Nonconvulsive status epilepticus and continuous spike and slow wave of sleep in children

Forced normalization of Lennox-Gastaut syndrome using lacosamide: A case report

PURPOSE

Forced normalization (FN) indicates psychotic episodes associated with seizure remission and disappearance of epileptiform activity on EEG. FN is likely to occur when frequent seizures are abruptly terminated by anti-epileptic drugs (AEDs) or epilepsy surgery.

METHODS

We describe an atypical case of a patient with FN induced by lacosamide (LCM).

RESULTS

A 23-year-old female patient with Lennox-Gastaut syndrome (LGS) was administered AEDs for LGS and hospitalised with weight loss and abnormal behaviour. Her condition fulfilled the FN criteria, which was considered to be induced by LCM. After a reduction in LCM dose, her abnormal behaviour and appetite improved. During LCM use, the patient developed no seizures, and the high amplitude diffuse sharp and slow wave complexes that were frequently observed before LCM disappeared on EEG. The LCM dose was tapered to 150 mg per day, and she became calmer with socially appropriate behaviours, although a few mild focal seizures relapsed.

CONCLUSION

LCM was effective for treating LGS in this patient and induced FN. Initially, it was difficult to recognise FN in cases of psychiatric disorders, especially in patients with intellectual disability. Patients with FN induced by LCM are rare, and only four patients have been previously reported who were treated by antipsychotic drug for psychosis.

Non-Convulsive Status Epileptics Presenting with Periodic Lateralized Epileptiform Discharges and Coma after Cerebral Hemorrhage: A Case Report

Background

Non-convulsive status epileptics (NCSE) is a common neurological emergency necessitating rapid assessment and management, but is often underdiagnosed as it lacks specific electroencephalographic features. The diagnostic value of periodic lateralized epileptiform discharges (PLEDs) in NCSE is still unclear. Herein, we reported a case with NCSE manifesting as PLEDs and coma.

Case Report

A 62-year-old man presented with epileptic seizures. Based on clinical and radiological profiles, he was diagnosed with frontal hemorrhage, coma, and NCSE. An electroencephalogram (EEG) revealed PLEDs. A combined antiepileptic regimen was initiated and, over a follow-up period of 2 months, a favorable outcome was achieved.

Conclusion

EEG may help identify potential NCSE in comatose patients, and PLEDs can be an atypical manifestation of NCSE, which can be effectively treated with antiepileptic drugs. The emphasis in NCSE is on early identification and individualized therapeutic regimens.

Non-Convulsive Status Epilepticus in the Presence of Catatonia: A Clinically Focused Review

INTRODUCTION

Catatonia is classically associated with psychiatric conditions but may occur in medical and neurologic disorders. Status epilepticus (SE) is a seizure lasting more than five minutes or two or more seizures within a five-minute period without interictal recovery of consciousness. Non-convulsive status epilepticus (NCSE) is SE without prominent motor activity that may present with catatonic symptoms. The relevance of NCSE as a potential etiology for catatonia is not clear in the literature.

METHODS

A systematic review was completed to evaluate the literature on NCSE presenting with catatonia. PubMed and PsycInfo databases were searched and articles were reviewed for the presence of catatonia and NCSE.

RESULTS

15 articles describing 27 cases meeting inclusion criteria were identified. The authors add 1 case to the literature. The most common catatonic symptoms identified in NCSE were mutism and stupor. Clinical features frequent in NCSE presenting with catatonia included new catatonic symptoms, age over 50 years, comorbid neurological conditions, or a change in medications that affect seizure threshold. A documented psychiatric history was also common and may contribute to delayed diagnosis.

DISCUSSION/CONCLUSION

It is important to consider NCSE in the differential diagnosis of new catatonic symptoms. A suggested approach to diagnostic evaluation is provided.

Non-convulsive status epilepticus in two patients with tuberous sclerosis

Tuberous sclerosis (TSC) is an autosomal dominantly inherited genetic disorder that chiefly affects the central nervous system, along with the other multiple systems. While phenomenology and symptom severity may vary greatly from one individual to another, the most common neurological presentation is epilepsy, which may be refractory in a considerable number of patients. Convulsive SE is seen frequently in TSC patients due to the high ratio of refractory seizures in well-studied cohorts. Status epilepticus (SE) is a life-threating condition and requires urgent medical care. Non-convulsive status epilepticus (NCSE) is an epileptic state with no convulsive seizures but impaired consciousness and corresponding electrophysiological findings. Due to its heterogeneity of clinical features, it is generally hard to recognize, and thus difficult to treat promptly. The relationship between TSC and NCSE is a relatively less emphasized issue in the literature. Here, we present two cases of TSC with NCSE with a view to increasing clinicians' awareness of the association between refractory epilepsy and NCSE.

