Muscle weakness

Muscular weakness - insufficient contractility of muscles.

[1], [2], [3], [4],

Causes of the muscle weakness

Pathological conditions, manifested by muscle pain or muscle weakness, can be the result of a wide range of various neuromuscular diseases. The cause of muscle weakness can be either direct damage to muscle tissue, or to the nervous system or neuromuscular synapse, so the issue of differential diagnosis in such patients is particularly acute.

Primary-Muscular Diseases

[5], [6],

Amyloidosis

The onset of the disease can be in 30-50 years, the course is chronic, progressive. It is characterized by the defeat of cross-striped and smooth muscles (there may be paralysis of the eye muscles, macroglossia, amyotrophies, the absence of tendon reflexes, impotence), vessels, skin, mucous membranes, peripheral nerves, opacity of the vitreous. Macroscopically, the muscle looks pale and hard. When determining the activity of CKD, there are no abnormalities. In the morphological study of skeletal muscles, diffuse or focal amyloid deposits are found in the perimension, atrophy of the muscle fibers.

[7], [8], [9]

Myositis

Granulomatous myositis can be with sarcoidosis, Crohn's disease, viral and parasitic infections. Distinguish between acute and chronic form. In a number of cases, the formation of palpable nodules in the muscles of the upper and lower extremities is noted. Clinically pronounced muscular weakness is noted in 0.5% of cases. The disease progresses slowly: the changes in the muscles of the proximal parts of the extremities (amyotrophy, sometimes pseudohypertrophy) are more often noted; characterized by the defeat of long back muscles (the development of hyperlordosis), peripheral nerves. Cases of skin syndrome resembling dermatomyositis are described. In the general analysis of urine, hypercalciuria. The activity of CK can be normal. In the morphological study of the biopsy specimen of skeletal muscle, there is evidence of spleenoid-cell sarcoid granulomas.

Dermatomyositis; polymyositis; juvenile dermatomyositis; myositis associated with CDST (overlap-syndromes), with malignant tumors, with "inclusions".

Infectious myositis; bacterial infections (pyomyositis, tuberculous myositis), protozoal infection (toxoplasmosis, sarcosporidiosis), helminthiases (trichinosis, cysticercosis, echinococcosis), viral myositis (influenza A or B, parainfluenza, adenovirus, cytomegalovirus, Varicella zoster, measles, Epstein-Barr virus, Coxsackie, HIV) - may increase the activity of CK.

Viral myositis occurs with a variety of symptoms; small short-term to diffuse diffuse myalgias (with plumpness, soreness in palpation). Perhaps the development of rhabdomyolysis. The defeat of muscles with an echovirus infection can resemble a typical dermatomyositis.

Infectious diseases

• Toxoplasmosis - fever, lymphadenopathy, hepatosplenomegaly is possible. Muscle weakness can mimic polymyositis, eosinophilia in a general blood test is not a permanent symptom.
• Trichinosis. Muscle weakness reaches a peak at week 3. Myalgia and muscle weakness can be diffuse or local, mark pain when palpation of the muscles. Sometimes observed: periorbital edema; damage to the muscles of the proximal parts of the extremities and back, diaphragm, esophagus, intercostal and external muscles of the eye (ptosis). Often - cutaneous manifestations, similar to those with dermatomyositis. In the general analysis of blood - eosinophilia (up to 60%).
• Cysticercosis. More often, muscle damage is asymptomatic, but there may be pseudohypertrophies and muscle weakness. As a rule, the muscles of the pelvic girdle are not included in the process. When palpation of the muscles marked significant soreness, subcutaneous compaction. Characteristic: fever, CNS damage, in the general analysis of blood - eosinophilia.
• Echinococcosis. The most frequent localization: the muscles of the back, pelvic and shoulder girdles. Usually one area is affected (a tumor-like seal associated with surrounding tissues, moderate pain during movement). There is a risk of rupture of the echinococcal cyst.

Drug and toxic myopathies

Because of the intake of glucocorticosteroids, penicillamine, delagil, plakveil, colchicine, statins, long-term therapy with high doses of thyroid hormones, etc.: alcoholic, narcotic (cocaine) intoxication. The severity of clinical manifestations depends on the severity of the toxic damage (from minimal myalgias and weakness to the development of rhabdomyosis). Mark the normal or increased activity of CK.

Alcoholic myopathy can be acute (from myalgia to rhabdomyolysis) and chronic (proximal muscle weakness, amyotrophy - type 2 atrophy). The activity of CK is within normal limits.

