EPILEPSY WITH MYOCLONIC ATONIC SEIZURES (EMAtS)

Overview

Epilepsy with myoclonic atonic seizures (previously known as Doose syndrome) is a syndrome characterized by the usually abrupt onset of multiple generalized seizure types, including myoclonic-atonic seizures in early childhood. Developmental stagnation or regression is typically seen during the phase of active seizures. Despite initial drug-resistant seizures, two thirds of children achieve epilepsy remission.

Clinical context

This condition usually begins abruptly, with frequent generalized seizures appearing, between 2-6 years of age (range 6 months to 8 years). Both sexes are affected, with a male predominance. Antecedent and birth history is usually unremarkable, approximately a quarter of children have prior febrile seizures. Neurological examination and head size are normal. Prior development and cognition are normal in two thirds of children. Developmental stagnation or regression can occur when seizures are frequent when behaviour and sleep disorders, executive dysfunction and ataxia are seen. Seizures are drug-resistant but two thirds of children achieve epilepsy remission, usually within 3 years of epilepsy onset. Remaining patients continue to have seizures and developmental impairments, factors predictive of poorer outcome include tonic seizures, recurring nonconvulsive status, slow (<2.5Hz) spike wave or generalized paroxysmal fast activity on EEG.

CAUTION ~5% of cases are due to glucose transporter 1 deficiency syndrome. This disorder is important to diagnose due to implications for treatment.

NOTE Epilepsy with myoclonic atonic seizures is a syndrome with epileptic encephalopathy.