Effect of epileptic seizures on the cerebrospinal fluid--A systematic retrospective analysis

Clinical and paraclinical features of first unprovoked seizures in the elderly

PURPOSE

The prevalence of unprovoked seizures and epilepsy rises significantly in later life stages. This study examines various factors in elderly patients (over 65 years) with their first unprovoked seizures, comparing findings with younger patients.

METHODS

We analyzed electronic medical records of individuals with first unprovoked seizures retrospectively. Diagnosis was based on patient history and witness accounts, and exclusion of other potential causes. Data included demographics, physical examination, seizure characteristics, neuroimaging, EEG findings, laboratory markers, potential causes, prescribed anti-seizure medications (ASMs) at diagnosis and follow-up, seizure-related injuries and hospital stay length.

RESULTS

We enrolled 391 patients (mean age 73.02 ± 16.5, 219 females). Most had late-onset (≥65 years) seizures (n = 295, 75.5 %). Status epilepticus was diagnosed in 10.2 %, more in the late-onset group. Elderly patients most often had focal seizures with impaired consciousness, while younger patients had focal to bilateral tonic-clonic seizures. (55.9 % vs 36.5 %). Late-onset seizures were linked to cerebrovascular diseases, small vessel disease, and cerebral atrophy, while early-onset cases were associated with brain tumors or unknown causes. Brain imaging revealed potentially epileptogenic abnormalities in 59.1 %. Positive paraneoplastic or autoimmune antibodies were found in 0.8 %. Abnormal EEGs were present in 25.9 %, more in the late-onset group. Most patients were discharged with levetiracetam (LEV) or lamotrigine (LTG) monotherapy. Nine patients with late-onset seizures died during in-hospital follow-up.

CONCLUSION

Our findings can contribute to the improved identification and characterization of patients with late-onset seizures, facilitating targeted diagnostics and appropriate treatment in this challenging patient population.

New Onset Seizures in Hospitalized COVID-19 Patients; A Systematic Review and Meta-Analysis

Objective

Seizures in COVID-19 patients continue to be a common reason for consulting the neurology service in the inpatient setting. This paper assesses the frequency of new onset seizures in adult hospitalized COVID-19 patients.

Method

PubMed and EMBASE were searched, with fifteen cohort studies identified to calculate the primary outcome, which was the frequency of new onset seizures in hospitalized COVID-19 patients. An inverse variance meta-analysis of single proportions with a random effects model was applied to these cohort studies to calculate the primary outcome. Risk of bias in individual studies was assessed using the 10-item risk of bias tool for prevalence studies.

Results

The meta-analysis revealed a frequency of .71% (95% confidential interval: .32-1.25, I2 = 89%, 147/28242 patients) for acute symptomatic seizures in patients with COVID-19. For secondary outcomes, the risk of seizures in patients who had EEG completed was 8.49% (95% confidential interval: .62-24.07, I2 = 14%, 44/535 patients). Slightly less than half of patients with COVID-19 and seizures were reported to have acute imaging abnormalities (45.7%) with acute vascular insults being commonly reported. Only a small percentage of COVID-19 patients with seizures (2.8%) met the criteria for COVID-19 encephalitis as determined by the international encephalitis consortium.

Conclusion

The frequency of seizures in COVID-19 was .71% (95% confidential interval: .32-1.25). Slightly less than half of COVID-19 patients had head imaging abnormalities as a complication of COVID-19 infection. Only a small percentage of patients with seizures and COVID-19 met the criteria for COVID-19 encephalitis.

Fluid Biomarkers of Neuro-Glial Injury in Human Status Epilepticus: A Systematic Review

As per the latest ILAE definition, status epilepticus (SE) may lead to long-term irreversible consequences, such as neuronal death, neuronal injury, and alterations in neuronal networks. Consequently, there is growing interest in identifying biomarkers that can demonstrate and quantify the extent of neuronal and glial injury. Despite numerous studies conducted on animal models of status epilepticus, which clearly indicate seizure-induced neuronal and glial injury, as well as signs of atrophy and gliosis, evidence in humans remains limited to case reports and small case series. The implications of identifying such biomarkers in clinical practice are significant, including improved prognostic stratification of patients and the early identification of those at high risk of developing irreversible complications. Moreover, the clinical validation of these biomarkers could be crucial in promoting neuroprotective strategies in addition to antiseizure medications. In this study, we present a systematic review of research on biomarkers of neuro-glial injury in patients with status epilepticus.

Cerebrospinal fluid biomarkers in psychiatric autoimmune encephalitis: a retrospective cohort study

Background

Psychiatric autoimmune encephalitis (pAE) is a growing field of interest in diagnosis and therapy in psychiatric hospitals and institutions. This study investigates the relevant extent to which there are potential biomarkers in cerebrospinal fluid (CSF) that can differentiate against a cohort with neurodegenerative disease.

Methods

We included in this study a total of 27 patients with possible and definite psychiatric autoimmune encephalitis and compared with a cohort with CSF-based AD (n = 27) different biomarkers in CSF such as lactate, cell count, % lymphocytes, % monocytes, total protein content, albumin, immunoglobulins G (IgG), M (IgM) and A (IgA), CSF/serum albumin ratio, CSF/serum IgG ratio, CSF/serum IgA ratio, intrathecal IgG synthesis, blood-brain barrier disruption, specific antibody synthesis for measles, rubella, herpes simplex virus, varicella zoster virus, Ebstein-Barr virus and cytomegalovirus, total tau protein (t-tau), phosphorylated tau protein 181 (p-tau181), amyloid beta 42 (Aß42), amyloid beta 40 (Aß40) and the amyloid beta 42/ amyloid beta 40 (Aß42/40) ratio.

