Status epilepticus: Clinical characteristics and EEG patterns associated with and without MRI diffusion restriction in 69 patients

A longitudinal MRI and TSPO PET-based investigation of brain region-specific neuroprotection by diazepam versus midazolam following organophosphate-induced seizures

Acute poisoning with organophosphorus cholinesterase inhibitors (OPs), such as OP nerve agents and pesticides, can cause life threatening cholinergic crisis and status epilepticus (SE). Survivors often experience significant morbidity, including brain injury, acquired epilepsy, and cognitive deficits. Current medical countermeasures for acute OP poisoning include a benzodiazepine to mitigate seizures. Diazepam was long the benzodiazepine included in autoinjectors used to treat OP-induced seizures, but it is now being replaced in many guidelines by midazolam, which terminates seizures more quickly, particularly when administered intramuscularly. While a direct correlation between seizure duration and the extent of brain injury has been widely reported, there are limited data comparing the neuroprotective efficacy of diazepam versus midazolam following acute OP intoxication. To address this data gap, we used non-invasive imaging techniques to longitudinally quantify neuropathology in a rat model of acute intoxication with the OP diisopropylfluorophosphate (DFP) with and without post-exposure intervention with diazepam or midazolam. Magnetic resonance imaging (MRI) was used to monitor neuropathology and brain atrophy, while positron emission tomography (PET) with a radiotracer targeting translocator protein (TSPO) was utilized to assess neuroinflammation. Animals were scanned at 3, 7, 28, 65, 91, and 168 days post-DFP and imaging metrics were quantitated for the hippocampus, amygdala, piriform cortex, thalamus, cerebral cortex and lateral ventricles. In the DFP-intoxicated rat, neuroinflammation persisted for the duration of the study coincident with progressive atrophy and ongoing tissue remodeling. Benzodiazepines attenuated neuropathology in a region-dependent manner, but neither benzodiazepine was effective in attenuating long-term neuroinflammation as detected by TSPO PET. Diffusion MRI and TSPO PET metrics were highly correlated with seizure severity, and early MRI and PET metrics were positively correlated with long-term brain atrophy. Collectively, these results suggest that anti-seizure therapy alone is insufficient to prevent long-lasting neuroinflammation and tissue remodeling.

Clinical and diagnostic characteristics of Hashimoto's encephalopathy: a single-center, retrospective study

BACKGROUND AND PURPOSE

Diagnosing Hashimoto's encephalopathy (HE) is challenging. In contrast to other types of autoimmune encephalitis, HE shows an excellent response to steroid treatment. We aimed to investigate the rates of antithyroid antibodies (ATAs) and probable HE in patients with unexplained mental dysfunction and compare the clinical characteristics between the good- and poor-outcome groups.

METHODS

We retrospectively reviewed the medical records and electroencephalography (EEG) and neuroimaging findings of patients admitted to the Department of Neurology of our hospital from March 1, 2006, to February 28, 2023. Using our proposed diagnostic criteria for probable HE, we compared the clinical characteristics between the good- and poor-outcome groups. We also investigated the rates of ATA positivity and probable HE.

RESULTS

In total, 198 patients exhibited altered mentation, rapidly progressive cognitive decline, or myoclonus. ATA tests were performed on 86 patients, and the detection rates of ATAs and probable HE were 29.1% and 25.6%, respectively. Of the 22 patients enrolled, the good- and poor-outcome groups comprised 19 and 3 patients, respectively. Clinical seizures occurred in seven patients. Nonconvulsive status epilepticus on EEG was observed in six patients, all of whom were intractable to antiepileptic drugs. Nineteen of 21 patients (90.5%) treated with immunosuppressants showed good outcomes.

CONCLUSIONS

HE is a rare clinical disorder, but not as rare as previously thought. When HE is suspected, steroids should be considered the first-line treatment. Early diagnosis and adequate treatment are critical to achieve good outcomes in HE.

The split apparent diffusion coefficient sign: A novel magnetic resonance imaging biomarker for cortical pathology with possible implications in autoimmune encephalitis

INTRODUCTION

MRI is the imaging modality of choice for assessing patients with encephalopathy. In this context, we discuss a novel biomarker, the "split ADC sign," where the cerebral cortex demonstrates restricted diffusion (high DWI signal and low ADC) and the underlying white matter demonstrates facilitated diffusion (high or low DWI signal and high ADC). We hypothesize that this sign can be used as a biomarker to suggest either acute encephalitis onset or to raise the possibility of an autoimmune etiology.

MATERIALS AND METHODS

A full-text radiological information system search of radiological reports was performed for all entities known to produce restricted diffusion in the cortex excluding stroke between January 2012 and June 2022. Initial MRI studies performed upon onset of clinical symptoms were screened for the split ADC sign.

RESULTS

25 subjects were encountered with a positive split ADC sign (15 female; median age = 57 years, range 18-82). Diagnosis included six herpes simplex encephalitis, three peri-ictal MRI changes, eight PRES, two MELAS, and six autoimmune (3 anti-GABAAR, two seronegative, and one anti-Ma2/Ta). Subjects were imaged at a mean 1.8 days after the onset of symptoms (range 0-8).

DISCUSSION

We present a novel visual MRI biomarker, the split ADC sign, and highlight its potential usefulness in subjects with encephalopathy to suggest acute disease onset or to raise the possibility of an autoimmune etiology when location-based criteria are applied. When positive, the sign was present on the initial MRI and can therefore be used to help focus further clinical and laboratory workup.

