Risk of recurrence in patients with an unprovoked tonic-clonic seizure and generalized epileptiform discharges on EEG.

OBJECTIVE: The decision to initiate treatment in patients with a first unprovoked seizure remains controversial. Studies have reported a recurrence rate ranging from 21%-50%, but most have included patients with different etiologies, electroencephalography (EEG) findings, and seizure types. This study aimed to determine the risk of recurrence in patients with a first unprovoked generalized tonic-clonic (GTC) seizure with evidence of generalized spike-wave discharges (GSWDs) on EEG and compare the efficacy of antiseizure medications (ASMs) in preventing recurrence. METHODS: This prospective study included consecutive patients who presented with a single GTC seizure, evidence of GSWDs on EEG, and a follow-up period of at least 1 year. All patients underwent extensive evaluation, including a 3-hour sleep-deprived video-EEG recording and an epilepsy protocol brain magnetic resonance imaging (MRI). Treatment with ASMs was recommended for all patients. The decision regarding the specific ASM to be used was left to the treating physician's discretion. RESULTS: A total of 57 patients with a median age of 19 years were included. A total of 41 patients agreed to be started on an ASM while 16 declined. Seizure recurred in 6 of 41 patients (14.6%) in the treated group compared to 11 of 16 (68.8%) in the untreated group (p = .00006). Valproate was significantly more efficacious than levetiracetam or lamotrigine (p = .04). Of the 15 patients who discontinued ASM treatment after remaining seizure-free for an average of 30 months, 6 (40%) experienced a seizure recurrence. SIGNIFICANCE: Patients with a first unprovoked GTC seizure and evidence of GSWDs on EEG have a high risk of recurrence if left untreated. Valproate is the most efficacious ASM for preventing recurrence in this population. A sizeable proportion of patients can be successfully tapered off medication after a period of seizure freedom. This study provides valuable information for guiding treatment decisions in this patient population.

Hyperventilation-induced high-amplitude rhythmic slowing: A mimicker of absence seizures in children.

PURPOSE: Hyperventilation (HV) in children can lead to HV-induced high-amplitude rhythmic slowing (HIHARS) on the EEG (electroencephalogram) which is sometimes associated with altered awareness (AA) and concomitant semiological features. Our aims were to determine the frequency of HIHARS in children, to assess if the associated semiological features were temporally related to HV, and to evaluate if specific semiological features can differentiate HIHARS with AA from absence seizures. METHODS: Consecutive children with suspected new onset seizure(s) underwent HV and awareness testing during video-EEG acquisition. Hyperventilation-induced high-amplitude rhythmic slowing was defined as 2.5- to 5-Hz generalized rhythmic slowing with amplitude ≥100 µv lasting for ≥3 s. The associated semiological features were compared between the group of children with HIHARS and AA, an age- and gender-matched control group without HIHARS, and in children who experienced absence seizures during HV. RESULTS: One hundred sixteen children with a mean age of 9.8 years were included. Hyperventilation-induced high-amplitude rhythmic slowing occurred in 39 children (33.6%) with AA documented in 30 (76.9%). The probability of developing AA during HIHARS was significantly and positively correlated with the HIHARS duration. The frequencies of HIHARS were not significantly different between children diagnosed with seizure(s) and those with nonepileptic spells. Hyperventilation cessation and staring did not occur in any child of the control group. Fidgeting and yawning were significantly more common in the group with HIHARS with AA while staring and blinking were significantly more frequent in the group of children with absence seizures. CONCLUSIONS: We ascertained that HIHARS with AA is a relatively common occurrence in children and most likely represents an age-related nonepileptic phenomenon. When associated with fidgeting or yawning, it can help differentiate this phenomenon from absence seizures. However, recording the concomitant presence of generalized spike wave discharges on the EEG remains essential to confirm the diagnosis of absence seizures.

Catastrophic relapses following initiation of dimethyl fumarate in two patients with neuromyelitis optica spectrum disorder.

We report two cases of neuromyelitis optica spectrum disorder (NMOSD) who were misdiagnosed as multiple sclerosis (MS) and developed catastrophic relapses following initiation of dimethyl fumarate. Both patients developed a severe myelitis extending from the cervical cord to the medulla with significant cord swelling, resulting in complete quadriplegia and respiratory difficulties, in addition to severe bilateral visual loss in one patient. It is of note that both catastrophic relapses occurred 2 and 3 months following initiation of dimethyl fumarate.