Diazepam for outpatient treatment of nonconvulsive status epilepticus in pediatric patients with Angelman syndrome

Nonconvulsive status epilepticus (NCSE) is present in multiple pediatric neurogenetic syndromes with epileptic encephalopathies. While intravenous (IV) medications are used inpatient for treatment of critical illness-related NCSE, there is no consensus on treatment of ambulatory NCSE. Up to 50% of patients with Angelman syndrome (AS) have NCSE with myoclonic or atypical absence status. Here we report our experience in pediatric patients with AS and NCSE treated outpatient with a tapering course of oral diazepam. We conducted a chart review of 104 patients seen in the Angelman Syndrome Clinic at Massachusetts General Hospital from January 2008 to March 2017, who met the criteria. Response to treatment was defined as cessation of NCSE symptoms with electroencephalogram (EEG) confirmation when possible. Twenty-one patients with NCSE were identified, and 13 patients (9 male) with 25 episodes of NCSE were included. Mean age at NCSE episode was 5years 4months (15months-12years). Six patients had one episode of NCSE, and 7 patients had recurrent episodes (mean: 2.7; range: 2-4). Median diazepam treatment was 6days (4-12days), with a mean dose of 0.32mg/kg/day divided over 2-3 administrations, decreased every 2days. Nine episodes required multiple courses; however, oral diazepam alone was ultimately successful in 80% (20/25) of NCSE episodes. Oral diazepam was well-tolerated with no major side effects. A short course of oral diazepam is well-tolerated and effective in patients with AS who have ambulatory NCSE. It may be considered prior to escalating to inpatient care in AS and possibly other epilepsy syndromes.

Expert Opinion on the Management of Lennox-Gastaut Syndrome: Treatment Algorithms and Practical Considerations

Lennox–Gastaut syndrome (LGS) is a severe epileptic and developmental encephalopathy that is associated with a high rate of morbidity and mortality. It is characterized by multiple seizure types, abnormal electroencephalographic features, and intellectual disability. Although intellectual disability and associated behavioral problems are characteristic of LGS, they are not necessarily present at its outset and are therefore not part of its diagnostic criteria. LGS is typically treated with a variety of pharmacological and non-pharmacological therapies, often in combination. Management and treatment decisions can be challenging, due to the multiple seizure types and comorbidities associated with the condition. A panel of five epileptologists met to discuss consensus recommendations for LGS management, based on the latest available evidence from literature review and clinical experience. Treatment algorithms were formulated. Current evidence favors the continued use of sodium valproate (VPA) as the first-line treatment for patients with newly diagnosed de novo LGS. If VPA is ineffective alone, evidence supports lamotrigine, or subsequently rufinamide, as adjunctive therapy. If seizure control remains inadequate, the choice of next adjunctive antiepileptic drug (AED) should be discussed with the patient/parent/caregiver/clinical team, as current evidence is limited. Non-pharmacological therapies, including resective surgery, the ketogenic diet, vagus nerve stimulation, and callosotomy, should be considered for use alongside AED therapy from the outset of treatment. For patients with LGS that has evolved from another type of epilepsy who are already being treated with an AED other than VPA, VPA therapy should be considered if not trialed previously. Thereafter, the approach for a de novo patient should be followed. Where possible, no more than two AEDs should be used concomitantly. Patients with established LGS should undergo review by a neurologist specialized in epilepsy on at least an annual basis, including a thorough reassessment of their diagnosis and treatment plan. Clinicians should always be vigilant to the possibility of treatable etiologies and alert to the possibility that a patient’s diagnosis may change, since the seizure types and electroencephalographic features that characterize LGS evolve over time. To date, available treatments are unlikely to lead to seizure remission in the majority of patients and therefore the primary focus of treatment should always be optimization of learning, behavioral management, and overall quality of life.

Should We Treat Electroencephalographic Discharges in the Clinic or in the Intensive Care Unit, and if so When and How?

The important question that often emerges in the clinic is how aggressive the therapy for nonconvulsive status epilepticus and electrical status epilepticus in sleep ought to be and how continuous the discharges in each of these 2 entities should be before therapy is aimed at them. Additionally, as the use of electroencephalographic monitoring continues to expand to include the clinic and intensive care unit populations, it is important to identify epileptiform patterns that warrant identification and treatment. This review will present the state-of-the-art data and suggest algorithms to manage these conditions.

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".

Spectrum of nonconvulsive status epilepticus in patients with cancer

PURPOSE

Determine incidence, clinical presentation, electrographic correlates, and outcome of nonconvulsive status epilepticus (NCSE) in cancer patients on whom an EEG was performed.

