Myoclonus is characterized by the occurrence of brief muscle twitches. These are manifested by involuntary and sudden movements. There are different forms including sleep myoclonus, or secondary myoclonus that occur especially in cases of epilepsy.
Definition: What is myoclonus?
Myoclonus refers to brief muscle twitches that cause involuntary, sudden, abrupt movements. They can occur spontaneously or occur in response to a stimulus such as a noise or flash of light. Shaking can occur in a single muscle or in a muscle group.
The usual example of myoclonus is hiccups , or phrenoglottic myoclonus. It is the result of a succession of involuntary muscle contractions.
Explanations: what are the causes of myoclonus?
Myoclonus can be caused by sudden muscle contraction or abrupt cessation of muscle activity. These phenomena can have several explanations. Depending on the case, there are three types of myoclonus:
- physiological myoclonies , which are related to the functioning of the body;
- secondary myoclonus , which is caused by the occurrence of a disorder in the body;
- iatrogenic myoclonus , which is the result of medical treatment.
Causes of physiological myoclonus
Myoclonus may be related to the functioning of the body. For example, we can mention:
- phrenoglottic myoclonia , better known as hiccups;
- the myoclonus of sleep , or sleep myoclonus, which is manifested by a sudden start of sleep and usually occurs during the first few minutes of falling asleep.
Other physiological causes have also been identified. These include anxiety , physical exercise or diet.
Causes of secondary myoclonus
Secondary myoclonus may be due to various disorders such as:
- the Epilepsy , a neurological disorder which myoclonus is one of the main signs;
- dementia, especially in Creutzfeldt-Jakob disease , Alzheimer’s disease , diffuse Lewy body disease, frontotemporal dementia or Rett’s syndrome;
- spinocerebellar degeneration, which occurs in the context of several neurodegenerative diseases such as Parkinson’s disease, Huntington’s disease, Ramsay-Hunt syndrome or Wilson’s disease;
- physical and hypoxic encephalopathies, cerebral dysfunctions that occur in particular during an electric shock, heat stroke , hypoxia, traumatic brain injury and decompression sickness;
- toxic encephalopathies, cerebral disorders that are the result of heavy metal intoxication;
- infections, including encephalitis lethargic, herpes simplex encephalitis, post-infectious encephalitis, malaria , syphilis and Lyme disease;
- certain metabolic disorders, such as hyperthyroidism , hepatic insufficiency, renal failure , hypoglycemia , non – ketotic hyperglycemia and hyponatremia.
Causes of iatrogenic myoclonus
Myoclonus can sometimes be the result of medical treatment. It can for example be a follow-up to:
- psychiatric treatment, especially when using lithium, antidepressants or neuroleptics;
- some anti-infective treatments, especially when using quinolones;
- some treatments in cardiology;
- the use of sleeping pills;
- the use of anticonvulsants;
- taking anesthetics.
Evolution: what are the consequences of myoclonus?
The clinical manifestations of myoclonus vary according to the case. They can in particular vary in amplitude and frequency. In the most severe cases, muscle twitches can be generalized with the onset of seizures.
Treatment: what to do in case of myoclonus?
When myoclonus is generalized, persists or repeats, emergency medical consultation is recommended. Medical management can identify and treat the cause of myoclonus.
To define the origin of the myoclonus, it is generally necessary to perform electrophysiological recording of abnormal movements.
To relieve muscle twitches, symptomatic treatment can sometimes be put in place. This can be based on the use of different drugs:
- benzodiazepines, such as clonazepam, which constitute a class of psychotropic drugs;
- antiepileptics such as valproate;
- nootropics like piracetam;
- anticonvulsants such as leviracetam.