Which EEG patterns in coma are nonconvulsive status epilepticus?

Perampanel as an Add-On Therapy in Patients with Refractory Status Epilepticus and Postanoxic Encephalopathy: A Real-Life Single-Center Retrospective Cohort Study

BACKGROUND

Data on the efficacy of perampanel in refractory status epilepticus (RSE) and postanoxic encephalopathy (PAE) are limited; its use in such conditions is currently off-label.

METHODS

We conducted a retrospective cohort study of consecutive adult patients with RSE, including PAE, exhibiting electroencephalographic patterns indicative of status epilepticus who were treated at our center (January 2018 to December 2022) with assessment of clinical and electroencephalographic outcomes.

RESULTS

Thirty-six patients were included in the study, of whom 29 had nonanoxic RSE and 7 had PAE. Within the nonanoxic RSE subgroup, 45% (13 of 29; 95% confidence interval [CI] 27-63%) of study participants were responders, 34% (10 of 29; 95% CI 17-52%) were partial responders, and 21% (6 of 29; 95% CI 6-35%) were nonresponders. In the PAE subgroup (n = 7), no patients fully responded to perampanel; 43% (3 of 7; 95% CI 6-80%) were partial responders, and 57% (4 of 7; 95% CI 20-95%) were nonresponders. Responder and nonresponder study participants exhibited overlapping baseline characteristics. No significant differences in duration of hospitalization were observed between responders and nonresponders in both subgroups. Responders in the RSE subgroup had a median discharge modified Rankin Scale score of 3 (interquartile range 3-4), and nonresponders had a median discharge modified Rankin Scale score of 5 (interquartile range 5-6).

CONCLUSIONS

Despite limitations from the retrospective design and the small population size, this study suggests that perampanel use in nonanoxic RSE appears to yield promising results at moderate doses, including a tendency toward a better functional outcome at discharge, without significant adverse effects. However, in patients with PAE, the drug seems to show suboptimal performance. Perampanel appears to have promising efficacy as an add-on therapy in nonanoxic RSE. However, in patients with PAE, its efficacy seems to be lower. Further studies are warranted to confirm these observations.

Ketamine in the treatment of refractory and super-refractory status epilepticus: Experience from two centres

PURPOSE

There is insufficient evidence on the management of refractory status epilepticus (RSE) and super-RSE (SRSE). Ketamine is a N-methyl-d-aspartate receptor antagonist in the treatment of these entities. Our objectives were to study the effectiveness and safety of ketamine in the treatment of adult patients with RSE and SRSE, to determine the factors that can influence the response to ketamine, and to explore its use in patients without mechanical ventilation.

METHODS

Adult patients who had received intravenous ketamine for the treatment of RSE or SRSE at Hospital Universitario Clínico San Carlos (Madrid, Spain) or Hospital Universitari Vall d'Hebron (Barcelona, Spain) from 2017 to 2023 were retrospectively analysed.

RESULTS

This study included 58 adult patients, mean (standard deviation) age 60.2 (15.7) years, of whom 41 (70.7 %) were male; 33 (56.9 %) patients responded to ketamine without recurrence, with a low rate of adverse effects (8.6 %). The presence of SRSE at the time of ketamine initiation (OR 0.287, p = 0.028) and the time elapsed between status epilepticus onset and ketamine administration (OR 0.991, p = 0.034) were associated with worse response to ketamine. Patients treated without mechanical ventilation had similar rates of response without recurrence (62.5% vs 56.9 %) and lower mortality (37.5% vs 53.5 %) compared to the overall group.

CONCLUSION

Ketamine is an effective drug with few adverse effects. Prompt administration should be considered in patients with RSE requiring anaesthesia, in patients with SRSE, and in patients with RSE who do not respond to standard antiseizure drugs and in whom mechanical ventilation is not advised.

Nonconvulsive status epilepticus in patients with acute subarachnoid hemorrhage is associated with negative arterial spin labeling on peri-ictal magnetic resonance images

Purpose

Non-convulsive status epilepticus (NCSE) is characterized by repetitive or continuous seizures without convulsions. Arterial spin labeling (ASL) is useful for assessing hyperperfusion due to neurovascular unit coupling in patients with NCSE; subarachnoid hemorrhage (SAH) impairs the neurovascular unit. We hypothesized that the sensitivity of ASL in detecting NCSE is low in patients with SAH during the acute phase.

Methods

Based on ASL findings obtained within 48 h after the clinical suspicion of focal-onset NCSE, we divided 34 patients into ASL-negative (no hyperperfusion; n = 10) and ASL-positive (confirmed hyperperfusion; n = 24) groups. We further divided the two groups according to the NCSE etiology: patients who were diagnosed with NCSE within 14 days after SAH onset (acute SAH, n = 11) and patients with NCSE due to factors other acute SAH (n = 23) and compared their characteristics.

Results

In 10 of the 34 patients (29.4 %) the ASL findings were normal. The rate of acute SAH was significantly higher in ASL-negative- (n = 8, 80.0 %) than ASL-positive patients (n = 3, 12.5 %). The rate of patients in aphasic status was significantly lower in ASL-negative patients (n = 1, 10 %) than in ASL-positive patients (n = 12, 50.0 %).

Conclusion

Normal ASL findings alone should not be used to exclude a diagnosis of NCSE particularly in patients in the acute phase of SAH with deterioration or no improvement in consciousness.

Neuroimaging correlation with EEG in status epilepticus

PURPOSE

This study was to correlate EEG patterns with peri‑ictal perfusion CT abnormality (PCA) or peri‑ictal MR abnormality (PMA) in patients with status epilepticus (SE).

METHODS

This is a retrospective study done with SE patients from January 2016 to December 2021. We defined the PCA as single or multi-territorial cortical and/or thalamic hyper-perfusion. The PMA was defined as increased signal intensity in multiple brain regions including the cortex and subcortical regions. EEG patterns were categorized into electrographic seizure (ESz)/electroclinical seizure (ECSz), ictal-interictal continuum (IIC), and lateralized periodic discharges (LPDs) per the American Clinical Neurophysiology Society's guideline. We analyzed the association between the patterns of EEG and the presence of PCA or PMA.

RESULTS

Among 73 patients, 26 % (19/73) showed PCA and 25 % (18/73) demonstrated PMA. The patterns of EEG were as follows; ESz/ECSz in 25 % (18/73), IIC in 34 % (25/73), and LPD in 12 % (9/73). There was a significant correlation between the patterns of EEG and the presence of PMA, but not PCA. 48 % (12/25) had both PMA and PCA whereas 52 % (13/25) showed either PMA (6/25) or PCA (7/25).

CONCLUSION

Although PCA did not reveal an electro-radiographical correlation, PMA was strongly linked to ESz, ECSz, IIC, and LPD.

Nonconvulsive Status Epilepticus: A Review for Emergency Clinicians

BACKGROUND

Status epilepticus is associated with significant morbidity and mortality and is divided into convulsive status epilepticus and nonconvulsive status epilepticus (NCSE).

OBJECTIVE

This review provides a focused evaluation of NCSE for emergency clinicians.

DISCUSSION

NCSE is a form of status epilepticus presenting with prolonged seizure activity. This disease is underdiagnosed, as it presents with nonspecific signs and symptoms, most commonly change in mental status without overt convulsive motor activity. Causes include epilepsy, cerebral pathology or injury, any systemic insult such as infection, and drugs or toxins. Mortality is primarily related to the underlying condition. Patients most commonly present with altered mental status, but other signs and symptoms include abnormal ocular movements and automatisms such as lip smacking or subtle motor twitches in the face or extremities. The diagnosis is divided into electrographic and electroclinical, and although electroencephalogram (EEG) is recommended for definitive diagnosis, emergency clinicians should consider this disease in patients with prolonged postictal state after a seizure with no improvement in mental status, altered mental status with acute cerebral pathology (e.g., stroke, hypoxic brain injury), and unexplained altered mental status. Assessment includes laboratory evaluation and neuroimaging with EEG. Management includes treating life-threatening conditions, including compromise of the airway, hypoglycemia, hyponatremia, and hypo- or hyperthermia, followed by rapid cessation of the seizure activity with benzodiazepines and other antiseizure medications.

