Aggravation of epilepsy by anti-epileptic drugs

Managing severe epilepsy syndromes of early childhood

Managing severe epilepsy syndromes of early childhood is challenging as the seizures are typically resistant to treatment and may cause disabling mental and behavioral problems in later life. A comprehensive treatment plan includes pharmacologic, nonpharmacologic, and surgical options. This article reviews clinical studies examining the efficacies of antiepileptic medications in reducing seizure frequency in Dravet syndrome, Doose syndrome, and Lennox-Gastaut syndrome. The benefits of the ketogenic diet for children with these severe epilepsies, together with the advantages of vagus nerve stimulation and corpus callosotomy in those patients with Lennox-Gastaut syndrome, are also discussed. Special treatment considerations for each syndrome are also highlighted to improve the management of patients with these syndromes.

Seizure aggravation-evidence that oxcarbazepine requires monitoring

Aggravation of Seizures and/or EEG Features in Children Treated with Oxcarbazepine Monotherapy. Vendrame M, Khurana DS, Cruz M, Melvin J, Valencia I, Legido A, Kothare SV. Epilepsia 2007;48(11):2116–2120. Epub 2007 Jul 21. PURPOSE: Exacerbation of epilepsy may occur following initiation of therapy with antiepileptic drugs (AEDs). The aim of this study is to analyze the clinical and EEG characteristics of a group of pediatric patients with worsening of seizures and/or EEG deterioration while on oxcarbazepine (OXC). METHODS: A retrospective analysis of a clinical database was performed to identify patients with epilepsy treated with OXC over the past 3 years. History, neurological examination, and EEG findings were reviewed to identify any who had developed exacerbation of seizures or new abnormalities on EEG. RESULTS: Of 290 patients on OXC, we identified 12 patients with new onset seizures, all with initial normal neurological exam and normal EEG, who developed either worsening of preexisting seizures, new seizure types, and/or EEG deterioration following introduction of OXC monotherapy. EEG changes were primarily characterized by new onset of generalized epileptiform activity not reported on the initial baseline EEG. Following substitution of OXC with a broad spectrum AED, significant improvement of seizure control and improvement in the EEG was observed. CONCLUSIONS: These findings suggest that OXC can aggravate seizures and/or worsen EEG features in children. Following initiation of therapy with OXC, monitoring of patients with follow-up EEGs may be important, especially in patients who do not show adequate response to therapy.

Antidepressant-associated myoclonic status in a patient with symptomatic generalized epilepsy: does risk occur with therapeutic doses?

The clinical and EEG data of a 49-year-old man with myoclonic and generalized tonic-clonic seizures resulting from early childhood encephalitis are described. He experienced no tonic-clonic seizure for 10 years before brief exposure first to 60 mg/day duloxetine and then to 20mg/day paroxetine for depressive symptoms. These drugs were separately prescribed at a 9-month interval, and after beginning each drug, the patient experienced tonic-clonic seizures of worsening intensity and myoclonus of increasing frequency. Clinical features correlated with subcontinuous, generalized spike-wave discharges on the EEG. Discontinuation of antidepressant treatment resulted in rapid disappearance of clinical and electrophysiological manifestations of myoclonic status. We suggest care must be taken when using serotonin-noradrenaline reuptake inhibitors (SNRIs) or selective serotonin reuptake inhibitors (SSRIs), as these drugs pose the risk of complications in the specific population of people with myoclonic seizures.

A simple quantitative method for analyzing electrographic status epilepticus in rats

Electrographic status epilepticus (ESE) is a medical emergency consisting of repetitive seizures and may result in death or severe brain damage. Epilepsy can develop following ESE. The properties of ESE (e.g., duration and intensity) are variable, as are the effects of putative therapeutic treatments. Therefore a straightforward method to quantify different components of ESE would be beneficial for both researchers and clinicians. A frequency range close to the gamma band was selected for extraction of seizure-related activity from the EEG. This filtering strategy reduced motion artifacts and other noise sources in the electrophysiological recordings, thus increasing the signal-to-noise ratio of the EEG spike activity. EEG spiking was quantified using an energy operator and modeled by an eighth-order polynomial. In a benzodiazepine-resistant rat model of pilocarpine-induced ESE, the efficacy of various pharmaceutical agents at suppressing ESE was analyzed with this and other methods on data collected for < or =24 h after ESE induction. This approach allows for the objective, quantitative, and rapid assessment of the effects of both short- and long-lasting pharmacological manipulations on ESE and other forms of prolonged repetitive electrical activity.

