Diagnosis Of Nonconvulsive Status Epilepticus Research Articles

EEG and acute confusional state at the emergency department

ObjectivesAcute confusional state (ACS) is a common cause of admission to the emergency department (ED). It can be related to numerous etiologies. Electroencephalography (EEG) can show specific abnormalities in cases of non-convulsive status epilepticus (NCSE), or metabolic or toxic encephalopathy. However, up to 80% of patients with a final diagnosis of NCSE have an ACS initially attributed to another cause. The exact place of EEG in the diagnostic work-up remains unclear. MethodsData of consecutive patients admitted to the ED for an ACS in a two-year period and who were referred for an EEG were collected. The initial working diagnosis was based on medical history, clinical, biological and imaging investigations allowing classification into four diagnostic categories. Comparison to the final diagnosis was performed after EEG recordings (and sometimes additional tests) were performed, which allowed the reclassification of some patients from one category to another. ResultsSeventy-five patients (mean age: 71.1 years) were included with the following suspected diagnoses: seizures for 8 (11%), encephalopathy for 14 (19%), other cause for 34 (45%) and unknown for 19 (25%). EEG was recorded after a mean of 1.5 days after symptom onset, and resulted in the reclassification of patients as follows: seizure for 15 (20%), encephalopathy for 15 (20%), other cause for 29 (39%) and unknown cause for 16 (21%). Moreover, ongoing epileptic activity (NCSE or seizure) and interictal epileptiform activity were found in eight (11%) patients initially diagnosed in another category. DiscussionIn our cohort, EEG was a key examination in the management strategy of ACS in 11% of patients admitted to the ED. It resulted in a diagnosis of epilepsy in these patients admitted with unusual confounding presentations.

The role of EEG and neuroimaging in the diagnosis of non-convulsive status epilepticus in Subacute Encephalopathy with Seizures in Alcoholics (SESA syndrome): a case report and overview of the literature.

Epileptic seizures are frequently associated with liver dysfunction and alcoholism. Subacute encephalopathy with seizures in chronic alcoholics (SESA) is an underrecognized condition with peculiar clinical, EEG and neuroradiological features.We report the case of a 58-year-old man with previous alcohol use disorder (AUD) and acute-on chronic liver failure on alcohol-related cirrhosis, referred for urgent Orthotopic Liver Transplantation evaluation. The patient presented with delirium, aphasia and progressive deterioration of consciousness leading to intensive care unit admission. EEG showed slow activity with superimposed lateralized periodic discharges (LPDs) over the left temporo-occipital regions and ictal discharges with focal motor phenomena, consistent with focal status epilepticus. Antiseizure treatment with lacosamide and levetiracetam was administered with progressive improvement of consciousness.Brain MRI disclosed T2/FLAIR areas of hyperintensity in the left pulvinar and T2/FLAIR hyperintensity with corresponding DWI hyperintensity in the left hippocampal cortex, suggestive of post/peri-ictal excitotoxic changes with anatomical correspondence to focal LPDs distribution. SWI demonstrated decreased prominence of cortical veins in the left temporo-occipital region consistent with increased venous blood oxygenation in compensatory hyperperfusion.In conclusion, SESA should be suspected in the differential diagnosis of patients with AUD presenting with focal neurological deficits, seizures and focal EEG abnormalities. In this context, EEG and brain MRI represent useful tools with both diagnostic and prognostic value.

Non-convulsive status epilepticus possibly induced by a rapid correction of severe hyperkalemia: a case report and literature review

BackgroundPatients with chronic kidney disease frequently develop neurological complications including confusion and altered consciousness. Non-convulsive status epilepticus, which is characterized by a change in behavior and/or mental process accompanied by epileptiform discharges on electroencephalogram in the absence of convulsive seizures, is one of the overlooked causes of altered consciousness. The incidence and precise pathophysiological mechanism of non-convulsive status epilepticus in patients with kidney disease, and especially in patients with electrolyte disturbances, remains unknown. We recently treated an older patient with chronic kidney disease and severe hyperkalemia in whom non-convulsive status epilepticus developed following a correction of severe hyperkalemia.Case presentationAn 82-year-old male was admitted to our hospital at midnight because of weakness of all four limbs (Day 1). He underwent urgent hemodialysis for severe hyperkalemia (9.84 mEq/L) and his serum potassium concentration decreased to 4.97 mEq/L. He regained full consciousness and his limb weakness improved on the morning of Day 2, but he became confused in the evening. Electroencephalogram revealed repeated low-voltage ictal discharges in the right occipital region and a diagnosis of non-convulsive status epilepticus was made. Following medication with fosphenytoin and phenytoin, the patient became fully alert and orientated on Day 8.ConclusionWe speculate that a rapid correction of hyperkalemia was the possible cause of non-convulsive status epilepticus development. To our knowledge, this is the first report of non-convulsive status epilepticus from a potassium abnormality. We described a case of this condition in detail and summarized 78 previous case reports of non-convulsive status epilepticus with kidney disease or electrolyte disturbances.

