Corticosteroids as treatment of epileptic syndromes with continuous spike-waves during slow-wave sleep

To assess the efficacy and tolerability of steroids in epileptic syndromes with continuous spike-waves during slow-wave sleep (CSWS), charts of 44 children (25 boys) who received corticosteroids for cognitive and/or behavioral deterioration associated with CSWS were retrospectively reviewed. Awake and sleep electroencephalography (EEG) records, clinical and neuropsychological assessments were available before, during, and after corticosteroid therapy. Evaluation focused on effects on EEG, behavior, and cognition. All but two patients received hydrocortisone (initial dose of 5 mg/kg/day). The treatment was slowly tapered with a total duration of 21 months. There were 18 symptomatic and 26 cryptogenic cases. Mean age was 7 years and mean intelligence quotient/developmental quotient (IQ/DQ) was 65. Mean CSWS duration before corticosteroid treatment was 1.7 years. Twenty patients had tried more than two antiepileptic drugs (AEDs) before steroids. Positive response to steroids was found during the first 3 months of treatment in 34 of 44 patients (77.2%), with normalization of the EEG in 21 patients. Relapse occurred in 14 of them. Hence, 20 patients (45.4%) were long-term responders after a single but prolonged trial of steroids, including all four cases of Landau-Kleffner syndrome. Positive response to steroids was highly significantly associated with higher IQ/DQ. Shorter CSWS duration, but not age, etiology, or previous AED trials, was associated with positive response to steroids. Early discontinuation of the treatment for side effects was encountered in seven patients. We conclude that corticosteroids are safe and efficient for treatment of epilepsy with CSWS. Poor responders are patients with very low IQ and long duration of CSWS.     

Electrical status epilepticus during slow-wave sleep: a review

Electrical status epilepticus during sleep (ESES) is primarily an EEG-defined syndrome in children characterized by the occurrence of continuous spike and slow waves during non-rapid-eye-movement (non-REM) sleep, the paroxysmal abnormalities being substantially less frequent during the awake state and REM sleep. Etiologically, cases can be divided into symptomatic and cryptogenic varieties. Partial motor seizures, frequently nocturnal, precede the emergence of ESES, whereas absence seizures often occur during the phase of ESES. The emergence of ESES is associated with neuropsychological regression. The characteristic electrographic pattern and epilepsy generally disappear during adolescence and are associated with an improvement in neuropsychological function. However, if the cases reported in the literature are representative, then there is a high probability of considerable residual dysfunction. A number of factors, broadly termed ascertainment biases, likely contribute to the paucity of reports from North America and the greater recognition of the syndrome in Europe and Japan. The current information on ESES is critiqued in this review.     

Nonconvulsive status epilepticus with continuous diffuse spike-and-wave discharges during sleep in childhood

On three epileptic conditions with common characteristics of almost continuous diffuse spike-and-wave discharges during sleep in EEG, clinical and electroencephalographic studies were undertaken to elucidate their pathophysiologies and interrelationships; namely on five cases of epilepsy with electrical status epilepticus during slow sleep (ESES), seven cases of a peculiar type of nonconvulsive status epilepticus in childhood (PNSE) and three cases of atypical benign partial epilepsy (ABPE). The dominant seizure types were absences and/or GTC in ESES, whereas they were focal motor seizures in PNSE and ABPE with more focalized epileptic discharges on EEGs than those in ESES. All the three conditions showed both features of generalized and partial epilepsies, although the former features were more prominent in ESES and the latter in PNSE and ABPE.     

A review of the relationships between Landau-Kleffner syndrome, electrical status epilepticus during sleep, and continuous spike-waves during sleep

The goal of this report is to review the relationships between Landau-Kleffner syndrome (LKS), electrical status epilepticus during sleep (ESES), and continuous spike-waves during sleep (CSWS). LKS is a clinical syndrome involving mainly acquired aphasia and sometimes seizures. Other clinical findings include cognitive impairments and global regression of behavior. The EEG may evolve from more benign conditions into ESES (or CSWS), seen in 50% of patients with LKS, or may also show focal findings. Seizures include atypical absence, generalized tonic-clonic, atonic, and partial motor attacks. Effective medications are discussed. The EEG patterns CSWS and ESES are likely equivalent terms. CSWS is used by some authors, and ESES by others. Patients with these patterns usually show mental retardation, seizures, and global regression. More benign EEG patterns, like focal discharges, may develop into these more severe generalized patterns, which are associated with atypical absences, negative myoclonus, and cognitive disturbances. Memory disorders are common, because the nearly continuous generalized discharges in sleep do not allow for the memory consolidation that also occurs during sleep. Medications and possible etiologies are discussed.     

