Myoclonus

Most of us have experienced those little twitches or jerky movements as we're falling asleep, or we've seen other people have them. These are familiar examples of myoclonus that occur in healthy people and don't cause any problems. But sometimes serious forms of myoclonus develop in response to infection, head or spinal cord injury, stroke, brain tumors or other disorders.

For children, teens and young adults who develop more serious myoclonus disorders, there is a team of renowned neuroscientists at Cook Children's who are ready to treat them and help them have as active a life as possible.

Myoclonus refers to a sudden, involuntary jerking of a muscle or group of muscles. In its simplest form, myoclonus consists of a muscle twitch followed by relaxation. In some cases, myoclonus begins in one region of the body and spreads to muscles in other areas. More severe cases of myoclonus may involve persistent, shock-like contractions in a group of muscles, distort movement and severely limit a person's ability to eat, talk or walk. These types of myoclonus may indicate an underlying disorder in the brain or nerves.

Myoclonic jerking may develop in children, teens and young adults who have disorders such as multiple sclerosis, juvenile Parkinson's disease or epilepsy, a disorder in which the electrical activity in the brain becomes disordered and leads to seizures. In some instances, myoclonus may develop in response to infection, head or spinal cord injury, stroke, brain tumors, kidney or liver failure, lipid storage disease, chemical or drug poisoning, or other disorders. It can occur by itself, but most often it is one of several symptoms associated with a wide variety of nervous system disorders.

Myoclonic symptoms vary from mild to severe. This depends on the cause of the problem. It may begin in childhood or adulthood. The sudden jerking or twitching may occur once in a while or often. It may be limited to one region of the body or affect all muscle groups.

Light, sound, touch or movement may be triggers. Or, it may happen for no known reason. Movements can occur at rest or during other movements. There may be one or a series of twitches. Sometimes, the jerking occurs in a pattern. Other times, there is no pattern. Myoclonus can become so severe that it interferes with eating, speaking, or walking.

Your doctor will ask about your child's symptoms and medical history, including a family medical history. A physical exam will be done and a complete blood work up. Your doctor will try to determine the following:

The localization of the myoclonus in the nervous system
If an underlying condition is responsible for the symptoms\

The doctor may have your child's brain and muscle activity measured and recorded. This can be done with:

Electroencephalogram (EEG)
Electromyogram (EMG)

Pictures may be taken of your brain and spinal cord. This can be done with:

MRI scan
CT scan
Single photon emission computed tomography (SPECT)

Treatment will begin by caring for any underlying causes, such as tumors or electrolyte imbalances. Treatment of myoclonus also focuses on medications that may help reduce symptoms. The drug of first choice is clonazepam, a type of tranquilizer. Many of the drugs used for myoclonus, such as barbiturates, phenytoin, and primidone, are also used to treat epilepsy. Sodium valproate is an alternative therapy for myoclonus and can be used either alone or in combination with clonazepam. Myoclonus may require the use of multiple drugs for effective treatment.

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Myoclonus

What is myoclonus?

What causes it?

What are the signs and symptoms?

Testing and diagnosis

How is it treated?

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