Results

The p-tau 181 was elevated above cut-off values in both possible pAE and AD. However, in definitive pAE, p-tau181 levels were not elevated. When elevated p-tau181 levels in possible AE were compared with those in AD, we found relevant differences, such as a relative increase in p-tau181 in AD patients. Elevated p-tau181 levels were detected in possible psychiatric AEs with IgLON5, glycine, recoverin, titin, and nonspecific neuropil antibodies in serum and IgLON5, titin, Yo, and nonspecific neuropil autoantibodies in CSF. In addition, we detected elevated levels of p-tau181 and IgLON5 autoantibodies in serum and CSF, and Yo autoantibodies in CSF in patients with definitive pAE. Interestingly, we observed a higher CSF/serum IgM ratio in possible and definitive pAE than in AD patients.

Conclusion

Our results suggest that neuroaxonal brain damage may occur in specific psychiatric AEs associated with IgLON5, glycine, recoverin, and titin autoantibodies. Further research should focus on the CSF/serum IgM ratio as an early marker of autoantibody production in pAE compared to AD as a potential biomarker for differential diagnosis.

Respiratory brain impulse propagation in focal epilepsy

Respiratory brain pulsations pertaining to intra-axial hydrodynamic solute transport are markedly altered in focal epilepsy. We used optical flow analysis of ultra-fast functional magnetic resonance imaging (fMRI) data to investigate the velocity characteristics of respiratory brain impulse propagation in patients with focal epilepsy treated with antiseizure medication (ASM) (medicated patients with focal epilepsy; ME, n = 23), drug-naïve patients with at least one seizure (DN, n = 19) and matched healthy control subjects (HC, n = 75). We detected in the two patient groups (ME and DN) several significant alterations in the respiratory brain pulsation propagation velocity, which showed a bidirectional change dominated by a reduction in speed. Furthermore, the respiratory impulses moved more in reversed or incoherent directions in both patient groups vs. the HC group. The speed reductions and directionality changes occurred in specific phases of the respiratory cycle. In conclusion, irrespective of medication status, both patient groups showed incoherent and slower respiratory brain impulses, which may contribute to epileptic brain pathology by hindering brain hydrodynamics.

Diagnostic value of cerebrospinal fluid analysis in epileptic cats with unremarkable brain MRI or hippocampal signal changes only

OBJECTIVES

Cerebrospinal fluid (CSF) analysis is used in the diagnostic investigation of cats with epileptic seizures. The aim of this retrospective study was to evaluate the diagnostic value of CSF analysis in cats with epileptic seizures that have unremarkable brain MRI or only hippocampal signal changes.

METHODS

Unremarkable brain MRI or MRI studies with signal alterations in the hippocampus only in cats with suspected epilepsy and CFS analysis performed at the Small Animal Internal Department or Diagnostic Imaging Department at Vetmeduni Vienna, Austria, between 2011 and 2017 were reviewed. Total nucleated cell count, total protein, blood contamination and cytology data from CSF analysis were evaluated.

RESULTS

In total, 87 cats were included. Seventy cats (80.5%) had unremarkable MRI, five (5.7%) had hippocampal signal changes with contrast enhancement and 12 (13.8%) had hippocampal signal changes without contrast enhancement. Overall, four cats (4.6%) had abnormalities on CSF analysis; all (100%) had an increased total nucleated cell count (22 cells/μl, 7 cells/μl, 6 cells/μl and 6 cells/μl, respectively), and no cat had increased total protein (100%), although in one cat total protein was not evaluated. Three of these cats had unremarkable MRI and one had hippocampal signal changes without contrast enhancement. The median duration of epileptic signs prior to the MRI study was 2 days.

CONCLUSIONS AND RELEVANCE

Our results show that, in our cohort of epileptic cats with unremarkable brain MRI or with hippocampal signal changes, CSF analysis was usually normal. This should be considered before performing a CSF tap.

Seizures in adults with suspected central nervous system infection

Background

Seizures can be part of the clinical presentation of central nervous system (CNS) infections. We describe patients suspected of a neurological infection who present with a seizure and study diagnostic accuracy of clinical and laboratory features predictive of CNS infection in this population.

Methods

We analyzed all consecutive patients presenting with a seizure from two prospective Dutch cohort studies, in which patients were included who underwent cerebrospinal fluid (CSF) examination because of the suspicion of a CNS infection.

Results

Of 900 episodes of suspected CNS infection, 124 (14%) presented with a seizure. The median age in these 124 episodes was 60 years (IQR 45–71) and 53% of patients was female. CSF examination showed a leukocyte count ≥ 5/mm³ in 41% of episodes. A CNS infection was diagnosed in 27 of 124 episodes (22%), a CNS inflammatory disorder in 8 (6%) episodes, a systemic infection in 10 (8%), other neurological disease in 77 (62%) and in 2 (2%) episodes another systemic disease was diagnosed. Diagnostic accuracy of clinical and laboratory characteristics for the diagnosis of CNS infection in this population was low. CSF leukocyte count was the best predictor for CNS infection in patients with suspected CNS infection presenting with a seizure (area under the curve 0.94, [95% CI 0.88 – 1.00]).

Conclusions

Clinical and laboratory features fail to distinguish CNS infections from other causes of seizures in patients with a suspected CNS infection. CSF leukocyte count is the best predictor for the diagnosis of CNS infection in this population.

Insights into the development of pentylenetetrazole-induced epileptic seizures from dynamic metabolomic changes

Epilepsy is often considered to be a progressive neurological disease, and the nature of this progression remains unclear. Understanding the overall and common metabolic changes of epileptic seizures can provide novel clues for their control and prevention. Herein, a chronic kindling animal model was established to obtain generalized tonic-clonic seizures via the repeated injections of pentylenetetrazole (PTZ) at subconvulsive dose. Dynamic metabolomic changes in plasma and urine from PTZ-kindled rats at the different kindling phases were explored using NMR-based metabolomics, in combination with behavioral assessment, brain neurotransmitter measurement, electroencephalography and histopathology. The increased levels of glucose, lactate, glutamate, creatine and creatinine, together with the decreased levels of pyruvate, citrate and succinate, ketone bodies, asparagine, alanine, leucine, valine and isoleucine in plasma and/or urine were involved in the development and progression of seizures. These altered metabolites reflected the pathophysiological processes including the compromised energy metabolism, the disturbed amino acid metabolism, the peripheral inflammation and changes in gut microbiota functions. NMR-based metabolomics could provide brain disease information by the dynamic plasma and urinary metabolic changes during chronic epileptic seizures, yielding classification of seizure stages and profound insights into controlling epilepsy via targeting deficient energy metabolism.