Epilepsy with continuous discharges during slow-wave sleep. Treatment with clobazam

The authors describe the case of a 12 years old boy suffering from an epilepsy with complex partial seizures evolving to a syndrome of epilepsy with continuous spikes-waves during sleep. A dramatic improvement follows clobazam introduction in the treatment. The originality of this case report and the possible mechanism of action of clobazam are discussed.     

Treatment of electrical status epilepticus during slow-wave sleep with high-dose corticosteroid

A 4-year-old female patient with epilepsy with continuous spike-and-waves during slow-wave sleep not classified as Landau-Klefner syndrome, refractory to antiepileptic drugs including valproate, benzodiazepines, and lamotrigine, was treated successfully with high-dose intravenous methylprednisolone therapy. Valproate, clobazam, and lamotrigine were continued at the same dose during and after high-dose intravenous corticosteroid therapy. During corticosteroid therapy, awake and sleep electroencephalogram was recorded every day. On day 7, a dramatic clinical and electroencephalographic response was observed. After high-dose intravenous methylprednisolone, prednisolone was administered orally (2 mg/kg daily) for 2 months, then gradually withdrawn. After the withdrawal of corticosteroid therapy, the patient maintained the clinical improvement in behavior, and no continuous spike-and-wave electrical status epilepticus during slow-wave sleep occurred on routine monthly sleep electroencephalogram performed for the last 6 months. In the present case, an add-on high-dose intravenous corticosteroid seems to be effective in the treatment of patients with electrical status epilepticus during slow-wave sleep syndrome, especially when antiepileptic drugs fail.     

Long-term outcome after cognitive and behavioral regression in nonlesional epilepsy with continuous spike-waves during slow-wave sleep

Purpose: To present the long‐term follow‐up of 10 adolescents and young adults with documented cognitive and behavioral regression as children due to nonlesional focal, mainly frontal, epilepsy with continuous spike‐waves during slow wave sleep (CSWS). Methods: Past medical and electroencephalography (EEG) data were reviewed and neuropsychological tests exploring main cognitive functions were administered. Key Findings: After a mean duration of follow‐up of 15.6 years (range, 8–23 years), none of the 10 patients had recovered fully, but four regained borderline to normal intelligence and were almost independent. Patients with prolonged global intellectual regression had the worst outcome, whereas those with more specific and short‐lived deficits recovered best. The marked behavioral disorders resolved in all but one patient. Executive functions were neither severely nor homogenously affected. Three patients with a frontal syndrome during the active phase (AP) disclosed only mild residual executive and social cognition deficits. The main cognitive gains occurred shortly after the AP, but qualitative improvements continued to occur. Long‐term outcome correlated best with duration of CSWS. Significance: Our findings emphasize that cognitive recovery after cessation of CSWS depends on the severity and duration of the initial regression. None of our patients had major executive and social cognition deficits with preserved intelligence, as reported in adults with early destructive lesions of the frontal lobes. Early recognition of epilepsy with CSWS and rapid introduction of effective therapy are crucial for a best possible outcome.     

Tuberculous meningitis presenting with nonconvulsive status epilepticus

Nonconvulsive status epilepticus (NCSE) is an enduring epileptic condition characterized by alteration in consciousness and continuous ictal discharges on the EEG. Various etiologies have been reported. We describe the case of a 66-year-old woman with altered mental status who was diagnosed with NCSE. A workup to explain the etiology revealed tuberculous meningitis (TBM) with increased cerebrospinal fluid protein and positive tuberculous DNA polymerase chain reaction and interferon-γ assay tests. She was treated according to the status epilepticus protocol with a four-drug anti-tuberculosis regimen to which she responded. TBM is a serious disease with insidious presentation and still constitutes a diagnostic challenge with its various presentations. Among the many presentations of tuberculosis, clinicians should consider NCSE.     