CONCLUSIONS

An understanding of the presentation and management of NCSE can assist emergency clinicians in the care of these patients.

Valproate-related hyperammonemic encephalopathy with generalized suppression EEG: a case report

BACKGROUND

Valproic acid (VPA) is a prevalent antiseizure medication (ASM) used to treat epilepsy. Valproate-related hyperammonemic encephalopathy (VHE) is a type of encephalopathy that can occur during neurocritical situations. In VHE, the electroencephalogram (EEG) displays diffuse slow waves or periodic waves, and there is no generalized suppression pattern.

CASE PRESENTATION

We present a case of a 29-year-old female with a history of epilepsy who was admitted for convulsive status epilepticus (CSE), which was controlled by intravenous VPA, as well as oral VPA and phenytoin. The patient did not experience further convulsions but instead developed impaired consciousness. Continuous EEG monitoring revealed a generalized suppression pattern, and the patient was unresponsive. The patient's blood ammonia level was significantly elevated at 386.8 μmol/L, indicating VHE. Additionally, the patient's serum VPA level was 58.37 μg/ml (normal range: 50-100 μg/ml). After stopping VPA and phenytoin and transitioning to oxcarbazepine for anti-seizure and symptomatic treatment, the patient's EEG gradually returned to normal, and her consciousness was fully restored.

DISCUSSION

VHE can cause the EEG to display a generalized suppression pattern. It is crucial to recognize this specific situation and not to infer a poor prognosis based on this EEG pattern.

Treatment of Status Epilepticus after Traumatic Brain Injury Using an Antiseizure Drug Combined with a Tissue Recovery Enhancer Revealed by Systems Biology

We tested a hypothesis that in silico-discovered compounds targeting traumatic brain injury (TBI)-induced transcriptomics dysregulations will mitigate TBI-induced molecular pathology and augment the effect of co-administered antiseizure treatment, thereby alleviating functional impairment. In silico bioinformatic analysis revealed five compounds substantially affecting TBI-induced transcriptomics regulation, including calpain inhibitor, chlorpromazine, geldanamycin, tranylcypromine, and trichostatin A (TSA). In vitro exposure of neuronal-BV2-microglial co-cultures to compounds revealed that TSA had the best overall neuroprotective, antioxidative, and anti-inflammatory effects. In vivo assessment in a rat TBI model revealed that TSA as a monotherapy (1 mg/kg/d) or in combination with the antiseizure drug levetiracetam (LEV 150 mg/kg/d) mildly mitigated the increase in plasma levels of the neurofilament subunit pNF-H and cortical lesion area. The percentage of rats with seizures during 0-72 h post-injury was reduced in the following order: TBI-vehicle 80%, TBI-TSA (1 mg/kg) 86%, TBI-LEV (54 mg/kg) 50%, TBI-LEV (150 mg/kg) 40% (p < 0.05 vs. TBI-vehicle), and TBI-LEV (150 mg/kg) combined with TSA (1 mg/kg) 30% (p < 0.05). Cumulative seizure duration was reduced in the following order: TBI-vehicle 727 ± 688 s, TBI-TSA 898 ± 937 s, TBI-LEV (54 mg/kg) 358 ± 715 s, TBI-LEV (150 mg/kg) 42 ± 64 (p < 0.05 vs. TBI-vehicle), and TBI-LEV (150 mg/kg) combined with TSA (1 mg/kg) 109 ± 282 s (p < 0.05). This first preclinical intervention study on post-TBI acute seizures shows that a combination therapy with the tissue recovery enhancer TSA and LEV was safe but exhibited no clear benefit over LEV monotherapy on antiseizure efficacy. A longer follow-up is needed to confirm the possible beneficial effects of LEV monotherapy and combination therapy with TSA on chronic post-TBI structural and functional outcomes, including epileptogenesis.

Spectrum of Ictal-Interictal Continuum: The Significance of 2HELPS2B Score and Background Suppression

PURPOSE

The aims of this study were to identify (1) the spectrum of ictal-interictal continuum (IIC) using the two dimensions of 2HELPS2B score and background suppression and (2) the response to subsequent anti-seizure drugs depends on the spectrum of IIC.

METHODS

The study prospectively enrolled 62 patients with IIC on EEG. The diagnosis of nonconvulsive status epilepticus was attempted with Salzburg criteria as well as clinical and neuroimaging data. IICs were dichotomized into patients with nonconvulsive status epilepticus and coma-IIC. The 2HELPS2B score was evaluated as the original proposal. The suppression ratio was analyzed with Persyst software.

RESULTS

Forty-seven cases (75.8%) were nonconvulsive status epilepticus-IIC and 15 cases (24.2%) were coma-IIC. Multivariate analysis revealed that the 2HELPS2B score was the only significant variable dichotomizing the spectrum of IIC (odds ratio, 3.0; 95% confidence interval, 1.06-8.6; P = 0.03 for nonconvulsive status epilepticus-IIC). In addition, the suppression ratio was significantly negatively correlated with 2HELPS2B scores (Spearman coefficient = -0.37, P = 0.004 for left hemisphere and Spearman coefficient = -0.3, P = 0.02 for right hemisphere). Furthermore, patients with higher 2HELPS2B score (74% [14/19] in ≥2 points vs. 44% [14/32] in <2 points, P = 0.03 by χ 2 test) and lower suppression ratio (62% [23/37] in ≤2.18 vs. 35% [6/17] in >2.18, P = 0.06 by χ 2 test) seemed to be more responsive to subsequent anti-seizure drug.

CONCLUSIONS

The 2HELPS2B score and background suppression can be used to distinguish the spectrum of IIC and thereby predict the response to subsequent anti-seizure drug.

Neurofilament light (NfL) as biomarker in serum and CSF in status epilepticus

OBJECTIVE

We explored the potential of neurofilament light chain (NfL) in serum and cerebrospinal fluid as a biomarker for neurodestruction in status epilepticus.

METHODS

In a retrospective analysis, we measured NfL in serum and cerebrospinal fluid samples of patients with status epilepticus using a highly sensitive single-molecule array technique (Simoa). Status epilepticus was diagnosed according to ILAE criteria. Additionally, we employed an alternative classification with more emphasis on the course of status epilepticus. We used data from three large control groups to compare NfL in status epilepticus versus neurologically healthy controls.

RESULTS

We included 28 patients (mean age: 69.4 years, SD: 15 years) with a median status duration of 44 h (IQR: 80 h). Twenty-one patients (75%) suffered from convulsive status epilepticus and seven (25%) from non-convulsive status epilepticus. Six patients died (21%). Cerebrospinal fluid and serum NfL concentrations showed a high correlation (r = 0.73, p < 0.001, Pearson). The main determinant of NfL concentration was the status duration. NfL concentrations did not differ between convulsive status epilepticus and convulsive status epilepticus classified according to the ILAE or to the alternative classification without and with adjusting for status duration and time between status onset and sampling. We found no association of NfL concentration with death, treatment refractoriness, or prognostic scores.

CONCLUSION

The results suggest that neurodestruction in status epilepticus measured by NfL is mainly determined by status duration, not status type nor therapy refractoriness. Therefore, our results suggest that regarding neurodestruction convulsive and non-convulsive status epilepticus are both neurological emergencies of comparable urgency.