Tauopathy and Epilepsy Comorbidities and Underlying Mechanisms

Tau is a microtubule-associated protein known to bind and promote assembly of microtubules in neurons under physiological conditions. However, under pathological conditions, aggregation of hyperphosphorylated tau causes neuronal toxicity, neurodegeneration, and resulting tauopathies like Alzheimer's disease (AD). Clinically, patients with tauopathies present with either dementia, movement disorders, or a combination of both. The deposition of hyperphosphorylated tau in the brain is also associated with epilepsy and network hyperexcitability in a variety of neurological diseases. Furthermore, pharmacological and genetic targeting of tau-based mechanisms can have anti-seizure effects. Suppressing tau phosphorylation decreases seizure activity in acquired epilepsy models while reducing or ablating tau attenuates network hyperexcitability in both Alzheimer's and epilepsy models. However, it remains unclear whether tauopathy and epilepsy comorbidities are mediated by convergent mechanisms occurring upstream of epileptogenesis and tau aggregation, by feedforward mechanisms between the two, or simply by coincident processes. In this review, we investigate the relationship between tauopathies and seizure disorders, including temporal lobe epilepsy (TLE), post-traumatic epilepsy (PTE), autism spectrum disorder (ASD), Dravet syndrome, Nodding syndrome, Niemann-Pick type C disease (NPC), Lafora disease, focal cortical dysplasia, and tuberous sclerosis complex. We also explore potential mechanisms implicating the role of tau kinases and phosphatases as well as the mammalian target of rapamycin (mTOR) in the promotion of co-pathology. Understanding the role of these co-pathologies could lead to new insights and therapies targeting both epileptogenic mechanisms and cognitive decline.

Revealing the Antiepileptic Effect of α-Asaronol on Pentylenetetrazole-Induced Seizure Rats Using NMR-Based Metabolomics

α-Asaronol from Acorus tatarinowii (known as "Shichangpu" in Traditional Chinese medicine) has been proved to possess more efficient antiepileptic activity and lower toxicity than α-asarone (namely "Xixinnaojiaonang" as an antiepileptic drug in China) in our previous study. However, the molecular mechanism of α-asaronol against epilepsy needs to be known if to become a novel antiepileptic medicine. Nuclear magnetic resonance (NMR)-based metabolomics was applied to investigate the metabolic patterns of plasma and the brain tissue extract from pentylenetetrazole (PTZ)-induced seizure rats when treated with α-asaronol or α-asarone. The results showed that α-asaronol can regulate the metabolomic level of epileptic rats to normal to some extent, and four metabolic pathways were associated with the antiepileptic effect of α-asaronol, including alanine, aspartate, and glutamate metabolism; synthesis and degradation of ketone bodies; glutamine and glutamate metabolism; and glycine, serine, and threonine metabolism. It was concluded that α-asaronol plays a vital role in enhancing energy metabolism, regulating the balance of excitatory and inhibitory neurotransmitters, and inhibiting cell membrane damage to prevent the occurrence of epilepsy. These findings are of great significance in developing α-asaronol into a promising antiepileptic drug derived from Traditional Chinese medicine.

The Interconnected Mechanisms of Oxidative Stress and Neuroinflammation in Epilepsy

One of the most important characteristics of the brain compared to other organs is its elevated metabolic demand. Consequently, neurons consume high quantities of oxygen, generating significant amounts of reactive oxygen species (ROS) as a by-product. These potentially toxic molecules cause oxidative stress (OS) and are associated with many disorders of the nervous system, where pathological processes such as aberrant protein oxidation can ultimately lead to cellular dysfunction and death. Epilepsy, characterized by a long-term predisposition to epileptic seizures, is one of the most common of the neurological disorders associated with OS. Evidence shows that increased neuronal excitability—the hallmark of epilepsy—is accompanied by neuroinflammation and an excessive production of ROS; together, these factors are likely key features of seizure initiation and propagation. This review discusses the role of OS in epilepsy, its connection to neuroinflammation and the impact on synaptic function. Considering that the pharmacological treatment options for epilepsy are limited by the heterogeneity of these disorders, we also introduce the latest advances in anti-epileptic drugs (AEDs) and how they interact with OS. We conclude that OS is intertwined with numerous physiological and molecular mechanisms in epilepsy, although a causal relationship is yet to be established.

Advances regarding Neuroinflammation Biomarkers with Noninvasive Techniques in Epilepsy

A rapidly growing body of evidence supports that neuroinflammation plays a major role in epileptogenesis and disease progression. The capacity to identify pathological neuroinflammation in individuals with epilepsy is a crucial step on the timing of anti-inflammatory intervention and patient selection, which will be challenging aspects in future clinical studies. The discovery of noninvasive biomarkers that are accessible in the blood or molecular neuroimaging would facilitate clinical translation of experimental findings into humans. These innovative and noninvasive approaches have the advantage of monitoring the dynamic changes of neuroinflammation in epilepsy. Here, we will review the available evidence for the measurement of neuroinflammation in patients with epilepsy using noninvasive techniques and critically analyze the major scientific challenges of noninvasive methods. Finally, we propose the potential for use in clinical applications.

