Prognostic scores in status epilepticus: A systematic review and meta-analysis

Metabolic alkalosis: a new red flag in status epilepticus

BACKGROUND

Status epilepticus (SE) is a heterogeneous neurological emergency with significant variability in prognosis, influenced by underlying disease and pathophysiological context. Acid-base disturbances are common in critically ill patients, yet their distribution and impact in SE patients remain poorly understood.

METHODS

This was an observational cohort study including non-hypoxic SE patients with available blood gas analysis within the first 24 h of SE, treated at the University Hospital of Geneva, Switzerland between 2015 and 2023. Acid-base disturbances were classified using the Henderson-Hasselbalch equation, with prevalent metabolic alkalosis confirmed through the Stewart approach. Primary outcomes were in-hospital mortality, Glasgow Outcome Scale (GOS) at discharge, and return to premorbid neurologic function.

FINDINGS

Among 540 SE patients, 365 were included. Half of patients exhibited acid-base disturbances within the initial 24 h of SE, with metabolic and respiratory acidosis being the most prevalent, though not prognostically significant. After correction for possible confounders, metabolic alkalosis (6%) was associated with increased in-hospital mortality (P = 0.011; OR = 4.87, 95% CI = 1.29-7.84), worse GOS (P = 0.012; OR = 3.18, 95% CI = 1.29-7.84), and reduced likelihood of returning to premorbid function (P = 0.017; OR = 3.30, CI95% = 1.24-8.80). Following the Stewart approach, 9% of patients had predominant metabolic alkalosis, associated with worse GOS (P = 0.005; OR:3.37, 95%CI = 1.45-7.82), and reduced chance of returning to baseline (P = 0.012; OR = 3.29, CI95% = 1.30-8.32). Metabolic alkalosis was related to hypoalbuminemia and lower serum potassium.

CONCLUSION

Metabolic alkalosis strongly predicts mortality and adverse functional outcome in SE patients. Prospective studies should assess whether early detection and correction of metabolic alkalosis and related electrolyte imbalances can improve SE prognosis.

Mortality and morbidity of status epilepticus over the long term

Status epilepticus is associated with high mortality and morbidity, both in the acute phase and over the long term. However, the long-term outcome of SE is not well studied, and there is no consensus on how to measure and predict it. Moreover, the factors that influence the long-term outcome of SE are complex and multifactorial, and may vary depending on the patient's characteristics, the SE etiology and type, and the treatment and complications. The aim of this article is to review the current literature on the mortality and morbidity of SE over the long term and to discuss the challenges and perspectives for future research. Proceedings of the 9th London-Innsbruck Colloquium on Status Epilepticus and acute seizures.

Periodic discharges and status epilepticus: A critical reappraisal

OBJECTIVE

Periodic Discharges (PDs) in Status Epilepticus (SE) are historically related to negative outcome, and the Epidemiology-based Mortality Score in SE (EMSE) identifies PDs as an EEG feature associated with unfavorable prognosis. However, supportive evidence is conflicting. This study aims to evaluate the prognostic significance of interictal PDs during and following SE.

METHODS

All 2020-2023 non-hypoxic-ischemic SE patients with available EEG during SE were retrospectively assessed. Interictal PDs during SE (SE-PDs) and PDs occurring 24-72 h after SE resolution (post-SE-PDs) were examined. In-hospital death was defined as the primary outcome.

RESULTS

189 SE patients were finally included. SE-PDs were not related to outcome, while post-SE-PDs were related to poor prognosis confirmed after multiple regression analysis. EMSE global AUC was 0.751 (95%CI:0.680-0.823) and for EMSE-64 cutoff sensitivity was 0.85, specificity 0.52, accuracy 63%. We recalculated EMSE score including only post-SE-PDs. Modified EMSE (mEMSE) global AUC was 0.803 (95%CI:0.734-0.872) and for mEMSE-64 cutoff sensitivity was 0.84, specificity 0.68, accuracy 73%.

CONCLUSION

Interictal PDs during SE were not related to outcome whereas PDs persisting or appearing > 24 h after SE resolution were strongly associated to unfavorable prognosis. EMSE performed well in our cohort but considering only post-SE-PDs raised specificity and accuracy for mEMSE64 cutoff.

SIGNIFICANCE

This study supports the utility of differentiating between interictal PDs during and after SE for prognostic assessment.

Risk factors and a predictive model for the occurrence of adverse outcomes in patients with new-onset refractory status epilepsy

Objectives

To determine risk factors for the occurrence of adverse outcomes in patients with new-onset refractory status epilepsy (NORSE) and to construct a concomitant nomogram.

Methods

Seventy-six adult patients with NORSE who were admitted to the Department of Neurology, First Affiliated Hospital of Sun Yat-sen University between January 2016 and December 2022 were enrolled for the study. Participants were divided into two-those with good and poor functional outcomes-and their pertinent data was obtained from the hospital medical recording system. Univariate analysis was used to identify potential causes of poor outcomes in both groups and a multivariate logistic regression model was used to identify risk factors for the occurrence of poor outcomes. Using the R programming language RMS package, a nomogram was created to predict the occurrence of poor outcomes.

