Abstracts

Tonic status epilepticus (TSE) has been classically associated with secondary generalized epilepsy (SGE) and catastrophic epilepsies. Its occurrence in patients with idiopathic generalized epilepsy (IGE) is not well recognized. The objective of this study was to report episodes of TSE in patients with IGE. We retrospectively reviewed the clinical and EEG evaluation of two patients with IGE who presented with episodes of TSE: both had childhood onset absence seizures and developed nocturnal tonic seizures in their teens. Patient 1 is a 24 year-old woman had typical childhood absences diagnosed at age five. She had no identifiable risk factors or family history of epilepsy. Neurological examination was normal and her EEGs showed three Hz generalized spike and slow wave (GSSW) discharges. Nocturnal tonic seizures, symmetrical and lasting 10 to 20 seconds, appeared during adolescence, mostly related to her periods. They increased in frequency and after age 15 she had several hospitalizations for clusters of such seizures. Her MRI was normal. Tonic seizures were characterized by elevation of both arms, flexion of the neck and trunk, upward eye deviation, and unresponsiveness lasting up to four seconds and ictal EEGs showed generalized polyspike activity.Patient 2 is a 21-year-old man who developed generalized tonic clonic and absence seizures at the age of eight years. The absences were not typical since he partially retained consciousness but was unable to answer. He had no cognitive deficits. His EEG showed irregular GSSW with some additional rhythmic discharges over the left frontal region. He then developed episodes while falling asleep, characteristically related to fatigue and occurring in series or clusters. He was admitted for video-EEG monitoring and many seizures were recorded. They consisted of brief tonic asymmetric posturing of both arms, more evident on the right, upward eye deviation, and contraction of perioral muscles with some downward deviation of the labial commissures. These were associated with generalized polyspikes with fragmentation and irregular GSSW. He also had isolated bilateral myoclonus of the chin. He improved with treatment with lamotrigine and topiramate. Although the pathophysiology of TSE in IGE patients is unknown, GABA mediated changes may disrupt the classical GSSW pattern associated with absence seizures. The perimenstrual progesterone reduction may explain the TSE in patient 1. The worse prognosis associated with perioral myoclonia with absences in patient 2 may relate to the development of TSE. Recognition of this seizure pattern highlights the presence of a continuum in some patients between IGE and SGE. (EK receives a Preston Robb fellowship from the Montreal Neurological Institute)