Time dependency of CSF cell count, lactate and blood-CSF barrier dysfunction after epileptic seizures and status epilepticus

BACKGROUND

This retrospective observational study was conducted to examine the temporal relationship between increased cell count, lactate concentration in cerebrospinal fluid (CSF) and blood-CSF barrier dysfunction and the onset of a seizure event.

METHODS

Patients with a seizure event who underwent lumbar puncture for CSF analysis during diagnostic work-up (interindividual analysis) and those with at least one follow-up CSF analysis (intraindividual analysis) were studied. Pathologically altered parameters, such as cell count, lactate concentration, and blood-CSF barrier dysfunction as indicated by the albumin quotient (Q_Alb=CSF albumin/serum albumin), were examined with regard to the changes over time after seizure onset.

RESULTS

An increased CSF cell count (>4/µl) was shown in 3% of our patients, whereas pathological lactate concentrations were found in 24% after single seizures and 28% after status epilepticus (SE)/recurring seizures. However, lactate levels showed a marked decrease with increasing time after an isolated seizure (p<0.0001) but not after SE/recurring seizures. Lactate levels were most frequently and significantly elevated within the first six hours after a single seizure (p<0.0001). Blood-CSF barrier dysfunction was detected in 34% after isolated seizures and in 47% after SE/recurrent seizures. Blood-CSF barrier dysfunction showed no association with latency between seizure onset and time of CSF collection.

CONCLUSIONS

Changes in lactate and CSF protein concentrations are common after epileptic seizures. In contrast, CSF pleocytosis is uncommon and should prompt careful investigation for the presence of intrathecal infection or autoimmune CNS disease. Elevated lactate levels more than 6 h after the seizure event may indicate ongoing epileptic activity.

Diagnostic utility of cerebrospinal fluid (CSF) findings in seizures and epilepsy with and without autoimmune-associated disease

Patients with seizures and epilepsy routinely undergo multiple diagnostic tests, which may include cerebrospinal fluid (CSF) analysis. This review aims to outline different CSF parameters and their alterations in seizures or epilepsy. We then discuss the utility of CSF analysis in seizure patients in different clinical settings in depth. Some routine CSF parameters are frequently altered after seizures, but are not specific such as CSF protein and lactate. Pleocytosis and CSF specific oligoclonal bands are rare and should be considered as signs of infectious or immune mediated seizures and epilepsy. Markers of neuronal damage show conflicting results, and are as yet not established in clinical practice. Parameters of neuronal degeneration and more specific immune parameters are less well studied, and are areas of further research. CSF analysis in new-onset seizures or status epilepticus serves well in the differential diagnosis of seizure etiology. Here, considerations should include autoimmune-associated seizures. CSF findings in these disorders are a special focus of this review and are summarized in a comprehensive overview. Until now, CSF analysis has not yielded clinically helpful biomarkers for refractory epilepsy or for assessment of neuronal damage which is a subject of further studies.

Cerebrospinal Fluid Pleocytosis Not Attributable to Status Epilepticus in First 24 Hours

BACKGROUND

Status epilepticus (SE) has traditionally been thought to cause cerebrospinal fluid (CSF) pleocytosis. However, attributing CSF pleocytosis solely to SE without addressing the underlying etiology may lead to poor outcomes. Leukocyte recruitment to CSF has been shown to peak around 24 hours after prolonged seizures in animal studies, suggesting that CSF pleocytosis within the first 24 hours of SE onset may be due to underlying causes. The goal of this study is to assess if SE is associated with CSF pleocytosis, independent of other causes within the first 24 hours of onset.

METHODS

We completed a historical cohort study of adult patients with SE admitted to the intensive care unit of Vancouver General Hospital between March 2010 and May 2019.

RESULTS

Of the 441 patients admitted with SE during the study period, 107 met our inclusion criteria leading to 111 lumbar punctures (LPs), with 4 patients receiving two LPs. CSF pleocytosis was seen in 12 of 72 patients who underwent an LP within the first 24 hours of SE onset. In all 12 patients, a secondary etiology for the pleocytosis was observed aside from SE. Of the six CSF samples collected after 24 hours of onset that demonstrated pleocytosis, four had no cause for pleocytosis other than SE.

CONCLUSIONS

In all 12 patients with CSF pleocytosis in the first 24 hours of onset of SE, an underlying etiology was identified. Therefore, any pleocytosis noticed within the first 24 hours of onset of refractory SE should not be attributed solely to SE.

Serum biomarkers of cerebral cellular stress after self-limiting tonic clonic seizures: An exploratory study

OBJECTIVE

It has been debated for decades whether single, self-limited seizures damage cerebral cells. Meanwhile, very sensitive measurements of biomarkers have become available, i.e. tau, neurofilament protein light (NFL), glial fibrillary acidic protein (GFAP) and ubiquitin carboxyterminate hydrolase L1 (UCHL-1), which we explored in this study.

METHODS

Adult patients of the epilepsy monitoring unit were admitted to the study after written consent. Blood samples were drawn at baseline, immediately after a TCS and after two, six and 24 h. The markers were measured from frozen samples with a single-molecule array (SIMOA).

RESULTS

20 patients and 20 seizures were included. All markers showed subtle but significant postictal increases and returned to normal within the next few hours (p < 0.05). An increase of at least 100 % from baseline was noted in 30 % of patients for tau, 25 % for UCHL-1 and 15 % for GFAP, while NFL levels never increased above 100 %. Lactate was slightly correlated with the tau increase (r = 0.47, p = 0.037), leukocytes were correlated with postictal changes of GFAP (r = 0.68 p = 0.001).

CONCLUSION

Our data supports the assumption that significant cerebral stress occurs in some but not all self-limited TCS. The postictal inflammatory response in particular seems to play an important role.

Cerebrospinal fluid lactate concentrations in dogs with seizure disorders

BACKGROUND

Cerebrospinal fluid (CSF) lactate concentrations increase after seizure activity in many human patients independent of the underlying disease process. The effect of seizure activity on CSF lactate concentration in dogs is unknown.