Glucocorticoid myopathy - the primary lesion of the muscles of the shoulder and pelvic girdle, may be myalgia.

Penicillamine, plaquenyl, deligil. When they are used, the development of proximal muscle weakness is described.

Statins. When they are used, the development of severe rhabdomyolysis is described.

[10], [11]

Metabolic myopathies

Disturbance of the metabolism of muscle glycogen, lipids. In rest of patients nothing disturbs. The main clinical manifestation is a decrease in exercise tolerance: fatigue and muscle weakness in the proximal limbs are noted a few minutes after the onset of intense physical activity, painful myogenic contractures, convulsions. At laboratory researches: there can be a myoglobinuria, activity CKK normal, at an exercise stress - there can be an increase.

Mitochondrial myopathies

Kearns-Seyr syndrome, LHON-syndrome (Lebera), MERRF syndromes, MELAS, NARP, MMS. The clinical picture is diverse. In the laboratory study, the activity of CK can be increased. In the biopsy of the striated muscle - "torn" red muscle fibers, a large number of mitochondria in myofibrils, the replacement of muscle tissue fatty or connective, shortening and thinning of muscle fibers, with immunohistochemical study - an increase in the content of oxidative enzymes.

• LHON-syndrome. More than 70% of the cases are men. His debut is possible in 8-60 years, more often - in the third decade of life. The flow is often acute - atrophy of the optic nerve.
• MELAS-syndrome: a gradient type of flow of myopathy: encephalomyopathy, lactic acidosis, stroke-like seizures, possibly - growth hormone insufficiency and diabetes mellitus.
• MERRF-syndrome: myoclonus-epilepsy, cerebellar ataxia, muscle weakness, less often - sensorineal deafness, peripheral polyneuropathy, atrophy of optic nerves, spastic hemi- or tetraplegia, dementia.
• NARP-syndrome. The debut is possible from infancy to the second decade of life: developmental delay, muscle weakness, ataxia, pigmentary degeneration of the retina.
• MMC-syndrome: infantilism, cardiomyopathy, mental retardation, generalized tonic-clonic convulsions: glomerulosclerosis.
• Syndrome Kearns-Seira: cerebellar syndrome, blockade of the conduction system of the heart, pigmentary degeneration of the retina.

Violation of electrolyte exchange

Decrease in the concentration in the blood of ions of potassium, calcium, magnesium, sodium, phosphorus. Characterized by malaise, muscle weakness, myalgia, hyperesthesia, violation of deep sensitivity, fascination, convulsive syndrome, etc.

Non-progressive muscular dystrophies

Nemalinovaya myopathy, central rod disease, myotubular myopathy are benign, they are found in 40-50 years, characterized by an unexpressed diffuse or proximal muscle weakness, there may be dysplastic changes in the skeleton. Sometimes the pubertal period is marked by a regression of the symptoms, it is possible to involve the oculomotor muscles in the pathological process, a moderate bilateral ptosis, there may be bone deformations. Patients usually remain able to work. In determining the activity of CKC, a slight increase in the index was noted.

Progressing muscular dystrophies

Including amyotrophy of Aran-Duchenne, Bekker's myopathy, Landuzi-Dezherin, Rottauf-Mortier-Beier, myocardial infarction of Erba-Roth, etc. Clinical manifestations: "ascending" type of lesion (in the beginning - the muscles of the lower extremities, then - the upper ones): hypotrophy muscles of the hips and pelvic floor, then - the shoulder girdle; "Pterygoid scapula"; pseudohypertrophy of the leg muscles, "duck walk", strengthening lumbar lordosis.

At the beginning of the disease, an increase in the activity of CKF is noted, in far-reaching cases the normal value. Morphological picture: pronounced atrophy and hypertrophy of muscle fibers, at the onset of the disease there may be necrosis and an inflammatory reaction.

Endocrine myopathies

Can be with Addison's disease, hypercorticosis, thyrotoxicosis, hypothyroidism (most often), acromegaly, hyperparathyroidism. At laboratory research mark normal or increased (for example, at a hypothyrosis) activity KFK.