Non-linear EEG analysis in children with epilepsy and electrical status epilepticus during slow-wave sleep (ESES)

OBJECTIVE: The objective of this work was to study the non-linear aspects of electroencephalography (EEG) in children with epilepsy and electrical status epilepticus during slow-wave sleep (ESES). METHODS: In this study, we recorded the sleep EEG in 5 subjects with ESES (4 males and one female, aged 6.5-10 years) who were also mentally retarded and affected by cerebral palsy (3 subjects) and hydrocephalus (two subjects). The signals were sampled at 128Hz and stored on hard disk. All the subsequent computational steps were performed on EEG epochs (4096 data points) selected from wakefulness and non-rapid eye movement (non-REM) (with ESES) or REM sleep. The dynamic properties of the EEG were assessed by means of the non-linear cross prediction (NLCP) test which uses 3 different 'model' time series in order to predict non-linearly the original data set (Pred, Ama and Tir). Pred is a measure of the predictability of the time series and Ama and Tir are measures of asymmetry, indicating non-linear structure. Moreover, the correlation dimension (D2) was estimated by means of the algorithm by for the epochs showing non-linear nature. RESULTS: The NLCP test provided evidence of significant non-linear dynamics in all epochs of non-REM sleep, when ESES was evident. Only during this stage, the possible presence of low-dimensional chaos could also be suspected (average D2=4.02; range 3.16-6.21). EEG without ESES could not be distinguished from linearly filtered noise. CONCLUSIONS: The results of the present study seem to indicate that subjects with ESES show a profound modification of their EEG dynamics with the occurrence, during sleep, of long periods characterized by non-linear dynamics and, probably, low-dimensional chaotic structure able to modify in a substantial way their brain functioning during sleep.     

Use of pregabalin for nonconvulsive seizures and nonconvulsive status epilepticus

PurposeTo determine the efficacy of pregabalin (PGB) in treatment of frequent nonconvulsive seizures (NCS) and nonconvulsive status epilepticus (NCSE) in critically ill patients.MethodsIn this retrospective study, 21 patients were identified as having received pregabalin for the treatment of NCS as determined by continuous electroencephalographic monitoring. The patients were considered to be responders if their seizures were terminated within 24 h of initiation of PGB without the addition of another antiepileptic agent.ResultsOf the 21 patients who received PGB for treatment of NCS or NCSE, 11 (52%) were responders. PGB was administered via a nasogastric tube or orally and was the 2nd to 4th agent used. The average initial dose and total daily dose of PGB was similar in the responders and non-responders (342 mg vs. 360 mg, respectively). PGB was more effective in aborting NCS (9 patients, 82%) than NCSE (2 patients, 18%). Of the 9 brain tumor patients, PGB resulted in seizure cessation in 67% (6 patients). In contrast, all patients with hypoxic injury (4) did not respond to PGB. The responders were noted to have better clinical outcome (64% vs. 9% discharged home). Most of the patients tolerated the medication without any significant short term adverse effects, except two patients who were noted to have dizziness and sedation.ConclusionsPregabalin may be safe option for add-on treatment for nonconvulsive seizures in critically ill patients when conventional therapy fails.     

Observation of continuous spike-waves during slow sleep in children with myelomeningocele

Cases Two patients with myelomeningoceles (MMC) and shunt-treated hydrocephalus are reported. At 5 and 7 years respectively, when they began presenting mental deterioration and behavioural disorders, sleep EEG showed continuous spike-waves during slow sleep (CSWS). Discussion These are the first cases of CSWS described in patients with MMC. The mechanisms of CSWS are considered. The role of hydrocephalus and the thalamic injuries found in one of the patients is discussed in detail. The usefulness of monitoring sleep EEG in patients with hydrocephalus or thalamic lesions is stressed, considering the effects of CSWS on the cognitive competencies and the soft or subclinical course that epilepsy complicated with CSWS may follow.     

