Safety of Valproate in Porphyria Cutanea Tarda

Treatment of epileptic seizures in patients with hepatic porphyrias is a challenging problem due to enzymatic induction activity of phenobarbital (PB), phenytoin (PHT), carbamazepine (CBZ), and clonazepam (CZP). We present the case of a patient with partial seizures treated with PHT and showing clinical signs and biochemical abnormalities of porphyria cutanea tarda (PCT). We withdrew PHT and treated the patient with sodium valproate (VPA). We followed the patient for 6 months during VPA therapy. During this period, clinical signs of PCT disappeared and biochemical values normalized. Our study shows that VPA is a safe treatment in epileptic patients with PCT.     

Monotherapy with Valproate in Primary Generalized Epilepsies

Summary: Sodium valproate enteric-coated tablets were administered as monotherapy to 118 patients (median age, 19 years) with primary generalized epilepsies. More than half (56%) of these patients were transferred from prior drug therapy, most of them because of inadequate seizure control, and some because of adverse effects. Seventy-one percent of the patients experienced tonic-clonic seizures, either alone or in combination with other types of seizures, principally absences. Mean duration of follow-up was 18 months (median, 17 months; range, 1–68 months). At a mean daily dosage of <20 mg/kg, 83% of the patients became seizure-free. Therapy was equally effective against tonic-clonic seizures, absences, and myoclonic seizures. Tonic-clonic seizures were suppressed in 85% of cases (89% when patient had only one seizure type), absences in 82% (95% when patient had only one seizure type), and myoclonic seizures in 82%. Paroxysmal activity was present in 88% of the electroencephalogram (EEG) records before valproate monotherapy, and in 32.4% at the study's end. These results were achieved with generally mild and mostly transient side effects; side effects were reported by 16% of patients during the first month, and 2% at the last follow-up. No hematologic or hepatic toxicity was observed. The lag time between attaining steady-state serum concentrations and achieving maximal clinical improvement suggests that sodium valproate monotherapy should be given an adequate trial to ensure that patients derive the greatest possible benefit before adding or switching to another drug.     

The effect of prophylactic therapy with valproate sodium and phenobarbital in two patients with cyclic vomiting syndrome

Cyclic vomiting syndrome (CVS) is a disorder characterized by recurrent, stereotypic episodes of incapacitating nausea, vomiting, and other symptoms, separated by intervals of comparative wellness. Associated symptoms include nausea, abdominal pain, headache, and motion sickness. Recently, CVS was categorized as a migraine. Case 1 was a girl aged 4 years and 11 months, who had frequent and severe episodes of vomiting since she was 3 years old. The diagnosis of CVS was established on the basis of clinical symptoms and laboratory data. Her electroencephalogram was normal. Prophylactic therapy using a single drug such as amitriptyline, carbamazepine, phenytoin, cyproheptadine, valproate sodium or phenobarbital was not effective. However, her recurring vomiting disappeared with prophylactic therapy using valproate sodium and phenobarbital. Case 2 was a boy aged 10 years and 7 months, who had frequent episodes of vomiting since he was 1 year and 10 months old. He had been receiving intravenous hyperalimentation therapy at home since infancy because of frequent vomiting and failure to thrive. His electroencephalogram showed no abnormality. Prophylactic therapy using a single drug such as diazepam, phenytoin, valproate sodium or phenobarbital was not effective. However, his recurring vomiting disappeared with prophylactic therapy using valproate sodium and phenobarbital. There were no adverse effects in both patients. The combination therapy with valproate sodium (20 - 26 mg/kg/day) and phenobarbital (4 - 5 mg/kg/day) was effective as a prophylactic therapy in these two patients. The combination therapy with valproate sodium and phanobarbital for prophylaxis of vomiting may be helpful in patients with intractable CVS.     