Brain MRI in status epilepticus: Relevance of findings

Status epilepticus (SE) represents one of the most common neurological emergencies, associated with high mortality and an important risk of functional sequelae in survivors. Magnetic resonance imaging (MRI) offers the possibility of early and noninvasive observation of seizure-induced parenchymal disturbances secondary to the epileptic process. In the present review, we propose a descriptive and comprehensive understanding of current knowledge concerning seizure-induced MRI abnormalities in SE, also called peri-ictal MRI abnormalities (PMAs). We then discuss how PMAs, as a noninvasive biomarker, could be helpful to optimize patient prognostication in SE management. Finally, we discuss alternative promising MRI approaches, including arterial spin labeling (ASL), susceptibility-weighted imaging (SWI), dynamic contrast-enhanced (DCE) MRI and dynamic susceptibility contrast (DSC) MRI that could refine our understanding of SE, particularly in non-convulsive form.

Status epilepticus in BRAF-related cardio-facio-cutaneous syndrome: Focus on neuroimaging clues to physiopathology

OBJECTIVE

Cardio-facio-cutaneous syndrome (CFC) is a genetic disorder due to variants affecting genes coding key proteins of the Ras/MAPK signaling pathway. Among the different features of CFC, neurological involvement, including cerebral malformations and epilepsy, represents a common and clinically relevant aspect. Status epilepticus (SE) is a recurrent feature, especially in a specific subgroup of CFC patients with developmental and epileptic encephalopathy (DEE) and history of severe pharmacoresistant epilepsy. Here we dissect the features of SE in CFC patients with a particular focus on longitudinal magnetic resonance imaging (MRI) findings to identify clinical-radiological patterns and discuss the underlying physiopathology.

METHODS

We retrospectively analyzed clinical, electroencephalogram (EEG), and MRI data collected in a single center from a cohort of 23 patients with CFC carrying pathogenic BRAF variants who experienced SE during a 5-year period.

RESULTS

Seven episodes of SE were documented in 5 CFC patients who underwent EEG and MRI at baseline. MRI was performed during SE/within 72 hours from SE termination in 5/7 events. Acute/early post-ictal MRI findings showed heterogenous abnormalities: restricted diffusion in 2/7, focal area of pcASL perfusion change in 2/7, focal cortical T2/FLAIR hyperintensity in 2/7. Follow-up images were available for 4/7 SE. No acute changes were detected in 2/7 (MRI performed 4 days after SE termination).

SIGNIFICANCE

Acute focal neuroimaging changes concomitant with ictal EEG focus were present in 5/7 episodes, though with different findings. The heterogeneous patterns suggest different contributing factors, possibly including the presence of focal cortical malformations and autoinflammation. When cytotoxic edema is revealed by MRI, it can be followed by permanent structural damage, as already observed in other genetic conditions. A better understanding of the physiopathology will provide access to targeted treatments allowing to prevent long-term adverse neurological outcome.

PLAIN LANGUAGE SUMMARY

Cardio-facio-cutaneous syndrome is a genetic disorder that often causes prolonged seizures known as status epilepticus. This study has a focus on electroclinical and neuroimaging patterns in patients with cardio-facio-cutaneous syndrome. During these status epilepticus episodes, we found different abnormal brain imaging patterns in patients, indicating various causes like brain malformations and inflammation. Understanding these patterns could help doctors find specific treatments, protecting cardio-facio-cutaneous syndrome patients from long-term brain damage.

Guidelines for Neuroprognostication in Comatose Adult Survivors of Cardiac Arrest

BACKGROUND

Among cardiac arrest survivors, about half remain comatose 72 h following return of spontaneous circulation (ROSC). Prognostication of poor neurological outcome in this population may result in withdrawal of life-sustaining therapy and death. The objective of this article is to provide recommendations on the reliability of select clinical predictors that serve as the basis of neuroprognostication and provide guidance to clinicians counseling surrogates of comatose cardiac arrest survivors.

METHODS

A narrative systematic review was completed using Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Candidate predictors, which included clinical variables and prediction models, were selected based on clinical relevance and the presence of an appropriate body of evidence. The Population, Intervention, Comparator, Outcome, Timing, Setting (PICOTS) question was framed as follows: "When counseling surrogates of comatose adult survivors of cardiac arrest, should [predictor, with time of assessment if appropriate] be considered a reliable predictor of poor functional outcome assessed at 3 months or later?" Additional full-text screening criteria were used to exclude small and lower-quality studies. Following construction of the evidence profile and summary of findings, recommendations were based on four GRADE criteria: quality of evidence, balance of desirable and undesirable consequences, values and preferences, and resource use. In addition, good practice recommendations addressed essential principles of neuroprognostication that could not be framed in PICOTS format.

RESULTS

Eleven candidate clinical variables and three prediction models were selected based on clinical relevance and the presence of an appropriate body of literature. A total of 72 articles met our eligibility criteria to guide recommendations. Good practice recommendations include waiting 72 h following ROSC/rewarming prior to neuroprognostication, avoiding sedation or other confounders, the use of multimodal assessment, and an extended period of observation for awakening in patients with an indeterminate prognosis, if consistent with goals of care. The bilateral absence of pupillary light response > 72 h from ROSC and the bilateral absence of N20 response on somatosensory evoked potential testing were identified as reliable predictors. Computed tomography or magnetic resonance imaging of the brain > 48 h from ROSC and electroencephalography > 72 h from ROSC were identified as moderately reliable predictors.

CONCLUSIONS

These guidelines provide recommendations on the reliability of predictors of poor outcome in the context of counseling surrogates of comatose survivors of cardiac arrest and suggest broad principles of neuroprognostication. Few predictors were considered reliable or moderately reliable based on the available body of evidence.

Magnetic Resonance Imaging in Status Epilepticus: Useful Scrying Board or Expensive Stopwatch?

