By: Iris Zhao
Photo Credit: www.depositphotos.com
Atonic Seizures
What are Atonic Seizures?
Atonic seizures are known as “drop seizures” that occur after an abnormal burst of electrical activity in the brain. They are a type of onset seizure where a person experiences a brief and sudden loss of muscle tone and consciousness, leading them to go limp or unexpectedly fall. Most often, these seizures occur in people with Lennox-Gastaut and Dravet syndrome, and may also occur alongside other types of seizures in the same person. Atonic seizures most typically start in one’s childhood but may last into adulthood. It’s crucial to note that atonic seizures are frequently linked to injuries since many people suddenly fall during an episode. For this reason, it’s critical to seek treatment to manage the seizures and stay safe.
(Cleveland Clinic, 2024; Kiriakopoulos, n.d.)
Classification
Atonic seizures can be classified into two forms based on the origin of where the seizure occurs. They are usually referred to as a type of focal onset seizure (also known as “partial seizures”) if the seizure begins in one hemisphere of the brain. Focal onset seizures can be further classified into motor seizures or nonmotor seizures based on whether they have a physical component to them. In this case, atonic seizures are a type of focal motor seizure as it causes a sudden loss of muscle tone and muscle control. However, if the seizure begins in both hemispheres of the brain, they would be referred to as generalized onset atonic seizures. (Kiriakopoulos, n.d.)
Risk Factors
Atonic seizures occur when certain brain regions that control muscle tone, such as the brainstem or frontal lobe, experience an aberrant spike in electrical activity. Although the exact cause of this phenomenon is unknown, a person may be more susceptible to atonic seizures if they are under the age of eighteen, have a history of seizures in their infant years, or have an underlying condition like Lennox-Gastaut syndrome or Dravet syndrome.
Although some atonic seizures may last into adulthood, it is less common to actually receive a diagnosis when the person is an adult.
(Cleveland Clinic, 2024)
Symptoms
Atonic seizure symptoms include a sudden and temporary loss of consciousness and muscle tone in part or all of your body, leaving your muscles limp or weak. Other symptoms may include drooping eyelids, head nods, or jerking. Your muscle control and muscle tone should return to normal after the seizure, which usually only lasts 15 seconds or less.
As atonic seizures happen without warning, injuries and accidents are highly prevalent. This is due to how these seizures can cause someone to suddenly fall down, close their eyes, slouch down, drop their head to their shoulder or chest, and drop their arms and objects they were carrying. Hence, many people choose to wear protective gear such as helmets to prevent potential facial or head injuries.
As a result of these seizures and the associated loss of muscle control, it may lead to cuts, bruises, broken bones, or even traumatic brain injuries. Therefore, many people with atonic seizures may refrain from doing activities such as driving or operating heavy machinery as it can be very dangerous if a seizure were to occur.
(Cleveland Clinic, 2024; LGS Foundation, 2022)
Diagnosis
Your doctor or other healthcare professional will often diagnose an atonic seizure following a neurological or physical examination. Having someone you know who saw the seizure accompany you during the examination could help your doctor better understand what transpired while you are being diagnosed. If they can’t be there in person, handing your doctor written descriptions by observers of what happened or video recordings of your seizures would be very beneficial in diagnosing atonic seizures. If your seizures do not stop with medications or if the diagnosis is not clear, additional tests such as an EEG (electroencephalogram) monitoring may also help to provide a clearer diagnosis.
To rule out other conditions or causes of a sudden loss in muscle control and consciousness, your doctor or a healthcare professional may also order blood tests, an MRI (magnetic resonance imaging), or a PET scan (positron emission tomography).
X-rays may also be taken if you get an injury during the seizure in order to see if it resulted in any broken bones.
(Cleveland Clinic, 2024; Kiriakopoulos, n.d.)
Treatment
If a seizure occurs at home, it is important to have a loved one or someone you know be aware of how to provide first aid. Atonic seizures are usually very quick therefore, a person near you should do all they can to ensure your safety. People with atonic seizures should be kept safe in padded areas and should wear a seizure helmet or protective gear whenever it is possible.
Atonic seizures are typically treated with antiseizure medications prescribed by your healthcare provider. These medicines such as benzodiazepines, felbamate, levetiracetam, topiramate, valproic acid (valproate), and zonisamide, may be used to treat seizures.
Although, it is important to note that medications may sometimes have limited effectiveness on atonic seizures. Thus, if antiseizure medications are unsuccessful in treating your seizures, your provider may consider other forms of treatment possible. For instance, these other forms of treatment may include surgery and vagus nerve stimulation. Dietary therapies may also be suggested such as having the person undergo a ketogenic diet which may also help manage the seizures.
Any injuries that occur from an atonic seizure should be treated immediately by your healthcare provider.
(Cleveland Clinic, 2024; Kiriakopoulos, n.d.; LGS Foundation, 2022)
Conclusion
Atonic seizures are a serious and potentially dangerous type of seizure characterized by a sudden and temporary loss of muscle tone and consciousness, often leading to unexpected falls and injuries. While they most commonly affect children and are frequently associated with conditions such as Lennox-Gastaut syndrome and Dravet syndrome, these seizures can persist into adulthood. Early diagnosis through medical evaluation and appropriate testing, along with effective treatment options such as antiseizure medications and lifestyle adjustments, is essential for managing these seizures. Because atonic seizures occur without warning, prioritizing safety measures and maintaining ongoing medical care are crucial for reducing risks and improving the quality of life for those affected.
References
Cleveland Clinic. (2024). Atonic Seizure: What It Is, Causes, Symptoms, & Treatment. Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/atonic-seizure
Kiriakopoulos, E. (n.d.). Atonic seizures. Epilepsy Foundation. https://www.epilepsy.com/what-is-epilepsy/seizure-types/atonic-seizures
LGS Foundation. (2022, February 26). Atonic seizures. LGS Foundation. https://www.lgsfoundation.org/atonic-seizures/