Electroencephalographic effects of antiepileptic drug therapy

We investigated the effects of therapeutic levels of antiepileptic drug (AED) monotherapy on computed measures of EEG frequency in seizure patients with normal interictal EEGs. Fourteen patients were taking phenobarbital, 14 were taking phenytoin, 13 were taking carbamazepine, and 12 were taking valproate. One-minute EEG spectra were recorded from Oz-A1 + A2. We measured the predominant alpha band frequency (modal alpha frequency—MAF), fastest alpha band frequency (maximal alpha frequency—MxAF), and highest prominent frequency between 13 and 30 Hz (spectral edge frequency—SEF). Patients taking phenobarbital or valproate had significantly lower MAF than those taking carbamazepine or phenytoin. MxAF did not differ significantly among the four patient groups. SEF was significantly lower in patients on valproate and carbamazepine than in those on other AEDs. Phenobarbital slowed background activity in the interictal EEG, whereas phenytoin and carbamazepine at therapeutic levels did not have such an effect. Valproate produced alpha and beta frequency decrease in the otherwise normal interictal EEG.     

Quantitative EEG effects and plasma concentration of sodium valproate: acute and long-term administration to epileptic patients

The quantitative background EEG effects (power spectral analysis) and plasma concentration of sodium valproate were studied after acute single-dose administration and during long-term single-drug treatment, in 10 previously untreated epileptic patients with generalized nonconvulsive seizures. A transient decrease of the signal amplitude (preponderant on anterior scalp areas) and of the 12.5 to 45.0-Hz relative power (limited to the posterior electrode derivations) was observed during the first weeks of chronic treatment. These EEG effects were not correlated with the drug plasma concentration levels or with the occurrence of behavioral side effects (e.g. drowsiness), while being concomitant with the reduction of specific epileptic EEG phenomena. Opposite trends of variation were observed after single-dose acute administration, though with limited statistical significance across subjects.     

Ictus emeticus presenting as an unusual seizure type in chromosome 22q11.2 deletion syndrome

We present a case study of a patient with chromosome 22q11.2 deletion syndrome presenting with ictus emeticus, together with a review of the relevant literature. The patient developed generalized tonic‐clonic seizures at 3 months old, and seizures eventually remitted after calcium therapy. He then experienced vigorous vomiting that occurred during sleep, with glassy eyes and legs flexion. Video‐EEG recordings exhibited a switch in background activity from organized reactivity during normal sleep to left lateralized temporal delta activity, which was bilaterally synchronized during an emetic attack. The ictal vomiting ceased following management with oxcarbazepine, high‐dose phenobarbital, and a ketogenic diet. The unique seizure type and rare ictal EEG findings are the first reported in a child with chromosome 22q11.2 deletion syndrome. This case highlights that ictus emeticus without detectable epileptic discharge on EEG is one potential epileptic presentation in this genetic syndrome. [Published with video sequence on www.epilepticdisorders.com ]     

Valproate-ethosuximide combination therapy for refractory absence seizures

Five patients had absence seizures refractory to treatment with either ethosuximide or valproate sodium. To determine their response to combination therapy with the two drugs, four of the five had serial 24-hour intensive monitoring studies that included cable telemetric EEG recording, closed-circuit television observation, and frequent antiepileptic drug (AED) serum level determinations. The resultant data confirmed the clinical and EEG effects of serial alterations in AED programs. All five became seizure free with combination therapy. Combination therapy with ethosuximide and valproate should be considered in patients whose absence seizures do not respond to standard therapeutic measures.     

Computerized Analysis of EEG Background Activity in Epileptic Patients

Background activity was studied in 128 idiopathic epilepsy patients and 30 normal controls using EEG topography and t-statistic significance probability mapping (t-SPM). In epileptic patients, EEG background activity showed a marked increase in delta, theta, alpha 1, and beta 1, and a decrease in alpha 2 activity as compared with controls. Untreated epileptic patients had a significant increase in delta, theta, and alpha 1 as compared with controls. For epileptic patients treated with antiepileptic drugs (AEDs), the most marked slowing was observed in the polytherapy group, followed by the monotherapy group and then the untreated group. Among seizure types, patients with partial seizures (PS) tended to exhibit more slowing than patients with only generalized tonic-clonic seizures (GTC). Moreover, PS had a right-left asymmetry in alpha 2 and beta 1 activities. In a comparison of AEDs, patients receiving carbamazepine (CBZ) and phenobarbital (PB) showed no significant difference as compared with the untreated group. In contrast, patients receiving valproate (VPA) showed a decrease in slow and fast activities. EEG changes associated with each AED were different in GTC and PS. Patients receiving VPA for GTC showed a decrease in theta and beta 1 activities, but those with PS showed a decrease only in delta activity.     