Electroencephalographic patterns in a mechanically ventilated cat with permethrin intoxication

Case summary

A 1-year-old male castrated domestic shorthair cat was presented in a condition of status epilepticus following incidental permethrin spot-on administration by its owner. General anaesthesia and mechanical positive pressure control ventilation were necessary to control the epileptic seizures and a progressive condition of hypoventilation. The cat was managed with an intravenous constant rate infusion of midazolam, propofol and ketamine associated with a low-dose intravenous lipid emulsion. A condition of non-convulsive status epilepticus was detected by serial continuous electroencephalogram (cEEG) monitoring. Initial cEEG showed paroxysmal epileptiform discharges; thus, antiseizure treatment with phenobarbital was added and a bolus of hypertonic saline solution was administered to treat suspected intracranial hypertension. A second cEEG performed 24 h later showed the presence of rare spikes and a burst-suppression pattern, so the decision was made to discontinue propofol. A third cEEG, 72 h post-hospitalisation, showed a normal encephalographic pattern; therefore, anaesthetic drugs were progressively tapered, and the patient was extubated. Five days after admission the cat was discharged on phenobarbital treatment, which was gradually tapered during the following months.

Relevance and novel information

This is the first reported case to describe cEEG monitoring during hospitalisation for feline permethrin intoxication. cEEG should be encouraged in cats with altered mental status that have previously suffered cluster seizures or status epilepticus, which could guide clinicians in the choice of antiseizure drugs.

Epileptiform patterns predicting unfavorable outcome in postanoxic patients: A matter of time?

OBJECTIVE

Historically, epileptiform malignant EEG patterns (EMPs) have been considered to anticipate an unfavorable outcome, but an increasing amount of evidence suggests that they are not always or invariably associated with poor prognosis. We evaluated the prognostic significance of an EMP onset in two different timeframes in comatose patients after cardiac arrest (CA): early-EMPs and late-EMPs, respectively.

METHODS

We included all comatose post-CA survivors admitted to our intensive care unit (ICU) between 2016 and 2018 who underwent at least two 30-minute EEGs, collected at T0 (12-36 h after CA) and T1 (36-72 h after CA). All EEGs recordings were re-analyzed following the 2021 ACNS terminology by two senior EEG specialists, blinded to outcome. Malignant EEGs with abundant sporadic spikes/sharp waves, rhythmic and periodic patterns, or electrographic seizure/status epilepticus, were included in the EMP definition. The primary outcome was the cerebral performance category (CPC) score at 6 months, dichotomized as good (CPC 1-2) or poor (CPC 3-5) outcome.

RESULTS

A total of 58 patients and 116 EEG recording were included in the study. Poor outcome was seen in 28 (48%) patients. In contrast to late-EMPs, early-EMPs were associated with a poor outcome (p = 0.037), persisting after multiple regression analysis. Moreover, a multivariate binomial model coupling the timing of EMP onset with other EEG predictors such as T1 reactivity and T1 normal voltage background can predict outcome in the presence of an otherwise non-specific malignant EEG pattern with quite high specificity (82%) and moderate sensitivity (77%).

CONCLUSIONS

The prognostic significance of EMPs seems strongly time-dependent and only their early-onset may be associated with an unfavorable outcome. The time of onset of EMP combined with other EEG features could aid in defining prognosis in patients with intermediate EEG patterns.

Power spectrum analysis and outcomes of non-convulsive status epilepticus: a single-center study

OBJECTIVES

Diagnosis of non-convulsive status epilepticus (NCSE) is challenging and outcomes during follow-up are not clear. This study aimed to conduct power spectrum analysis in NCSE and measure outcomes of patients.

METHODS

We searched continuous EEG monitoring (cEEG) recordings to identify patients of NCSE. An artifact-free cEEG epoch of continuous 60 s was chosen for spectral power analysis. We also collected electronic medical records of the patients for extracting clinical information. Patients recruited were followed up at least every half a year.

RESULTS

There were 48 patients with 64 independent NCSE episodes during different course of disease recruited in the study, with a mean age of 40.3 ± 19.1 years (range, 12-72 years), including 24 males (50%) and 24 females (50%). When the spectral power of 60 s equaled to 11.30 μV² for predicting impairment of consciousness, (sensitivity, specificity) = (0.979, 0.625). When the spectral power of 60 s equaled to 52.70 μV² for predicting myoclonic jerks, (sensitivity, specificity) = (0.783, 0.756). There were 27 patients (56.3%) followed up with a duration over 12 months. Nineteen patients (70.4%) continued to have seizures. Eleven (40.7%) resisted to at least two kinds of appropriate anti-seizure medication at maximum tolerated levels. Five patients with prolonged NCSE suffered from loss of brain parenchymal volume on follow-up MRI scans.

CONCLUSION

Spectral power analysis can be used to detect mental status and limb jerks. Early diagnosis and treatment of NCSE are important, which can influence outcomes of the patients during follow-up.

Electroencephalography Findings in Traumatic Brain Injury

Traumatic Brain Injury (TBI) or also known as a head injury is one of the leading causes of death among young people and is also one of the health problems defined as impact, penetration, and rapid movement of the brain within the skull that can result in changes in mental status and is often referred to as the silent epidemic.

Head injuries can also result in electrophysiological abnormalities seen on electroencephalography (EEG) recordings. Electroencephalography was the first clinical neurodiagnostic assessment to reveal abnormal brain function after a head injury. For detecting brain injury, EEG may be more sensitive than clinical neurologic examination.

In general conditions, electroencephalography is performed on patients with moderate to severe head injuries to provide information about the severity of the head injury, and establish a diagnosis of non-convulsive status epilepticus. This diagnosis often follows head injuries because patients with loss of consciousness are difficult to identify without an EEG examination. This also helps determine a prognosis for recovery and the likelihood of post-traumatic seizures.

Electroencephalography features in head injuries depend on the severity of the injury and the location of the head itself. Electroencephalography after head injury shows slowing of the posterior dominant rhythm and increasing diffuse theta slowing, which returns to normal within hours or may subside more slowly over several weeks. Electroencephalography changes are not the same in each individual, due to differences in the severity of head injuries. It is important to know that there is no clear or specific EEG for mild traumatic brain injury.

Nonconvulsive status epilepticus due to pneumocephalus after suprasellar arachnoid cyst fenestration with transsphenoidal surgery: illustrative case

BACKGROUND

Nonconvulsive status epilepticus (NCSE) requires prompt diagnosis and treatment, particularly after neurosurgical procedures for cerebral damage. Here, the authors reported an extremely rare case of suprasellar arachnoid cyst presenting with NCSE after cyst fenestration with transsphenoidal surgery, which was associated with pneumocephalus.

OBSERVATIONS

A 61-year-old man presented with visual impairment and was diagnosed with a suprasellar arachnoid cyst on magnetic resonance imaging (MRI). The patient received cyst fenestration with endonasal transsphenoidal surgery. His visual symptoms improved immediately after the operation; however, on postoperative day 3, semicoma appeared and was prolonged. The patient was diagnosed with NCSE due to pneumocephalus based on MRI and electroencephalography (EEG) findings. The administration of antiepileptic drugs (AEDs) improved his clinical symptoms and the abnormal findings on MRI and EEG.

LESSONS

This is the first case of NCSE with pneumocephalus after transsphenoidal surgery for a suprasellar arachnoid cyst. Pneumocephalus due to cerebrospinal fluid leakage can cause NCSE. Arterial spin labeling perfusion imaging and diffusion-weighted imaging are as useful for differentially diagnosing NCSE as EEG and AED tests.

Prognostic indicators of non-convulsive status epilepticus in intensive care unit

BACKGROUND

To determine the rate of non-convulsive status epilepticus with/without prominent motor phenomena (SE-PM/ NCSE) and predictive value of electroclinical findings of continious electroencephalography (cEEG) monitoring of these patients and its association with prognosis in intensive care units (ICU).

METHODS

We retrospectively collected data of 218 patients whose cEEG was performed in ICU between 2016 and 2018. The cEEG for NCSE diagnosis was evaluated according to Salzburg Consensus Criteria (SCC).