Results

The NORSE risk of adverse outcome nomogram model included four predictors, namely duration of mechanical ventilation (OR = 4.370, 95% CI 1.221-15.640, p = 0.023), antiviral therapy (OR = 0.045, 95% CI 0.005-0.399, p = 0.005), number of anesthetics (OR = 13.428, 95% CI 2.16-83.48, p = 0.005) and neutrophil count/lymphocyte count ratio (NLR) (OR = 5.248, 95% CI 1.509-18.252, p = 0.009). The nomogram had good consistency and discrimination in predicting risk and can thus assist clinical care providers to assess outcomes for NORSE patients. Through ordinary bootstrap analyses, the results of the original set prediction were confirmed as consistent with those of the test set.

Conclusion

The nomogram model of risk of adverse outcomes in NORSE adult patients developed in this study can facilitate clinicians to predict the risk of adverse outcomes in NORSE patients and make timely and reasonable interventions for patients at high risk of adverse outcomes.

Brain MRI in status epilepticus: Relevance of findings

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

Impact of frailty, biomarkers and basic biochemical parameters on outcomes of comatose patients in status epilepticus: a single-center prospective pilot study

BACKGROUND

Status epilepticus (SE) is a severe acute condition in neurocritical care with high mortality. Searching for risk factors affecting the prognosis in SE remains a significant issue. The primary study's aim was to test the predictive values of the Clinical Frailty Scale (CFS) and the Modified 11-item Frailty Index (mFI-11), the biomarkers and basic biochemical parameters collected at ICU on the Glasgow Outcome Scale (GOS) assessed at hospital discharge (hosp), and three months later (3 M), in comatose patients with SE. The secondary aim was to focus on the association between the patient's state at admission and the duration of mechanical ventilation, the ICU, and hospital stay.

METHODS

In two years single-centre prospective pilot study enrolling 30 adult neurocritical care patients with SE classified as Convulsive SE, A.1 category according to the International League Against Epilepsy (ILAE) Task Force without an-/hypoxic encephalopathy, we evaluated predictive powers of CFS, mFI-11, admission Status Epilepticus Severity Score (STESS), serum protein S100, serum Troponin T and basic biochemical parameters on prognosticating GOS using univariate linear regression, logistic regression and Receiver Operating Characteristic (ROC) analysis.

RESULTS

Our study included 60% males, with a mean age of 57 ± 16 years (44-68) and a mean BMI of 27 ± 5.6. We found CFS, mFI-11, STESS, and age statistically associated with GOS at hospital discharge and three months later. Among the biomarkers, serum troponin T level affected GOS hosp (p = 0.027). Serum C-reactive protein significance in prognosticating GOS was found by logistic regression (hosp p = 0.008; 3 M p = 0.004), and serum calcium by linear regression (hosp p = 0.028; 3 M p = 0.015). In relation to secondary outcomes, we found associations between the length of hospital stay and each of the following: age (p = 0.03), STESS (p = 0.009), and serum troponin T (p = 0.029) parameters.

CONCLUSIONS

This pilot study found promising predictive powers of two frailty scores, namely CFS and mFI-11, which were comparable to age and STESS predictors regarding the GOS at hospital discharge and three months later in ICU patients with SE. Among biomarkers and biochemical parameters, only serum troponin T level affected GOS at hospital discharge.

Prognostic value of Salzburg nonconvulsive status epilepticus criteria: The SACE score

OBJECTIVE

This study was undertaken to investigate the association between the Salzburg nonconvulsive status epilepticus (NCSE) criteria and in-hospital outcome, to determine the predictive accuracy of the Status Epilepticus Severity Score (STESS), modified STESS (mSTESS), Epidemiology-Based Mortality Score in Status Epilepticus (EMSE), and END-IT (encephalitis, NCSE, diazepam resistance, imaging features, and tracheal intubation) in NCSE patients, and to develop a new prognostic score specifically designed for NCSE patients.

METHODS

Clinical and electroencephalographic (EEG) data of adult patients treated for NCSE from 2020 to 2023 were retrospectively assessed. Age, sex, modified Rankin Scale at admission, comorbidities, history of seizures, etiology, status epilepticus type, and outcome were collected from the patients' digital charts. EEG data were assessed and categorized applying the Salzburg NCSE criteria. In-hospital death was defined as the primary outcome.

RESULTS

A total of 116 NCSE patients were included. Multivariable logistic regression revealed that Salzburg NCSE criterion A2 (ictal morphological, spatial, and temporal evolution) was associated with in-hospital survival. The best STESS cutoff was ≥4 (sensitivity = .62, specificity = .69, accuracy = 67%). mSTESS ≥ 5 reached a sensitivity of .68, a specificity of .57, and an overall accuracy of 60%, EMSE ≥ 64 a sensitivity of .82, a specificity of .39, and an overall accuracy of 52%, and END-IT ≥ 3 a sensitivity of .65, a specificity of .44, and an overall accuracy of 50%. Through a hypothesis-generating approach, we developed the SACE score, which integrates EEG features (criterion A2) with patient age (with a 75-year cutoff), history of seizures, and level of consciousness. With a cutoff of ≥3, it had a sensitivity of .77, a specificity of .74, and an overall accuracy of 76%, performing better than other prognostic scores.