HYPOTHESIS/OBJECTIVES

Cerebrospinal fluid lactate concentration is unaffected by seizure activity in dogs and is more dependent on the underlying disease process causing the seizures.

ANIMALS

One-hundred eighteen client-owned dogs with seizure disorders.

METHODS

Case series. Cerebrospinal fluid lactate concentration was determined using a commercially available lactate monitor. Seizure semiology, time from last seizure to CSF collection, number of seizures within the 72 hours preceding CSF collection, and clinical diagnosis were recorded.

RESULTS

Dogs with focal seizures had higher CSF lactate concentrations than did those with generalized seizures (P = .03). No differences in lactate concentrations were found among dogs with single seizures, cluster seizures or status epilepticus (P = .12), among dogs with CSF collection at different time points after the last seizure activity (P = .39) or among dogs having different numbers of seizures within the 72 hours preceding CSF collection (P = .42). A significant difference (P = .001) was found in CSF lactate concentrations among diagnostic groups, and dogs with inflammatory and neoplastic disease had higher concentrations than did dogs with idiopathic or unknown epilepsy.

CONCLUSIONS AND CLINICAL IMPORTANCE

Cerebrospinal fluid lactate concentration is minimally affected by seizure activity in dogs and increased concentrations are more likely associated with the underlying disease process.

Postanoxic electrographic status epilepticus and serum biomarkers of brain injury

AIM

To explore if electrographic status epilepticus (ESE) after cardiac arrest causes additional secondary brain injury reflected by serum levels of two novel biomarkers of brain injury: neurofilament light chain (NfL) originating from neurons and glial fibrillary acidic protein (GFAP) from glial cells.

METHODS

Simplified continuous EEG (cEEG) and serum levels of NfL and GFAP, sampled at 24, 48 and 72 h after cardiac arrest, were collected during the Target Temperature Management (TTM)-trial. Two statistical methods were used: multivariable regresssion analysis; and a matched control group of patients without ESE matched for early predictors of poor neurological outcome.

RESULTS

128 patients had available biomarkers and cEEG. Twenty-six (20%) patients developed ESE, the majority (69%) within 24 h. ESE was an independent predictor of elevated serum NfL (p < 0.001) but not of serum GFAP (p = 0.16) at 72 h after cardiac arrest. Compared to a control group matched for early predictors of poor neurological outcome, patients who developed ESE had higher levels of serum NfL (p = 0.03) and GFAP (p = 0.04) at 72 h after cardiac arrest.

CONCLUSION

ESE after cardiac arrest is associated with higher levels of serum NfL which may suggest increased secondary neuronal injury compared to matched patients without ESE but similar initial brain injury. Associations with GFAP reflecting glial injury are less clear. The study design cannot exclude imperfect matching or other mechanisms of secondary brain injury contributing to the higher levels of biomarkers of brain injury seen in the patients with ESE.

Blood and cerebrospinal fluid immune cell profiles in patients with temporal lobe epilepsy of different etiologies

Inflammation plays a role in the pathogenesis of immune-mediated epilepsy, but also in epilepsy of other etiology such as hippocampal sclerosis. This study aimed to characterize immune cell signatures in the peripheral blood (PB) and cerebrospinal fluid (CSF) in temporal lobe epilepsy (TLE) of different etiologies. We retrospectively evaluated CSF routine parameters and immune cell profiles using flow cytometry in a cohort of 51 patients and 45 age-matched controls with functional disorders. Groups were comprised of patients with nonlesional TLE (n = 26), TLE due to hippocampal sclerosis (n = 14), or limbic encephalitis with antibodies against the 65-kDa isoform of glutamic acid decarboxylase (GAD65-LE; n = 11). TLE patients showed increased proportions of human leukocyte antigen-DR isotype (HLA-DR)-expressing CD4⁺ T lymphocytes in the CSF. Furthermore, they were characterized by a shift in monocyte subsets toward immature CD14^low CD16⁺ cells in the PB and blood/CSF-barrier dysfunction. Whereas TLE patients in general showed similar immune cell profiles, patients with GAD65-LE differed from other TLE patients by increased proportions of HLA-DR-expressing CD8⁺ T lymphocytes and type 2/3 oligoclonal bands. These findings point to a role of innate and adaptive immunity in TLE. CSF parameters may help to discriminate epilepsy patients from controls and different forms of TLE from each other.

Diagnostic utility of cerebrospinal fluid analysis in dogs with suspected idiopathic epilepsy

BACKGROUND

Idiopathic epilepsy (IE) is the most common cause of repeated seizures in dogs. The International Veterinary Epilepsy Task Force consensus guidelines recommend performing magnetic resonance imaging (MRI) of the brain and cerebrospinal fluid (CSF) analysis as part of a tier II diagnosis of IE, and these procedures have documented risks. The aim of this retrospective study was to identify how often dogs with suspected IE have abnormalities on CSF analysis.

METHODS

Dogs aged between 6 months and 6 years that were presented with a history of two or more seizures with at least 24 h between seizure episodes, a normal neurologic examination, no evidence of toxic or metabolic causes, a normal MRI scan (including contrast administration) and CSF analysis were included.

RESULTS

Eighty-two dogs were included. Of these, nine dogs (10.9%) had abnormalities on CSF analysis: five of nine dogs (55.5%) had albuminocytologic dissociation, three of nine dogs (33.3%) had mild increases in total nucleated cell count (TNCC), and one of nine dogs (11.1%) had mild increase in both total protein and TNCC. Cytology in dogs with elevated TNCC revealed a mononuclear pleocytosis. One of the nine dogs with abnormal CSF had a seizure within the 24 h before investigations, and six of nine dogs had a seizure within 1 month before investigation.