Complex partial seizures: EEG foci and response to carbamazepine and sodium valproate.

The EEG and clinical records were reviewed of 85 subjects who had been treated for complex partial seizures with carbamazepine alone or with a combination of carbamazepine and sodium valproate. There was a correlation between the site of the EEG abnormality and the therapeutic response to anticonvulsant therapy. Subjects who had a left sided temporal lobe EEG abnormality responded better to carbamazepine alone, while those who had an abnormality on the right responded to a combination of carbamazepine and sodium valproate.     

Exacerbation of Partial Seizures and Onset of Nonepileptic Myoclonus with Carbamazepine

A child had two to three generalized tonic-clonic (GTC) seizures per week unresponsive to phenobarbital (PB) and valproate (VPA). Interictal EEG demonstrated left occipital spikes. When carbamazepine (CBZ) therapy was started, he developed very frequent (4-6/day) complex partial seizures (CPS) characterized on ictal EEG by focal right temporal lobe discharges. The seizure exacerbation, which was associated with development of nonepileptic, multifocal myoclonus, resolved 24 h after CBZ was discontinued. The exacerbation occurred with therapeutic CBZ serum levels, but may have been related to the toxic levels of carbamazepine-10, 11-epoxide (CBZE).     

Early-onset absence epilepsy: clinical and electroencephalographic features in three children

To describe the clinical and electroencephalographic features of three infants diagnosed as having early-onset absence seizures. Two males and one female, aged 21-29 months were seen in our neuropaediatric outpatient clinic because of daily episodes of motor arrest and loss of contact. Neurological examination and mental development was considered normal in all of them. Two out three had first-degree relatives with seizures with onset in the childhood and favourable evolution in the adulthood. A video-electroencephalogram was requested. Ictal EEG revealed a normal background and generalised spike-and-wave complexes at 3-3.5 Hz accompanied by disruption of ongoing activity in keeping with absence seizures. The duration of seizures ranged from 2 to 10s. One child (patient 2) experienced rhythmic myoclonic jerks in upper limbs and head as those described in myoclonic absences. Clinical and electroencephalographic follow-up ranged from 8 months to 4 years. Two children were on treatment with valproate and in the case of the patient 3, the combination of valproate and ethosuximide was necessary. Control of absence seizures was achieved in all our cases. Absence seizures should be considered as a possible cause of transient impairment of consciousness even among infants minor than 3 years of age. A video-electroencephalogram is the method of choice in the diagnostic evaluation and syndromic classification of these paroxysmal events.     

Myoclonus and Seizures in a Patient with Parkinsonism: Induction by Levodopa and Its Confirmation on SEPs

Abstract: A 68-year-old woman with parkinsonism showed cortical myoclonus and seizures under antiparkinsonian medication. Myoclonus was induced and enhanced by L-dopa, developing into generalized seizures. EEG was abnormal and somatosensory-evoked potentials (SEPs) showed giant SEPs, transcortical reflex (C reflex) and jerk locked potentials. Myoclonus and seizures disappeared after discontinuation of L-dopa and the introduction of valproate sodium (VPA). We described the occurrence of L-dopa-induced myoclonus and seizures in a case of parkinsonism with its SEPs findings.     