RESULTS

The mean age of patients was 57.09 ± 18.9 (16-95) years and 49.1% (107) were female. Of 218 patients, 32 (14.7%) had SE-PM/NCSE. According to SCC the rate of NCSE (NCSE + possible NCSE) was 9.6% (n = 21). Prior to cEEG recording, 38.9% (n = 85) of overall patients had a history of seizure/convulsion, and 22.7% (n = 21) of these patients diagnosed with NCSE based on cEEG. The mortality rates in critically ill patients were 41.3% (30.8%, 42.8%; for SE-PM and NCSE respectively). Prognosis was associated with age, epilepsy diagnosis, having convulsion/seizure history on follow-up, GCS, need for ventilation, kind of drugs, sepsis diagnosis, and minimum frequency of background activity of the cEEG (p = 0.001, 0.002, 0.001, 0.020, 0.001, 0.001, 0.001, 0.0001 respectively).

CONCLUSIONS

NCSE findings are mostly found in patients who were comatose and had seizure/convulsion history on follow-up. Mortality is higher in patients diagnosed with NCSE followed in the ICU compared to SE-PM.

Potential neurological manifestations of COVID-19: a narrative review

Neurological manifestations are increasingly reported in a subset of COVID-19 patients. Previous infections related to coronaviruses, namely Severe Acute Respiratory Syndrome (SARS) and Middle Eastern Respiratory Syndrome (MERS) also appeared to have neurological effects on some patients. The viruses associated with COVID-19 like that of SARS enters the body via the ACE-2 receptors in the central nervous system, which causes the body to balance an immune response against potential damage to nonrenewable cells. A few rare cases of neurological sequelae of SARS and MERS have been reported. A growing body of evidence is accumulating that COVID-19, particularly in severe cases, may have neurological consequences although respiratory symptoms nearly always develop prior to neurological ones. Patients with preexisting neurological conditions may be at elevated risk for COVID-19-associated neurological symptoms. Neurological reports in COVID-19 patients have described encephalopathy, Guillain-Barré syndrome, myopathy, neuromuscular disorders, encephalitis, cephalgia, delirium, critical illness polyneuropathy, and others. Treating neurological symptoms can pose clinical challenges as drugs that suppress immune response may be contraindicated in COVID-19 patients. It is possible that in some COVID-19 patients, neurological symptoms are being overlooked or misinterpreted. To date, neurological manifestations of COVID-19 have been described largely within the disease trajectory and the long-term effects of such manifestations remain unknown.

Status epilepticus: review on diagnosis, monitoring and treatment

Status epilepticus (SE) is a frequent neurological emergency associated with high morbidity and mortality. According to the new ILAE 2015 definition, SE results either from the failure of the mechanisms responsible for seizure termination or initiation, leading to abnormally prolonged seizures. The definition has different time points for convulsive, focal and absence SE. Time is brain. There are changes in synaptic receptors leading to a more proconvulsant state and increased risk of brain lesion and sequelae with long duration. Management of SE must include three pillars: stop seizures, stabilize patients to avoid secondary lesions and treat underlying causes. Convulsive SE is defined after 5 minutes and is a major emergency. Benzodiazepines are the initial treatment, and should be given fast and an adequate dose. Phenytoin/fosphenytoin, levetiracetam and valproic acid are evidence choices for second line treatment. If SE persists, anesthetic drugs are probably the best option for third line treatment, despite lack of evidence. Midazolam is usually the best initial choice and barbiturates should be considered for refractory cases. Nonconvulsive status epilepticus has a similar initial approach, with benzodiazepines and second line intravenous (IV) agents, but after that, aggressiveness should be balanced considering risk of lesion due to seizures and medical complications caused by aggressive treatment. Usually, the best approach is the use of sequential IV antiepileptic drugs (oral/tube are options if IV options are not available). EEG monitoring is crucial for diagnosis of nonconvulsive SE, after initial control of convulsive SE and treatment control. Institutional protocols are advised to improve care.

Factors associated with the use of anesthetic drug infusion in patients with status epilepticus and their relation to outcome: a prospective study

Status epilepticus (SE) is one of the most dreadful neurological emergencies; unfortunately, studies targeting SE are still inadequate. This study aims to identify factors associated with the use of CIVAD in patients presenting with status epilepticus and detect those impact the clinical outcome. A prospective study involving 144 episodes of SE in 144 patients. Patients were categorized according to whether or not they received CIVAD. Subjects underwent clinical assessment, brain imaging, and EEG. The consciousness level was assessed using the Glasgow coma scale (GCS) and the Full outline of responsiveness (FOUR) scale. SE severity score (STESS) and Epidemiology-based mortality score (EMSE) were used as scales for outcome prediction. Continuous IV anesthetic drug infusion was initiated in 36% of patients (+ CIVAD). Such groups showed a significantly worse initial level of consciousness (< 0.001), an unstable course of seizure evolution (0.009), and all of them showed abnormal EEG patterns. A significantly higher number of patients (+ CIVAD) developed complications (< 0.001), had higher outcome prediction scores (< 0.001), and mortality rates (< 0.001) compared to those who did not need CIVAD (- CIVAD). Mortality was associated with acute symptomatic etiology and higher total doses of propofol. Among the study population, mortality among patients who received CIVAD was associated with acute symptomatic SE and prolonged propofol infusion rather than any clinical parameters or predictor scores.

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.

Critical care EEG standardized nomenclature in clinical practice: Strengths, limitations, and outlook on the example of prognostication after cardiac arrest

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Optimal use of the ACNS nomenclature implies integration of clinical information.

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Knowledge of pathophysiological mechanisms of EEG patterns may help interpretation.

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Standardized therapeutic procedures for critical care patients are needed.

We discuss the achievements of the ACNS critical care EEG nomenclature proposed in 2013 and, from a clinical angle, outline some limitations regarding translation into treatment implications. While the recently proposed updated 2021 version of the nomenclature will probable improve some uncertainty areas, a refined understanding of the mechanisms at the origin of the EEG patterns, and a multimodal integration of the nomenclature to the clinical context may help improving the rationale supporting therapeutic procedures. We illustrate these aspects on prognostication after cardiac arrest.

Nonconvulsive Status Epilepticus Caused by Cerebrospinal Fluid Dissemination of a Salivary Duct Carcinoma: A Case Report

Salivary duct carcinoma (SDC) is a rare and highly aggressive salivary gland tumor with rapid growth, distant metastasis, and a high recurrence rate. Moreover, the parotid gland is the most common site with a poor prognosis. A lower frequency of distance metastasis to the liver, skin, and brain has also been reported, although the lungs, bones, and lymph nodes are the most common sites of SDC metastasis. We report a case of nonconvulsive status epilepticus (NCSE) in a 73-year-old male comatose patient having SDC of the parotid gland with an unusual metastasis to the skin and brain diagnosed by frequent cerebrospinal fluid examinations. Meningeal carcinomatosis usually has a poor prognosis, and NCSE is a reversible cause of altered mentation. Clinicians should know the unique set of epilepsy etiologies in patients with malignant tumors.

Behavioral Assessment of Patients With Disorders of Consciousness

SUMMARY

Brain injury resulting in coma may evolve into a prolonged disorder of consciousness, including the vegetative and minimally conscious states. Early detection of emerging consciousness has positive prognostic significance, and improvement in consciousness at any point may indicate the potential for meaningful communication and environmental control. Despite the importance of accurate assessment of consciousness, research indicates that as many as 40% of patients with a disorder of consciousness may be assessed incorrectly. Assessment of consciousness is challenging for many reasons, including the fact that consciousness cannot be measured directly but must be inferred from patterns of behavioral activity, that many patients have confounding deficits and treatments that may mask consciousness, and that patient performance may be highly variable over time. In this manuscript, we discuss strategies for optimizing patient status during assessment and review a number of structured assessment approaches that can be used. The available assessment techniques vary in their length and cost, and the expertise required to use them. Which of these approaches is most applicable to a given acute or subacute setting will vary with the volume of patients with a disorder of consciousness and the available resources. Importantly, lack of consciousness in the acute setting should not be used to justify the withdrawal of care or denial of rehabilitation services.