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Association of Peri-ictal MRI Abnormalities With Mortality, Antiseizure Medication Refractoriness, and Morbidity in Status Epilepticus

BACKGROUND AND OBJECTIVES

Status epilepticus (SE) is a life-threatening emergency requiring a prompt assessment of patient prognosis to guide management. MRI allows the identification of peri-ictal MRI abnormalities (PMAs) and provides insight into brain structural modifications induced by SE. However, little is known about the significance of PMA in SE prognosis. The aim of this study was to determine whether PMAs are associated with an increased mortality in SE and to establish the association between PMA and refractoriness to antiseizure medications, complications encountered, and induced morbidity.

METHODS

We conducted a retrospective observational cohort study including all eligible consecutive patients over 15 years old and hospitalized with SE at Bordeaux University Hospital (France) between January 2015 and December 2019. The primary end point was in-hospital mortality. A dedicated neuroradiologic reassessment was performed, together with a comprehensive medical review assessing baseline characteristics, in-hospital death, SE characterization, drug refractoriness, and following outcome in survivors.

RESULTS

Of 307 patients included, 79 (26%) showed PMA related to SE. Demographic, functional status at baseline and median delay between SE onset and MRI examination were similar in the PMA-positive and PMA-negative groups. In-hospital death occurred in 15% (45/307) patients and was significantly higher in the PMA-positive group (27%, 21/79 vs 11%, 24/228; p < 0.001). In multivariate analysis, the presence of PMA (odds ratio [OR] 2.86, 95% CI 1.02-8.18; p = 0.045), together with SE duration (OR 1.01, 95% CI 1.01-1.02; p = 0.007), older age at SE onset (OR 1.05, 95% CI 1.01-1.09; p = 0.013), preexisting ultimately fatal comorbidity (OR 4.01, 95% CI 1.56-10.6; p = 0.004), and acute lesional SE etiology (OR 3.74, 95% CI 1.45-10.2; p = 0.007) were independent predictors associated with in-hospital death. Patients with PMA had a higher risk of refractory SE (71 vs 33%, p < 0.001). Among survivors, delayed-onset epilepsy (40% vs 21%, p = 0.009) occurred more frequently in the PMA-positive group.

DISCUSSION

PMA-positive cases had a higher mortality rate in the largest cohort so far to assess the prognosis value of PMA in SE. As a noninvasive and easily available tool, PMA represents a promising structural biomarker for developing a personalized approach to prognostication in patients with SE receiving MRI.

Specific profiles of new-onset vs. non-inaugural status epilepticus: From diagnosis to 1-year outcome

While new-onset status epilepticus (NOSE) is a harbinger of chronic epilepsy, prospective medical data are sparse in terms of specifying whether the evolution of status epilepticus (SE) and seizure expression in NOSE resembles what occurs in patients who have already been diagnosed with epilepsy [non-inaugural SE (NISE)] in all aspects apart from its inaugural nature. The aim of this study was to compare the clinical, MRI, and EEG features that could distinguish NOSE from NISE. We conducted a prospective monocentric study in which all patients ≥18 years admitted for SE over a 6-month period were included. A total of 109 patients (63 NISE and 46 NOSE cases) were included. Despite similar modified Rankin scores before SE, several aspects of the clinical history distinguished NOSE from NISE patients. NOSE patients were older and frequently had neurological comorbidity and preexisting cognitive decline, but they had a similar prevalence of alcohol consumption to NISE patients. NOSE and NISE evolve in the same proportions as refractory SE (62.5% NOSE, 61% NISE) and share common features such as the same incidence (33% NOSE, 42% NISE, and p = 0.53) and volumes of peri-ictal abnormalities on MRI. However, in NOSE patients, we observed greater non-convulsive semiology (21.7% NOSE, 6% NISE, and p = 0.02), more periodic lateral discharges on EEG (p = 0.004), later diagnosis, and higher severity according to the STESS and EMSE scales (p < 0.0001). Mortality occurred in 32.6% of NOSE patients and 21% of NISE patients at 1 year (p = 0.19), but with different causes of death occurring at different time points: more early deaths directly linked to SE at 1 month occurred in the NOSE group, while there were more remote deaths linked to causal brain lesions in the NISE group at final follow-up. In survivors, 43.6% of the NOSE cases developed into epilepsy. Despite acute causal brain lesions, the novelty related to its inaugural nature is still too often associated with a delay in diagnosing SE and a poorer outcome, which justifies the need to more clearly specify the various types of SE to constantly raise awareness among clinicians. These results highlight the relevance of including novelty-related criteria, clinical history, and temporality of occurrence in the nosology of SE.

Association of ictal imaging changes in status epilepticus and neurological deterioration

OBJECTIVE

In patients with status epilepticus (SE), the clinical significance of ictal changes on magnetic resonance imaging (MRI) is insufficiently understood. We here studied whether the presence of ictal MRI changes was associated with neurological deterioration at discharge.

METHODS

The retrospective cohort comprised all identifiable patients treated at Odense University Hospital in the period 2008-2017. All amenable MRIs were systemically screened for ictal changes. Patient demographics, electroencephalography, seizure characteristics, treatment, and SE duration were assessed. Neurological status was estimated before and after SE. The predefined endpoint was the association of neurological deterioration and ictal MRI changes.

RESULTS

Of 261 eligible patients, 101 received at least one MRI during SE or within 7 days after cessation; 43.6% (44/101) had SE due to non- or less brain-damaging etiologies. Patients who received MRI had a longer duration of SE, less frequently had a history of epilepsy, and were more likely to have SE due to unknown causes. Basic characteristics (including electroencephalographic features defined by the Salzburg criteria) did not differ between patients with (n = 20) and without (n = 81) ictal MRI changes. Timing of MRI was important; postictal changes were rare within the first 24 h and hardly seen >5 days after cessation of SE. Ictal MRI changes were associated with a higher risk of neurological deterioration at discharge irrespective of etiology. Furthermore, they were associated with a longer duration of SE and higher long-term mortality that reached statistical significance in patients with non- or less brain-damaging etiologies.