Excellent results with clorazepate in recalcitrant childhood epilepsies

Eleven children with severe incapacitating generalized seizures were treated with sodium valproate and clorazepate and responded with a marked decrease in seizure frequency. Three children received clorazepate alone, either because of valproate toxicity or because of parental concern over side effects. These children, 5 males and 6 females, ranged in age from 3 to 17 years. They manifested normal to severely retarded intelligence. Although valproate levels were in the therapeutic range, seizure control was inadequate. When clorazepate was added to valproate therapy a marked reduction in seizure frequency occurred within 24 hours and became optimal within 48 to 72 hours. Side effects were minimal with the exception of a nocturnal generalized tonic-clonic seizure in a single patient. Three children were withdrawn from therapy after a year because of recurrent seizures. One patient was restarted on therapy after 6 months and seizure control improved. Clorazepate may be a useful adjunct in the treatment of primary generalized seizures in children.     

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.     

Effects of antiepileptic drugs on evoked potentials in epileptic children

To evaluate the visual and auditory function in children and adolescents who are undergoing monotherapy with sodium valproate, carbamazepine, and phenobarbital visual-evoked potentials and brainstem auditory-evoked potentials were measured in 58 epileptic patients (30 males and 28 females), ages 13.7 ± 6.9 years. Fifty healthy sex- and age-matched children served as controls. The measurements were performed before the beginning of therapy and after 12 months. Before the beginning of therapy, there were no significant differences in visual- and auditory-evoked potentials between the control group and the three groups of epileptic children. After 12 months of therapy, patients treated with carbamazepine demonstrated a significant (P < 0.001) increase of P100 latencies when compared with baseline data and control values; moreover, these patients exhibited a significant increase of peak latencies of waves I-III-V and interpeak interval I-V at auditory second evaluation. The patients treated with sodium valproate manifested a significant (P < 0.05) increase in VEP P100 latencies. On the contrary, children receiving phenobarbital did not manifest any significant abnormality at visual- and auditory-evoked potentials measurements. Our study demonstrates that for patients treated with carbamazepine and sodium valproate, an electrophysiologic dysfunction of visual and auditory sensory pathways can be present after 12 months of treatment.     

Comparative trial of valproate sodium and clonazepam in chronic epilepsy.

A crossover comparative study of valproate sodium and clonazepam in the treatment of 32 adult epileptic patients receiving multiple drug therapy is described. Serum concentrations of other anticonvulsant drugs were unchanged by the addition of clonazepam. However, patients receiving high doses of other anticonvulsant drugs had lower serum concentrations of clonazepam (p less than .01). With valproate sodium, phenobarbital concentrations increased (P less than .05) in patients receiving phenobarbital but not significantly in patients receiving primidone. Phenytoin concentrations were reduced (P less than .05) during treatment with valproate sodium. Both drugs significantly reduced the frequency of minor seizures, with valproate sodium having the greater effect. However, it is important to monitor serum concentrations of other anticonvulsant drugs during treatment with valproate sodium since changes in these may influence seizure control or cause side effects.     

Sodium valproate in the treatment of intractable seizure disorders: a clinical and electroencephalographic study.

A 12-week study of clinical response, EEG changes and serum antiepileptic drug (AED) levels using sodium valproate (VAL) was undertaken. The study showed that VAL is a powerful adjunct in the treatment of intractable epilepsy. It was most effective in patients with generalized seizures, but no seizure type was totally resistant. No serious adverse effects were encountered; nausea was easily overcome by readjusting the drug dosage. In most cases the only EEG change was decrease of epileptiform activity, and this correlated well with decreased frequency of clinical seizures. These two features in turn were most often seen with a serum VAL level of 40 microgram per milliliter or greater. Intoxication with VAL was accompanied by marked slowing of the background rhythms, but no increase in beta activity. Other modifications of the EEG were probably due to changes in the plasma levels of other drugs. Interactions between VAL and conventional antiepileptic drugs occur, so that serum concentrations of all drugs must be monitored in patients receiving VAL.     