Seizure Management in the Intensive Care Unit

Purpose of this review

This review presents current therapy for seizures in the intensive care unit. The reader is provided with recent evidence regarding the use of EEG in determining treatment for acute seizures. Proposed treatment approaches for seizures and status epilepticus are provided. Controversies and complexity of selecting treatments are discussed.

Recent findings

Critical Care EEG Monitoring Research Consortium analyzed the association of periodic and rhythmic electroencephalographic patterns with seizures and found that lateralized and generalized periodic discharges and lateralized rhythmic delta were associated with increased seizure risk. Applications using modified EEG techniques have demonstrated more rapid feedback to the ICU than was previously possible.

Summary

Accurate diagnosis and efficient treatment of seizures in the ICU is challenging due to patient factors, complexities of antiepileptic drug therapy, and the required expertise for EEG interpretation. Selection of optimally effective therapy for seizures or status epilepticus depends on multiple factors, making collaboration between neurophysiologists and the ICU team of paramount importance.

Can occurrence of convulsive status epilepticus during video telemetry be predicted? Observations from an epilepsy monitoring unit

PURPOSE

The objective of the study was to evaluate the frequency, clinical, and video-electroencephalographic (VEEG) predictors of convlusive status epilepticus (CSE) in the epilepsy-monitoring unit (EMU).

METHODS

The data of all patients who had CSE in our EMU between 2008 and 2017 were reviewed. For each case, two age- and diagnosis-matched subjects who underwent VEEG and did not develop CSE were taken as internal controls. Electro-clinical data of both the groups were compared. Predictors of CSE were assessed using logistic regression analysis.

RESULTS

Out of 11,188 video-telemetries were conducted between 2008-17, forty-three events of CSE (0.38%) were recorded. On comparisons with 86 internal controls no differences were apparent on prevalence of cognitive impairment, structural lesion, number of baseline anti-seizure medications (ASM), ASM taper schedule, ictal patterns, and duration of VEEG monitoring. Inter-ictal rhythmic periodic patterns had significantly higher prevalence in cases (p = 0.028). Logistic regression analysis revealed that odds of CSE were higher with past history of SE [p = 0.008; adjusted odds ratio (OR) = 5.48 (confidence intervals {CI} 1.55-19.28)] and in presence of rhythmic spike and wave discharges [p = 0.016, OR = 33.518(CI = 1.93-581.4)]; the odds were lower if the first two seizures recorded did not evolve into CSE [p = 0.009, OR = 0.247 (CI = 0.08-0.70)] and if there was prior history of daily seizures [p = 0.02, OR = 0.250 (CI = 0.07-0.84)].

CONCLUSION

CSE is a rare yet important adverse event in EMU. Clinical predictors are more relevant in comparison to EEG variables. Extent of ASM withdrawal may not directly account for occurrence of CSE; factors inherent to a patient's epilepsy are deterministic.

Epidemiology, management and outcome of status epilepticus in adults: single-center Italian survey

The official variations of status epilepticus (SE) International League Against Epilepsy (ILAE, 2015) diagnostic criteria and the non-convulsive SE (NCSE) Salzburg Consensus Criteria (2013), impose the collection of updated population-based epidemiological Italian data. In this study, we aimed at evaluating (a) the frequency of SE in our hospital adopting the new ILAE 2015 SE diagnostic criteria and NCSE Salzburg Consensus Criteria, (b) the frequency of adherence to current treatment guidelines for SE and their relationship with patients' outcome, and (c) reliability of standardized prognostic scales (Status Epilepticus Severity Score-STESS-and modified STESS) for short-term outcome prediction in the setting of the newest diagnostic criteria for SE and NCSE. Detailed clinical and electrophysiological data collected in a 1-year retrospective hospital-based single-center survey on SE at Parma Hospital, Northern Italy are provided. Non-adherence to current treatment guidelines was recorded in around 50% cases, but no relation to outcome was appreciated. Mortality in our cohort increased from 30 to 50% when follow-up was extended to 30 days. STESS score was strongly correlated with short-term mortality risk (OR 18.9, 2.2-163.5, CI), and we confirm its role as easy-to-use tool for outcome evaluation also when the new ILAE diagnostic SE criteria are applied.

Are Triphasic Waves Different From Generalized Spike-Wave Discharges?

SUMMARY

Generalized periodic discharges with triphasic morphology were previously referred to as triphasic waves but have now been subsumed into the ACNS classification as generalized periodic discharges. Although triphasic waves and generalized spike-wave complexes may resemble each other and hence may be incorrectly identified in comatose critically ill patients, many authors believe that there are different entities, with definable morphologic and clinical differences attributable to each waveform. The occurrence of both patterns in the same patient is extremely rare with only a single prior case report. Here the authors report a patient with typical triphasic waves and generalized spike-wave complexes and highlight the morphologic and EEG differences between the two patterns. The occurrence of both waveforms in the same EEG recording supports the notion of different cerebral generators and pathways, further differentiating rather than merging these morphologies.

Spectrum and Evolution of EEG Changes in Anti-NMDAR Encephalitis

Background:

NMDA receptor encephalitis (NMDARE) is the most prevalent autoimmune encephalitis and it encompasses a spectrum of clinical features. It is most commonly associated with alteration in consciousness, seizures, neuro-psychiatric symptoms, and movement disorders. Electroencephalography (EEG) plays a vital role and can give clues to diagnosis in a subset of patients.

Methods:

We retrospectively characterized the clinical and EEG findings in our NMDARE patients (n = 48). A total of 131 EEGs were analyzed.

Results:

We observed that patients with seizures had a younger age of onset (p < 0.001). The most common EEG pattern that was noted was diffuse slowing (n = 20) followed by generalized rhythmic delta activity (n = 9), focal spikes and slowing (n = 8 each). Delta brush pattern was seen in only 3 EEGs. Focal ictal rhythms were seen in 3 EEGs. There was no significant difference in outcomes such as seizure recurrence, modified Rankin score (mRS) at follow up/discharge or relapse between groups of patients who had EEG abnormalities in the first EEG and with those who did not.

Conclusions:

NMDARE has varied EEG findings, most of them being non-specific. When combined with clinical presentation, EEG is a useful tool in the diagnosis and management of NMDARE.

Therapies to Restore Consciousness in Patients with Severe Brain Injuries: A Gap Analysis and Future Directions

Background/Objective

For patients with disorders of consciousness (DoC) and their families, the search for new therapies has been a source of hope and frustration. Almost all clinical trials in patients with DoC have been limited by small sample sizes, lack of placebo groups, and use of heterogeneous outcome measures. As a result, few therapies have strong evidence to support their use; amantadine is the only therapy recommended by current clinical guidelines, specifically for patients with DoC caused by severe traumatic brain injury. To foster and advance development of consciousness-promoting therapies for patients with DoC, the Curing Coma Campaign convened a Coma Science Work Group to perform a gap analysis.

Methods

We consider five classes of therapies: (1) pharmacologic; (2) electromagnetic; (3) mechanical; (4) sensory; and (5) regenerative. For each class of therapy, we summarize the state of the science, identify gaps in knowledge, and suggest future directions for therapy development.

Results

Knowledge gaps in all five therapeutic classes can be attributed to the lack of: (1) a unifying conceptual framework for evaluating therapeutic mechanisms of action; (2) large-scale randomized controlled trials; and (3) pharmacodynamic biomarkers that measure subclinical therapeutic effects in early-phase trials. To address these gaps, we propose a precision medicine approach in which clinical trials selectively enroll patients based upon their physiological receptivity to targeted therapies, and therapeutic effects are measured by complementary behavioral, neuroimaging, and electrophysiologic endpoints.