Nonconvulsive status epilepticus characteristics in glioma patients: a retrospective study

PurposeEpilepsy is a common complication of gliomas. The diagnosis of nonconvulsive status epilepticus (NCSE) is challenging because it causes impaired consciousness and mimics glioma progression. NCSE complication rate in the general brain tumor patient population is approximately 2%. However, there are no reports focusing on NCSE in glioma patient population. This study aimed to reveal the epidemiology and features of NCSE in glioma patients to enable appropriate diagnosis.MethodsWe enrolled 108 consecutive glioma patients (45 female, 63 male) who underwent their first surgery between April 2013 and May 2019 at our institution. We retrospectively investigated glioma patients diagnosed with tumor-related epilepsy (TRE) or NCSE to explore disease frequency of TRE/NCSE and patient background. NCSE treatment approaches and Karnofsky Performance Status Scale (KPS) changes following NCSE were surveyed. NCSE diagnosis was confirmed using the modified Salzburg Consensus Criteria (mSCC).ResultsSixty-one out of 108 glioma patients experienced TRE (56%), and five (4.6%) were diagnosed with NCSE (2 female, 3 male; mean age, 57 years old; WHO grade II 1, grade III 2, grade IV 2). All NCSE cases were controlled by stage 2 status epilepticus treatment as recommended in the Clinical Practice Guidelines for Epilepsy by the Japan Epilepsy Society. The KPS score significantly decreased after NCSE.ConclusionHigher prevalence of NCSE in glioma patients was observed. The KPS score significantly decreased after NCSE. Actively taking electroencephalograms analyzed by mSCC may facilitate accurate NCSE diagnosis and improve the activities of daily living in glioma patients.

Status Epilepticus: Convulsive and Nonconvulsive

Status epilepticus(SE)is common, particularly among neurological emergency physicians. SE includes convulsive SE(CSE)and nonconvulsive SE(NCSE). Recently, the number of elderly patients with status epilepticus has increased. Most patients were diagnosed with NCSE. Prolonged SE often impairs neuronal function and is sometimes life threatening. Prompt diagnosis of SE and treatment initiation are essential for good outcomes. However, an accurate diagnosis of NCSE is difficult because the clinical symptoms of NCSE may vary, and electroencephalography may show various characteristics. Recent advances in the diagnosis and treatment of SE have been reported, particularly with regard to electroencephalography(EEG)and newly available drugs.

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.

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

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. We searched continuous EEG monitoring (cEEG) recordings to identify patients of NCSE. An artifact-free cEEG epoch of continuous 60s 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. 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 ± 19.1years (range, 12-72years), including 24 males (50%) and 24 females (50%). When the spectral power of 60s equaled to 11.30 μV2 for predicting impairment of consciousness, (sensitivity, specificity) = (0.979, 0.625). When the spectral power of 60s 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 12months. 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. 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.

Salzburg consensus criteria are associated with long-term outcome after non-convulsive status epilepticus

Purpose: To investigate differences in long-term survival and short-term neurological deficits in adult patients fulfilling either sub-criterion of the Salzburg Consensus Criteria (SC) for non-convulsive status epilepticus (NCSE).Methods: We retrospectively identified a cohort of patients with first-time NCSE epilepticus at Odense University Hospital from 2014 to 2017. Results of electroencephalograms at admission were dichotomized according to the SC (more than 25 epileptiform discharges/10 s was defined as the fast criterion), and groups were compared statistically through survival analysis and in a logistic regression model adjusting for established prognostic determinants in status epilepticus. Secondary outcomes were the associations between SC and neurological deficits at discharge.Results: One-hundred and six patients fulfilled the SC and were included in the main analysis. In addition, 27 patients had possible NCSE. The fast criterion was significantly associated with decreased mortality 2 years following NCSE (OR 0.31, 95% CI 0.11–0.85, p = 0.039) in a logistic regression analysis after correction for age, etiology, semiology and comorbidity. None of the individual subcomponents of the slow criterion could explain the difference in survival in an exploratory analysis. Functional outcome did not differ between patients fulfilling fast and slow criteria. Patients with a clinical diagnosis of NCSE not fulfilling the SC more often had non-refractory NCSE and a more favorable functional outcome.Conclusion: The fast diagnostic criterion for NCSE was identified as a new, independent variable associated with long-term survival after NCSE. The results may allow prognostication in patients with NCSE at the time of diagnosis, which could guide decision-making in the clinical setting.

