Effectiveness and tolerability of rufinamide in children and adults with refractory epilepsy: first European experience

OBJECTIVE

The aim of the study was to explore the effectiveness and tolerability of rufinamide in a heterogeneous group of patients with refractory epilepsies in Europe, immediately after the drug became available as an orphan drug for the adjunctive treatment of Lennox-Gastaut syndrome (LGS).

METHODS

This observational study was conducted as a collection of retrospective data from multiple centers in Germany and Austria. Clinical course in patients treated with rufinamide was documented. Initial dosage and titration schedule of rufinamide were at the discretion of the treating physician according to medical need. The observation period was 12 weeks. Effectiveness was evaluated by comparing the frequency of seizures with limitations to the countability between baseline and the last 4-week period of observation.

RESULTS

The study population consisted of 45 children and 15 adults (mean age: 14.5+/-11.6 years, range: 1-50) with various severe and inadequately controlled epilepsy syndromes, that is, LGS (n=31), idiopathic generalized epilepsy syndromes (n=5), cryptogenic unclassified generalized epilepsy (n=7), and partial epilepsy (n=17). The response rate (50% reduction in countable seizures) was 46.7% (28 of 60 patients) in total; 25.0% experienced a 75% reduction in seizure frequency and 21.7% experienced a 50-75% reduction. Complete seizure control was achieved by 8.3%. The highest response rate was observed in patients with LGS (17/31, 54.8%), and the lowest in patients with partial epilepsy (4/17, 23.5%). Response rate in patients with unclassified generalized epilepsy was 42.8% (3/7 patients). A total of 67 adverse events were reported by 35 of 60 patients. The most frequently occurring adverse events were fatigue (18.3%), vomiting (13.3%), and loss of appetite (10.0%). No serious adverse events were observed.

CONCLUSIONS

These preliminary data suggest that rufinamide may be effective and well tolerated in the treatment of children and adults with various epilepsy syndromes and difficult-to-control seizures. The results of our study suggest that the efficacy of rufinamide in patients with generalized epilepsy might be comparable to that in patients with LGS, whereas rufinamide was less effective in patients with partial epilepsy.

Thrombocytopenia during levetiracetam therapy

A 64-year-old patient with symptomatic epilepsy developed thrombocytopenia during treatment with levetiracetam (LEV). As no other medical reason could be evaluated, a medication side effect was postulated. The only new drugs were valproic acid (since 3 weeks) and levetiracetam (since 3 days). After valproic acid medication was ended, thrombocytopenia did not improve and even worsened further. Finally levetiracetam administration was ended and trombocytopenia resolved rapidly and completely within few days.

The Wada test in Austrian, Dutch, German, and Swiss epilepsy centers from 2000 to 2005: a review of 1421 procedures

Twenty-six Austrian, Dutch, German, and Swiss epilepsy centers were asked to report on use of the Wada test (intracarotid amobarbital procedure, IAP) from 2000 to 2005 and to give their opinion regarding its role in the presurgical diagnosis of epilepsy. Sixteen of the 23 centers providing information had performed 1421 Wada tests, predominantly the classic bilateral procedure (73%). A slight nonsignificant decrease over time in Wada test frequency, despite slightly increasing numbers of resective procedures, could be observed. Complication rates were relatively low (1.09%; 0.36% with permanent deficit). Test protocols were similar even though no universal standard protocol exists. Clinicians rated the Wada test as having good reliability and validity for language determination, whereas they questioned its reliability and validity for memory lateralization. Several noninvasive functional imaging techniques are already in use. However, clinicians currently do not want to rely solely on noninvasive functional imaging in all patients.

Association of ABCB1 genetic variants 3435C>T and 2677G>T to ABCB1 mRNA and protein expression in brain tissue from refractory epilepsy patients

PURPOSE

There is evidence from studies in rodents that P-glycoprotein (P-gp) overexpression is implicated in the causation of refractory epilepsy. Genetic variants in the human ABCB1 (MDR1) gene were shown to affect the expression levels of the transporter in various tissues and to be associated with refractory epilepsy. However, the effect of the genetic variants on the P-gp level in epileptogenic brain tissue is poorly investigated. In the present study, we examined the impact of putatively functional polymorphisms 3435C>T and 2677G>T in the ABCB1 gene on the ABCB1 mRNA expression and P-gp content in human brain tissue from epileptogenic foci of the patients with refractory epilepsy.

METHODS

Fresh brain tissue specimens were obtained from therapy-refractory epilepsy patients during neurosurgery of the epileptogenic focus. We determined the ABCB1 mRNA expression in 23 samples using 5' exonuclease-based real-time polymerase chain reaction (PCR) as well as the P-gp content in 32 samples determined by immunohistochemistry, genotyping was performed by PCR/restriction fragment length polymorphism (RFLP).

