A myoclonic seizure is a sudden, brief, shock-like muscle contraction. Myoclonic seizures can be generalized or partial. They
appear most often during the first year of life.
What are other terms for myoclonic seizures?
Other terms for tonic-clonic seizures that you may come across include:
How can you tell if your child has myoclonic seizures?
A child having a myoclonic seizure will have one or many brief muscle jerks, often in the shoulders or arms, either in the
whole body or just in one arm or leg. Unlike clonic seizures, the jerks are not rhythmic. The child will remain conscious.
Sometimes myoclonic seizures are not strong enough to cause visible movement, but the child feels a shock-like feeling in
his muscles.
In some syndromes, like juvenile myoclonic epilepsy, myoclonic seizures happen in the morning just after the child has woken
up. Objects such as toothbrushes or mugs may fly out of the child’s hands. The child and his parents may assume that he is
just sleepy or clumsy.
How many other children have myoclonic seizures?
Up to 10% of children with epilepsy have myoclonic seizures.
What causes myoclonic seizures?
Myoclonic seizures are seen in many different epilepsy syndromes, including benign myoclonic epilepsy of infancy, juvenile
absence epilepsy, juvenile myoclonic epilepsy, Lennox-Gastaut syndrome, and the progressive myoclonus epilepsies. For this
reason, it is often difficult for a doctor to tell exactly what syndrome a child has. To make the diagnosis, the doctor will
look at the location of the seizures, whether they are symmetrical, the child’s EEG pattern, and any factors that trigger
the seizures.
How are myoclonic seizures treated?
Anti-epileptic drugs are used to treat myoclonic seizures. Which one is chosen usually depends on the specific epilepsy syndrome.
Vagus nerve stimulation (VNS) treatment or the ketogenic diet may also be used.
What should I do when my child has a myoclonic seizure?
There is no specific intervention for a myoclonic seizure. If seizures occur in prolonged clusters, your doctor may prescribe
a medication to help stop the clusters. Continuous myoclonic seizures may require urgent treatment.
What is the outlook for a child with myoclonic seizures?
The outlook depends largely on the diagnosis. Some epilepsy syndromes will go away when the child gets older. In some cases,
the child may need to keep taking anti-epileptic drugs all his life but will otherwise develop normally. A few syndromes that
cause myoclonic seizures also cause neurological deterioration, which can have serious consequences.