• Acromegaly: muscle weakness; fast fatiguability; pseudohypertrophy and later - muscle wasting; often - painful cramps.
• Addison's disease: generalized muscle weakness; convulsions: fast fatigue and a long recovery period after physical exertion; hyponatremia; flaccid hyperkalemic tetraparesis; hyperpigmentation of the skin.
• Hypercorticism: defeat of the pelvic and shoulder muscles; gradual development of muscle weakness.
• Hyperparathyroidism: muscle weakness in the proximal parts of the limbs, convulsions.
• Hypothyroidism: in 40% of patients, muscle weakness in proximal limbs, mild fatigue, myalgia, and sometimes dysarthria are noted.
• Thyrotoxicosis: muscle weakness and hypotrophy; convulsions; myalgia; acute thyrotoxic myopathy - rapid increase in weakness, oculomotor disorders, weakness of the masticatory muscles, muscles of the pharynx, tongue.

[12], [13], [14], [15], [16]

Neurogenic diseases

Atrophy of the peroneal type of muscle (Charcot-Marie-Toot's disease)

The onset of the disease is in childhood or adolescence (symmetrical lesion is not always observed): amyotrophy of the distal lower limbs (peroneal group), formation of a high arch of the foot, later involvement of the distal parts of the upper limbs in the process of the muscles, sensory disorders like "gloves" and " socks ", fasciculations are possible, the reflexes decrease or disappear.

[17], [18]

Amyotrophic lateral sclerosis

Patients with asymmetric atrophy and weakness of the muscles of the distal parts of the hands, then - the muscles of the shoulder, and pelvic girdle, fasciculation, hypertonia, hyperreflexia, pathological reflexes, bulbar disorders (speech disorder, swallowing, respiratory failure). When determining the activity of CKK, sometimes an increase in the index is noted.

[19], [20], [21], [22], [23], [24]

Demyelinating polyneuropathies

• chronic inflammatory demyelinating polyneuropathy subacute development, note muscle weakness in the proximal and distal parts of the limbs, often sensory disorders, amyotrophies, hyporeflexia;
• acute demyelinating inflammatory polyneuropathy (Guillain-Barre syndrome) acute development of muscle weakness, ascending type of disorders (leg muscles, pelvic girdle, torso, respiratory muscles, brachial muscle search, neck possible involvement of cranial muscles), rapid development of hyporeflexia, areflexia and sensory disturbances.

In determining the activity of CKK, a normal or slightly elevated value of the indicator is sometimes noted.

[25], [26]

Poliradiculopathy (including diabetic)

More often, one-sided muscle weakness, sensory disorders in one or more dermatomes, possibly a disruption of the pelvic organs, the disappearance of tendon reflexes. When determining the activity of CKD, there are no abnormalities.

Spinal amyotrophy of Kugelberg-Welander

Initial signs of the disease are noted in 4-8, less often in 15-30 years: muscle atrophies, "ascending" type of lesion, fascination, fibrillation of the tongue, small finger tremor, pseudohypertrophy of the gastrocnemius muscles, involvement in the pathological process of the paravertebral muscles. In determining the activity of CKK, a normal or slightly elevated value of the indicator is sometimes noted.

The lesion at the level of the neuromuscular synapse

For diagnosis, it is necessary to investigate neuromuscular transmission with the help of a decrement test:

• myasthenia gravis weakness mainly in the proximal parts of the extremities. Weakness of the muscles of the neck, respiratory muscles, there is involvement of cranial muscles (ptosis, diplopia, violation of the act of chewing, swallowing, nasal voice), pronounced pathological muscle fatigue;
• myasthenic syndrome Lambert-Eaton (often observed with a combination of lung carcinoma) - weakness and increased fatigue of the muscles of the proximal lower extremities (may be a generalized process), characterized by a symptom of "working", cholinergic disa-autonomy (lack of saliva and dry mouth).

Rhabdomyolysis

A massive necrosis of muscle tissue can develop against the background of the above pathological conditions. Its development can contribute to: excessive physical stress (especially in patients with metabolic myopathies), electrolyte disorders, various infections, prolonged muscle contraction, alcohol and cocaine intoxication, and medication. Clinical manifestations of rhabdomyolysis: myalgia, muscle weakness of varying severity. The course of rhabdomyolysis can be either short or long. In 16% of cases, it is possible to develop acute renal failure. In laboratory studies: myoglobinuria, a significant increase in the activity of CK.

Forms

Muscle weakness:

• proximal;
• distal;
• common.

[27], [28], [29], [30], [31]

Diagnostics of the muscle weakness

It is extremely important to distinguish between muscle weakness and fatigue and muscle pain. First of all, the determination of the activity of creatine phosphokinase (CK), an increase in the index indicates a myolysis. Needle EMG makes it possible to distinguish between primary and muscle disease from neurological disorders that cause muscle weakness.

[32], [33], [34]