atonic seizure
Pronunciation: ay-TAHN-ick
A type of generalized seizure characterized by sudden loss of muscle tone, causing the patient to fall or drop their head.
Full Definition
Atonic seizures, also known as drop attacks or drop seizures, are generalized epileptic seizures characterized by sudden, brief loss of muscle tone that typically lasts 1-3 seconds. During these episodes, children may experience complete body collapse and fall to the ground, or they may have partial atonic components affecting only the head, arms, or trunk. The sudden nature of these seizures makes them particularly dangerous due to injury risk from falls. Atonic seizures are commonly seen in epileptic encephalopathies such as Lennox-Gastaut syndrome and Doose syndrome. They are often resistant to treatment and may require specialized interventions including protective equipment and dietary therapies.
Usage
Usage note: Distinguish from 'astatic' which is an older term for the same seizure type. Modern terminology favors 'atonic.'
In Context
- "The patient experienced multiple atonic seizures daily, requiring a protective helmet to prevent head injury." — Safety assessment note
- "Atonic seizures in this child with Lennox-Gastaut syndrome proved refractory to multiple antiepileptic drugs." — Treatment resistance evaluation