Hidden in plain sight: Non-convulsive status epilepticus-Recognition and management

Diagnosing epileptic seizures in patients with Alzheimer's disease and deciding on the appropriate treatment plan

INTRODUCTION

Alzheimer's disease (AD) is the predominant cause of dementia and a significant contributor to morbidity among the elderly. Patients diagnosed with AD face an increased risk of epileptic seizures.

AREAS COVERED

Herein, the authors review the challenges in the diagnosis of seizures in patients with AD, the risks of seizures related to medications used in AD and the pharmacological treatment of seizures in AD. The authors also provide the reader with their expert opinion on the subject matter and future perspectives.

EXPERT OPINION

Healthcare professionals should maintain a vigilant approach to suspecting seizures in AD patients. Acute symptomatic seizures triggered by metabolic disturbances, infections, toxins, or drug-related factors often have a low risk of recurrence. In such cases, addressing the underlying cause may suffice without initiating antiseizure medications (ASMs). However, unprovoked seizures in certain AD patients carry a higher risk of recurrence over time, warranting the use of ASMs. Although data is limited, both lamotrigine and levetiracetam appear to be reasonable choices for controlling seizures in elderly AD patients. Decisions should be informed by the best available evidence, the treating physician's clinical experience, and the patient's preferences.

Nonconvulsive Status Epilepticus: Clinical Findings, EEG Features, and Prognosis in a Developing Country, Mexico

PURPOSE

There is a lack of clinical and epidemiological knowledge about nonconvulsive status epilepticus (NCSE) in developing countries including Mexico, which has the highest prevalence of epilepsy in the Americas. Our aim was to describe the clinical findings, EEG features, and outcomes of NCSE in a tertiary center in Mexico.

METHODS

We conducted a retrospective case series study (2010-2020) including patients (≥15 years old) with NCSE according to the modified Salzburg NCSE criteria 2015 with at least 6 months of follow-up. We extracted the clinical data (age, sex, history of epilepsy, antiseizure medications, clinical manifestations, triggers, and etiology), EEG patterns of NCSE, and outcome. Descriptive statistics and multinomial logistic regression were used.

RESULTS

One hundred thirty-four patients were analyzed; 74 (54.8%) women, the total mean age was 39.5 (15-85) years, and 71% had a history of epilepsy. Altered state of consciousness was found in 82% (including 27.7% in coma). A generalized NCSE pattern was the most common (32.1%). The NCSE etiology was mainly idiopathic (56%), and previous uncontrolled epilepsy was the trigger in 48% of patients. The clinical outcome was remission with clinical improvement in 54.5%. Multinomial logistic regression showed that the patient's age (P = 0.04), absence of comorbidities (P = 0.04), history of perinatal hypoxia (P = 0.04), absence of clinical manifestations (P = 0.01), and coma (P = 0.03) were negatively correlated with the outcome and only the absence of generalized slowing in the EEG (P = 0.001) had a significant positive effect on the prognosis.

CONCLUSIONS

Age, history of perinatal hypoxia, coma, and focal ictal EEG pattern influence negatively the prognosis of NCSE.

EEG criteria for diagnosing nonconvulsive status epilepticus in comatose - An unsolved puzzle: A narrative review

Introduction

Nonconvulsive status epilepticus (NCSE) is an important and often unrecognized cause of impaired awareness especially in critically ill patients, which can easily be missed. Electroencephalography (EEG) findings in clinically suspected cases are the mainstay of diagnosis.

Review summary

The EEG diagnostic criteria for NCSE have evolved over the past three decades. Furthermore, recent advancements in EEG technologies such as continuous EEG monitoring, and emergency department EEG, along with development of different diagnostic criteria, have increased the detection rate for NCSE in suspected cases. However, treating physicians should have a higher index of clinical suspicion and a lower threshold for recommending this valuable investigation. The introduction of different diagnostic criteria has made it easier for electroencephalographers to report NCSE; nevertheless, diagnosis is not always straightforward. This narrative review aimed to define and discuss the available literature on different EEG diagnostic criteria for NCSE.

