Myotonia is a muscle disorder that results in prolonged muscle contractions. Usually, the cause of myotonia are congenital genetic disorders, but a similar clinical picture may also appear, for example, as a result of thyroid dysfunction. Myotonia can definitely hinder everyday functioning, but not all patients who experience it require treatment.
The term " litter " comes from the Greek myo, meaning muscle, and the Latin tonus, meaning tension. The essence of myotonia is that during this disorder, prolonged contractions of various types of muscles occur. The ultimate effect of myotonia is muscle relaxation disorders and increased muscle stiffness.
Littermate: reasons
Myotonia occurs when a muscle cell - even after the excitatory stimuli from the nervous system stops reaching it - is still active. The reason for this is usually inherited genetic disorders that lead to disturbances in the transport of electrolytes (e.g. sodium or chlorine ions) through ion channels in the membranes of muscle cells. Examples of diseases in which myotonia occurs include:
- myotonic dystrophy
- Becker's muscular dystrophy
- Thomsen's disease
- congenital paramiotonia
- potassium-dependent litter
- myotonia with constant symptoms and myotonia with variable symptoms
There are also conditions in which symptoms resembling disorders of the myotonia spectrum may appear. Examples of such units include:
- thyroid dysfunction
- neuromyotonia (Isaac's syndrome)
- stiff man syndrome
Myotonia: clinical course
Myotonia can involve various types of muscles - disorders can affect both the muscles around the eyeball, as well as the muscles of the lower limbs or the muscles of the hands. For this reason, prolonged contraction of the muscles may make it difficult, for example, to straighten bent fingers, after sneezing, the patient may have problems with lifting the eyelids, and after yawning, a patient with myotonia may have a short-term problem with closing his mouth. Restrictions may also apply to changing the position of the body -Patients with myotonia, as a result of prolonged muscle contractions, may have problems e.g. with getting up from a sitting position. It is definitely a dangerous phenomenon, as it may lead to an increased tendency to falls. The clinical picture in patients with myotonia is variable and depends on the disease associated with the presence of myotonia in the patient. It happens that repeated repetition of the same activity (eg bending and straightening the fingers several times) leads to a temporary reduction in the intensity of the myotonia - this phenomenon is called "warm-up". In some patients, however, the opposite occurs - repeatedly, the same movement increases the symptoms of myotonia in them. So far, it has not been established what is responsible for the occurrence of these two phenomena, but some theories are available. One of them, explaining the genesis of the "warm-up" phenomenon, is based on the fact that repetition of a given movement may stimulate the activity of (malfunctioning) ion channels and thus lead to a temporary reduction in the intensity of myotonia. The influence of temperature on the occurrence of myotonia symptoms is sometimes also noticed. . Heat generally alleviates discomfort in patients, while in the case of cold scientists differ in opinion. In the past, it was thought that low temperature could exacerbate myotonia or even trigger it, and it is now being noticed that there are patients whose symptoms decrease after exposure to cold.
Littermate: diagnostics
The neurological examination is of fundamental importance in the diagnosis of myotonia. The neurologist may ask the patient to clench his fist and then try to straighten it - in the case of myotonia, there will be a noticeable delay in straightening the fingers. Sometimes it is also possible to induce the phenomenon of myotonia and the associated state of prolonged muscle contraction by hitting the belly of the muscle. To detect dysfunction of the muscle cells themselves, electromyographic examination (EMG) is used, in which it is possible to detect excessive contractile activity of these cells, occurring even in the period when the muscle fiber relaxes. In turn, determining the cause of myotonia is possible by performing genetic tests in the patient.
Littermate: treatment
Not all myotonic patients require treatment for this condition. Treatment is available to alleviate the symptoms of the aforementioned conditions, however causal treatment aimed at and the correction of genetic disorders is unknown. Agents such as anticonvulsants, phenytoin, carbamazepine andquinine. Rehabilitation is also very important for maintaining the highest possible fitness of patients.