Myoclonus refers to a quick, involuntary muscle jerk. For example, hiccups are a form of myoclonus. So are the sudden jerks, or "sleep starts," you may experience just before falling asleep. These forms of myoclonus occur in healthy people and rarely present a problem.
Most often, you hear of myoclonus as a symptom of a nervous system disorder, such as epilepsy, or of a metabolic condition, or as a reaction to a medication.
Ideally, treating the underlying cause will help control your myoclonus symptoms. If the cause of myoclonus is unexplained or can't be specifically treated, then treatment focuses on reducing the effects of myoclonus on your quality of life.
People with myoclonus often describe the symptoms as "jerks," shakes" or "spasms" that are:
When to see a doctor
Myoclonus may be caused by a variety of underlying problems. Doctors often separate the types of myoclonus based on their causes, which helps determine treatment. Types of myoclonus include the following categories.
Symptomatic (secondary) myoclonus
Preparing for your appointment
You'll probably first discuss your concerns with your family doctor, who may decide to refer you to a neurologist. Because appointments can be brief, it's a good idea to come prepared to make the best use of the time allotted.
What you can do
What to expect from your doctor
Your doctor may try to provoke your myoclonus symptoms, so he or she can see how many muscle groups are involved and if there are any other neurological abnormalities that occur at the same time.
Tests and diagnosis
Determining the cause of myoclonus usually is a process of elimination. To rule out potential causes, your doctor may recommend the following types of tests:
Magnetic resonance imaging (MRI)
Treatments and drugs
Treatment of myoclonus is most effective when a reversible underlying cause can be found — such as a medication or toxin that can be discontinued or "flushed out" of your body. Most of the time, however, the underlying cause can't be cured or eliminated, so treatment is aimed at easing myoclonus symptoms, especially when they're disabling. There are no drugs specifically designed to treat myoclonus, but doctors have borrowed from other disease treatment arsenals to relieve myoclonic symptoms.
Deep brain stimulation has also been tried in some people with inherited disorders that are hard to treat.
Last Updated: 2010-07-01
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