Conclusions

This personalized approach can be realized through rigorous clinical trial design and international collaboration, both of which will be essential for advancing the development of new therapies and ultimately improving the lives of patients with DoC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12028-021-01227-y.

Clinical Correlates of Electroencephalographic Patterns in Critically Ill Patients

OBJECTIVE

The objective of this study was to determine the frequency and clinical correlates of different electroencephalographic patterns and their association with clinical outcomes in critically ill patients.

SUBJECTS AND METHODS

This retrospective cross-sectional study was performed in the Neurology Department of King Fahd Hospital of the University, Kingdom of Saudi Arabia and involved a review and analysis of medical records pertaining to 179 intensive care unit patients who underwent electroencephalography (EEG) in the June to November 2018 period.

RESULTS

Among the different etiologies, presence of spike and wave or sharp wave (SWs) was associated with encephalitis (P = .01) and large artery stroke (P = .01), whereas markedly attenuated EEG activity (p = .04) and burst suppression (P = .01) were associated with large artery stroke and hypoxic ischemic encephalopathy (HIE), respectively. Generalized theta activity (P = .01) was significantly found in patients of septic encephalopathy, while generalized delta activity (P = .02) and asymmetrical background (P = .04) were significantly associated with traumatic brain injury. Presence of periodic discharges in EEG was significantly associated with more adverse clinical outcomes (P = .001), whereas rhythmic delta activity (RDA) (P = .03), persistent focal slow wave activity (P = .01), and asymmetric background (P = .002) were found in patients who were discharged from hospital with sequelae of current illness.

CONCLUSION

Certain EEG patterns are associated with particular underlying etiologies like SWs for encephalitis, markedly attenuated EEG activity and burst suppression with large artery stroke and HIE, respectively. Whereas few EEG patterns, including periodic discharges, RDA, persistent focal slow wave activity have some prognostic value in critically ill patients. However, they cannot be used as markers for prognostic assessment of patients without considering other clinical and diagnostic variables. Further larger prospective studies with continuous EEG monitoring with control of confounding factors are needed.

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.

Evaluation and Management of Seizures and Status Epilepticus

Seizures are frequently triggered by an inciting event and result from uninhibited excitation and/or decreased inhibition of a pool of neurons. If physiologic seizure abortive mechanisms fail, the ensuing unrestrained synchronization of neurons-status epilepticus-can be life-threatening and is associated with the potential for marked morbidity in survivors and high medical care costs. Prognosis is intimately related to etiology and its response to therapeutic measures. Timely implementation of pharmacologic therapy while concurrently performing a stepwise workup for etiology are paramount. Neurodiagnostic testing should guide titration of pharmacologic therapies, and help determine if there is a role for immune modulation.

Nonconvulsive Status Epilepticus in Metabolic Encephalopathy in Indonesia Referral Hospital

Background

Nonconvulsive status epilepticus (NCSE) is often underdiagnosed in patients with metabolic encephalopathy (ME). The diagnosis of ME should be made specifically to recognize the underlying etiology. Delay in seizure identification and making a diagnosis of NCSE contributed to the poor outcome.

Objective

This study aimed to find the incidence and outcome of NCSE in patients with ME.

Methods and Material

This was an observational prospective cross-sectional study in patients with ME in emergency and critical care units in Cipto Mangunkusumo General Hospital. The diagnosis of NCSE was based on EEG using Salzburg Criteria for Nonconvulsive Status Epilepticus (SCNC). The outcome was assessed within 30 days after the NCSE diagnosis has been made.

Results

A total of 50 patients with ME were involved in this study. NCSE was confirmed in 32 subjects (64%). The most common etiology of ME was sepsis (58%). The mortality rate in the NCSE and non-NCSE group was 40.6% vs 44.4%. Multiple aetiologies were risk factors to poor outcome in the NCSE group.

Conclusions

The incidence of NCSE among patients with ME at our hospital was high. Despite the anti-epileptic treatment of the NCSE group, the underlying cause of ME is still the main factor that affected the outcome. Therefore, aggressive treatment of anti-epileptic drug (AED) should be very carefully considered knowing the possible side-effect that might worsen the outcome of patients with ME.

Etiology of Burst Suppression EEG Patterns

Burst-suppression electroencephalography (EEG) patterns of electrical activity, characterized by intermittent high-power broad-spectrum oscillations alternating with isoelectricity, have long been observed in the human brain during general anesthesia, hypothermia, coma and early infantile encephalopathy. Recently, commonalities between conditions associated with burst-suppression patterns have led to new insights into the origin of burst-suppression EEG patterns, their effects on the brain, and their use as a therapeutic tool for protection against deleterious neural states. These insights have been further supported by advances in mechanistic modeling of burst suppression. In this Perspective, we review the origins of burst-suppression patterns and use recent insights to weigh evidence in the controversy regarding the extent to which burst-suppression patterns observed during profound anesthetic-induced brain inactivation are associated with adverse clinical outcomes. Whether the clinical intent is to avoid or maintain the brain in a state producing burst-suppression patterns, monitoring and controlling neural activity presents a technical challenge. We discuss recent advances that enable monitoring and control of burst suppression.

Pearls and Pitfalls of Introducing Ketogenic Diet in Adult Status Epilepticus: A Practical Guide for the Intensivist

Background: Status epilepticus (SE) carries an exceedingly high mortality and morbidity, often warranting an aggressive therapeutic approach. Recently, the implementation of a ketogenic diet (KD) in adults with refractory and super-refractory SE has been shown to be feasible and effective. Methods: We describe our experience, including the challenges of achieving and maintaining ketosis, in an adult with new onset refractory status epilepticus (NORSE). Case Vignette: A previously healthy 29-year-old woman was admitted with cryptogenic NORSE following a febrile illness; course was complicated by prolonged super-refractory SE. A comprehensive work-up was notable only for mild cerebral spinal fluid (CSF) pleocytosis, elevated nonspecific serum inflammatory markers, and edematous hippocampi with associated diffusion restriction on magnetic resonance imaging (MRI). Repeat CSF testing was normal and serial MRIs demonstrated resolution of edema and diffusion restriction with progressive hippocampal and diffuse atrophy. She required prolonged therapeutic coma with high anesthetic infusion rates, 16 antiseizure drug (ASD) trials, empiric immunosuppression and partial bilateral oophorectomy. Enteral ketogenic formula was started on hospital day 28. However, sustained beta-hydroxybutyrate levels >2 mmol/L were only achieved 37 days later following a comprehensive adjustment of the care plan. KD was challenging to maintain in the intensive care unit (ICU) and was discontinued due to poor nutritional state and pressure ulcers. KD was restarted again in a non-ICU unit facilitating ASD tapering without re-emergence of SE. Discussion: There are inconspicuous carbohydrates in commonly administered medications for SE including antibiotics, electrolyte repletion formulations, different preparations of the same drug (i.e., parenteral, tablet, or suspension) and even solutions used for oral care-all challenging the use of KD in the hospitalized patient. Tailoring comprehensive care and awareness of possible complications of KD are important for the successful implementation and maintenance of ketosis.

Will MRI replace the EEG for the diagnosis of nonconvulsive status epilepticus, especially focal?

