A seizure results from a temporary, uncontrolled burst of electrical activity within the brain, which can lead to changes in movement, behavior, or awareness. Atonic seizures are a specific type characterized by a sudden, brief loss of muscle tone. This abrupt relaxation of muscles can cause an individual to suddenly become limp, often resulting in a fall.
What Exactly Is an Atonic Seizure?
Atonic seizures are often referred to as “drop attacks” or “drop seizures” because individuals frequently collapse without warning due to an abrupt, temporary loss of muscle tone. The manifestation varies depending on the muscles affected. For instance, if head muscles are involved, the head may suddenly drop forward. If trunk muscles are affected, the person might slump while sitting or collapse if standing.
When the entire body loses muscle tone, the individual falls to the ground like a “rag doll.” These seizures are typically very brief, lasting only one to two seconds, and rarely extending beyond 15 seconds. Consciousness is usually briefly impaired or lost, but recovery is rapid, with muscle control returning almost immediately. Despite their short duration, the sudden loss of muscle tone can lead to injuries from falls, particularly to the head or face.
Identifying the Causes
Atonic seizures often emerge not as isolated events, but as a component of broader epilepsy syndromes, indicating a more complex underlying neurological condition. While the precise cause of atonic seizures is sometimes unknown, they are frequently observed in specific forms of severe childhood epilepsy.
Common conditions associated with atonic seizures include Lennox-Gastaut Syndrome and Dravet Syndrome. These syndromes are characterized by multiple seizure types and often involve developmental considerations. Genetic factors can also play a role, with some individuals inheriting a predisposition to epilepsy that manifests as atonic seizures.
Diagnosing and Treating Atonic Seizures
Identifying atonic seizures involves a combination of medical evaluation and diagnostic tools. Healthcare professionals rely heavily on detailed descriptions or video recordings from observers who witness the events, as these provide crucial insights into the seizure’s characteristics. An electroencephalogram (EEG) is a standard diagnostic test, where electrodes placed on the scalp record the brain’s electrical activity. This can reveal specific patterns of electrical discharge associated with atonic seizures, helping to confirm the diagnosis and distinguish them from other conditions that might cause falls.
The primary approach to managing atonic seizures involves anti-seizure medications (ASMs), also known as anti-epileptic drugs. Various medications can be prescribed, and finding the most effective drug and dosage often requires a period of trial and error, as individual responses vary.
For cases where medications are not sufficiently effective, other treatment options may be considered. These include dietary therapies, such as the ketogenic diet, a high-fat, low-carbohydrate regimen that can help reduce seizure frequency. In rare instances, surgical interventions like corpus callosotomy may be an option, particularly when seizures are severe and resistant to medication. This procedure involves cutting nerve fibers connecting the brain’s hemispheres to prevent seizure activity from spreading.
Immediate Action: What to Do During an Atonic Seizure
When someone experiences an atonic seizure, immediate action should focus on ensuring their safety during the sudden fall. If possible, quickly clear the area around them to remove any objects they might hit as they collapse. Attempting to cushion their head if feasible can help prevent head injuries.
Given the brief nature of atonic seizures, typically lasting only seconds, individuals usually recover muscle tone and awareness very quickly. Once the seizure is over, they can often stand up immediately if no injury occurred. Generally, no further medical intervention is needed unless the person sustains an injury during the fall, such as a cut, bruise, or broken bone. Emergency medical help should be sought if an injury occurs, if the seizure is unusually prolonged for an atonic seizure, or if it is the person’s first seizure.