SIGNIFICANCE

In this retrospective cohort, ictal changes on MRI were associated with a higher risk of neurological deterioration at discharge and, possibly, with a longer duration of SE and poorer survival.

Management of Status Epilepticus, Refractory Status Epilepticus, and Super-refractory Status Epilepticus

PURPOSE OF REVIEW

Status epilepticus is a serious condition caused by disorders and diseases that affect the central nervous system. In status epilepticus, hypersynchronous epileptic activity lasts longer than the usual duration of isolated self-limited seizures (time t1), which causes neuronal damage or alteration of neuronal networks at a certain time point (time t2), depending on the type of and duration of status epilepticus. The successful management of status epilepticus includes both the early termination of seizure activity and the earliest possible identification of a causative etiology, which may require independent acute treatment. In nonconvulsive status epilepticus, patients present only with subtle clinical signs or even without any visible clinical manifestations. In these cases, EEG allows for the assessment of cerebral function and identification of patterns in need of urgent treatment.

RECENT FINDINGS

In 2015, the International League Against Epilepsy proposed a new definition and classification of status epilepticus, encompassing four axes: symptomatology, etiology, EEG, and age. Various validation studies determined the practical usefulness of EEG criteria to identify nonconvulsive status epilepticus. The American Clinical Neurophysiology Society has incorporated these criteria into their most recent critical care EEG terminology in 2021. Etiology, age, symptomatology, and the metabolic demand associated with an increasing duration of status epilepticus are the most important determinants of prognosis. The consequences of status epilepticus can be visualized in vivo by MRI studies.

SUMMARY

The current knowledge about status epilepticus allows for a more reliable diagnosis, earlier treatment, and improved cerebral imaging of its consequences. Outcome prediction is a soft tool for estimating the need for intensive care resources.

De novo aphasic status epilepticus: Finally making the diagnosis by long-term EEG

Aphasic status epilepticus (SE) is a rare manifestation of non-convulsive SE (NCSE) and may occasionally be under-recognized. We report a 69-year-old male patient with a pre-existing left parietal oligodendroglioma WHO III after two resections and radio-chemotherapy. The patient was left with some word finding difficulties but had no history of overt seizures. He developed aphasic NCSE, which was only detected by long-term electroencephalography (EEG) monitoring. The 24-hour EEG revealed paroxysmal rhythmic theta-delta activity in left posterior regions that propagated to left temporo-parietal areas. Rhythmic activity appeared every 15-30 min and lasted for 10-110 s. Aphasia was continuously present with superimposed short-lasting clinical deteriorations during the day. Magnetic resonance imaging showed peri-ictal edema on diffusion-weighted images in the insula and fronto-parietal cortex, which supported the diagnosis of SE. NCSE persisted for seven months. The patient recovered upon addition of intravenous phenytoin. One should not only consider aphasic SE when language impairment is episodic, but also when there are prolonged manifestations, especially when the typical differential diagnoses have been excluded. Intravenous therapy may be required to terminate NCSE. With this report, we would like to draw attention to aphasic SE as a rare phenomenon that may be difficult to diagnose and delay management in clinical practice.

Magnetic resonance imaging findings in focal-onset status epilepticus

BACKGROUND AND PURPOSE

Magnetic resonance imaging (MRI) is commonly used in the diagnostic work-up for status epilepticus (SE). The purpose of this study was to characterize MRI features in SE patients and determine their association with clinical and electroencephalography (EEG) findings. The mid-term consequences of baseline MRI features were also analysed.

METHODS

This is a prospective study including consecutive patients with SE who underwent brain MRI within 240 h after SE onset. The MRI protocol included T1-weighted (T1WI), T2-weighted (T2W), fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging (DWI) sequences. Follow-up MRI was performed after SE resolution in some patients.

RESULTS

Sixty patients (56.7% men, mean age 58.3 years) were included. SE-related MRI abnormalities were seen in 31 (51.7%), manifesting as hyperintensities on T2W/FLAIR imaging (58.1%) and DWI (74.2%) sequences. Hippocampal and pulvinar involvement was seen in 58.0% and 25.8% of patients, respectively. MRI abnormalities were associated with a longer SE duration (p = 0.013) and the presence of lateralized periodic discharges (LPDs) on EEG (p < 0.001). Amongst the 33 follow-up MRIs, nine (27.3%) showed mesial temporal sclerosis (MTS), which was associated with severe clinical status (p = 0.031), hippocampal oedema (p = 0.001) and LPDs (p = 0.001) at baseline. A poorer clinical outcome was associated with baseline T2W/FLAIR imaging hyperintensities (p = 0.003).

CONCLUSION

MRI showed abnormalities in more than half of SE patients. A longer SE duration and LPDs on EEG were associated with SE-related MRI abnormalities and the development of MTS.