Magnetic resonance imaging (MRI) can now be used to diagnose or to provide confirmation of focal nonconvulsive status epilepticus (NCSE). Approximately half of patients with status epilepticus (SE) have signal changes. MRI can also aid in the differential diagnosis with generalized NCSE when there is a clinical or EEG doubt, e.g. with metabolic/toxic encephalopathies or Creutzfeldt-Jakob disease. With the development of stroke centers, MRI is available 24h/24 in most hospitals. MRI has a higher spatial resolution than electroencephalography (EEG). MRI with hyperintense lesions on FLAIR and DWI provides information related to brain activity over a longer period of time than a standard EEG where only controversial patterns like lateralized periodic discharges (LPDs) may be recorded. MRI may help identify the ictal nature of LPDs. The interpretation of EEG tracings is not easy, with numerous pitfalls and artifacts. Continuous video-EEGs require a specialized neurophysiology unit. The learning curve for MRI is better than for EEG. It is now easy to transfer MRI to a platform with expertise. MRI is more accessible than single photon emission computed tomography (SPECT) or positron emission tomography (PET). For the future, it is more interesting to develop a strategy with MRI than SPECT or PET for the diagnosis of NCSE. With the development of artificial intelligence, MRI has the potential to transform the diagnosis of SE. Additional MRI criteria beyond the classical clinical/EEG criteria of NCSE (rhythmic versus periodic, spatiotemporal evolution of the pattern…) should now be systematically added. However, it is more complicated to move patients to MRI than to perform an EEG in the intensive care unit, and at this time, we do not know how long the signal changes persist after the end of the SE. Studies with MRI at fixed intervals and after SE cessation are necessary.

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.

Role of EEG in Predicting Outcome of Hepatic Encephalopathy Patients

Introduction: A retrospective analysis of 151 patients with hepatic encephalopathy (HE) who were admitted to the liver intensive care unit (LICU) and liver transplant intensive care unit (TICU) and underwent electroencephalographic (EEG) testing was performed. We describe a method of grading the EEGs of patients with HE and predicting their subsequent outcomes. Methods: All liver failure patients with HE who underwent routine EEG testing in the LICU or TICU between October 1, 2018 and March 31, 2019, at the Institute of Liver and Biliary Sciences (ILBS) were enrolled in this analysis. The data was analyzed using Statistical Package for the Social Sciences (SPSS). The patients were divided into four grades of HE based on established EEG criteria (HE-EEG). Results: One hundred fifty-one patients [127 Male (84%), 24 Female (16%)] with HE who underwent EEG testing were enrolled. Ages ranged from 3 to 74 years, with a mean age of 48.34 years and median interquartile range (IQR) of 49 years (38-60 years). Ninety-five patients (62.9%) had grade 1 and 2 hepatic encephalopathy, with a statistically significant, worse outcome seen in grades 3 and 4 HE patients. Seizures were seen in 30 (20.1%) of HE patients. Fifteen of 30 patients with seizures (50%) were in the ethanol and nonalcoholic steatohepatitis (NASH) groups. Forty-four of 59 (74.6%) MRIs and 35 of 60 (58.3%) CTs demonstrated some type of brain abnormality in these patients. Imaging abnormalities and the presence of seizures did not contribute to a statistically worse outcome. Conclusion: EEG has an important role in predicting the outcome and prognosis in HE. Patients with grade 3 or 4 HE-EEG, or with progressive worsening of HE-EEG grading were associated with the highest mortality rates.

Status Epilepticus: Work-Up and Management in Adults

Status epilepticus is one of the most common neurological emergencies and is likely to have increasing prevalence in coming years given an aging "baby boomer" population in the United States. Because status epilepticus is associated with significant morbidity and mortality, identification and treatment are paramount. Care should be taken to exclude nonorganic mimics and infectious and metabolic causes. Status epilepticus can be classified into stages with associated recommendations for escalation in therapy, increasing from push-dose benzodiazepines to continuous anesthetic infusions and other nontraditional therapies. Concurrent electroencephalogram monitoring helps to identify, localize, and assess resolution of ictal patterns alongside antiseizure drug administration. A protocol is proposed for the management of status epilepticus in a step-wise fashion.

Status Epilepticus: Definition, Classification, Pathophysiology, and Epidemiology

Status epilepticus (SE) is the state of continuous or repetitive seizures, which can occur with or without convulsions. Evolving definitions of SE take into account the concept that neuronal injury may occur at different times in different types of SE.SE that does not respond to initial treatment may become refractory or even super-refractory. Nonconvulsive SE is increasingly recognized in comatose patients in critical care units, with the growing use of continuous electroencephalogram monitoring. SE is a neurologic emergency that carries a high risk of mortality and morbidity.

Brain Oscillatory Activity during Tactile Stimulation Correlates with Cortical Thickness of Intact Areas and Predicts Outcome in Post-Traumatic Comatose Patients

In this study, we have reported a correlation between structural brain changes and electroencephalography (EEG) in response to tactile stimulation in ten comatose patients after severe traumatic brain injury (TBI). Structural morphometry showed a decrease in whole-brain cortical thickness, cortical gray matter volume, and subcortical structures in ten comatose patients compared to fifteen healthy controls. The observed decrease in gray matter volume indicated brain atrophy in coma patients induced by TBI. In resting-state EEG, the power of slow-wave activity was significantly higher (2–6 Hz), and the power of alpha and beta rhythms was lower in coma patients than in controls. During tactile stimulation, coma patients’ theta rhythm power significantly decreased compared to that in the resting state. This decrease was not observed in the control group and correlated positively with better coma outcome and the volume of whole-brain gray matter, the right putamen, and the insula. It correlated negatively with the volume of damaged brain tissue. During tactile stimulation, an increase in beta rhythm power correlated with the thickness of patients’ somatosensory cortex. Our results showed that slow-wave desynchronization, as a nonspecific response to tactile stimulation, may serve as a sensitive index of coma outcome and morphometric changes after brain injury.

Nonconvulsive status epilepticus after surgery for ruptured intracranial aneurysms: Incidence, associated factors, and impact on the outcome

OBJECTIVE

To evaluate the incidence of nonconvulsive status epilepticus (NCSE) after surgery for ruptured intracranial aneurysms, to define factors associated with this complication, and to determine its impact on the outcome.

PATIENTS AND METHODS

Clinical and neurophysiological data of 66 patients with aneurysmal subarachnoid hemorrhage (aSAH) who underwent continuous EEG (cEEG) monitoring after microsurgical clipping (53 cases) or endovascular coiling (13 cases) of the ruptured aneurysm were analyzed retrospectively. The diagnosis of NCSE was based on the American Clinical Neurophysiology Society and Salzburg Consensus criteria.

RESULTS

NCSE was revealed in 10 patients (15 %), all of whom underwent craniotomy and aneurysm clipping. In comparison to the subgroup without NCSE, among those who were diagnosed with this complication there was a significantly greater proportion of men (70 % vs. 34 %; P = 0.041), cases with the Glasgow Coma Scale score at admission < 13 (90 % vs. 36 %; P = 0.004), the Hunt and Hess aSAH grades 3-5 (90 % vs. 45 %; P = 0.013), and hydrocephalus (70 % vs. 29 %; P = 0.044). In addition, they required a significantly longer hospital stay (medians, 62.5 vs. 39.5 days; P = 0.015) and showed trend for the lower rate of favorable disability outcomes (20 % vs. 54 %; P = 0.084).

CONCLUSIONS

NCSE is encountered rather often after the microsurgical clipping of ruptured intracranial aneurysms, especially in severely disabled patients with high-grade aSAH and/or associated hydrocpephalus, and may significantly affect the clinical course and prolong recovery. cEEG monitoring may be helpful for timely diagnosis and treatment of this complication.

[Electroencephalography in acute stroke]

OBJECTIVE

To determine the incidence of non-convulsive status epilepticus, epileptiform activity, rhythmic and periodic patterns in patients with acute stroke.

MATERIAL AND METHOD

An analysis of electroencephalography (EEG) in 86 stroke patients in the neurointensive care unit of the tertiary medical center was performed. Criteria for starting EEG recording were epileptic seizures or clinical suspicion of uncontrolled epileptic status. The ictal-interictal continuum biomarkers and the diagnostic value of EEG for prediction of survival and recovery were assessed.

