atrophies, decrease or lack of tendon jerks. At separate forms of a disease the pseudo-hypertrophy (fig. 3) when the volume of the affected muscles is increased though force them is reduced the same as at an atrophy is noted. At localization of miodistrofichesky process in a face the mimicry of patients becomes poor. Gipomimiya leads to a characteristic look — «the myopathic person». «the cross smile» is a consequence of an atrophy of a circular muscle of a mouth. Lips are thickened and a little twisted knaruzh — «lips of a tapir». On a forehead there are no wrinkles — a symptom of «the polished forehead». Damage of cross-striped muscles of eyes leads to a partial or full ophthalmoplegia, a ptosis, an exophthalmos, a lagophthalmia. Damage of muscles of a soft palate, throat and throat is shown by disturbance of swallowing and phonation. Symptoms of damage of muscles of a shoulder girdle — restriction of volume of active movements in proximal departments of hands, lag of shovels from a trunk — a symptom of «alate shovels» (fig. 4), lack of resistance of muscles of a shoulder girdle during the lifting of the patient for armpits — a symptom of «free nadplechiya» (fig. 5.); shoulders of the patient rise up, and the head as if fails between them. The atrophy of long muscles of a back and a pelvic girdle is shown by disturbance of a bearing and gait: the hyperlordosis of a backbone is expressed, the head is thrown a little back back, the trunk during the walking is rhythmically shaken — «duck gait». Lifting on a ladder, a rising from a sitting position is complicated. To accept vertical position, the patient is forced to resort to the help of hands, leaning on the next objects or own hips — a rising «short flight of stairs» (a symptom of «ladder» — fig. 6, and, c). At an atrophy of oblique muscles of a stomach the symptom of «wasp waist» is observed. Disturbance of gait as «steppage» or «cock gait» is characteristic of localization of miodistrofichesky process in muscles of a shin and foot. Damage of muscles leads to restriction of mobility of joints up to formation of contractures. The pulmonary heart joining, as a rule, in a late stage of a disease is a consequence of miodistrofichesky process in a myocardium and respiratory muscles. At an elektromiografichesky research reveal decrease in amplitude of oscillations, high frequency of polyphase potentials, shortening of time of separate oscillations.

The Kliniko-morfologichesky characteristic of some most common forms

Along with the general a wedge, and morfol, the signs characteristic of myopathies, the separate forms are had distinctive a wedge. - morfol, signs; establishment of a form of not progressing inborn M. is possible only on the basis of a detailed gistol, a research of muscles.

A myopathy of Erba — the Company — the progressing muscular dystrophy, proximal, autosomal and recessive. Its histologic feature is formation of huge muscle fibers with the subsequent their splitting, as a result to-rogo groups of flours are formed. Boys are ill slightly more often than girls. Depending on time of emergence of the first symptoms allocate the early nursery, children's and youthful forms. Damage of smooth muscles of intestines, development of cardiopulmonary insufficiency, contractures of large joints at rather long safety of muscles of distal departments of extremities is characteristic and persons. The form of a disease beginning with damage of muscles of a pelvic girdle with the ascending type of defeat is known in literature under the name Leiden Myopathy — Möbius (see. Leiden dystrophy ).

Dyushenn's myopathy - the progressing muscular dystrophy, the early nursery, proximal, psudohypertrophic, recessive, linked to X-chromosome. Boys are ill. The similar disease which is found at girls is considered a psudohypertrophic autosomal and recessive form. Idiosyncrasy patomorfol. changes in a muscle already at early stages of process growth of fatty and connecting tissue and substitution by them muscular is, than and existence of a pseudo-hypertrophy speaks. The disease is characterized by emergence of weakness and an atrophy of muscles aged up to 3 years, a malignant current and existence of pseudo-hypertrophies, especially in gastrocnemius muscles. Patients can have neuroendocrinal disturbances in the form of obesity, a hyperhidrosis, etc.

A frequent symptom of a disease — lag in intellectual development. Early the myocardium is surprised, there can be dysfunction of a diaphragm and unstriated muscles went. - kish. path and bladder. In a blood plasma and urine considerably hyperactivity of muscular enzymes.