CONCLUSION

CSF analysis can play an important role in the diagnostic investigation of the underlying causes of repeated seizures. However, in dogs with a normal inter-ictal neurological examination and MRI scan, it rarely reveals significant abnormalities, and the risk of performing a CSF tap may outweigh the potential diagnostic gain.

Alzheimer-like amyloid and tau alterations associated with cognitive deficit in temporal lobe epilepsy

Temporal lobe epilepsy represents a major cause of drug-resistant epilepsy. Cognitive impairment is a frequent comorbidity, but the mechanisms are not fully elucidated. We hypothesized that the cognitive impairment in drug-resistant temporal lobe epilepsy could be due to perturbations of amyloid and tau signalling pathways related to activation of stress kinases, similar to those observed in Alzheimer's disease. We examined these pathways, as well as amyloid-β and tau pathologies in the hippocampus and temporal lobe cortex of drug-resistant temporal lobe epilepsy patients who underwent temporal lobe resection (n = 19), in comparison with age- and region-matched samples from neurologically normal autopsy cases (n = 22). Post-mortem temporal cortex samples from Alzheimer's disease patients (n = 9) were used as positive controls to validate many of the neurodegeneration-related antibodies. Western blot and immunohistochemical analysis of tissue from temporal lobe epilepsy cases revealed increased phosphorylation of full-length amyloid precursor protein and its associated neurotoxic cleavage product amyloid-β*56. Pathological phosphorylation of two distinct tau species was also increased in both regions, but increases in amyloid-β1-42 peptide, the main component of amyloid plaques, were restricted to the hippocampus. Furthermore, several major stress kinases involved in the development of Alzheimer's disease pathology were significantly activated in temporal lobe epilepsy brain samples, including the c-Jun N-terminal kinase and the protein kinase R-like endoplasmic reticulum kinase. In temporal lobe epilepsy cases, hippocampal levels of phosphorylated amyloid precursor protein, its pro-amyloidogenic processing enzyme beta-site amyloid precursor protein cleaving enzyme 1, and both total and hyperphosphorylated tau expression, correlated with impaired preoperative executive function. Our study suggests that neurodegenerative and stress-related processes common to those observed in Alzheimer's disease may contribute to cognitive impairment in drug-resistant temporal lobe epilepsy. In particular, we identified several stress pathways that may represent potential novel therapeutic targets.

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.

Etiological assessment of status epilepticus

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

Diagnostic value of cerebrospinal fluid analysis in a population of dogs with suspected idiopathic epilepsy

Cerebrospinal fluid (CSF) analysis is commonly used in the diagnostic investigation of seizure disorders in order to exclude possible inflammatory underlying aetiology. The medical records were searched for dogs presenting with epileptic seizures (ES) that had normal interictal neurological examination, normal complete blood count and biochemistry analysis, unremarkable MRI of the brain and had CSF analysis performed as part of the diagnostic investigation. A total of 200 dogs met the inclusion criteria. The CSF was abnormal in 30 dogs with a median total nucleated cell count of two cells/µl (IQR 1.5-6) and median protein concentration of 0.37 g/l (IQR 0.31-0.41). Pleocytosis was recorded in 14/30 dogs and the CSF protein was increased in 22/30. There was no correlation between abnormal CSF and the type or number of seizures or the time interval between the last seizure and CSF collection. A significant correlation was found between the number of red blood cells on CSF and having an abnormal CSF. The prevalence of having a diagnosis other than suspected idiopathic epilepsy (IE) was 0.5 per cent (1/200). These results suggest that performing CSF analysis in dogs with recurrent ES that have normal interictal neurological examination and unremarkable MRI has a low diagnostic value.

Postictal syndrome: The forgotten continent. An overview of the clinical, biochemical and imaging features

Postictal syndrome (PIS) encompasses the clinical, biological, electroencephalographic (EEG) and magnetic resonance imaging (MRI) signs that follow the termination of a seizure. These signs occur as soon as the epileptic discharge ends, but might remain for a substantially long period of time, making them amenable to clinical observation. As a direct consequence, neurologists and intensivists are more frequently attending patients with PIS than during their seizure. Moreover, careful PIS documentation may help physicians to diagnose epileptic seizure from other non-epileptic disorders. Careful analysis of PIS could also be helpful to better characterize the seizure (seizure subtypes, and to some extent, the localization and/or lateralization of the seizure). This article aims to review the main clinical, biological, EEG and MRI components of PIS, discuss differential diagnoses and propose a general clinical attitude, based on the acronym "WAITTT": W for "Watch", to monitor and investigate PIS in order to provide relevant information on seizure, AIT for "Avoid Inappropriate Treatment", to underscore the risk carrying out unnecessary drug injections and intensive care procedures in the setting of a self-limited symptomatology, and TT for "Take Time", to keep in mind that time remains the clinician's best ally for treating patients with PIS.

Nonlesional late-onset epilepsy: Semiology, EEG, cerebrospinal fluid, and seizure outcome characteristics

INTRODUCTION

Incidence and prevalence of epilepsy increase with advancing age. Although the majority of late-onset epilepsies are of lesional origin, a considerable proportion of patients present with unknown etiology. The aim of this study was to evaluate the semiological, electroencephalographic (EEG), and cerebrospinal fluid (CSF) characteristics as well as the 12-month seizure outcome in a cohort of patients with nonlesional late-onset epilepsy (≥55 years).

METHOD

A total of 54 patients with newly diagnosed nonlesional late-onset epilepsy (NLLOE) were retrospectively evaluated for seizure type using the most recent International League Against Epilepsy (ILAE) classification of seizure types, EEG characteristics, and CSF profile and followed-up for at least 12 months after epilepsy onset. Results were compared with a gender-matched control group of 58 patients with nonlesional early-onset epilepsy (NLEOE).