SIGNIFICANCE

We developed a new user-friendly scoring system, the SACE score, which integrates EEG features with other established outcome-related variables assessable in early stages, to assist neurologists and neurointensivists in making more tailored prognostic decisions for NCSE patients.

Comparison of the status epilepticus severity score and the epidemiology-based mortality score in predicting 30-day mortality and status epilepticus cessation

OBJECTIVE

To evaluate the role of the Status Epilepticus Severity Score (STESS) and the Epidemiology-based Mortality score (EMSE) in predicting 30-day mortality and SE (Status epilepticus) cessation, and their prognostic performance in subgroups of patients with specific characteristics.

METHODS

We reviewed consecutive episodes of SE occurring in patients aged ≥14 years at Baggiovara Civil Hospital (Modena, Italy) from 2013 to 2021. We evaluated the predictive accuracy of EMSE and STESS for 30-day mortality and SE cessation through stepwise regression binary logistic models adjusted for possible univariate clinical confounders.

RESULTS

Seven hundred and eleven patients were enrolled. The mean value of STESS was 3.2 (SD 1.7) and of EMSE was 80.1 (SD 52.6). Within 30 days of the onset of SE, 28.4% of patients (202/711) died. EMSE had higher discriminatory ability for 30-day mortality compared with STESS (AUROC: 0.799; 95% CI: 0.765-0.832 versus 0.727; 95% CI: 0.686-0.766, respectively; p = 0.014). SE cessation within 1 h for convulsive SE and within 12 h for nonconvulsive SE was achieved in 35.3% (251/711) of patients. No significant difference was found between EMSE and STESS in discriminatory ability for SE cessation (AUROC: 0.516; 95% CI: 0.488-0.561 and 0.518; 95% CI: 0.473-0.563, respectively; p = 0.929). EMSE was superior to STESS in predicting 30-day mortality in patients with specific characteristics. No difference between the two scores was found in predicting SE cessation in subgroups of patients with specific characteristics.

CONCLUSIONS

EMSE seems superior to STESS in predicting 30-day mortality, particularly in specific patient categories. Conversely, there is no difference in the ability of these scores in predicting SE cessation, which is overall rather low.

Electroencephalography as a Biomarker of Prognosis in Acute Brain Injury

Electroencephalography (EEG) is a noninvasive tool that allows the monitoring of cerebral brain function in critically ill patients, aiding with diagnosis, management, and prognostication. Specific EEG features have shown utility in the prediction of outcomes in critically ill patients with status epilepticus, acute brain injury (ischemic stroke, intracranial hemorrhage, subarachnoid hemorrhage, and traumatic brain injury), anoxic brain injury, and toxic-metabolic encephalopathy. Studies have also found an association between particular EEG patterns and long-term functional and cognitive outcomes as well as prediction of recovery of consciousness following acute brain injury. This review summarizes these findings and demonstrates the value of utilizing EEG findings in the determination of prognosis.

Nonconvulsive status epilepticus in neurocritical care: A critical reappraisal of outcome prediction scores

OBJECTIVE

Nonconvulsive status epilepticus (NCSE) is a frequent condition in the neurocritical care unit (NCCU) patient population, with high morbidity and mortality. We aimed to assess the validity of available outcome prediction scores for prognostication in an NCCU patient population in relation to their admission reason (NCSE vs. non-NCSE related).

METHODS

All 196 consecutive patients diagnosed with NCSE during the NCCU stay between January 2010 and December 2020 were included. Demographics, Simplified Acute Physiology Score II (SAPS II), NCSE characteristics, and in-hospital and 3-month outcome were extracted from the electronic charts. Status Epilepticus Severity Score (STESS), Epidemiology-Based Mortality Score in Status Epilepticus (EMSE), and encephalitis, NCSE, diazepam resistance, imaging features, and tracheal intubation score (END-IT) were evaluated as previously described. Univariable and multivariable analysis and comparison of sensitivity/specificity/positive and negative predictive values/accuracy were performed.

RESULTS

A total of 30.1% died during the hospital stay, and 63.5% of survivors did not achieve favorable outcome at 3 months after onset of NCSE. Patients admitted primarily due to NCSE had longer NCSE duration and were more likely to be intubated at diagnosis. The receiver operating characteristic (ROC) for SAPS II, EMSE, and STESS when predicting mortality was between .683 and .762. The ROC for SAPS II, EMSE, STESS, and END-IT when predicting 3-month outcome was between .649 and .710. The accuracy in predicting mortality/outcome was low, when considering both proposed cutoffs and optimized cutoffs (estimated using the Youden Index) as well as when adjusting for admission reason.

SIGNIFICANCE

The scores EMSE, STESS, and END-IT perform poorly when predicting outcome of patients with NCSE in an NCCU environment. They should be interpreted cautiously and only in conjunction with other clinical data in this particular patient group.

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

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