RESULTS

Pathological changes on EEG were recorded in 84% of patients. These patients showed the absence of the dominant occipital rhythm (66%) and hemispheric slowing (42%). Diffuse slowing below the theta range was observed in 41% of patients. EEG reactivity was absent in 20%. Sporadic epileptiform discharges were recorded in 36% of patients and rhythmic and periodic patterns in 26%. Reliable predictors of the unfavorable outcome were the absence of dominant occipital rhythm, lack of reactivity, and low amplitude of the background EEG. No association between the recording of epileptiform activity and the probability of death was shown.

CONCLUSION

The most useful EEG biomarkers for predicting survival are amplitude, dominant frequency of background EEG activity and reactivity to external stimulus. Sporadic epileptiform discharges, rhythmic, and periodic patterns are not mandatory associated with a negative prognosis in stroke patients.

Continuous video electroencephalogram for herpes simplex encephalitis: a case report and literature review

Background

Electroencephalogram (EEG) is an important tool for the diagnosis of herpes simplex virus encephalitis (HSE). However, the diagnosis of non-convulsive status epilepticus (NCSE) in HSE is challenging without the help of continuous video EEG (CVEEG), and whether EEG is a predictor of outcome remains controversial.

Case presentation

A 63-year-old woman presented with a 5 day history of fever, coma and seizures. Results of EEG, magnetic resonance imaging and polymerase chain reaction (PCR) in cerebrospinal fluid (CSF) were suggestive of herpes simplex encephalitis-1 (HSE-1). Preliminary EEG showed periodic discharges at the prefrontal and temporal lobes, which were particularly synchronized with intermittent lip smacking movements, and the discharges were terminated by diazepam. After 2-week treatment with acyclovir, high-dose hormone pulse therapy and high-dose immunoglobulin therapy, the CSF was improved, but the patient’s consciousness became worsen, consistent with the diffuse slow waves in the delta range and low voltage of EEG activity. In the following 1 month, the patient had non-responsiveness to pain and sound as shown by CVEEG with diffuse slow waves. Sometimes paroxysmal very slow waves (0.5–1 Hz) were synchronized with intermittent paroxysmal eye movements, pupil abnormality, and sweating in the frontal area. After 2 months of treatment, the EEG abnormalities improved to have alpha rhythm.

Conclusion

The CVEEG not only helps identify NCSE but can also be used to monitor HSE progression.

Clinical, Electroencephalographic Features and Prognostic Factors of Cefepime-Induced Neurotoxicity: A Retrospective Study

BACKGROUND

The incidence of cefepime-induced neurotoxicity (CIN) has been previously underestimated, and there have only been sporadic reports from critical neurological settings. The present study aimed to investigate the potential factors associated with disease development, electroencephalography (EEG) sub-classification, and outcome measures.

METHODS

The 10-year medical records of patients who underwent EEG between 2007 and 2016 at a tertiary medical center in Taiwan, and developed encephalopathy after cefepime therapy were retrospectively reviewed. Age- and sex-matched controls were included for further analysis. Demographic data, the occurrence of clinical seizures, non-convulsive status epilepticus (NCSE), use of antiepileptic drugs (AEDs), receiving maintenance or urgent hemodialysis, EEG findings, and functional outcomes were analyzed. The Chi-square test and a logistic regression model were applied to survey significant prognostic factors relating to mortality.

RESULTS

A total of 42 CIN patients were identified, including 25 patients from wards and 17 from intensive care units; their mean age was 75.8 ± 11.8 years. Twenty-one patients (50%) had chronic kidney disease, and 18 (43%) had acute kidney injury. Among these patients, 32 (76%) received appropriate cefepime dose adjustment. Three patients had a normal renal function at the time of CIN onset. The logistic regression model suggested that maintenance hemodialysis and longer duration of cefepime use were independently associated with the development of CIN, with odds ratios of 3.8 and 1.2, respectively. NCSE was frequently noted in the CIN patients (64%). Generalized periodic discharge with or without triphasic morphology was the most common EEG pattern (38%), followed by generalized rhythmic delta activity and generalized spike-and-waves. AEDs were administered to 86% of the patients. A total of 17 patients (40%) did not survive to hospital discharge. Adequate cefepime dose adjustment and early cefepime discontinuation led to a better prognosis.

CONCLUSIONS

CIN was associated with high mortality and morbidity rates. Neurotoxic symptoms could still occur when the cefepime dose was adjusted, or in patients with normal renal function. Patients with maintenance hemodialysis or a longer duration of cefepime therapy tended to develop CIN. Early recognition of abnormal EEG findings allowed for the withdrawal of the offending agent, resulting in clinical improvements and a better prognosis at discharge.

Recommandations Formalisées d’Experts SRLF/SFMU : Prise en charge des états de mal épileptiques en préhospitalier, en structure d’urgence et en réanimation dans les 48 premières heures (A l’exclusion du nouveau-né et du nourrisson)

La Société de réanimation de langue française et la Société française de médecine d’urgence ont décidé d’élaborer de nouvelles recommandations sur la prise en charge de l’état mal épileptique (EME) avec l’ambition de répondre le plus possible aux nombreuses questions pratiques que soulèvent les EME : diagnostic, enquête étiologique, traitement non spécifique et spécifique. Vingt-cinq experts ont analysé la littérature scientifique et formulé des recommandations selon la méthodologie GRADE. Les experts se sont accordés sur 96 recommandations. Les recommandations avec le niveau de preuve le plus fort ne concernent que l’EME tonico-clonique généralisé (EMTCG) : l’usage des benzodiazépines en première ligne (clonazépam en intraveineux direct ou midazolam en intramusculaire) est recommandé, répété 5 min après la première injection (à l’exception du midazolam) en cas de persistance clinique. En cas de persistance 5 min après cette seconde injection, il est proposé d’administrer la seconde ligne thérapeutique : valproate de sodium, (fos-)phénytoïne, phénobarbital ou lévétiracétam. La persistance avérée de convulsions 30 min après le début de l’administration du traitement de deuxième ligne signe l’EMETCG réfractaire. Il est alors proposé de recourir à un coma thérapeutique au moyen d’un agent anesthésique intraveineux de type midazolam ou propofol. Des recommandations spécifiques à l’enfant et aux autres EME sont aussi énoncées.

Prevalence of electrographic seizure in dogs and cats undergoing electroencephalography and clinical characteristics and outcome for dogs and cats with and without electrographic seizure: 104 cases (2009-2015)

OBJECTIVE

To determine the prevalence of electrographic seizure (ES) and electrographic status epilepticus (ESE) in dogs and cats that underwent electroencephalography (EEG) because of suspected seizure activity and to characterize the clinical characteristics, risk factors, and in-hospital mortality rates for dogs and cats with ES or ESE.

DESIGN

Retrospective case series.

ANIMALS

89 dogs and 15 cats.

PROCEDURES

Medical records of dogs and cats that underwent EEG at a veterinary neurology service between May 2009 and April 2015 were reviewed. Electrographic seizure was defined as ictal discharges that evolved in frequency, duration, or morphology and lasted at least 10 seconds, and ESE was defined as ES that lasted ≥ 10 minutes. Patient signalment and history, physical and neurologic examination findings, diagnostic test results, and outcome were compared between patients with and without ES or ESE.

RESULTS

Among the 104 patients, ES and ESE were diagnosed in 21 (20%) and 12 (12%), respectively. Seventeen (81%) patients with ES had no or only subtle signs of seizure activity. The in-hospital mortality rate was 48% and 50% for patients with ES and ESE, respectively, compared with 19% for patients without ES or ESE. Risk factors for ES and ESE included young age, overt seizure activity within 8 hours before EEG, and history of cluster seizures.

CONCLUSIONS AND CLINICAL REVELANCE

Results indicated that ES and ESE were fairly common in dogs and cats with suspected seizure activity and affected patients often had only subtle clinical signs. Therefore, EEG is necessary to detect patients with ES and ESE.