RESULTS

The predominant seizure types in NLLOE were focal to bilateral tonic-clonic seizures (30%) as well as focal onset impaired awareness motor seizures (IAMS) (22%) and focal onset impaired awareness nonmotor seizures (IANMS) (22%). The predominant seizure types in NLEOE were focal to bilateral tonic-clonic seizures (43%) as well as focal onset aware nonmotor seizures (ANMS) (31%) and IAMS (31%). Focal onset impaired awareness nonmotor seizures were found to be more characteristic in patients with NLLOE (p = 0.019; α < 0.05; NLLOE: 22.2% vs. NLEOE: 8.6%). Electroencephalography revealed no significant differences between groups. Of interest, three patients with NLLOE (8%) presented with oligoclonal bands (OCB) in CSF albeit absence of antineuronal antibodies. Seizure-free rate was 70%. Adverse effects from medication leading to antiepileptic drug (AED) change were reported in 12 patients (22%), valproate was the best tolerated AED in patients with NLLOE [adverse effects in 9%, compared with 12% (gabapentin) and 26% (levetiracetam)].

CONCLUSIONS

Using the most recent classification system, different patterns of semiological characteristics were identified: NLLOE more frequently present with IANMS, whereas patients with NLEOE rather have ANMS. Oligoclonal bands were only detected in patients with NLLOE, indicating that careful exclusion of autoimmune encephalitis in this patient group is warranted. Our findings may help to more accurately identify and characterize patients with NLLOE to improve targeted diagnostics and adequate treatment in this challenging group of patients.

Cerebrospinal fluid lactate concentration and bacterial encephalitis diagnosis

OBJECTIVES

A French national study on infectious encephalitis enrolled 253 patients in 2007. Fifty-two per cent of patients had a proven etiological diagnosis; 16% had bacterial encephalitis. We aimed to assess the predictive value of CSF lactate concentration to diagnose bacterial encephalitis.

PATIENTS AND METHODS

Patients from the 2007 cohort whose CSF lactate concentration was available were included. Clinical and biological features associated with a bacterial etiology were assessed using univariate analysis and multivariate logistic regression. The ROC curve of CSF lactate concentration was used to define the most appropriate cut-off associated with bacterial etiology.

RESULTS

Fifty-seven patients (37 men, 20 women) were included. Ten patients had bacterial encephalitis, 20 patients had viral encephalitis. The mean CSF white blood cells (WBC), protein, glucose, and lactate levels were respectively 92 cells/mm³ (range: 0-450), 1.2g/L (range: 0.2-8.2), 3.9mmol/L (range: 0.8-8.8), and 2.8mmol/L (range: 0-9.4). In univariate analysis, CSF protein level (P<0.01), WBC count (P=0.02), and lactate concentration (P<0.01) were significantly associated with bacterial etiology. The only factor independently associated with bacterial etiology in the multivariate analysis was CSF lactate concentration. The area under the ROC curve of CSF lactate for the diagnosis of bacterial encephalitis was 0.86. The cut-off value of 3.4 mmol/L correctly classified 87.8% of patients with 70% sensitivity, 91.5% specificity, 64% positive predictive value, and 93% negative predictive value.

CONCLUSION

A high CSF lactate level seems to be a better predictor than WBC or proteins to differentiate bacterial encephalitis from other etiologies.

Cerebrospinal fluid findings in non-infectious status epilepticus

OBJECTIVE

Ictal activity itself can cause pathological cerebrospinal fluid (CSF) findings. However, data regarding pathological CSF findings caused by SE itself to date remain scarce. We here evaluated the frequency and specificity of pathological CSF findings in non-infectious SE.

METHODS

We performed a retrospective analysis of CSF samples in adult patients with episodes of non-infectious SE, who had been admitted to the Department of Neurology, University Hospital of Cologne. The following parameters were assessed: cell count, protein, and lactate content, CSF/serum glucose quotient (Q_Glc), disturbances of blood-brain-barrier function assessed by CSF/serum albumin quotient (Q_Alb), and qualitative intrathecal IgG synthesis assessed by unmatched oligoclonal bands in CSF.

RESULTS

We analysed 54 episodes of non-infectious SE in which CSF had been obtained. CSF pleocytosis was infrequent (6%). Elevated CSF protein content was present in 44% of all cases, whereas elevated CSF lactate content was found in 23% of the cases. A decreased Q_Glc was present in 9%. Dysfunction of blood-brain-barrier (BBBD) was the most frequent pathological finding, amounting to 55%. Unmatched oligoclonal bands in CSF were seen in 10% of non-infectious SE. Further analysis revealed that elevated CSF protein content was found predominantly in recfractory SE (p = 0.04). Elevated CSF lactate content was associated with shorter latency between onset of SE and CSF retrieval (p = 0.004), positive history of epilepsy (p = 0.02) and an acute symptomatic etiology (p = 0.04). BBBD was also present more often in acute symptomatic SE (p = 0.001) and was the sole pathological CSF parameter associated with clinical outcome: presence of BBBD was associated with a less favorable outcome (p = 0.02).

SIGNIFICANCE

Non-infectious SE itself does not commonly cause CSF pleocytosis. Data suggest that the detection of CSF pleocytosis should prompt further diagnostics for an underlying infectious or neoplastic etiology. In contrast, elevation of CSF protein content and BBBD were found frequently in non-infectious SE.

Periodic EEG patterns in sporadic Creutzfeld-Jakob-Disease can be benzodiazepine-responsive and be difficult to distinguish from non-convulsive status epilepticus

PURPOSE

Periodic discharges in EEG and a history of rapidly progressive dementia are known to be associated with sporadic Creutzfeld-Jakob Disease (sCJD). Doubts regarding this rare but fatal diagnosis can arise, when episodic symptoms (seizures, psychiatric features, speech disturbances) are present and the EEG shows epileptiform discharges within this periodicity. This scenario may indicate non-convulsive status epilepticus (NCSE), which is - in contrast to sCJD - a treatable and frequent condition.

