Atonic seizures are a type of generalized seizure. They involve a sudden loss of muscle tone, so that the child goes limp and falls to the ground. They are often present in children who also have other seizure types, such as tonic or myoclonic seizures. They occur in all age groups, but are more common in children.
What are other terms for atonic seizures?
Other terms for atonic seizures that you may come across include:
- astatic seizure
- drop seizure
- drop attack
How can you tell if your child has atonic seizures?
Possible signs and symptoms of an atonic seizure include:
- sudden loss of muscle tone
- the child goes limp and falls straight to the ground
- the child remains conscious or has a brief loss of consciousness
- eyelids droop, head nods
- jerking
- the seizure usually lasts less than 15 seconds, although some may last several minutes
- the child quickly becomes conscious and alert again after the seizure
When we stand or sit, many of our muscles are slightly contracted, working to keep us upright. When a child has an atonic seizure, the muscles in his body lose their tone and go limp, and the child falls straight to the ground. It may be hard to recognize an atonic seizure if the child is sitting or lying down, because he will not fall.
An atonic seizure may begin with one or more myoclonic jerks. There are several different seizure types that may cause a child to fall, including tonic seizures; with atonic seizures, however, the child falls straight to the ground, and is not pushed forward or backward by muscle contractions as with tonic seizures.
In babies, who cannot stand up, atonic seizures most often appear as a head drop.
How many other children have atonic seizures?
Atonic seizures are rare, although they are seen more often in children than in adults. Approximately 1% to 3% of children with epilepsy have atonic seizures.
What causes atonic seizures?
Researchers do not really understand the causes of atonic seizures yet. They are seen in various kinds of symptomatic epilepsy and rarely in idiopathic epilepsy.
How are atonic seizures treated?
Atonic seizures are treated with anti-epileptic drugs, although they do not always respond well to them. They may also be treated with the ketogenic diet, vagus nerve stimulation, or a type of surgical procedure called a corpus callosotomy.
What should I do when my child has an atonic seizure?
These seizures are often known as “drop attacks” because they can cause your child to fall down suddenly if he is standing when the seizure begins. It can be difficult or impossible to intervene in time. If your child often has seizures of this type, he may need to wear a helmet to protect his head from injury.
No specific intervention is needed for one of these seizures, unless your child was injured in falling.
What is the outlook for a child with atonic seizures?
The outlook depends largely on the diagnosis. Some epilepsy syndromes will go away when the child gets older. In other cases, the child may need to keep taking anti-epileptic drugs all his life.