Hyperperfusion in the thalamus on arterial spin labelling indicates non-convulsive status epilepticus

Non-convulsive status epilepticus describes the syndrome of unexplained impaired consciousness in critically ill patients. Non-convulsive status epilepticus is very likely to lead to delayed diagnosis and poor outcomes because of the absence of convulsive symptoms. EEG is essential for the diagnosis of non-convulsive status epilepticus to establish the association between periodic discharges and rhythmic delta activity in addition to ictal epileptiform discharges according to the Salzburg criteria. Arterial spin labelling, a type of perfusion MRI, has been applied for rapid and non-invasive evaluation of the ictal state. Ictal cerebral cortical hyperperfusion is the most common finding to demonstrate focal onset seizures. Hyperperfusion of the thalamus on single photon emission computed tomography was found in patients with impaired awareness seizures. We hypothesized that thalamocortical hyperperfusion on arterial spin labelling identifies non-convulsive status epilepticus and such thalamic hyperperfusion specifically associates with periodic/rhythmic discharges producing impaired consciousness without convulsion. We identified 27 patients (17 females; age, 39-91 years) who underwent both arterial spin labelling and EEG within 24 h of suspected non-convulsive status epilepticus. We analysed 28 episodes of suspected non-convulsive status epilepticus and compared hyperperfusion on arterial spin labelling with periodic/rhythmic discharges. We evaluated 21 episodes as a positive diagnosis of non-convulsive status epilepticus according to the Salzburg criteria. We identified periodic discharges in 15 (12 lateralized and 3 bilateral independent) episodes and rhythmic delta activity in 13 (10 lateralized, 1 bilateral independent and 2 generalized) episodes. Arterial spin labelling showed thalamic hyperperfusion in 16 (11 unilateral and 5 bilateral) episodes and cerebral cortical hyperperfusion in 24 (20 unilateral and 4 bilateral) episodes. Thalamic hyperperfusion was significantly associated with non-convulsive status epilepticus (P = 0.0007; sensitivity, 76.2%; specificity, 100%), periodic discharges (P < 0.0001; 93.3%; 84.6%), and rhythmic delta activity (P = 0.0006; 92.3%; 73.3%). Cerebral cortical hyperperfusion was significantly associated with non-convulsive status epilepticus (P = 0.0017; 100%; 57.1%) and periodic discharges (P = 0.0349; 100%; 30.8%), but not with rhythmic delta activity. Thalamocortical hyperperfusion could be a new biomarker of non-convulsive status epilepticus according to the Salzburg criteria in critically ill patients. Specific thalamic hyperexcitability might modulate the periodic discharges and rhythmic delta activity associated with non-convulsive status epilepticus. Impaired consciousness without convulsions could be caused by predominant thalamic hyperperfusion together with cortical hyperperfusion but without ictal epileptiform discharges.

Brain networks involved in generalized periodic discharges (GPD) in post-anoxic-ischemic encephalopathy

AIM

Generalized periodic discharge (GPD) is an EEG pattern of poor neurological outcome, frequently observed in comatose patients after cardiac arrest. The aim of our study was to identify the neuronal network generating ≤2.5 Hz GPD using EEG source localization and connectivity analysis.

METHODS

We analyzed 40 comatose adult patients with anoxic-ischemic encephalopathy, who had 19 channel-EEG recording. We computed electric source analysis based on distributed inverse solution (LAURA) and we estimated cortical activity in 82 atlas-based cortical brain regions. We applied directed connectivity analysis (Partial Directed Coherence) on these sources to estimate the main drivers.

RESULTS

Source analysis suggested that the GPD are generated in the cortex of the limbic system in the majority of patients (87.5%). Connectivity analysis revealed main drivers located in thalamus and hippocampus for the large majority of patients (80%), together with important activation also in amygdala (70%).

CONCLUSIONS

We hypothesize that the anoxic-ischemic dysfunction, leading to hyperactivity of the thalamo-cortical (limbic presumably) circuit, can result in an oscillatory thalamic activity capable of inducing periodic cortical (limbic, mostly medial-temporal and orbitofrontal) discharges, similarly to the case of generalized rhythmic spike-wave discharge in convulsive or non-convulsive status epilepticus.

Etiological assessment of status epilepticus

Status epilepticus (SE) is a potentially serious condition that can affect vital and functional prognosis and requires urgent treatment. Etiology is a determining factor in the patient's functional outcome and in almost half of all cases justifies specific treatment to stop progression. Therefore, identifying and addressing the cause of SE is a key priority in SE management. However, the etiology can be difficult to identify among acute and remote causes, which can also be multiple and interrelated. The most common etiologies are the discontinuation of antiepileptic medication in patients with a prior history of epilepsy, and acute brain aggression in cases of new onset SE (cerebrovascular pathologies are the most common). The list of remaining possible etiologies includes heterogeneous pathological contexts. Refractory SE and especially New-Onset Refractory Status Epilepticus (NORSE) lead to an extension of the etiological assessment in the search for encephalitis of autoimmune or infectious origin in adults and in children, as well as a genetic pathology in children in particular. This is an overview of current knowledge of SE etiologies and a pragmatic approach for carrying out an etiological assessment based on the following steps: - Which etiological orientation is identified according to the field and clinical presentation?; - Which etiologies to look for in an inaugural SE?; - Which first-line assessment should be carried out? The place of the biological, EEG and imaging assessment is discussed; - Which etiologies to look for in case of refractory SE?

Early seizures after ischemic stroke: focus on thrombolysis

INTRODUCTION

Stroke is a significant underlying cause of epilepsy. Seizures due to ischemic stroke (IS) are generally categorized into early seizures (ESs) and late seizures (LSs). Seizures in thrombolysis situations may raise the possibility of other etiology than IS.

AIM

We overtook a systematic review focusing on the pathogenesis, prevalence, risk factors, detection, management, and clinical outcome of ESs in IS and in stroke/thrombolysis situations. We also collected articles focusing on the association of recombinant tissue-type plasminogen activator (rt-PA) treatment and epileptic seizures.

RESULTS

We have identified 37 studies with 36,775 participants. ES rate was 3.8% overall in patients with IS with geographical differences. Cortical involvement, severe stroke, hemorrhagic transformation, age (<65 years), large lesion, and atrial fibrillation were the most important risk factors. Sixty-one percent of ESs were partial and 39% were general. Status epilepticus (SE) occurred in 16.3%. 73.6% had an onset within 24 h and 40% may present at the onset of stroke syndrome. Based on EEG findings seizure-like activity could be detected only in approximately 18% of ES patients. MRI diffusion-weighted imaging and multimodal brain imaging may help in the differentiation of ischemia vs. seizure. There are no specific recommendations with regard to the treatment of ES.

