From the Guidelines
Myoclonic jerks can be caused by a variety of factors, including physiologic myoclonus, epileptic disorders, metabolic disturbances, certain medications, neurodegenerative diseases, infectious diseases, brain injury, and autoimmune disorders, as reported in a 2023 study 1.
Common Causes of Myoclonic Jerks
- Physiologic myoclonus: occurs in healthy individuals during sleep transitions, anxiety, exercise, or fatigue
- Epileptic disorders: such as juvenile myoclonic epilepsy and progressive myoclonic epilepsy
- Metabolic disturbances: kidney or liver failure, electrolyte imbalances, hypoglycemia, and hyponatremia
- Certain medications: levodopa, antipsychotics, antidepressants, opioids, and alcohol withdrawal
- Neurodegenerative diseases: Alzheimer's, Parkinson's, and multiple system atrophy
- Infectious diseases: viral encephalitis, Creutzfeldt-Jakob disease
- Brain injury: oxygen deprivation, stroke, or head trauma
- Autoimmune disorders
Treatment of Myoclonic Jerks
Treatment depends on identifying and addressing the underlying cause, which may involve:
- Medication adjustments
- Treating metabolic disorders
- Using specific antimyoclonic drugs like levetiracetam, valproic acid, or clonazepam when necessary, as recommended in a 2015 study 1
- Collaboration with a specialist, such as an epileptologist or movement disorders neurologist, for patients with suggestive features, as suggested in a 2023 study 1
From the Research
Causes of Myoclonic Jerks
- Myoclonus is a sudden, brief, involuntary muscle jerk caused by abrupt muscle contraction or sudden cessation of ongoing muscular activity 2.
- The underlying physiology of myoclonus can be classified into different types, including cortical, subcortical, and spinal myoclonus 2, 3.
- Myoclonus can have various origins, including the cortex, subcortical structures, spinal cord, and peripheral nerves 3, 4.
- Certain conditions, such as multiple system atrophy, can cause postural and action myoclonus 5.
- Other factors, such as age of onset, character of myoclonus, precipitating or alleviating factors, family history, and associated symptoms and signs, can also contribute to the development of myoclonic jerks 2.
Classification of Myoclonus
- Myoclonus can be classified based on the underlying physiology, including:
- Cortical myoclonus: caused by abnormal activity in the cerebral cortex 2, 3.
- Subcortical myoclonus: caused by abnormal activity in subcortical structures, such as the basal ganglia or reticular system 3.
- Spinal myoclonus: caused by abnormal activity in the spinal cord 3, 4.
- Peripheral myoclonus: caused by abnormal activity in peripheral nerves 4.
Diagnostic Approaches
- Electrophysiological tests, such as surface polymyography and EEG, can help determine the underlying cause of myoclonus 2, 3, 4.
- Clinical characterization of myoclonus, including the age of onset, character of myoclonus, and associated symptoms and signs, can also aid in diagnosis 2.
- Neurophysiological investigations, such as jerk-locked back-averaging and somatosensory evoked potentials, can help classify myoclonus and determine its underlying cause 3, 4.