Conclusion

There is a need for further prospective research to strengthen the diagnostic accuracy of the available diagnostic criteria, the modified Salzburg Consensus Criteria for NCSE (mSCNC) and updated American Clinical Neurophysiology Society (ACNS) 21 criteria, to verify their accuracy to detect NCSE in comatose patients.

Different Clinicoradiological Characteristics of Posterior Reversible Encephalopathy Syndrome in Pediatric Oncology and Post-Bone Marrow Transplantation Cases: A Retrospective Study

Posterior reversible encephalopathy syndrome (PRES) is receiving increasing recognition in pediatrics. However, comparisons between PRES in pediatric oncology and post-bone marrow transplantation (BMT) are lacking. Therefore, we aimed to describe the risk factors and clinical and radiological features of PRES and investigate the differences between PRES in pediatric oncology and post-BMT. The PRES data of 13 patients from our center were combined with those of 217 cases from the PubMed, Scopus, and Web of Science databases. The patients were divided into either an oncology or a post-BMT group. We included 230 patients in the analysis, 26.1% of whom belonged to the post-BMT group. Oncology patients developed PRES at a younger age (p = 0.010) and were more likely to develop encephalopathy (p = 0.004). Systemic hypertension (S-HTN) preceding PRES occurred in 43.5% (66/154) of patients. Post-BMT patients were more likely to have S-HTN (p = 0.003). Cyclosporine levels were detected in 37 patients; 40.5% had supra-therapeutic levels. The radiological findings were atypical in 74.3% of patients, and delayed repeated imaging increased the occurrence of resolution (p = 0.004). Sixteen (7%) patients developed PRES recurrence after a median of 8 weeks, with the between-group difference being non-significant. Oncology patients were more likely to develop chronic epilepsy, while BMT patients were more likely to develop rare neurologic abnormalities (p < 0.001). In conclusion, atypical clinical presentation and imaging findings should not hinder the diagnosis of PRES. S-HTN is a risk factor, particularly in post-BMT patients. Supra-therapeutic levels of cyclosporine and previous exposure to immunosuppression did not increase the risk of recurrence.

New-onset non-lesional aphasic status epilepticus. Clinical description, diagnostic clues, and treatment algorithm

OBJECTIVES

De novo aphasic status epilepticus (ASE) in patients without a previous history of epilepsy and without cerebral lesions (aphasic NOSE) is rare. The aim of the study is to describe its clinical characteristics, etiologies, and outcome.

MATERIALS & METHODS

Single-center study including consecutive patients presenting to the emergency department between 2011 and 2019 with acute aphasia, which was finally diagnosed as aphasic NOSE. Subsequent episodes of aphasia (>5 min) were recorded and divided into confirmed ASE and postictal aphasic episodes (non-ASE). Clinical characteristics of the two types of episodes were compared.

RESULTS

Nineteen patients were included, suffering fifty episodes of epileptic aphasia, episodes per patient 2.6 (range 1-7). Fifteen patients (71.4%) were women, mean age at ASE onset was 66.05 years old (SD 6.3). Nine (47%) patients died, 6 of them (66.7%) during the aphasic episode. Ictal EEG was available in 37 episodes, confirming the diagnosis of ASE in 12 episodes; in 8 episodes, the EEG fulfilled the criteria of possible ASE. The most frequent etiologies were inflammatory and vascular. Comparing ASE with non-ASE episodes, ASE was longer than non-ASE (225 vs 65 h, p .024) and was treated more frequently with BZD (76 vs 24%, p .001) but with a longer delay (22.2 vs 1.5 h, p .06).

CONCLUSIONS

ASE is a treatable, highly relapsing emergency, with the subsequent relapses ASE or postictal aphasia. EEG is diagnostic in half of the patients, while in others imaging techniques are also useful. Benzodiazepines should be administered. Persistent aphasia, of more than 65 hours' duration, is highly suggestive of ASE.

