K. van Rijckevorsel

Non-epileptic seizures: delayed diagnosis in patients presenting with electroencephalographic (EEG) or clinical signs of epileptic seizures.

The clinical differentiation between epileptic seizures (ES) and non-epileptic seizures (NES) is often difficult and mostly based on the presence or absence of widely recognized features of ES such as tongue biting, falling, incontinence or concomitant epileptic abnormalities in the electroencephalogram (EEG). We retrospectively analysed the records of all patients referred to our Epilepsy Centre for refractory epilepsy and finally diagnosed with NES between 1980 and 1999 ( n= 103), half of them also exhibiting ES. The mean time-lapse between first attack and NES diagnosis was 8.7 +/- 1.3 years and 16.5 +/- 1.4 years for the NES and NES + ES groups respectively. At least one of the usual signs associated with generalized tonic-clonic seizures (tongue biting, falling or incontinence) was reported by 66% and 60% of patients with NES or NES + ES respectively. Interictal EEG abnormalities were recorded in 16% of NES patients vs. 80% of NES + ES patients. In the NES group, delay before establishing the correct diagnosis was significantly longer when the patients exhibited > or =1 symptom(s) of generalized seizures, or when patients exhibited interictal EEG abnormalities. Upon admission, 72% of NES patients and all NES + ES patients were being treated with antiepileptic drugs (AEDs).We conclude that EEG or clinical abnormalities suggestive of epileptic seizures are common in undiagnosed NES patients. Such diagnostic pitfalls, besides considerably delaying NES diagnosis, also considerably delay appropriate treatment implementation.

Cognitive problems related to epilepsy syndromes, especially malignant epilepsies.

Neurocognitive impairment is frequent in epilepsy patients. Causes are multiple, and may be influenced by several factors including the epilepsy syndrome. Most cognitive complaints in adult patients are mental slowness, memory difficulties and attention deficits. In children, cognitive problems are more diffuse, responsible for language troubles, learning difficulties, poor academic outcome, behavior problems and finally unfortunate socio-professional prognosis. The most devastating epilepsy syndromes such as epileptic encephalopathies are nearly exclusively described in infancy and childhood. This paper will review the major cognitive complaints in relation to the epilepsy syndrome, with a more detailed interest for the malignant epilepsies in infancy and childhood such as Ohtahara and West syndrome, Lennox-Gastaut syndrome and epileptic encephalopathis with continuous spike-and-wase during slow wave sleep. The impact of surgery on cognition will be briefly discussed in adults and youger patients.

Current approaches to the use of generic antiepileptic drugs

Generic substitution is encouraged as a cost containment strategy for the management of health care resources. However, in epilepsy, the consequences of loss of symptom control are important, and antiepileptic drugs have narrow therapeutic indices. For this reason, generic substitution may be problematic, and certain health authorities have excluded antiepileptic drugs from overall policy recommendations on generic prescribing. The absence of bioequivalence data among generic forms and the relatively broad criteria for bioequivalence with the branded drug allow differences in drug exposure to arise that may be clinically relevant and necessitate monitoring of plasma levels when switching formulations to avoid loss of seizure control or emergence of side effects. Management of these issues carries a significant cost, which should be weighed carefully against the cost savings acquired when purchasing the drug. Both physicians and patients have a right to be informed and approve before pharmacists make a generic substitution or switch between generics.

NEUROSERPIN MUTATION CAUSES ELECTRICAL STATUS EPILEPTICUS OF SLOW-WAVE SLEEP

Conformational diseases result from cellular dysfunctions induced by aberrant aggregation of proteins. They are caused either by excess of secretion of a normal protein, or more frequently, by mutation in a protein, as in prion diseases. Recently, one of them, familial encephalopathy with neuroserpin inclusion bodies (FENIB, OMIM #604218), an autosomal dominant dementia, was recognized. It is caused by mutations in PI12 (proteinase inhibitor 12, SERPINI1 or neuroserpin, OMIM #602445), a neuron-specific serine proteinase inhibitor (serpin).1,2 Neuroserpin was first identified in culture medium of chicken axons, then in human neurons.3 It plays roles in synapses and vessel permeability, and is known to be associated with learning, memory, and behavior. It belongs to the serpin super-family, members of which display at least 30% amino acid sequence homology with their archetype, alpha-1-antitrypsin. Mutated neuroserpin progressively polymerizes in neuronal endoplasmic reticulum, inducing cognitive impairment and sometimes myoclonic epilepsy. Neuropathology is characterized by neuronal intra-cytoplasmic rounded inclusions, homogeneously pale to intensely pink with eosin, and PAS positive after diastase treatment (Collins bodies). Four different mutations have been described in six families affected by FENIB: two in exon 2 (S49P and S52R) and two in exon 9 (H338R and G392E). Known mutations in serpins are localized in the mobile regions of the molecule (exon 2 and 9). They result in proteins …

Effect of levetiracetam in patients with epilepsy and interictal epileptiform discharges

