Atonic seizure is a form of generalized seizure characterized by abrupt loss of muscle tone where the individual goes limp and falls to the ground. This type of seizure is considered rare but likely to occur among children than adults. It is also present among children who have other types of seizures such as tonic or myoclonic seizures.
There is slight muscular contraction while sitting or standing that helps the individual stay upright. An individual loses this muscular contraction during an atonic seizure which causes him/her to fall abruptly. At the start of an episode, there is one or more myoclonic jerks.
What are the indications?
- Abrupt loss of muscular tone
Individual might be conscious or there is momentary loss of consciousness. - Individual turns limp and drops to the ground
- Individual might be conscious or there is momentary loss of consciousness
- Drooping of the eyelids
- Nodding of the head
- Loss of muscle tone and the individual becomes limp and drops straight to the ground
- Among infants who are not able to stand up, it manifests as head drop
- The length of an episode is usually less than 15 seconds but can last for several minutes in some cases
- An individual might have one episode or have several one after another
- After an atonic seizure, a child abruptly becomes conscious and alert
What are the possible causes and how is it diagnosed?
The precise cause of this type of seizure is not fully understood. The seizures are typically seen in various forms of symptomatic epilepsy and rarely in idiopathic epilepsy.
A diagnosis is made based on the description of the seizure. Some tests such as EEG are carried out to establish a diagnosis. Other tests including ECG are carried out to check for any alterations in the heart rhythm or blood pressure.
How to manage an atonic seizure
- Anti-epileptic drugs are used as treatment but the individual might not always respond to them effectively.
- A ketogenic diet can be started
- Vagus nerve stimulation
- A surgical procedure called corpus callosotomy is performed
- Treatment for injuries sustained after falling during an episode
The prognosis for this type of seizure depends on the diagnosis. In some cases of epilepsy syndromes, they gradually recede as a child grows up. In some instances, anti-epileptic medications should be taken for life.
Disclaimer / More Information
The information posted on this page on an atonic seizure is for learning and educational purposes only. To learn to properly manage seizures, register for first aid training at one of our training centers located throughout Canada. The training centers are in Edmonton, Calgary, Vancouver, Kelowna, Surrey, Winnipeg, Toronto, Ottawa and Halifax.