Limited-Montage EEG as a Tool for the Detection of Nonconvulsive Seizures

PURPOSE

Prefabricated arrays with a limited number of electrodes offer an opportunity to hasten the diagnosis of seizures; however, their accuracy to detect seizures is unknown. We examined the utility of two limited-montage EEG setups for the detection of nonconvulsive seizures.

METHODS

Thirty previously interpreted EEG segments with nonconvulsive seizures from 30 patients and 60 segments with background slowing or normal EEG from 60 patients were rendered in a bipolar "double banana" montage, a double distance "neonatal" montage, and a circumferential "hatband" montage. Experts reviewed 60 to 180 seconds long segments to determine whether seizures were present and if the EEG data provided were sufficient to make a decision on escalation of clinical care by ordering an additional EEG or prescribing anticonvulsants. The periodic patterns on the ictal-interictal continuum were specifically excluded for this analysis to keep the focus on definite electrographic seizures.

RESULTS

The sensitivities for seizure of the neonatal and hatband montages were 0.96 and 0.84, respectively, when compared with full montage EEG, whereas the specificities were 0.94 and 0.98, respectively. Appropriate escalation of care was suggested for 96% and 92% of occurrences of seizure patterns in neonatal and hatband montages, respectively. When compared with clinical EEG, the sensitivities of the neonatal and hatband montages for seizure diagnosis were 0.85 and 0.69, respectively.

CONCLUSIONS

Nonconvulsive seizures were detected with high accuracy using the limited electrode array configuration in the neonatal and hatband montages. The sensitivity of the neonatal montage EEG in detecting seizures was superior to that of a hatband montage. These findings suggest that in some patients with nonconvulsive seizures, limited-montage EEG may allow to differentiate ictal and slow patterns.

Early and late-onset nonconvulsive status epilepticus after stroke

BACKGROUND

Nonconvulsive status epilepticus (NCSE) is a condition that needs timely diagnosis and treatment. It has insignificant clinical features and presents high risk of misdiagnosis.

OBJECTIVE

To investigate NCSE among patients with stroke, given that stroke plays an important role in the etiology of NCSE.

METHODS

In this retrospective study, acute stroke patients who were admitted and followed up at a stroke outpatient clinic between January 2013 and March 2016 were included. Patients with previous histories of epilepsy, brain tumor, head trauma, hypertensive encephalopathy, arteriovenous malformation, subarachnoid hemorrhage or cerebral venous thrombosis were excluded. Demographic properties, stroke etiology, imaging method, EEG findings, stroke severity according to the NIHSS score, functional disability and modified Rankin Scale were recorded for all patients.

RESULTS

Thirty-nine out of 792 stoke patients experienced NCSE. The mean age of the study population was 70±1.2 years (min-max: 46‒90). The study population was composed of 28 females (71.8%) and 11 males (28.2%). NCSE had early onset in 23 patients (59%) and late onset in 16 (41%). The early-onset NCSE patients were older and this was statistically significant between the groups (early onset: 73.5±11.5; late onset: 65.9±12.1; p=0.04). A history of previous stroke was more frequent in the late-onset NCSE group (14; 87,5%) than in the early-onset group (11; 47.8%) (p=0.01). The prognosis was worse in the early-onset group, but without statistical significance.

CONCLUSION

Changes in mental status in the early stages of stroke are mostly attributed to stroke itself, but NCSE should be suspected in the right clinical setting, such as in older patients with suspicious anatomical and clinical associations.