Nonconvulsive status epilepticus (NCSE)

Nonconvulsive seizures (NCS) are seizures that have subtle or no clinical motor phenomena in a patient with impaired consciousness. Nonconvulsive status epilepticus (NCSE), is a subtype of status epilepticus. NCSE denotes an enduring epileptic condition with reduced or altered consciousness ranging from confusion to coma, behavioral and vegetative abnormalities, or merely subjective symptoms like auras, but without major convulsive movements (1) NCS occur in 10–25 % of patients with acute brain injury and are associated with worse outcomes (2). NCSE is also seen a third of patients presenting with altered mental status to the emergency department ( 3.) Indeed, a diagnosis of NCSE is often missed both in the emergency room and in the ICU, because of its pleomorphic presentation, often in the setting of other serious illnesses.

Pitfalls in EEG Analysis in Patients With Nonconvulsive Status Epilepticus: A Preliminary Study.

Objective: Electroencephalography (EEG) interpretations through visual (by human raters) and automated (by computer technology) analysis were still not reliable for the diagnosis of nonconvulsive status epilepticus (NCSE). This study aimed to identify typical pitfalls in the EEG analysis and make suggestions as to how those pitfalls might be avoided. Methods: We analyzed the EEG recordings of individuals who had clinically confirmed or suspected NCSE. Epileptiform EEG activity during seizures (ictal discharges) was visually analyzed by 2 independent raters. We investigated whether unreliable EEG visual interpretations quantified by low interrater agreement can be predicted by the characteristics of ictal discharges and individuals' clinical data. In addition, the EEG recordings were automatically analyzed by in-house algorithms. To further explore the causes of unreliable EEG interpretations, 2 epileptologists analyzed EEG patterns most likely misinterpreted as ictal discharges based on the differences between the EEG interpretations through the visual and automated analysis. Results: Short ictal discharges with a gradual onset (developing over 3 s in length) were liable to be misinterpreted. An extra 2 min of ictal discharges contributed to an increase in the kappa statistics of >0.1. Other problems were the misinterpretation of abnormal background activity (slow-wave activities, other abnormal brain activity, and the ictal-like movement artifacts), continuous interictal discharges, and continuous short ictal discharges. Conclusion: A longer duration criterion for NCSE-EEGs than 10 s that is commonly used in NCSE working criteria is recommended. Using knowledge of historical EEGs, individualized algorithms, and context-dependent alarm thresholds may also avoid the pitfalls.

Case Report: Hypopituitarism Presenting With Nonconvulsive Status Epilepticus

Introduction: Hypopituitarism is defined as one or more partial or complete pituitary hormone deficiencies. Nonconvulsive status epilepticus (NCSE) refers to a state of continuous or repetitive seizures without convulsions. In this paper, we review a case of an old female patient with hypopituitarism who presented with NCSE, which is rare in the clinic.Case Report: This paper describes a 67-year-old female patient with hypopituitarism who presented as NCSE. She had surgical resection of pituitary tumor half a year before the seizures and did not get regular hormone replacement therapy. She presented general convulsive status epilepsy as the initial symptom and got sedation and antiepileptic drug in the emergency room. The seizure was terminated but the patient fell in coma in the following days. The patient had magnetic resonance imaging (MRI) and other inspects, and EEG showed epileptic discharges. Combining these clinical symptoms and examinations, we made the diagnosis of NCSE. Finally, she regained consciousness after the treatment with diazepam.Conclusion: This case report and literature review investigated the possible mechanism of hypopituitarism presenting with NCSE.

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

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. 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. 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. 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.

Functional neuroimaging in nonepileptiform electroencephalographic patterns in status epilepticus.

The diagnosis of nonconvulsive status epilepticus (NCSE) in patients with nonepileptiform EEG patterns remains a challenge. To evaluate the usefulness of single photon emission computerized tomography (SPECT) and its quantification (QtSPECT) in the diagnosis of NCSE. We retrospectively reviewed patients admitted with clinical suspicion of NCSE who underwent an HMPAO-SPECT simultaneously with scalp EEG showing nonepileptiform patterns, in a 5-year period. After a complete diagnostic workup, treatment, and clinical evolution, disregarding the SPECT results, patients were classified into confirmed NCSE (n=11) and non-NCSE (n=8). Then, we compared the EEG and SPECT results in both groups. Lateralized rhythmic delta activity (LRDA) was predominant in the NCSE group (45.4%, p=.045), while lateralized irregular slowing was observed equally in both groups. Patients with NCSE showed significant hyperperfusion compared with non-NCSE patients (p=.026). QtSPECT correctly classified 91% of patients in NCSE and 75% patients with non-NCSE (p=.006). Regional cerebral blood flow measured with SPECT could be useful in the diagnosis of NCSE in cases of an EEG pattern with lateralized slow activity and high clinical suspicion.