CONCLUSION

ESs are rare complications of acute stroke with substantial burden. A significant proportion can be presented at the onset of stroke requiring an extensive diagnostic workup.

Peri-ictal magnetic resonance imaging in status epilepticus: Temporal relationship and prognostic value in 60 patients

PURPOSE

Magnetic resonance imaging (MRI) changes associated with status epilepticus (SE) have been described in recent studies. Our aim was to evaluate the diagnosis and prognosis of the peri-ictal MRI changes detected in SE patients.

METHOD

All adults diagnosed with SE and examined by MRI within 240 h after SE onset were enrolled (2011-2017). Demographic, clinical and electroencephalography data, and functional status at admission and discharge were collected. MRI findings were recorded and relationships between clinical and MRI data, and between these data and functional outcome were analyzed.

RESULTS

Sixty patients included, 50% women, mean age 57.5 years. Median duration of SE was 51.46 h and median time from SE onset to MRI was 86.5 h. Of the total, 41.7% had a restricted diffusion pattern on diffusion-weighted imaging (DWI) and 63.3% had hyperintensities suggestive of edema on T2-weighted (T2WI)/FLAIR sequences. The factors independently associated with T2WI hyperintensities were the presence of acute cerebral lesions (p = 0.023), baseline STESS (p = 0.007), and MRI performed within 84 h (p = 0.007). Variables independently associated with diffusion restriction were a potentially fatal cause (p = 0.020), SE duration >24 h (p = 0.022), and MRI performed within the first 84 h (p = 0.045). In patients undergoing MRI within 84 h, the DWI and T2WI abnormalities were both highly associated with an unfavorable outcome.

CONCLUSIONS

Characteristic signal changes on DWI and T2WI sequences were seen in approximately half our SE patients undergoing early (<84 h) brain MRI studies, and were independently related to the patients' functional status at discharge.

Seizure in code stroke: Stroke mimic and initial manifestation of stroke

BACKGROUND

Although seizure is one of the common causes of stroke mimics and can be an initial manifestation of acute stroke, accurate diagnosis of seizure during acute stroke management is frequently difficult. The objective of this study was to analyze the frequency, characteristics and results of neuroimaging including CT perfusion in patients with seizures manifesting initially as stroke-like symptoms.

METHODS

We retrospectively reviewed the medical records of patients who were treated with code stroke alarming system. We studied the frequency and characteristics of patients who were finally diagnosed with seizures and further correlated their clinical features with the results of neuroimaging including CT perfusion.

RESULTS

Among the 4673 patients who were treated with code stroke alarming system, seizure was the third most frequent diagnosis (188 patients, 4.0%) among the causes of stroke mimics including 27 patients who manifested seizure as an initial manifestation of acute stroke. CT perfusion showed perfusion changes in more than 25% of them (49 of 188 patients, 26.1%). Thrombolysis was not performed in six patients who presented with seizure as an initial presentation of stroke for delayed diagnosis while one patient underwent thrombolysis for misdiagnosis of seizure.

CONCLUSIONS

Seizure is a frequent final diagnosis in acute stroke management. However, careful interpretation of clinical features and results of perfusion imaging is necessary to avoid unnecessary thrombolysis in patients with seizure as a stroke mimic and thrombolysis failure due to delayed diagnosis of seizure as an initial manifestation of stroke.

Neuroimaging Correlates of Periodic Discharges

Despite being first described over 50 years ago, periodic discharges continue to generate controversy as to whether they are always, sometimes, or never "ictal." Investigators and clinicians have proposed adjunctive markers to help clarify this distinction-in particular measures of perfusion and metabolism. Here, we review the growing number of neuroimaging studies using Fluorodeoxyglucose-PET, MRI diffusion, Magnetic resonance perfusion, Single Photon Emission Computed Tomography, and Magnetoencepgalography to gain further insight into the physiology and clinical significance of periodic discharges. To date, however, no definitive consensus exists regarding the features of periodic discharges that warrant treatment intensification. However, an emerging consilience among neuroimaging modalities suggests that periodic discharges can induce a hyperexcitatory state with associated hypermetabolism and hyperperfusion, which may result in local metabolic failure.

What to Look for on Post-stroke Neuroimaging

The most feared complication after acute ischemic stroke is symptomatic or asymptomatic hemorrhagic conversion. Neuroimaging and clinical criteria are used to predict development of hemorrhage. Seizures after acute ischemic stroke or stroke-like symptoms from seizures are not common but may lead to confusion in the peristroke period, especially if seizures are repetitive or evolve into status epilepticus, which could affect neuroimaging findings. Malignant infarction develops when cytotoxic edema is large enough to lead to herniation and death. Post-stroke neuroimaging prognosticators have been described and should be assessed early so that appropriate treatment is offered before herniation leads to additional tissue injury.

Neuroimaging of status epilepticus

In the past 2 decades we have observed an extensive use of different neuroimaging techniques to evaluate patients with status epilepticus. Magnetic resonance imaging (MRI) in particular may show a broad spectrum of abnormalities that are either the causes or the consequences of sustained epileptic activity. Neuroimaging techniques can offer a contribution both in the clinical management of individual patients, identifying hemodynamic patterns that support the diagnosis, and also in the recognition of periictal reversible or irreversible alterations. For the future it is necessary to develop larger and prospective studies in which imaging techniques and electroencephalography (EEG) recordings are acquired closely to understand which EEG patterns are related to imaging biomarkers of neuronal damage.