RESULTS

There was lack of association of 3435C>T and 2677G>T as well as diplotype configurations on ABCB1 mRNA expression and P-gp content in epileptogenic brain tissues.

CONCLUSIONS

We cannot exclude an association of ABCB1 variants on P-gp function, but our results suggest that brain ABCB1 mRNA and protein expression is not substantially influenced by major ABCB1 genetic variants thus explaining in part results from case-control studies obtaining lack of association of ABCB1 polymorphisms to the risk of refractory epilepsy.

A case of hippocampal laminar necrosis following complex partial status epilepticus

Cortical laminar necrosis (CLN) is a metabolic injury pattern usually observed after cerebral hypoxia, hypoglycemia, or ischemia. We report serial magnetic resonance imaging findings in a patient with complex partial status epilepticus (SE) developing a band-like, T1-hyperintense lesion consistent with CLN along the surface of the left hippocampus without concurrent other causes of CLN. This observation suggests a direct pathogenetic link between SE and CLN involving combined damage to neurons and glia.

Waterjet dissection versus ultrasonic aspiration in epilepsy surgery

OBJECTIVE

Waterjet dissection is currently under close investigation in neurosurgery. Experimentally, precise brain parenchyma dissection with vessel preservation has been demonstrated. Clinically, the safety of the instrument has already been proved. However, precise data demonstrating that waterjet dissection indeed reduces surgical blood loss are still missing.

METHODS

The authors applied the waterjet device in a prospective randomized study in comparison with the ultrasonic aspirator. Because there is little variability in the procedure, 30 patients with temporal lobe epilepsy receiving a tailored temporal lobe resection between December 1999 and October 2002 were selected for this study. Intraoperative vessel preservation, intraoperative blood loss, surgical complications, and epilepsy outcome were evaluated. All patients were followed at 3-month intervals.

RESULTS

During surgery, both instruments were easy to handle. Only with the waterjet dissector, however, were even small intraparenchymal blood vessels preserved. Intraoperative blood loss was significantly reduced with the waterjet (mean, 70 +/- 46 ml) compared with the ultrasonic aspirator (mean, 121 +/- 48 ml). However, no difference in the necessity for blood transfusion occurred. No difference was observed with respect to operation time (238.6 +/- 37.0 min with the waterjet, 247.5 +/- 41.5 min with the ultrasonic aspirator), surgical complications, and outcome.

CONCLUSION

The waterjet dissector enables a significant reduction of intraoperative blood loss in the investigated setting. However, further studies are needed to confirm these results with a larger number of patients. Studies also are needed to prove that the reduction of blood loss is of clinical relevance for the outcome of the patients.

Fear conditioning following unilateral temporal lobectomy: dissociation of conditioned startle potentiation and autonomic learning

The present study investigated fear-potentiated startle and autonomic learning in brain-lesioned patients in a classical fear-conditioning paradigm. Startle blink and skin conductance responses of 30 patients who underwent unilateral temporal lobectomy because of drug-resistant epilepsy were compared with those of 32 healthy controls. As expected, temporal lobectomy patients showed a general impairment in fear conditioning relative to controls. This impairment did not differ with respect to the affected hemisphere. Moreover, while fear-conditioned startle potentiation in healthy controls was independent of contingency awareness, skin conductance discrimination was only observed for those participants who correctly recognized the stimulus contingencies. Patients who acquired a declarative memory of the contingencies also showed intact skin conductance discrimination but failed to exhibit fear-potentiated startle. The present findings support a two-levels-of-learning account of human fear conditioning and also demonstrate that the amygdala is crucially involved in fear learning.

Proteomic Identification of the Involvement of the Mitochondrial Rieske Protein in Epilepsy

PURPOSE

Kindled seizures are widely used to model epileptogenesis, but the molecular mechanisms underlying the attainment of kindling status are largely unknown. Recently we showed that achievement of kindling status in the Sprague-Dawley rat is associated with a critical developmental interval of 25 +/- 1 days; the identification of this long, well-defined developmental interval for inducing kindling status makes possible a dissection of the cellular and genetic events underlying this phenomenon and its relation to normal and pathologic brain function.

METHODS

By using proteomics on cerebral tissue from our new rat kindling model, we undertook a global analysis of protein expression in kindled animals. Some of the identified proteins were further investigated by using immunohistochemistry.