Interictal EEG prediction of response to antiepileptic drug monotherapy

Forty-eight patients had sleep-deprived EEGs prior to antiepileptic drug monotherapy. The majority were seizure-free after one year, or had more than 50% reduction in seizure frequency. Among those with normal EEGs 50% were seizure-free, while 75% with diffuse slowing, 44% with focal abnormality, and 83% with generalized epileptiform discharges were fully controlled. Freedom from seizures was achieved in 13% taking phenobarbital, 50% taking phenytoin, 63% taking carbamazepine, and 100% taking valproate. The sleep-deprived interictal EEG should be an integral part of initial assessment and drug selection in patients with clinical histories of convulsive seizure.     

Spectral EEG During Short-Term Discontinuation of Antiepileptic Medication in Partial Epilepsy

Summary: The effect of short-term discontinuation of antiepileptic drugs (AEDs) on spectral analysis of EEG background activity (spectral EEG) was studied in patients undergoing preoperative evaluation for epilepsy surgery. We also wished to clarify whether AED discontinuation would provide lateralizing evidence in spectral EEGs of patients with temporal lobe epilepsy (TLE). Spectral EEGs were performed in 15 patients receiving their regular medication regimen and again after a 1-week period during AED withdrawal. A subgroup of 9 patients who had previously undergone temporal lobectomies (TLE group) was studied separately. In this group, we evaluated the effect of preceding seizures on spectral EEG derived from temporal neocortical areas. In all patients, spectral EEG changes were detected even after a short-term AED withdrawal. The total amount of absolute delta activity was reduced and occipital peak frequency and relative alpha activity were increased as compared with baseline values. In TLE patients with habitual seizures occurring <20 h before the spectral EEG recording, lateralization was correctly identified by the greater amount of absolute delta activity ipsilateral to the epileptogenic focus. Epileptic seizures are accompanied by subtle focal slowing in spectral EEG for a much longer period than has been assumed. In addition, postictal spectral EEG over the temporal lobes may have lateralizing value. Further studies in larger numbers of patients are needed to evaluate the role of spectral EEG in the preoperative evaluation of patients for temporal lobe surgery.     

EEG wavelet analyses of the striatum-substantia nigra pars reticulata-superior colliculus circuitry: audiogenic seizures and anticonvulsant drug administration in Wistar audiogenic rats (War strain)

The importance of the substantia nigra pars reticulata (SNPr), striatum (STR) and superior colicullus (SC) in the blockade of experimental seizures is well known. But, in audiogenic seizures (brainstem tonic-clonic seizures), the anticonvulsant activity of these nuclei is still controversial. In the present study we aimed to analyze the STR-SNPr-CS circuitry in the audiogenic seizures of Wistar audiogenic rat (WAR). Behavioral and electroencephalographic (EEG) data were collected from WARs under no treatment or injection with systemic (phenobarbital) or intracerebral (intranigral) drugs (muscimol and phenobarbital). The main EEG frequency oscillation of STR, SNPr and SC seen before, during and after audiogenic seizures or during seizure protection, was determinated with wavelet spectral analyses. This method allows the association between behavior and EEG (video-EEG). Audiogenic seizures last only for half a minute in average, suggesting that the interruptions of seizures are probably not due to exhaustion. Systemic phenobarbital caused an acute and dose-dependent behavioral and EEGraphic anticonvulsant effect both in WARs. The dose of phenobarbital 15mg/kg protected animals almost completely, without side effects such as ataxia and sedation. In our data, this endogenous "natural" seizure blockade (or termination) seems to be similar to the "forced" seizure abolition, like the one caused by a systemic non-ataxic phenobarbital dose, because in both cases an intense decrease in the EEG main frequency oscillation can be seen in SNPr and SC. Intranigral phenobarbital or muscimol did not protect animals, and actually induced an increase in the main EEG frequency oscillation in SC. The main finding of the present study is that, in contrast to what is well believed about the incapacity to control audiogenic seizures by the striato-nigro-tectal circuitry, we collected here evidences that these nuclei are involved in the ability to block these seizures. However, the striato-nigro-tectal circuitry in WARs, a genetically developed strain, seems to have different functional mechanisms when compared with normal rats.