Computer modelling of epilepsy

Epilepsy is a complex set of disorders that can involve many areas of the cortex, as well as underlying deep-brain systems. The myriad manifestations of seizures, which can be as varied as déjà vu and olfactory hallucination, can therefore give researchers insights into regional functions and relations. Epilepsy is also complex genetically and pathophysiologically: it involves microscopic (on the scale of ion channels and synaptic proteins), macroscopic (on the scale of brain trauma and rewiring) and intermediate changes in a complex interplay of causality. It has long been recognized that computer modelling will be required to disentangle causality, to better understand seizure spread and to understand and eventually predict treatment efficacy. Over the past few years, substantial progress has been made in modelling epilepsy at levels ranging from the molecular to the socioeconomic. We review these efforts and connect them to the medical goals of understanding and treating the disorder.

Benzodiazepines in epilepsy: pharmacology and pharmacokinetics

Benzodiazepines (BZDs) remain important agents in the management of epilepsy. They are drugs of first choice for status epilepticus and seizures associated with post-anoxic insult and are also frequently used in the treatment of febrile, acute repetitive and alcohol withdrawal seizures. Clinical advantages of these drugs include rapid onset of action, high efficacy rates and minimal toxicity. Benzodiazepines are used in a variety of clinical situations because they have a broad spectrum of clinical activity and can be administered via several routes. Potential shortcomings of BZDs include tolerance, withdrawal symptoms, adverse events, such as cognitive impairment and sedation, and drug interactions. Benzodiazepines differ in their pharmacologic effects and pharmacokinetic profiles, which dictate how the drugs are used. Among the approximately 35 BZDs available, a select few are used for the management of seizures and epilepsy: clobazam, clonazepam, clorazepate, diazepam, lorazepam and midazolam. Among these BZDs, clorazepate has a unique profile that includes a long half-life of its active metabolite and slow onset of tolerance. Additionally, the pharmacokinetic characteristics of clorazepate (particularly the sustained-release formulation) could theoretically help minimize adverse events. However, larger, controlled studies of clorazepate are needed to further examine its role in the treatment of patients with epilepsy.

Electroencephalogram in unilateral multilobar polymicrogyria with nonconvulsive status epilepticus

This case report presents the epileptic encephalopathy in an 11-year-old girl with multilobar unilateral polymicrogyria and focal nonconvulsive status epilepticus where high epileptogenicity was responsible for progressive and severe cognitive dysfunction. Nonconvulsive status epilepticus in epileptic encephalopathy with unilateral multilobar polymicrogyria has not been reported previously.

Aggravation of Seizures and/or EEG Features in Children Treated with Oxcarbazepine Monotherapy

PURPOSE

Exacerbation of epilepsy may occur following initiation of therapy with antiepileptic drugs (AEDs). The aim of this study is to analyze the clinical and EEG characteristics of a group of pediatric patients with worsening of seizures and/or EEG deterioration while on oxcarbazepine (OXC).

METHODS

A retrospective analysis of a clinical database was performed to identify patients with epilepsy treated with OXC over the past 3 years. History, neurological examination, and EEG findings were reviewed to identify any who had developed exacerbation of seizures or new abnormalities on EEG.

RESULTS

Of 290 patients on OXC, we identified 12 patients with new onset seizures, all with initial normal neurological exam and normal EEG, who developed either worsening of preexisting seizures, new seizure types, and/or EEG deterioration following introduction of OXC monotherapy. EEG changes were primarily characterized by new onset of generalized epileptiform activity not reported on the initial baseline EEG. Following substitution of OXC with a broad spectrum AED, significant improvement of seizure control and improvement in the EEG was observed.

CONCLUSIONS

These findings suggest that OXC can aggravate seizures and/or worsen EEG features in children. Following initiation of therapy with OXC, monitoring of patients with follow-up EEGs may be important, especially in patients who do not show adequate response to therapy.