Pharmacotherapy for Nonconvulsive Seizures and Nonconvulsive Status Epilepticus

Most seizures in critically ill patients are nonconvulsive. A significant number of neurological and medical conditions can be complicated by nonconvulsive seizures (NCSs) and nonconvulsive status epilepticus (NCSE), with brain infections, hemorrhages, global hypoxia, sepsis, and recent neurosurgery being the most prominent etiologies. Prolonged NCSs and NCSE can lead to adverse neurological outcomes. Early recognition requires a high degree of suspicion and rapid and appropriate duration of continuous electroencephalogram (cEEG) monitoring. Although high quality research evaluating treatment with antiseizure medications and long-term outcome is still lacking, it is probable that expeditious pharmacological management of NCSs and NCSE may prevent refractoriness and further neurological injury. There is limited evidence on pharmacotherapy for NCSs and NCSE, although a few clinical trials encompassing both convulsive and NCSE have demonstrated similar efficacy of different intravenous (IV) antiseizure medications (ASMs), including levetiracetam, valproate, lacosamide and fosphenytoin. The choice of specific ASMs lies on tolerability and safety since critically ill patients frequently have impaired renal and/or hepatic function as well as hematological/hemodynamic lability. Treatment frequently requires more than one ASM and occasionally escalation to IV anesthetic drugs. When multiple ASMs are required, combining different mechanisms of action should be considered. There are several enteral ASMs that could be used when IV ASM options have been exhausted. Refractory NCSE is not uncommon, and its treatment requires a very judicious selection of ASMs aiming at reducing seizure burden along with management of the underlying condition.

Focal nonconvulsive status epilepticus in children: clinical and electroencephalographic features in 38 patients

PURPOSE

The aim of this study was to characterize clinically, etiologically, and electroencephalographically focal Nonconvulsive Status Epilepticus (NCSE) in children. Moreover, we tried to identify focal NCSE features distinguishing between different ages, NCSE etiologies, and cases of de novo onset.

METHODS

We retrospectively identified patients (aged 1 month to 18 years) who had EEG-documented focal NCSE between January 2001 and December 2019. We analyzed the clinical features, etiology, and EEG features of each event.

RESULTS

Thirty-eight patients were included in this study. NCSE had a de novo onset in 26 patients and was the first manifestation of previously undiagnosed epilepsy in 12 patients. NCSE etiology was acute symptomatic in 13 patients. Acute symptomatic NCSE events were mainly observed in hospitalized children, were usually longer, and had a significantly higher frequency of repetitive EEG patterns than other etiologies. In patients with epilepsy, the etiology of NCSE was remote symptomatic in 14, progressive in 6, and cryptogenic in 5; a definite or suspected genetic disorder was observed in 11. EEG localization was frequent in posterior regions (18 children). Eleven patients had refractory NCSE and 4 required admission to the intensive care unit.

CONCLUSION

Focal NCSE in children is more frequent in the first years of life, mainly involves posterior regions, and often has de novo onset. In the case of de novo focal NCSE both acute symptomatic NCSE and new-onset epilepsy must be considered and investigated. A higher frequency of repetitive EEG patterns and an inpatient setting are significantly associated with acute symptomatic NCSE.

De novo Absence Status Epilepticus in a pediatric cohort: Electroclinical pattern in a multicenter Italian patients cohort

PURPOSE

Absence Status epilepticus (AS) is a form of Non Convulsive Status Epilepticus defined as a prolonged, generalized and non-convulsive seizure, with an altered content of consciousness. We aim to describe a group of healthy children, who presented recurrent and unprovoked de novo AS as the only manifestation of their epilepsy, with an excellent response to antiepileptic drugs.

METHOD

We retrospectively reviewed the electroclinical and genetic features of 13 pediatric patients, referring to our epilepsy centers from 2005 to 2019, on the following criteria: (1) regular psychomotor development, (2) one or more unprovoked AS as the only epileptic manifestation, (3) normal blood testing, (4) normal neuroimaging, (5) EEG recording, (6) available follow-up (1-14 years).

RESULTS

Patients are 7 females and 6 males, aged 7-22, with a mean age at AS onset of 9,3 years. All of them started an antiepileptic therapy, with an excellent response to Valproic Acid (VPA) or Ethosuximide (ETS). 5 patients did not start the therapy immediately after the first AS and they presented recurrent AS (from 2 to 4 episodes). 10 of them performed aCGH, karyotype, NGS panel or Whole Exome Sequencing.