Acute DWI Reductions In Patients After Single Epileptic Seizures - More Common Than Assumed

Background: Changes of cerebral diffusivity detected by magnetic resonance imaging (MRI) have been reported in epilepsy. Diffusion weighted imaging (DWI) detects changes in the distribution of water molecules by measuring the apparent diffusion coefficient (ADC) and is mainly used in the diagnosis of ischemic stroke. DWI changes in epilepsy were reported in status epilepticus (SE) or series of seizures. It remains unclear whether this phenomenon also occurs after single seizures. Accordingly, possible pathomechanisms have only been discussed on the presumed basis of ongoing epileptic brain activity.

Methods: In this retrospective study, we systematically analyzed DWI alterations related to epileptic seizures in 454 patients who received MRI scanning within the first 24 h after seizure onset.

Results: DWI restrictions not classified as ischemic stroke were observed in 18 patients (4%). We found DWI restrictions in 19% of patients with SE/seizure series and in 3% of patients after single focal and 2.5% after single generalized seizures. 17 patients with DWI alterations were diagnosed with a structural epilepsy. DWI signal decreased in the majority of patients within the first days and could not be detected in follow-up imaging >3 months. In all patients except one, DWI alterations were detected in the same hemisphere as the lesion. In the case of seizure series or SE, DWI restrictions mostly presented with a typical “garland-like” pattern alongside the cortical band or on the border of a defined lesion, while in isolated seizures, the restrictions were often rather subtle and small.

Discussion: We show that DWI restrictions can be observed in patients after single epileptic seizures. As the vast majority of these patients was diagnosed with an epilepsy due to structural cerebral pathology, DWI restriction may reflect a higher vulnerability in these regions. This might also explain the fact that diffusivity changes were observed after single focal seizures as well as after multiple seizures or SE. The occurence itself on one side as well as the spatial pattern of this phenomenon on the other may thus not only be related to the duration of ictal activity, but to structural pathology.

Advancements in the critical care management of status epilepticus

PURPOSE OF REVIEW

Status epilepticus has a high morbidity and mortality. There are little definitive data to guide management; however, new recent data continue to improve understanding of management options of status epilepticus. This review examines recent advancements regarding the critical care management of status epilepticus.

RECENT FINDINGS

Recent studies support the initial treatment of status epilepticus with early and aggressive benzodiazepine dosing. There remains a lack of prospective randomized controlled trials comparing different treatment regimens. Recent data support further study of intravenous lacosamide as an urgent-control therapy, and ketamine and clobazam for refractory status epilepticus. Recent data support the use of continuous EEG to help guide treatment for all patients with refractory status epilepticus and to better understand epileptic activity that falls on the ictal-interictal continuum. Recent data also improve our understanding of the relationship between periodic epileptic activity and brain injury.

SUMMARY

Many treatments are available for status epilepticus and there are much new data guiding the use of specific agents. However, there continues to be a lack of prospective data supporting specific regimens, particularly in cases of refractory status epilepticus.

Updates in Refractory Status Epilepticus

Refractory status epilepticus is defined as persistent seizures despite appropriate use of two intravenous medications, one of which is a benzodiazepine. It can be seen in up to 40% of cases of status epilepticus with an acute symptomatic etiology as the most likely cause. New-onset refractory status epilepticus (NORSE) is a recently coined term for refractory status epilepticus where no apparent cause is found after initial testing. A large proportion of NORSE cases are eventually found to have an autoimmune etiology needing immunomodulatory treatment. Management of refractory status epilepticus involves treatment of an underlying etiology in addition to intravenous anesthetics and antiepileptic drugs. Alternative treatment options including diet therapies, electroconvulsive therapy, and surgical resection in case of a focal lesion should be considered. Short-term and long-term outcomes tend to be poor with significant morbidity and mortality with only one-third of patients reaching baseline neurological status.

An exploration of the spectrum of peri-ictal MRI change; a comprehensive literature review

PURPOSE

The aim of this review was to identify published studies in the literature relating to ictal induced MRI change and to identify certain common themes, practical points for clinicians and areas for future research.

METHODS

We identified 96 articles that satisfied our inclusion criteria yielding 575 cases. All articles were analysed; number of subjects, spectrum of MRI and EEG change, aetiology, and follow-up (both clinical and imaging) were noted.

RESULTS

The most frequent imaging changes were restricted diffusion, T2-hyperintensity and reduced ADC values. The mesial temporal structures and neocortex were most commonly affected locations though subcortical structures like the thalamus and pulvinar were also described. Practical clinical points included; the development of PLEDS concordant with ictal imaging change was associated with worse clinical prognosis, patients with seizures due to symptomatic aetiology may be more likely to develop ictal related imaging change and follow up is vitally important to ensure that ictal related oedema is not misidentified as a mass lesion or conversely that a mass lesion is not misidentified as ictal related change.

CONCLUSION

Qualitative MRI studies have provided clinicians with useful in-vivo insights into the dynamic ictal neuronal environment. Changes are not only localised to the ictal focus but can be remote and irreversible. Small patient numbers varying study design and high numbers of symptomatic seizures makes comparison between studies problematic. Also there is possible microstructural quantitative MRI changes that are missed on qualitative MRI. There is a need for prospective quantitative MRI studies in patients with epilepsy peri-icatlly with a uniform period of follow up and comparison to control data.