METHODS

Herein we report a small retrospective study of 4 elderly patients, who suffered from sCJD, but due to episodic symptoms and benzodiazepine-responsive epileptiform discharges in combination to a subacute cognitive decline, NCSE was considered as a potential differential diagnosis and therefore treated aggressively.

RESULTS

Ultimately, this treatment was not successful and sCJD was diagnosed in all cases. Hence, there was no diagnostic and prognostic value of abolishing periodic discharges in EEG via benzodiazepines in differentiating sCJD from NCSE in our series.

CONCLUSION

These findings indicate that periodic discharges in sCJD can be responsive to benzodiazepines andnot necessarily help to differentiate differentiation between sCJD and NCSE of other causes. We argue that an aggressive anticonvulsive treatment in this scenario should be considered cautiously, especially for invasive options like general anesthesia.

Cerebrospinal fluid pleocytosis level as a diagnostic predictor? A cross-sectional study

BACKGROUND

Lumbar puncture with quantification of leukocytes and differential count of cellular subsets in the cerebrospinal fluid is a standard procedure in cases of suspected neuroinfectious conditions. However, a number of non-infectious causes may result in a low leukocyte number (0-1000 cells/ml). We wanted to assess the diagnostic diversity of unselected adult patients with pleocytosis in the cerebrospinal fluid.

METHODS

The study is based on data from cerebrospinal fluid (CSF) analyses of all adult patients (15 years or older) admitted to a large university hospital in Denmark during a two-year period (2008-2009). Data from the local patient administrative system supplied with data from patient charts were combined with laboratory data.

RESULTS

A total of 5390 cerebrospinal fluid samples from 3290 patients were included. Pleocytosis >5 leucocytes/μl was found in samples from 262 patients of which 106 (40.5%) were caused by infection of the central nervous system (CNS), 20 (7.6%) by infection outside CNS, 79 (30.2%) due to non-infectious neurological diseases, 23 (8.8%) by malignancy, and 34 (13.0%) caused by other conditions. Significantly higher mean CSF leukocytes was found in patients suffering from CNS infection (mean 1135 cells/μl, p-value <0.0001).

CONCLUSIONS

CNS infection, non-infectious neurological disease, malignancy, and infection outside CNS can cause pleocytosis of the cerebrospinal fluid. Leukocyte counts above 100/μl is mainly caused by CNS infection, whereas the number of differential diagnoses is higher if the CSF leukocyte counts is below 50/μl. These conditions are most commonly caused by non-infectious neurological diseases including seizures.

Cerebrospinal Fluid Pleocytosis in Critical Care Patients With Seizures

OBJECTIVES

To assess the etiology of cerebrospinal fluid (CSF) pleocytosis in critical care patients with seizure(s) or status epilepticus (SE). Many previous studies, some performed decades ago, concluded that CSF pleocytosis may be entirely attributable to seizure activity.

METHODS

We undertook a retrospective chart review of adult patients with an admitting or acquired diagnosis of seizure(s) or SE in critical care units at the Winnipeg Health Sciences Centre between 2009 and 2012. Patients were identified through a critical care information database at a tertiary care center. We limited our study to patients who had lumbar punctures at our center within 5 days of seizure(s) or SE.

RESULTS

Of 426 patients with seizures in critical care units, 51 met the inclusion criteria. Seizure subtypes included focal seizures (5 or 10%), generalized seizures (14 or 27%), and SE (32 or 63%). Twelve (seven with SE) of the 51 (24%) were found to have CSF pleocytosis. A probable etiological cause for the CSF pleocytosis was identified in all 12 cases.

CONCLUSIONS

We conclude that seizures do not directly induce a CSF pleocytosis. Instead, the CSF pleocytosis more likely reflects the underlying acute or chronic brain process responsible for the seizure(s). This was not readily apparent in early studies without magnetic resonance imaging (MRI) of the brain and currently available laboratory investigations. An etiological cause of CSF pleocytosis must always be sought when patients present with seizures and it should never be assumed that seizures are the cause.

GC-MS-Based metabolomics discovers a shared serum metabolic characteristic among three types of epileptic seizures

OBJECTIVE

Understanding the overall and common metabolic changes of seizures can provide novel clues for their control and prevention. Here, we aim to investigate the global metabolic feature of serum for three types of seizures.

METHODS

We recruited 27 patients who had experienced a seizure within 48h (including 11 who had a generalized seizure, nine who had a generalized seizure secondary to partial seizure and seven who had a partial seizure) and 23 healthy controls. We analyzed the global metabolic changes of serum after seizures using gas chromatography-mass spectrometry-based metabolomics. Based on differential metabolites, the metabolic pathways and their potential to diagnose seizures were analyzed, and metabolic differences among three types of seizures were compared.

RESULTS

The metabolic profiles of serum were distinctive between the seizure group and the controls but were not different among the three types of seizures. Compared to the controls, patients with seizures had higher levels of lactate, butanoic acid, proline and glutamate and lower levels of palmitic acid, linoleic acid, elaidic acid, trans-13-octadecenoic acid, stearic acid, citrate, cysteine, glutamine, asparagine, and glyceraldehyde in the serum. Furthermore, these differential metabolites had common change trends among the three types of seizures. Related pathophysiological processes reflected by these metabolites are energy deficit, inflammation, nervous excitation and neurotoxicity. Importantly, transamination inhibition is suspected to occur in seizures. Lactate, glyceraldehyde and trans-13-octadecenoic acid in serum jointly enabled a precision of 92.9% for diagnosing seizures.

CONCLUSIONS

There is a common metabolic feature in three types of seizures. Lactate, glyceraldehyde and trans-13-octadecenoic acid levels jointly enable high-precision seizure diagnosis.

Single frequency analysis for clinical immunosensor design

A novel bioelectrochemical approach: Tau protein determination for the diagnosis of neurodiseases via time-dependant phase angle shift.