CONCLUSIONS

We suggest that de novo AS may be a well-defined age-related and self-limited epilepsy syndrome, with a good prognosis and excellent response to therapy, but it comes with a high risk of relapsing if not adequately treated with antiepileptic drugs.

Towards Successes in the Management of Nonconvulsive Status Epilepticus: Tracing the Detection-to-Needle Trajectories

PURPOSE

Data on the timeliness of emergent medication delivery for nonconvulsive status epilepticus (NCSE) are currently lacking.

METHODS

Retrospective chart reviews (between 2015 and 2018) and analyses of all patients with NCSE were performed at the University of Nebraska Medical Center, a level 4 epilepsy center, to determine the latencies to order and administration of the first, second, and third antiepileptic drugs (AEDs). Recurrent NCSE cases were considered independently and classified as comatose and noncomatose.

RESULTS

There were 77 occurrences of NCSE in 53 patients. The first, second, and third AEDs were delivered with substantial delays at median times of 80 (25%-75% interquartile range, 44-166), 126 (interquartile range, 67-239), and 158 minutes (interquartile range, 89-295), respectively, from seizure detection. The median times to the order of the first and second AEDs were 33 and 134.5 minutes longer in comatose NCSE patients compared with those with noncomatose forms, respectively (P = 0.001 and 0.004, respectively). The median times between the AED orders and their administration in these two groups were the same (P = 0.60 and 0.37, respectively). With bivariate analysis, the median latencies to administration of the first, second, and third AEDs were significantly increased by 33, 109.5, and 173 minutes, respectively, in patients who died within 30 days compared with those who survived (P = 0.047, P = 0.02, P = 0.0007, respectively).

CONCLUSIONS

The administration of the first, second, and third AEDs for NCSE was delayed. Slow initiation of acute treatment in comatose patients was caused by delays in the placement of the medication order.

Status epilepticus in Auckland, New Zealand: Incidence, etiology, and outcomes

OBJECTIVE

To determine the incidence, etiology, and outcome of status epilepticus (SE) in Auckland, New Zealand, using the latest International League Against Epilepsy (ILAE) SE semiological classification.

METHODS

We prospectively identified patients presenting to the public or major private hospitals in Auckland (population = 1.61 million) between April 6, 2015 and April 5, 2016 with a seizure lasting 10 minutes or longer, with retrospective review to confirm completeness of data capture. Information was recorded in the EpiNet database.

RESULTS

A total of 477 episodes of SE occurred in 367 patients. Fifty-one percent of patients were aged <15 years. SE with prominent motor symptoms comprised 81% of episodes (387/477). Eighty-four episodes (18%) were nonconvulsive SE. Four hundred fifty episodes occurred in 345 patients who were resident in Auckland. The age-adjusted incidence of 10-minute SE episodes and patients was 29.25 (95% confidence interval [CI] = 27.34-31.27) and 22.22 (95% CI = 20.57-23.99)/100 000/year, respectively. SE lasted 30 minutes or longer in 250 (56%) episodes; age-adjusted incidence was 15.95 (95% CI = 14.56-17.45) SE episodes/100 000/year and 12.92 (95% CI = 11.67-14.27) patients/100 000/year. Age-adjusted incidence (10-minute SE) was 25.54 (95% CI = 23.06-28.24) patients/100 000/year for males and 19.07 (95% CI = 16.91-21.46) patients/100 000/year for females. The age-adjusted incidence of 10-minute SE was higher in Māori (29.31 [95% CI = 23.52-37.14]/100 000/year) and Pacific Islanders (26.55 [95% CI = 22.05-31.99]/100 000/year) than in patients of European (19.13 [95% CI = 17.09-21.37]/100 000/year) or Asian/other descent (17.76 [95% CI = 14.73-21.38]/100 000/year). Seventeen of 367 patients in the study died within 30 days of the episode of SE; 30-day mortality was 4.6%.