METHODS

Retrospective review of 947 EEG reports on 658 patients in whom any type of EEG was performed at Memorial Sloan-Kettering Cancer Center (July 2006 to March 2008). Using the Epilepsy Research Foundation criteria, patients were classified as definite or probable NCSE. Medical records were reviewed for diagnosis, causes of NCSE, response to treatment, and outcome. Mortality was determined for patients with NCSE.

RESULTS

Twenty-six episodes of NCSE were identified in 25 patients (25/658, 4%). Eleven patients had primary brain tumor, 12 patients systemic cancer, and two had both. At diagnostic EEG, 18 were awake, 3 were lethargic, and 5 patients were comatose. EEG revealed a seizure in 62% of the patients, periodic lateralized epileptiform discharges in 42%, and periodic epileptiform discharges in 7.7%. Neuroimaging revealed new intracranial pathology in 54% of the patients. Seventy-seven percent of the patients achieved control; 65% required ≥3 antiepileptic drugs, and 33% required intubation. Three patients died from NCSE.

DISCUSSION

In our cohort, awake NCSE was more common than comatose NCSE. Treatment was successful in patients with heterogeneous central nervous system disease. EEG evaluation should be considered in patients with cancer because NCSE is treatable despite a high prevalence of structural brain disease. Nonconvulsive status epilepticus control did not always require intubation and burst suppression, but frequently required three or more antiepileptic drugs.

Automated quantification of spikes

Methods for rapid and objective quantification of interictal spikes in raw, unprocessed electroencephalogram (EEG) samples are scarce. We evaluated the accuracy of a tailored automated spike quantification algorithm. The automated quantification was compared with the quantification by two board-certified clinical neurophysiologists (gold-standard) in five steps: 1) accuracy in a single EEG channel (5 EEG samples), 2) accuracy in multiple EEG channels and across different stages of the sleep-wake cycles (75 EEG samples), 3) capacity to detect lateralization of spikes (6 EEG samples), 4) accuracy after application of a machine-learning mechanism (11 EEG samples), and 5) accuracy during wakefulness only (8 EEG samples). Our method was accurate during all stages of the sleep-wake cycle and improved after the application of the machine-learning mechanism. Spikes were correctly lateralized in all cases. Our automated method was accurate in quantifying and detecting the lateralization of interictal spikes in raw unprocessed EEG samples.

Electroencephalographic criteria for nonconvulsive status epilepticus: synopsis and comprehensive survey

There have been many attempts at defining the electroencephalography (EEG) characteristics of nonconvulsive status epilepticus (NCSE) without a universally accepted definition. This lack of consensus arises because the EEG expression of NCSE does not exist in isolation, but reflects status epilepticus under the variety of pathologic conditions that occur with age, cerebral development, encephalopathy, and epilepsy syndrome. Current NCSE definitions include "boundary conditions," in which electroencephalographic seizure activity occurs without apparent clinical seizures. Furthermore, what appears to one interpreter as status epilepticus, is not to another reader, reflecting the "art" of EEG interpretation. Seizures and epilepsy syndromes have undergone an evolution that has moved beyond a classification of focal or generalized conditions into a syndromic approach. It seems appropriate to make similar changes in the EEG analysis of the syndromes of NCSE. In effect, the literature on epilepsy classification has progressed to incorporate the different NCSE types with clinical descriptions, but the specific EEG evidence for these types is found largely in individual reports, and often by description only. NCSE classification of EEG patterns should derive from the aggregate of published EEG patterns in the respective clinical subtype, supported by an analysis of these EEG studies. The analysis that follows presents clinical descriptions and EEG patterns of NCSE in the neonatal period, infancy, childhood, adulthood, and late adulthood from a syndromic perspective based on age, encephalopathy, cerebral development, etiology, and syndrome. Proceeding from the proposed classification of status epilepticus syndromes in "Status epilepticus: its clinical features and treatment in children and adults" (published in 1994 by Cambridge University Press, New York), we have performed a systematic search for reports presenting EEG patterns of NCSE using the online medical search engine PubMed for 22 different search strategies. EEG patterns were reviewed by two board-certified epileptologists who reached consensus regarding presence of NCSE. From a total of 4,328 search results, 123 cases with corresponding EEG patterns could be allocated to underlying epilepsy syndromes. Typical characteristic, prominent electrographic patterns, and sequential arrangements are elucidated for the different NCSE syndromes. This compendium of patterns by NCSE syndrome classification with illustration of EEGs, and delineation of electroencephalographic features helps define the characteristics and semiologic borderlines among the types of NCSE.