Myoclonus is a violent and sudden contraction of individual muscle groups. Various problems can lead to their occurrence - in some people they develop spontaneous myoclonus, in others they are a symptom of a more or less serious disease, such as, for example, hyperthyroidism or a brain tumor. What are the causes and symptoms of myoclonus and what is their treatment?

Myoclonusas a concept (ang. Myoclonus) is derived from the combination of two Greek words, which are myos (muscle) and clonus (tumult, rush). Myoclonus belongs to the group of involuntary movements and was first described by Nikolas Friedreich. These are not very common in patients movement disorders - according to statistics, during a year pathological myoclonus occurs in 1.3 out of 100 thousand people. These types of involuntary movements can occur at any age - whether in a young child, in a young adult or in an elderly person.

Contents:

  1. Myoclonus: causes
  2. Myoclonus: Symptoms
  3. Myoclonus: diagnostics
  4. Myoclonus: treatment
  5. Myoclonus: prognosis

Above, the term "pathological myoclonus" appears - there are actually several different types of these disorders. In humans, the most common are physiological myoclonus, which include, for example, hiccups. However, myoclonus can also be one of the many symptoms of a disease and then they are referred to as symptomatic myoclonus. There are also spontaneous myoclonus (in which the appearance of the patient's characteristic muscle jerks is his only ailment), epileptic myoclonus and psychogenic myoclonus

Myoclonus: causes

Myoclonus may be triggered by disturbances in the functioning of various levels of the central nervous system, because both dysfunction of the spinal cord and the cerebral cortex, brain stem and various subcortical centers. The cause of physiological myoclonus may be physical exertion, they can also appear during falling asleep and during sleep (then they usually wake a person up).

Myoclonus are a manifestation of various forms of epilepsy. They are then referred to as myoclonic epilepsy and Lennox-Gastaut syndrome can be mentioned as examples,juvenile myoclonic epilepsy and Aicardi syndrome.

Myoclonus can occur in the course of a variety of pathologies - other, not yet mentioned causes of this type of involuntary movements are:

  • storage diseases (such as Gaucher disease or Tay-Sachs disease),
  • Friedreich's ataxia,
  • Wilson's disease,
  • Parkinson's disease,
  • Huntington's disease,
  • cortico-basal degeneration,
  • multi-system decay,
  • various types of dementia (including Alzheimer's disease, cortico-basal dementia or dementia with Lewy bodies),
  • central nervous system infections (e.g. herpetic encephalitis, central nervous system syphilis and subacute sclerosing encephalitis),
  • metabolic disorders (myoclonus may appear in the course of liver failure, but also in people with hyponatraemia, hypoglycaemia or in patients suffering from renal failure),
  • multiple sclerosis,
  • hyperthyroidism,
  • stroke,
  • paraneoplastic syndromes.

It is clearly visible that there are a lot of potential causes of myoclonus, but one, quite common, basis of these movement disorders has not been mentioned here. Well, they can also appear after taking a variety of pharmaceuticals - the drugs that may have such a side effect are primarily:

  • tricyclic antidepressants,
  • serotonin reuptake inhibitors,
  • benzodiazepines,
  • levodopa,
  • cephalosporins,
  • lit,
  • clozapine,
  • opioids,
  • antiepileptic drugs (such as gabapentin and pregabalin)
  • calcium channel blockers,
  • bismuth s alts.

Myoclonus: Symptoms

In colloquial language, myoclonus is referred to as muscle jerks and this nomenclature basically reflects the essence of this problem. Myoclonus can affect a single muscle or several muscle groups at the same time and consist of a sudden, involuntary onset of their contraction (more often) or relaxation (less frequently). They usually appear in the upper limbs or shoulder, but can lead to involuntary movements of the head or even the entire body. Myoclonus can occur both at rest and when a person is engaged in an activity.

Myoclonus can occur spontaneously, and it happens that they appear in connection with some stimuli. Reflex myoclonus are observed precisely in response to a stimulus (e.g. visual, auditory or sensory). Additionally, in some peoplethe intensity of the myoclonus increases when they feel fear or severely stressed.

Myoclonus: diagnostics

Looking at how different the causes of myoclonus are, it is not difficult to guess that diagnosis in a patient reporting this type of involuntary movements is definitely not easy. First of all, it is necessary to state that the patient is actually struggling with myoclonus and not some other involuntary movements (e.g. tremors, tics or chorea). For this purpose, recordings can be used, which show the presence of myoclonus in the patient.

Initially, each patient is subjected to a physical examination (i.e. a medical history is collected) and a physical examination (in this case, it is necessary to assess the patient's neurological condition). Later, various tests are ordered, such as head imaging tests, electroencephalography (EEG), electromyography (EMG), and various laboratory tests (e.g. assessing the levels of thyroid hormones in the blood or testing the levels of various electrolytes in it).

Exactly what tests will be recommended to the patient is determined by the information obtained during the medical interview and the abnormalities found during the neurological examination - the scope of diagnostic tests depends on the suspected cause of myoclonus.

Myoclonus: treatment

Accurate diagnosis in a patient with suspected myoclonus is important because most often the problem that led to it requires treatment. For example, in people who have a viral infection of the central nervous system, the use of appropriate antiviral preparations - thanks to which the infection is controlled - sometimes leads to the resolution of myoclonus.

It is similar in patients with hyperthyroidism, in whom the normalization of the hormonal balance may result in the cessation of involuntary movements in the patient. Then, when myoclonus developed in connection with the patient's taking a drug, discontinuing it and replacing it with another preparation may result in the resolution of movement disorders.

In the treatment of myoclonus, symptomatic treatment is also possible, the aim of which is to reduce only the involuntary movements. For this purpose, patients may be recommended to use various medications. valproic acid, levetiracetam, clonazepam and primidone. Usually, it is not possible to obtain satisfactory results with the use of one drug, therefore polypharmacotherapy is usually used in the treatment of myoclonus.

Myoclonus: prognosis

Patients who develop myoclonus often wonder whether they will experience this type of involuntary movement for the rest of their lives. There is no single answer here - it all depends on the cause of the problem. Symptomatic myoclonus typically resolve after the underlying disease has been healed.

It is a bit different in the case of spontaneous myoclonus - they can completely resolve thanks to appropriate symptomatic treatment, but unfortunately it is also possible that despite the use of drugs by the patient, the involuntary movements will be very intense and due to their occurrence had difficulty in carrying out normal, everyday activities such as walking, eating or speaking.

About the authorBow. Tomasz NęckiA graduate of medicine at the Medical University of Poznań. An admirer of the Polish sea (most willingly strolling along its shores with headphones in his ears), cats and books. In working with patients, he focuses on always listening to them and spending as much time as they need.

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Category:

Neurology