Necrotizing leukoencephalopathy associated with nonconvulsive status epilepticus and periodic short-interval diffuse discharges: a clinicopathological study.

We describe the clinical, neuroimaging and neuropathological features of an immunocompromised patient diagnosed as having refractory nonconvulsive status epilepticus (NCSE), and whose consecutive electroencephalograms (EEGs) revealed persistent periodic short-interval diffuse discharges (PSIDDs). Prominent subcortical white matter lesions in keeping with the diagnosis of multifocal necrotizing leukoencephalopathy may be neuropathological substrate of NCSE with persistent PSIDDs.     

Ifosfamide encephalopathy and nonconvulsive status epilepticus

BACKGROUND: Ifosfamide (IFX), an alkylating agent and isomer of cyclophosphamide, is used as a single agent or a component of multi-agent chemotherapy in the treatment of ovarian, testicular, head and neck cancers, sarcomas and lymphomas. Encephalopathy is manifested by cerebellar ataxia, confusional state, complex visual hallucinations, extrapyramidal signs, seizures, and mutism. CASE REPORTS: We report two patients with non-Hodgkin's lymphoma presenting with mutism and confusional state after IFX infusion. Nonconvulsive status epilepticus (NCSE) as the cause of confusion was diagnosed on the basis of EEG pattern and the apparent improvement following intravenous administration of diazepam. CONCLUSIONS: Electroencephalogram abnormalities during IFX treatment have been described but recordings are only available in six cases. In three of them, paroxysmal alterations warranted the diagnosis of NCSE; however, most cases of IFX encephalopathy might have associated NCSE.     

SPECT and epilepsy with continuous spike waves during slow-wave sleep

Ten cases of epilepsy with continuous spike waves in slow-wave sleep (CSWS) were evaluated using single photon emission computed tomography (SPECT); in eight patients the EEG paroxysmal abnormalities showed a predominant localization. SPECT carried out using^99mTc-HMPAO allows study of cerebral blood flow (CBF); the examination was performed during phases of drowsiness and the results compared to the EEG data. In four cases SPECT revealed areas of low CBF in sites corresponding to those of the prevalent EEG discharges; in two cases the areas of hypoperfusion did not correspond to those indicated by the EEG; lastly, in four cases SPECT results were negative. The areas of hypoperfusion were predominantly located in the frontal, temporal, and parietal regions. Furthermore, the percentage of positive SPECT results was significantly higher (five cases out of six) in the group in which the CSWS phase was prolonged for at least 1 year, compared to the group in which this phase lasted less than 1 year. Thus, in this type of epilepsy, SPECT reveals focal cortical areas of decreased CBF which correlated generally to the predominant sites of EEG abnormalities. A longer duration of the CSWS phase seems to be associated with a more significant cortical disorder, documented by the presence of areas of hypoperfusion.     

Sporadic Creutzfeldt-Jakob disease presenting with nonconvulsive status epilepticus

Creutzfeldt-Jakob disease (CJD) is a rare prion disease characterized by a spongiform encephalopathy in humans. Although the characteristic triad of myoclonus, dementia, and periodic EEG activity is easy to recognize, unusual manifestations of the disease may be challenging and create a diagnostic dilemma. We report a case of CJD that occurred in a 26-year-old patient who presented with a receptive (Wernicke's) aphasia secondary to nonconvulsive status epilepticus.     

Outcomes in pediatric patients with nonconvulsive status epilepticus

Recognition of nonconvulsive status epilepticus (NCSE) is gaining increasing attention in the assessment and evaluation of critically ill pediatric patients. The underlying cause of NCSE is often the most important factor in determining outcome. However, there is a growing body of literature suggesting that electrical seizure burden in NCSE also contributes to unfavorable outcomes. Determination of impact of NCSE on outcome based on current evidence involves consideration of heterogeneous study settings, study populations, and process of care and outcome measures. In addition, the lack of data on neurocognitive function prior to episodes of NCSE as well as limited long-term neurocognitive assessment data confines precise conclusions about neurocognitive changes.This article is part of a Special Issue entitled “Status Epilepticus”.