SIGNIFICANCE

In this population-based study, incidence and mortality of SE in Auckland lie in the lower range when compared to North America and Europe. For pragmatic reasons, we only included convulsive SE if episodes lasted 10 minutes or longer, although the 2015 ILAE SE classification was otherwise practical and easy to use.

Non-convulsive status epilepticus: mimics and chameleons

Non-convulsive status epilepticus (NCSE) is an enigmatic condition with protean manifestations. It often goes unrecognised, leading to delays in its diagnosis and treatment. The principal reason for such delay is the failure to consider and request an electroencephalogram (EEG), although occasional presentations have no scalp or surface electroencephalographic correlate. In certain settings with limited EEG availability, particularly out-of-hours, clinicians should consider treating without an EEG. Patients need a careful risk–benefit analysis to assess the risks of neuronal damage and harm versus the risks of adverse effects from various intensities of therapeutic intervention. Specialists in EEG, intensive care or epilepsy are invaluable in the management of patients with possible NCSE.

Clinical presentation, epidemiology, neurophysiological findings, treatment and outcome of nonconvulsive status epilepticus: a 3-year prospective, hospital-based study

Objective: This study reports the prevalence of Nonconvulsive Status Epilepticus (NCSE) in patients with altered mental status (AMS), and describes the clinical presentation, etiology, neurophysiological findings, neuroimaging, treatment, and outcome of NCSE in Qatar. Recording duration of continuous EEG monitoring was also discussed.

Methods: This was a 3-year, prospective, hospital-based study involving patients with AMS and continuous EEG monitoring admitted to the Emergency and ICUs of Hamad Hospital, Qatar. Patients with confirmed diagnosis of NCSE were compared to the patients who did not show EEG and clinical features compatible with NCSE. Descriptive statistics in terms of mean with standard deviation, as well as frequency and percentages for categorical variables, were calculated; Student’s t test as well as Chi-square tests or Fisher’s exact tests were applied. Logistic regressions NSCE was performed using significance level 0.05 for independent variables at univariate analysis.

Results: Number of patients with AMS and continuous EEG monitoring was 250. Number of patients with EEG compatible with NCSE: 65 (age range, 12–79 ys; m, 37; f, 28). Number of controls (defined as patients with EEG not compatible with NCSE): 185 (age range, 12–80 ys; m, 101; f, 84). Rate of occurrence of NCSE in patients with AMS: 26%. NCSE group was younger than controls (p < .001). Twenty patients with NCSE (31%) and 35 patients in the control group (19%) died. Death was more frequent in comatose NCSE compared to controls (p < .0007). NCSE proper and comatose NCSE had longer hospital stays than controls (p < .02 and p < .03, respectively). Complete recovery occurred in 26 NCSE patients (40%) and in 98 controls (53%) (p < .08). Twenty-one patients (31%) presented with refractory NCSE: 12 patients survived, 9 died.

Conclusion: This was the first prospective study reporting a high number of NCSE in Qatar, a small country in the MENA region. This prevalence (26%) was in the middle range. NCSE patients did not perform better than controls, outcome being worse with comatose NCSE. NCSE is an emergent condition warranting expedited diagnosis and management. Three days of continuous EEG monitoring were able to diagnose most cases of NCSE.

An update on the recognition and treatment of non-convulsive status epilepticus in the intensive care unit

INTRODUCTION

Non-convulsive status epilepticus (NCSE) is a complex and diverse condition which is often an under-recognised entity in the intensive care unit. When NCSE is identified the optimal treatment strategy is not always clear. Areas covered: This review is based on a literature review of the key literature in the field over the last 5-10 years. The articles were selected based on their importance to the field by the authors. Expert commentary: This review discusses the complex situations when a neurological consultation may occur in a critical care setting and provides an update on the latest evidence regarding the recognition of NCSE and the decision making around determining the aggressiveness of treatment. It also considers the ictal-interictal continuum of conditions which may be met with, particularly in the era of continuous EEG, and provides an approach for dealing with these. Suggestions for how the field will develop are discussed.