Becker's myopathy — the progressing muscular dystrophy, late, high-quality, proximal, psudohypertrophic, recessive, linked to X-chromosome. The disease is shown at the age of 20 — 30 years, progresses slowly; endocrine disturbances, damage of a myocardium and decrease in intelligence are not characteristic.

Landuzi-Dezherin's myopathy — the progressing muscular dystrophy a shoulder - scapular and front, juvenile, slowly progressing, autosomal and dominant. Histologically unlike other progressing muscular dystrophies usually find increase in average diameter of fibers and emergence of the flours characteristic of denervation.

The first symptoms of a disease appear usually at the age of 12 — 20 years, long safety of motive functions is characteristic. Depending on preferential defeat of these or those groups of muscles and the sequence of distribution patol, process distinguish the following forms of a disease: the person - scapularhumeral, the person - scapular shoulder-peroneal, the person - a scapular shoulder - buttock femoral, лице-лопаточно-плече-ягодично-бедренно-перонеальную and лице-лопаточно-плече-перонеально-ягодично - femoral. Option of a disease with later beginning (27 — 30 years), at Krom fibular muscles, and then, to a lesser extent, muscles of a shoulder girdle and the person originally are surprised, call a scapular and peroneal form of a myopathy of Davidenkov.

Govers's myopathy — Velandera (Nevin's Myopathy) — the progressing muscular dystrophy, distal, late, autosomal and dominant. Early gistol, changes remind changes at miotonichesky dystrophy (see. Miotoniya ), but in process of progressing of a disease prevailing there is a miodistrofichesky process. Symptoms of damage of muscles of distal departments of extremities appear at the age of 30 — 60 years, and almost only razgibatel are surprised; distribution patol, process, as a rule, descending, but if at first muscles of legs are surprised, then disturbance of gait quickly progresses. The myocardium is surprised not constantly.

A myopathy of the Kilogram — Nevina — the progressing muscular dystrophy, ophthalmoplegic, juvenile, autosomal and dominant. gistol, ophthalmoplegic M.'s feature, in particular a bulbar and ophthalmoplegic form, presence at muscle fibers of a large number of the so-called bordered vacuoles is distinctive, to-rye look as the openings from a puncher surrounded with material, the painted trikhromovy dye in bright red color. The first symptoms of a disease in the form of a bilateral ptosis appear aged up to 20 years. In process of progressing of a disease muscles of an eyeglobe are surprised that leads to a full outside ophthalmoplegia. In 25% of cases process extends to a circular muscle of an eye, other facial muscles, muscles of a throat and a throat (a bulbar and ophthalmoplegic form M.) and muscles of a shoulder girdle. In a late stage of a disease also muscles of a shoulder and pelvic girdle can be surprised. Also cases with later beginning and more high-quality current are described.

The myopathy which is not progressing inborn - group of the diseases which are characterized by inborn disturbances of structure or metabolism of muscular tissue, diffusion damage of muscles, lack of progressing or very slowly progressing current, in rare instances with age symptoms of a disease can become less expressed.

Among diseases of this group on a basis gistol, data allocate several forms.

1. The disease of the central core which histologically is characterized by presence at muscle fibers of the central sites to-rye are painted by eosine more intensively, than other sarcoplasm, are deprived of a glycogen and enzymatic activity. The core electronic microscopically is presented by the amorphous and incorrectly located fragments of myofilaments and Z-lines, mitochondrions and sarcoplasmic a reticulum are absent.

Fig. 7. The diffraction pattern of a muscle at not crimson myopathy: in subsarcolemmic space of muscle fiber the dark extended (threadlike) structures are visible (are specified by shooters); x 5600.

2. Not crimson M. which is characterized by existence in subsarcolemmic zones of a part of muscle fibers of threadlike structures (fig. 7). Histochemical in them ribonucleoproteins and high activity of a tyrosinase are revealed.

Fig. 8. Microdrug of a muscle (cross section) at a miotubulyarny myopathy: many kernels (are specified by shooters) are located in the center of muscle fibers; coloring hematoxylin-eosine; x 200.

3. The Miotubulyarny (tsentronuklearny) M. which is characterized by what 30 — 85% of muscle fibers contain it is central the located kernels, around to-rykh there are no myofibrils (fig. 8); in general such fibers remind miotubula of muscles of a fruit that formed the basis for the assumption that lack of maturing and a differentiation of muscular tissue is the cornerstone of a disease.