RESULTS

We report the identification of a modified variant of the Rieske iron-sulfur protein, a component of the mitochondrial cytochrome bc1 complex, whose isoelectric point is shifted toward more alkaline values in the hippocampus of kindled rats. By immunohistochemistry, the Rieske protein is well expressed in the hippocampus, except in the CA1 subfield, an area of selective vulnerability to seizures in humans and animal models. We also noted an asymmetric, selective expression of the Rieske protein in the subgranular neurons of the dorsal dentate gyrus, a region implicated in neurogenesis.

CONCLUSIONS

These results indicate that the Rieske protein may play a role in the response of neurons to seizure activity and could give important new insights into the molecular pathogenesis of epilepsy.

On the psychopathology of unilateral temporal lobe epilepsy

Personality adjustment of patients with unilateral temporal lobe epilepsy (TLE) was investigated in the light of special characteristics of the epilepsy process, psychosocial stressors, and the cognitive status of the patients. Thirty-seven patients with medically intractable unilateral temporal lobe epilepsy (16-55 years of age; 20 right temporal and 17 left temporal foci) were examined with standardized personality inventories (FPI, STAI, IPC, TSK) supplemented by a rating scale evaluated by the neuropsychologist (GEWLE). Patients with left temporal lobe epilepsy were characterized by increased emotional dependency, less externally judged composedness, increased depressive drive and mood, increased nervousness, increased search for information and exchange of disease experience, and greater tendency to persevere (P < 0.05). Cognitive status and psychosocial status did not significantly differ. The evaluation of personality adjustment contributes to the lateralization of the epileptogenic focus and reveals interesting patterns in the preoperative diagnostic puzzle, and in addition provides a strategy to individualize psychotherapeutic strategies.

Expression of multidrug transporters in dysembryoplastic neuroepithelial tumors causing intractable epilepsy

OBJECTIVE

Dysembryoplastic neuroepithelial tumors (DNT) are relatively benign brain lesions that often cause medically intractable epilepsy. There is mounting evidence that multidrug transporters such as P-glycoprotein (P-gp) or multidrug resistance-associated proteins (MRP) play an important role in the development of resistance to antiepileptic drugs (AED).

MATERIAL AND METHODS

In the present study, we examined the expression of several multidrug transporters in 14 cases of DNT. The peritumoral brain tissue as well as 9 cases of arteriovenous malformations (AVM) served as controls. P-gp, MRP2, MRP5 and breast cancer resistance protein (BCRP) expression was evaluated qualitatively and quantitatively using immunohistochemistry.

RESULTS

All transporters were overexpressed quantitatively in DNT, but each revealed a different labeling pattern. P-gp and BCRP were predominantly located in the endothelium of brain vessels. MRP5 was detected primarily in endothelial cells, but notably also in neurons. The expression of P-gp, MRP2 and MRP5 was low in AVM, whereas BCRP demonstrated strong staining. Examination of MDR1 gene polymorphisms revealed no correlation with P-gp expression whereas the MRP2 exon 10 G1249A polymorphism was associated with different MRP2 labelling.

CONCLUSIONS

Our results show that multidrug transporters are overexpressed in DNT. This finding supports the view that several of these transport proteins may play an important role in the mechanisms of drug resistance in epileptic brain tissue.

Clinicoradiologic subtypes of Marchiafava-Bignami disease

The clinical diagnosis of Marchiafava-Bignami disease (MBD) has considerably changed during recent decades with brain MRI providing the opportunity of a reliable in-vivo diagnosis. However, semiologic and neuroimaging characteristics of the currently known spectrum of MBD have not been investigated systematically, and knowledge of clinicoradiologic associations is sketchy. We report an illustrative case with limited callosal involvement on MRI and a favorable outcome and have reviewed literature on clinical and radiologic features in 50 cases of MBD diagnosed in vivo since 1985. Our reviewed data suggest the differentiation of two clinicoradiologic subtypes: Type A is characterized by major impairment of consciousness, T2-hyperintense swelling of the entire corpus callosum on early MRI and poor outcome. Type B shows at most slight impairment of consciousness, partial callosal lesions on MRI and a favorable outcome. Differentiation of these clinicoradiologic subtypes may help resolve inconsistencies of the established clinical classification resulting from new insights into the clinical course and prognosis of MBD by structural neuroimaging.

Serum neuron-specific enolase, prolactin, and creatine kinase after epileptic and psychogenic non-epileptic seizures

PURPOSE

To evaluate the discriminative power of serial, simultaneous determinations of serum neuron-specific enolase (NSE), prolactin (PRL) and creatine kinase (CK) in differentiating psychogenic non-epileptic seizures (PNES) from epileptic seizures (ES).

