An extensive group of genetically heterogeneous diseases of the nervous system, which are inherited, are neuromuscular diseases. Myotonia is a type of such pathology. This disease is represented by various syndromes. The work of the ion channels of chlorine and sodium changes. There is an increase in the excitability of membranes in muscle fibers. Tone disorders and permanent or transient muscle weakness become visible. This article will discuss Thomsen's myotonia.
Types of myotonic syndromes
Myotonic syndromes can be dystrophic and non-dystrophic. The first group consists of dominantly inherited diseases, the clinical picture of which consists of three leading syndromes:
- myotonic;
- dystrophic;
- vegetative-trophic.
The dystrophic form is accompanied by delayed relaxation of the muscles after their tension, increasing muscle weakness and dystrophy (atrophy) of the skeletal muscles.
Description of the disease
Myotonia Thomsen (Leiden - Thomsen) is a genetic disease in which the striated muscles are affected. The onset of tonic muscle spasms occurs at the end of vigorous activity, motor skills are impaired.
The disease has an autosomal dominant type of inheritance, which is quite rare: according to statistics, Thomsen's myotonia is found in seven people per million. The appearance of the first signs of the disease falls on the age of 8 to 20 years, then they accompany a person all his life. Men are more likely to suffer from this type of myotonia.
Causes for the development of pathology
Mutation of the CLCN1 gene leads to this hereditary disease. In etiopathogenesis, myoneural conduction is disturbed and pathology of intracellular membranes is observed, which is caused by a decrease in the penetration of chloride ions into the muscle fibers of the plasmolemma. The defect eventually leads to an ion imbalance: chloride ions do not penetrate inside, but accumulate on the surface of the microfibril, forming a bioelectrical instability in the muscle membrane.
How does Thomsen's congenital myotonia present?
In the muscles increases acetylcholine - an enzyme that regulates the excitability and contractility of muscle fibers. Reduces activity in cerebrospinal fluid and blood.
Suchtissue defect is typical for different myotonias. With the help of light microscopy, hypertrophy of some muscle fibers can be detected. What does she threaten? Muscle tissue of the second type decreases, moderate hypertrophy of the sarcoplasmic reticulum of muscle cells develops, the size of mitochondria increases, the telophragm of striated muscles expands - all this can be seen on electron microscopy.
Symptomatics
With Thomsen's myotonia, the detection of external clinical signs does not occur immediately after birth. Basically, the appearance of the first signs occurs in childhood and adolescence.
The peculiarity of the myotonic phenomenon is:
- muscle hypotonia at rest;
- hypertonicity, spasm of muscle fibers at the time of effort;
- prolonged relaxation of the muscles after the start of movement.
Myotonic attacks can affect the legs, arms, shoulder muscles, neck, face. The desire to spread fingers, clenched into a fist, take a step, close the jaw, close the eyes is accompanied by muscle spasms.
With Thomsen-Becker myotonia, the physical development of the child is difficult if the first signs of the disease were found in early childhood. The kid can not sit, get up, walk in the due time for each action, his body is uncontrollable.
With any voluntary movement at a later age, myotonic attacks of skeletal muscles are manifested when walking, getting up from a place, maintaining balance. The first motor act in the patient is accompanied by a sharp muscularspasm, after which the person is immobilized. If he wants to get up, he definitely needs to lean on something. It is the first step that is given with great difficulty, sometimes tonic spasms lead to a fall of the patient. At maximum effort, it is difficult to unclench the fingers that are gathered into a fist, this can last up to ten seconds. With subsequent movements, the spasms stop.
Active activity contributes to the fact that the affected muscles adapt to movement, spasms are not observed at all. But a short rest leads to the manifestation of muscle hypertonicity with the same strength. With Thomsen's myotonia, the clinic is characteristic.
In adulthood, a patient with this diagnosis has an athletic appearance, since the disease affects the muscles of the limbs and torso and, due to their constant overstrain, muscle mass grows. Muscles are hypertrophied and look large. They are very tense even with weak external stimuli. Even with a light blow to the affected muscles, their hypertonicity occurs. A tense roller of muscles appears, which takes time to relax.
At the very beginning of a voluntary movement, which requires the participation of diseased muscles, and when they are exposed to cold, a myotonic attack is observed. There are a large number of other provoking factors such as a long stay in a static position, a sharp loud sound, an emotional outburst.
How to detect pathology?
Diagnosis by external signs can be determined easily. It is important to carefully collect a family history and features of clinicalmanifestations.
At the first appointment, a neurological hammer is used by a specialist. With light tapping on problematic muscle areas, the neurologist determines the ability of the muscles to contract and fixes the relaxation time after the irritating effect. If a roller forms at the site of contact, this indicates a myotonic symptom.
Doctor invites the patient to clench his fingers into a fist and try to unclench them. The first movements may be difficult, and then there is a normalization of motor skills, which means that tonic spasms are present.
Muscle tissue is in good shape even at rest, tendon reflexes show myotonic signs.
Tonic symptom complex is typical not only for Thomsen's myotonia. It accompanies Eulenburg's paramyotonia, Becker's myotonia, Steiner's myotonia, as well as other neuromuscular and endocrine disorders. Differentiating the diagnosis and designating a specific type of myotonia is quite difficult to diagnose.
Diagnosis of disease
So, with Thomsen's myotonia, the diagnosis is as follows. It is advisable to prescribe invasive and laboratory tests:
- A muscle biopsy to reveal histological changes in fibers that lead to muscle cell dysfunction.
- Biochemical analysis of blood. There are no specific biochemical markers for this disease. In this way, the level of creatine phosphokinase activity in the blood serum is determined.
- DNA test. It allows you to determinemutation in the CLCN1 gene. The analysis is needed to confirm the clinical diagnosis.
- Electromyography (EMG). The needle electrode allows for this invasive examination. An instrument is inserted into the relaxed muscle, myotonic discharges are determined, and the potential of the motor units is recorded. The muscles are stimulated with an electrode and tapping, which leads to their contraction. Repeated stimulation reduces the strength of myotonic spasms.
- Electroneurography (ENMG). The functional state of muscle tissue and the ability to contract are diagnosed by stimulation with an electrical impulse. With ENMG, surface (cutaneous) and intramuscular (needle) electrodes are used. Graphic registration of the potential of motor units is carried out with needle electrodes. What is the treatment for Thomsen's myotonia?
Myotonia Therapy
Complete cure cannot be achieved. The main goal of physiological and drug therapy is to eliminate symptoms and achieve stable remission. Effective appointment:
- "Mexiletine" - a sodium channel blocker, the action of which is aimed at reducing muscle hypertonicity.
- Diuretic drugs - to maintain ionic balance, maintain magnesium levels and reduce potassium.
- Difenin is an effective anticonvulsant.
- "Diakarba" - improves membrane permeability.
- "Quinine" - reduces muscle excitability, increases the refractory period.
All drugs have numerous side effects.
Physiotherapy
Improvement of metabolic processes in muscle tissue and its tonic spasm is achieved with the help of:
- exercise therapy;
- electrophoresis;
- acupuncture;
- medical swimming.
Prevention measures
The prevalence of Thomsen's myotonia is low. The disease has a favorable prognosis, but it is impossible to permanently get rid of myotonic attacks. Preventive measures alleviate the condition of the patient and give a chance to live a full life.
It is necessary to exclude factors that provoke myotonic seizures. Hypothermia, stressful situations, intense physical activity, sudden movements, prolonged stay in one position, emotional upheavals are unacceptable.
We examined Thomsen's myotonia, clinic, diagnosis, treatment.