4. The inborn disproportion of types of fibers which is characterized by small reduction of diameter of fibers I gistol, type and increase in diameter of fibers II gistol, type.

5. Mitochondrial myopathies — group of the inborn slowly progressing diseases at which the main changes in muscular tissue are connected with anomalies of mitochondrions. Distinguish from diseases of this group: 1) the pleokonialny M. which is characterized by the fact that mitochondrions of muscle fibers contain multiple cristas and sometimes round osmiofilny inclusions; 2) the megakonialny M. which is characterized by presence at muscle fibers of accumulations of the mitochondrions increased a bizzare shape to-rye is might contain by unusual inclusions; 3) the mitochondrial M. with a hypermetabolism which is characterized by presence in perinuclear sites of a muscle cell of huge mitochondrions to-rye can be three types: the 1st Type — with tubular type of cristas, the 2nd type — with opaque little bodies, the 3rd type — consisting from dense concentric tyazhy. Histochemical in muscles high activity okislitelno - recovery enzymes comes to light.

The diagnosis

the Diagnosis is made on the basis of a clinical picture and data of a histologic research of muscular tissue (at not progressing inborn M. the diagnosis generally is based on the muscles given to histology of a bioptat). Diseases from group M. should be differentiated with spinal and neural amiotrofiya (see), miozitam (see), dermatomyositis (see), inborn atrophies of muscles (see. Atrophy muscular ), effects poliomyelitis (see), an inborn myosclerosis of Lovental, to-ry it is characterized by inborn symmetric rigidity of joints owing to a sklerozirovaniye of muscles and skin. It is necessary to distinguish also clinically similar diseases from group of glycogenoses and M. caused by disturbance of lipid metabolism with the known primary molecular defects from M. Among the first the most widespread and Mac-Ardla's disease is studied (see. Glycogenoses ). Hereditary deficit of a carnitine, hereditary deficit a carnitine palmitoyltransferase, hereditary deficit of a pyruvatedecarboxylase, a disease of accumulation of neutral lipids belong to the myopathies caused by accumulation of lipids. Diseases of this group are shown by muscular weakness and (or) a myoglobinuria, an atrophy of muscles, anorexia, a hypotrophy, increase in a liver and symptoms of a heart and renal failure are possible. Pathomorphologically at them dystrophic changes in cross-striped muscles, in a myocardium and adjournment in them of lipids, a necrosis and dystrophy of renal tubules, accumulation in them of fats, fatty infiltration of a liver come to light. Diagnosis of these diseases requires a research of activity of enzymes. As material for a research skin fibroblasts, muscles, lymphocytes of blood can serve.

Treatment

Treatment of all forms M. is pathogenetic and shall be directed to improvement of a trophicity of muscular tissue and carrying out an impulse on nerve fibril and through a myoneural synapse. For improvement of a trophicity of muscles appoint complexes of amino acids (glutaminic to - that, a leucine, methionine), ATP, anabolic steroids, orotat potassium, antikholinesterazny drugs (prozerin, Galantaminum, an ambenonium chloride, Nivalinum, Kalyminum), vitamins of group B. Repeated transfusions of donor blood, electrostimulation of muscles, a prozerin-electrophoresis are recommended. For the purpose of improvement of local blood circulation apply an oxygenobarotherapy, ultrasound, massage, thermal procedures, a balneolecheniye. Treatment is carried out constantly by courses, drugs appoint a wedge taking into account age of the patient, a form of a disease, severity, M.'s manifestations

the Forecast

the Forecast is defined by speed of progressing of dystrophic changes in skeletal muscles, and also age, in Krom the disease begins. At the most malignant form of a myopathy of Dyushenn already at children's age the full obezdvizhennost of patients develops. The lethal outcome can be caused by increase of pulmonary and heart failure, hypoventilating and hypostatic pneumonia. At the late forms beginning after 20 — 30 years, a current rather high-quality patients can keep a long time working capacity. Miotubulyarny, not crimson M., «a disease of the central core», mitochondrial M. usually differ in slow progressing, with age can gain stationary character.



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L. O. Badalyan, T. H. Kopyeva (stalemate. An.).

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