METHODS

Prospective measurement of the three markers after 44 single seizures (32 ES and 12 PNES) during continuous video-EEG monitoring at seven different sampling points.

RESULTS

Patients with ES had a significantly greater increase in PRL at 10, 20, 30 min, 1 and 6 h. The sensitivity for elevated NSE and CK was low. PRL showed a higher sensitivity. However, the corresponding positive predictive value was lower than in CK and NSE. Additionally, PRL had the lowest specificity of all parameters.

CONCLUSIONS

The limited discriminative power of PRL, CK, and NSE calls into question if these markers are helpful in differentiating PNES and ES.

Neuronavigation and complication rate in epilepsy surgery

The role of neuronavigation for complications in temporal lobe epilepsy surgery was evaluated. Thirty-seven patients operated on with neuronavigation (group N: 38 operations; mean age 33.9 years; etiology: cryptogenetic 31, symptomatic 7; lateralization: 22 right, 16 left) and 22 patients operated on without neuronavigation (group NN: 23 operations; mean age 29.7 years; etiology: cryptogenetic 9, symptomatic 14; lateralization: 13 right; 10 left) were analyzed. The minimal follow-up time was 2 years. There was a clear difference in the number of complications (N 7.9%; NN 21.7%), which consisted of hemiparesis (N: 1; NN: 2), cranial nerve palsy (N: 1; NN: 2), aphasia (N: 1; NN: 0), and postoperative infection (N: 0; NN: 1). In addition, there was a reduced need for temporal re-resection after intraoperative electrocorticography (N 30.6%; NN 47.1%). Operation time (N: 239+/-9.4 min; NN: 208+/-12.1 min), duration of postoperative in-hospital and in-ICU stay [N: 16.9+/-1.1 days (1.0+/-0.0 days); NN: 17.2+/-2.8 days (1.1+/-0.1 days)], extension of temporal lobe resection from polar (N: 41.2+/-1.5 cm; NN: 42.9+/-3.9 cm), and postoperative seizure frequency reduction (N 90.4%; NN 94.7%) were not different. Because of the trend towards a reduction of complications and re-resections after electrocorticography, the authors recommend neuronavigation despite its higher costs as an additional tool in epilepsy surgery.

Bilateral hypoglossal nerve injury following the use of the laryngeal mask without the use of nitrous oxide

Hypoglossal nerve injury is a rare complication of anaesthesia airway management in adults. Until now the use of nitrous oxide for anaesthesia supposedly contributed to this complication. We present a case of bilateral hypoglossal nerve injury following the use of a laryngeal mask airway without the use of nitrous oxide. At the conclusion of 3 h of surgery in extreme side rotation, a 15-year-old boy of 88 kg could not extend his tongue beyond his teeth. An MRI confirmed the absence of pharyngeal haematoma and the absence of thrombosis of the basilar artery. We conclude that even when patients have no medical history and nitrous oxide is not being used, prolongation of the operation in an extreme position might increase the risk of major complications with a laryngeal mask.

A splice-site mutation in GABRG2 associated with childhood absence epilepsy and febrile convulsions

CONTEXT

Missense mutations in the GABRG2 gene, which encodes the gamma 2 subunit of central nervous gamma-aminobutyric acid (GABA)(A) receptors, have recently been described in 2 families with idiopathic epilepsy. In one of these families, the affected individuals predominantly exhibited childhood absence epilepsy and febrile convulsions.

OBJECTIVE

To assess the role of GABRG2 in the genetic predisposition to idiopathic absence epilepsies.

DESIGN

The GABRG2 gene was screened by single-strand conformation analysis for mutations. Furthermore, a population-based association study assessing a common exon 5 polymorphism (C588T) was carried out.

PATIENTS

The sample was composed of 135 patients with idiopathic absence epilepsy and 154 unrelated and ethnically matched controls.

RESULTS

A point mutation (IVS6 + 2T-->G) leading to a splice-donor site mutation in intron 6 was found. The mutation, which is predicted to lead to a nonfunctional protein, cosegregates with the disease status in a family with childhood absence epilepsy and febrile convulsions. The association study did not find any significant differences in the allele and genotype frequencies of the common exon 5 polymorphism (C588T) between patients with idiopathic absence epilepsy and controls (P>.35).

CONCLUSIONS

Our study identified a splice-donor-site mutation that was probably causing a nonfunctional GABRG2 subunit. This mutation occurred in heterozygosity in the affected members of a single nuclear family, exhibiting a phenotypic spectrum of childhood absence epilepsy and febrile convulsions. The GABRG2 gene seems to confer a rare rather than a frequent major susceptibility effect to common idiopathic absence epilepsy syndromes.