The effect of acute treatment with the new antiepileptic drug (AED) levetiracetam (Keppra) on the frequency of interictal epileptiform discharges (IEDs) was evaluated in a double-blind, placebo-controlled, crossover study with therapeutic drug monitoring and serial electroencephalographic (EEG) observations. Acute (500 mg twice daily) and chronic (individualized, 500-1000 mg twice daily) doses of levetiracetam were administered as an add-on to current AED treatment. Efficacy was tested by measuring the frequency of IEDs in EEG recordings and the number of seizures. A single acute dose of levetiracetam induced a reduction of IEDs in eight out of ten patients. During the acute phase, an insufficient number of seizures occurred for analysis. During chronic treatment over 8 weeks, seven patients showed a reduction in seizure frequency (responder rate), and one patient remained seizure free. No correlation was seen between levetiracetam levels and IED frequency. Doses of levetiracetam of up to 2000 mg/day were well tolerated, and no interactions were seen with concomitant AEDs.

Takotsubo syndrome (TKS): A possible mechanism of sudden unexplained death in epilepsy (SUDEP)

We report a case of Takotsubo syndrome after epilepsy, and review the literature. We identified 59 cases of Takotsubo syndrome after focal or generalised epilepsy. As in Takotsubo syndrome in general, the patients were mostly female (84%), with a mean age of 63 years, and the evolution was generally favourable. There was one death and one stroke, and 4 cases were of relapsing Takotsubo after a new seizure. Takotsubo syndrome may induce cardiac arrhythmias. A near-SUDEP (sudden unexplained death in epilepsy) was reported in one patient. Animal models of SUDEP have shown similar cardiac lesions to those seen in Takotsubo syndrome, and strengthen the hypothesis of a link between these conditions. Takotsubo syndrome after epilepsy may be relatively common; we suggest measurement of serum troponin levels in high-risk patients and cardiac follow-up.

Bradycardia, an epileptic ictal manifestation

Two patients with recurrent paroxysmal cardio-vascular symptoms are described. The first, an adult, suffered from syncopal events which did not respond to carbamazepine treatment and had a normal interictal EEG and ECG. The second, a child, presented with attacks of cyanosis, apnoea, and non-responsiveness in clusters, with normal interictal examinations. In both patients, prolonged simultaneous EEG and ECG monitoring demonstrated ictal bradycardia accompanied by paroxysmal discharges in the left temporal area.

Clinical and EEG findings in six patients with altered mental status receiving tiagabine therapy

Tiagabine (TGB), a novel GABA reuptake inhibitor antiepileptic drug, has been reported to induce nonconvulsive status epilepticus (NCSE) in patients with generalized or partial onset seizures. We describe six patients with refractory partial epilepsy treated with add-on TGB. They developed acute intermittent or progressive chronic confusion associated with diffuse slowing of the electroencephalogram (EEG), shortly after an increase in dose of TGB. This remitted in each situation after reduction of the daily dose. The possibility of nonconvulsive status epilepticus or toxic encephalopathy is discussed.

The 'number needed to treat' with Levetiracetam (LEV): comparison with the other new antiepileptic drugs (AEDs)

Levetiracetam (LEV, Keppra) is a new antiepileptic drug for the add-on treatment of partial onset seizures. Pivotal studies have shown a significant efficacy for all tested doses (pooled data: 28% of responders with 1000 mg per day, 32% of responders with 2000 mg per day and 41% of responders with 3000 mg per day). Its safety profile is also quite encouraging: in pivotal studies, adverse events were mostly central nervous system related and manifested as somnolence, asthenia and dizziness; often being mild to moderate in severity. No life-threatening adverse events related to the study drug were described. Furthermore, LEV has a very straightforward pharmacokinetic profile: no protein binding, no potential or significant drug interactions, no hepatic metabolization, as well as displaying linear kinetics and no active metabolites. Because neurologists have received numerous new therapeutic possibilities over the last few years, it is important to compare this new antiepileptic drug (AED) to the others in terms of efficacy and potential new advantages. A first attempt to compare AEDs for efficacy and/or safety was made by Marson et al.1 using the odds ratios from meta-analysis of double-blind placebocontrolled studies. This analysis did not show significant differences between the new AEDs. This could be due to the fact that the odds ratio does not take into account the placebo response and the variability of the therapeutic answer between the different studies. Other comparative methods used include the Star Rating system of Brodie 2 and the improvement rates at recommendedoses suggested by Cramer et al.3. The first method is partially subjective while the second one could give some interpretations about the notion of ‘recommended’ doses. The number needed to Table 1: Comparative number needed to treat to obtain one addition (to placebo) responder.

Opinion of Belgian neurologists on antiepileptic drugs: Belgian Study on Epilepsy Treatment (BESET).

Objectives –  To describe the choice of treatment in adult patients with epilepsy in Belgium, to detect the presence or absence of consensus among neurologists in epilepsy treatment, and to analyze the gaps between current guidelines and prescriptions.