Myoclonus is a symptom rather than a diagnosis of a disease which is characterized by the involuntary jerking movement of muscles. These jerks can occur alone or in a sequence which may be infrequent or be present several times each minute. Several forms of myoclonus can occur normally in life among healthy individuals such as a hiccup causing no difficulties. However, in some cases, the condition can be widespread affecting a single region of the body spreading to other muscles. The severe cases can impact the individuals’ ability to perform everyday tasks such as walking, talking or eating which can be an indication of an underlying disorder of the nerves or the brain.
Causes
The exact cause of myoclonus is not completely understood. Myoclonus condition can occur because of the abnormal electrical impulse that is delivered to a muscle or a group of muscles from the central nervous system such as the brainstem, nerves or the brain’s cortex. Some of the underlying disorders associated with myoclonus include brain tumors, kidney or liver transplant, epilepsy, genetic disorders, nervous system disorders and head or spinal injuries. Some of the different types of myoclonus include essential myoclonus, opsoclonus myoclonus, action myoclonus and stimulus sensitive myoclonus. Essential myoclonus occurs without other symptoms and is not associated with other underlying conditions and the opsolonus myoclonus is a neurological condition presenting sudden muscle spasms with irregular eye movements. Action myoclonus can be disabling affecting the legs, face, arms and the voice while stimulus sensitive myoclonus is triggered by stimuli such as lights or movement.
Symptoms
The sign of myoclonus is the jerky movements or spasms that can be brief, shock-like, sudden, variable in intensity, localized to a single part of the body or can be all over the body interfering with eating, walking and speaking in some cases.
Diagnosis
The diagnosis is based on the medical history, exposure to toxins or medications and their general health. To identify the cause of the condition and to rule out other possible disorders various tests may be required. An EEG records the electrical activity of the brain to help understand where the myoclonus originates. The EMG measures the electrical discharges produced in muscles to understand the pattern of myoclonus. An MRI scan can determine the structural problems, tumors of the brain and the spinal cord which can also cause myoclonus. The blood and urine tests may also be necessary to determine the presence of conditions such as diabetes, liver or kidney disease, metabolic disorders and autoimmune disease.
Treatment
The treatment is based on the underlying disorder and aims to reduce the symptoms. The anti-convulsant medications, sedatives or tranquilizers can help reduce the intensity and the frequency of the episodes. In the case it is caused by a tumor, a surgical removal may be required or can be treated with chemotherapy and radiation. In some cases, triggering factors should be avoided such as exposure to flickering lights and fatigue.
References
https://my.clevelandclinic.org/health/articles/myoclonus
http://www.mayoclinic.org/diseases-conditions/myoclonus/diagnosis-treatment/diagnosis/dxc-20166245
https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Myoclonus-Fact-Sheet