Diagnosing Status Epilepticus

Both diffusion-weighted MRI(DWI)modalities and continuous electroencephalography(cEEG)are useful for diagnosing status epilepticus. In case 1, DWI showed hyperintense regions in the right-sided parieto-occipital cortex during peri-ictal status. Intensity of the regions normalized after left hemiparesis improved. In status epilepticus , DWI usually depicts some hyperintense regions, such as the cerebral cortex, hippocampus, and thalamic pulvinar, where ictal brain activity and its propagation are likely occur the seizure. In case 2, cEEG led to an accurate diagnosis of non-convulsive status epilepticus due to right-sided temporal contusion. Intravenous application of levetiracetam and lacosamide alleviated the clinical symptoms and electrographic seizures. Abnormal cEEG findings during status epilepticus vary from rhythmic delta activity and epileptiform and generalized periodic discharges to ictal discharges. Accurate diagnosis of status epilepticus using MRI and cEEG can offer earlier intervention, such as prompt administration of benzodiazepines, midazolam, lorazepam, ultimately resulting in a good recovery.

Heidenhain Variant of Sporadic Creutzfeldt-Jakob Disease: First Reported Case from East Africa

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare prion disease that causes rapidly progressive fatal neurodegeneration. The rarer Heidenhain variant of sCJD presents with visual symptoms and is rarely reported in the literature from sub-Saharan Africa. We report the case of a 57-year-old male with a three-week history of losing direction when driving home and visual hallucinations described as seeing rainbows. Magnetic resonance imaging (MRI) of the brain revealed unilateral parieto-occipital sulcal hyperintensities with restriction on diffusion-weighted imaging (DWI), and electroencephalography (EEG) showed right para-central slowing leading to an initial diagnosis of non-convulsive status epilepticus. He was treated with anti-epileptic medication but was re-admitted less than a month later with worsening spatial memory, aggression, ataxia, dysarthria, myoclonic jerks and a positive startle response, later developing generalised tonic-clonic seizures. Repeat MRI brain scan showed widespread posterior-predominant sulcal DWI restriction in a cortical ribboning pattern pathognomonic for sCJD. EEG showed diffuse slowing, and cerebrospinal fluid was analyzed for abnormal prion protein using real-time quaking-induced conversion but was inconclusive due to suboptimal sample collection. The patient fulfilled the diagnostic criteria for probable sCJD, Heidenhain variant; the family declined brain biopsy for definitive diagnosis. He was subsequently palliated at a local hospice where he died approximately three months after the onset of symptoms. Our case highlights the presence of a rare form of sCJD, and the diagnostic challenges faced in our resource-limited setting.

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.

Nonconvulsive Status Epilepticus in Metabolic Encephalopathy in Indonesia Referral Hospital.

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

Long-term EEG monitoring in patients with acute traumatic brain injury

To investigate the informativeness of long-term scalp EEG monitoring in patients with acute traumatic brain injury (TBI). The informativity of long-term EEG monitoring (LTM) was performed in 60 patients with acute severe TBI. Odd ratios (OR) of unfavorable outcome and non-convulsive status epilepticus (NCSE) among clinical, neurophysiological and radiological features were calculated. EEG features of the unfavorable outcome are: slowing of the dominant background rhythm below q range (OR 3.5, CI 1.2-10.7), absence of frontal-occipital gradient (OR 10.2, CI 1.89-10.12), absence of reactivity (OR 8.75, CI 2.14-35.7), absence of variability (OR 6.25, CI 1.72-22.6) and absence of NREM sleep, stage 2 (OR 5.8, CI 1.79-18.91). Clinical features associated with the unfavorable outcome are: a decrease in GCS score (OR 1.25, CI 1.07-1.47), TBI severity (OR 2.46, CI 1.16-5.18), axial dislocation (OR 4.45, CI 1.08-18.29). ORs for NCSE are significant for the following EEG features: presence of rhythmic and periodic patterns (RPP) (OR 11.92, CI 1.37-103.39), stimulus induced RPP (OR 23.14, CI 2.56-209.34), "plus" modifier (OR 4.11, CI 1.13-14.91) and electrographic evolution (OR 13.05, CI 3.59-47.39). Background rhythm slowing below q range reduces NCSE probability (OR 3.33, CI 1.09-10). Long-term EEG monitoring is an informative tool for prognosis of outcome and diagnosis of NCSE in patients with severe TBI. The risk of NCSE increases with Marshall score but NCSE is not associated with poor outcome that requires an individual selection of intensive care.

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.

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

ObjectiveTo 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 MethodsClinical 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. ResultsNCSE 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). ConclusionsNCSE 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.