Fatal Cerebral Edema With Status Epilepticus in Children With Dravet Syndrome: Report of 5 Cases

Dravet syndrome (DS) is a well-recognized developmental and epileptic encephalopathy associated with SCN1A mutations and 15% mortality by 20 years. Although over half of cases succumb to sudden unexpected death in epilepsy, the cause of death in the remainder is poorly defined. We describe the clinical, radiologic, and pathologic characteristics of a cohort of children with DS and SCN1A mutations who developed fatal cerebral edema causing mass effect after fever-associated status epilepticus. Cases were identified from a review of children with DS enrolled in the Epilepsy Genetics Research Program at The University of Melbourne, Austin Health, who died after fever-associated status epilepticus. Five children were identified, all of whom presented with fever-associated convulsive status epilepticus, developed severe brain swelling, and died. All had de novo SCN1A mutations. Fever of 40°C or greater was measured in all cases. Signs of brainstem dysfunction, indicating cerebral herniation, were first noted 3 to 5 days after initial presentation in 4 patients, though were apparent as early as 24 hours in 1 case. When MRI was performed early in a patient's course, focal regions of cortical diffusion restriction were noted. Later MRI studies demonstrated diffuse cytotoxic edema, with severe cerebral herniation. Postmortem studies revealed diffuse brain edema and widespread neuronal damage. Laminar necrosis was seen in 1 case. Cerebral edema leading to fatal brain herniation is an important, previously unreported sequela of status epilepticus in children with DS. This potentially remediable complication may be a significant contributor to the early mortality of DS.

Early diffusion restriction of white matter in infants with small subdural hematomas is associated with delayed atrophy

BACKGROUND

Traumatic brain injury (TBI) is a major cause of infant morbidity and mortality. In these patients, magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI) is the test of choice to describe the extent of microstructural injury.

CASE PRESENTATION AND DISCUSSION

In this case series, we describe novel acute and chronic MRI findings in four infants (6-19 months) with small, unilateral subdural hematomas in whom the etiology of head injury was suspicious for non-accidental trauma (NAT). Acute (<1-week post-injury) DWI revealed extensive areas of restricted diffusion isolated to the cerebral white matter predominantly ipsilateral to the subdural hematoma. After prolonged pediatric intensive care treatment including subdural evacuation (n = 2) or decompressive craniectomy (n = 1), all patients survived albeit with significant motor and cognitive deficits. Delayed structural MRI (6-9-year post-injury) demonstrated cortical and subcortical atrophy well-correlated with areas of acute restricted diffusion.

CONCLUSION

These four cases highlight that relatively small subdural hematomas can be associated with extensive white matter injury-detectable only by early DWI-which have long-term structural and functional consequences.

Suspected new-onset autoimmune temporal lobe epilepsy with amygdala enlargement

OBJECTIVE

Recent reports define temporal lobe epilepsy with amygdala enlargement (TLE-AE) as a distinct electroclinical syndrome comparable to TLE with hippocampal sclerosis. In this retrospective observational study, we present the largest consecutive series of patients with new-onset TLE-AE to date and describe clinical characteristics and seizure outcome, and we aim to explore underlying autoimmune mechanisms within this syndrome.

METHODS

We reviewed all consecutive patients between 2004 and 2014 at our tertiary epilepsy center at the University of Bonn, Germany, with new-onset (<5 years) TLE-AE, negative serum antibody (ab) test results, and with available follow-up data for at least 12 months.

RESULTS

We identified 40 patients (23 male) with TLE-AE with a median age at epilepsy onset of 51 years (range 10-73) and a median disease duration of 11 months (range 0.5-55) at first presentation. At follow-up, 50% of the entire cohort achieved seizure freedom. Of interest, patients with remittent features of AE at follow-up (N = 24) had a superior outcome compared to those with stable magnetic resonance imaging (MRI) features of AE (N = 16): 17 (71%) of 24 were seizure-free for at least 6 months compared to 3 (19%) of 16, respectively (p = 0.003). MRI volumetry confirmed significantly enlarged amygdalae in TLE-AE in relation to healthy controls, and additionally showed significantly greater volume reductions in patients with remittent AE compared to those with stable AE.

SIGNIFICANCE

TLE-AE is a clinical syndrome beginning mostly in middle age, and in addition to its known association with ab-positive limbic encephalitis, it occurs in an ab-negative condition. Remission of AE in the course of the disease could be identified as a predictor for a favorable clinical outcome and is suspicious of an autoimmune etiology, although we could not confirm this hypothesis unequivocally with currently available noninvasive diagnostic tools.

Lateralized periodic discharges associated with status epilepticus in the first year after stroke

Backgrand. Lateralized periodic discharges (LPDs) are infrequent electroencephalograph (EEG) findings, and may present in ictal or interictal form. They are regarded as potential electrophysiologic signs of convulsive or nonconvulsive status epilepticus (NCSE). We report four patients who presented with NCSE and one who presented with convulsive status epilepticus in the postictal period, characterized by LPDs in EEG recordings in the first year after stroke.

Material and methods. We prospectively evaluated patients who clinically presented with status epilepticus associated LPDs between March 2014 and March 2015. We investigated patients that presented with a new stroke occurrence. We excluded the other LPD etiologies. EEG studies of five patients (two men) who were admitted to our emergency unit with confusion, three of whom had visual symptoms; four were treated for NCSE as diagnosed with LPDs. The fifth patient had convulsive status epilepticus with LPD in the postictal period.

Results and Discussion. None of the five patients, who were aged between 68 and 92 years, showed any etiologic factor other than a history of cerebrovascular disease (CVD). Magnetic resonance imaging studies of the patients revealed old infarcts and transitional diffusion restrictions. The clinical and EEG findings decreased substantially upon antiepileptic drug treatment. Herein, we illustrate the first patient who had confusion, visual hallucinations, and ictal and interictal LPD in her consecutive EEGs.

Conclusions. CVDs may pave the way for LPDs in patients with a history of stroke because CVDs cause structural brain damage. Patients who present with a similar clinical profile and imaging signs of stroke should be checked for NCSE, particularly in the presence of LPDs in EEGs.