Evaluation of seizure treatment in anti-LGI1, anti-NMDAR, and anti-GABABR encephalitis

Multimodal prognostication of autoimmune encephalitis: an Australian autoimmune encephalitis consortium study

BACKGROUND AND OBJECTIVES

To identify factors predictive of a favourable modified Rankin score (mRS) at 12 months in patients with autoimmune encephalitis (AE). To evaluate predictors of a binary composite clinical-functional outcome measure, encompassing mRS, drug-resistant epilepsy (DRE) and memory impairment, at 12 months.

METHODS

Univariable and multivariable logistic regression analyses for predictors of a favourable mRS (i.e. mRS ≤ 2) and a composite clinical-functional outcome at 12 months were used.

RESULTS

A total of 231 patients with AE were recruited. Multivariable logistic regression identified factors predictive of reduced odds of favourable mRS at 12 months were older age (OR 0.97; 95% CI 0.95, 0.98; p < 0.001), T2/FLAIR hyperintensity on initial MRI (OR 0.27; 95% CI 0.13, 0.56; p < 0.001), RSE (OR 0.17; 95% CI 0.06, 0.52; p = 0.002) and first-line immunotherapy failure (OR 0.18; 95% CI 0.09, 0.37; p < 0.001). Anti-LGI1 antibody-mediated encephalitis relative to other subtypes (OR 4.46; 95% CI 1.55, 12.80; p = 0.006) was associated with a better 12-month mRS. We found concordant associations for a composite outcome at 12 months, with the addition of a diagnosis of definite autoimmune limbic encephalitis (AILE) predicting a poor outcome.

DISCUSSION

Older age, MRI T2/FLAIR hyperintensity, RSE and first-line immunotherapy failure predicted worse mRS and composite clinical-functional outcome at 12 months, while a diagnosis of anti-LGI1 antibody-mediated encephalitis was associated with favourable outcomes. Our data highlight acute clinical factors predictive of a more severe clinical and functional course at 12 months.

Neurodegeneration and the immune system: lessons from autoimmune encephalitis

The spectrum of autoimmune encephalitis (AE) is expanding to atypical clinical presentations that can mimic neurodegenerative disorders. Among the autoantibodies most frequently associated with manifestations mimicking neurodegenerative disorders-such as dementia, parkinsonism, ataxia and motor neuron disease-IgLON5-, LGI1- and CASPR2-antibodies, predominantly of the IgG4 subclass and associated with specific HLA haplotypes, are the most common. Since these forms of autoimmune encephalitis often lack inflammatory findings in cerebrospinal fluid or magnetic resonance imaging, recognizing clinical 'red flags' suggestive of an autoimmune etiology is crucial for accurate diagnosis and timely initiation of immunotherapy. Interestingly, in these forms of autoimmune encephalitis, both inflammatory and neurodegenerative disease mechanisms may be involved. The neurodegenerative component may result directly from antibody effects (e.g., tau deposition in IgLON5-antibody disease) or arise through other mechanisms (e.g., seizures or exacerbation of pre-existing pathology). Moreover, neuroinflammation has recently emerged as a key contributor to primary neurodegenerative disorders. For instance, microglial activation promotes tau pathology propagation, as observed in Alzheimer's disease and other primary neurodegenerative disorders. While the precise mechanisms linking inflammation and neurodegeneration remain to be fully understood, further research into the interplay between autoimmunity and neurodegeneration may enhance our understanding of disease mechanisms and expand therapeutic opportunities in both autoimmune and neurodegenerative neurological disorders.

GTE score on evaluating the degree of neurological impairment in anti-NMDA receptor encephalitis

This study mainly analyzed the EEG changes and the development of neurological impairment at different stages of the disease, and explored the clinical role of the Grand Total EEG score (GTE score) in evaluating the degree of neurological impairment function damage in anti-NMDA receptor encephalitis. The GTE scores of patients with anti-NMDA receptor encephalitis at different disease stages and the diagnostic validity of the GTE scores for evaluating the degree of neurological impairment were analyzed. 153 EEG cases were included in this study, with a course of 2 to 960 days. The abnormal EEG rates were 92% in the acute phase, 83% in the recovery phase, 76% in the short-term prognosis phase, and 30% in the long-term prognosis phase. The GTE score: acute phase=(5, 0-15); recovery phase=(2, 0-14); short-term prognosis phase= (2, 0-9); long-term prognosis phase = (0, 0-6). When the total GTE score is 5.5, the patient was more likely to have moderate to severe neurological impairment (mRS = 4), with sensitivity and specificity > 0.9. When the total GTE score was 7.5, the patient was more likely to have severe neurological impairment (mRS = 5), with sensitivity and specificity > 0.9. GTE score has a high diagnostic efficacy for the rating of neurological impairment. The total GTE score was superior to the assessment of neurological damage degree solely from background activity frequency or diffuse slow wave activity.

Long-Term Seizure Outcomes in Autoimmune Encephalitis

Introduction

Seizures are common in autoimmune encephalitis (AE), but identifying patients at risk of chronic epilepsy in the post-acute phase remains challenging. This study aims to identify risk factors of treatment-resistant postencephalitic epilepsy.

Methods

This retrospective cohort study included patients with AE who experienced new-onset seizures within one year of symptom onset from two tertiary care centers in New York. EEG findings were analyzed separately based on whether the EEG recording was obtained in the acute (<3 months from symptom onset) or subacute phase. A multivariate logistic regression model was used to identify independent predictors of postencephalitic epilepsy.

Results

Eighty-nine patients were included (median age: 33 years). Neural antibodies were present in 73% of patients (NMDAR: 35, LGI1: 19, GAD65: 9, Hu: 1, AGNA-1: 1). Over a median follow-up of 4.9 years, 29.2% developed treatment-resistant postencephalitic epilepsy. Independent predictors of postencephalitic epilepsy included focal slowing on acute EEG (OR 0.15, CI 0.02-0.90), interictal epileptiform discharges (IEDs) or periodic discharges (PDs) on subacute EEG (OR 20.01, CI 1.94-206.44), and cell surface antibodies (OR 0.21, CI 0.05-0.89). Immunotherapy within three months of onset was associated with decreased epilepsy development in patients with neural antibodies (OR 4.16, CI 1.11-16.30).

Conclusions

Nearly one-third of patients with AE and acute seizures developed treatment-resistant postencephalitic epilepsy, with significant predictors including absence of focal slowing on acute EEG, presence of IEDs and PDs on subacute EEG, absence of cell surface antibodies, and absence of early immunotherapy treatment of patients with positive neural antibodies.

Microglial Activation Visualized by [18F]-DPA714 PET Is a Potential Marker of Severity and Prognosis for Anti-LGI1 Encephalitis

BACKGROUND AND PURPOSE

Whether microglial activation plays an important role in the pathogenesis of autoimmune encephalitis (AE), such as anti-leucine-rich, glioma-inactivated-1 (LGI1) encephalitis, remains unknown. [18F]-DPA714 PET targeting the translocator protein (TSPO) is a novel method to detect neuroinflammation via visualizing activated microglia. In this study, we aimed to investigate the application of [18F]-DPA714 PET in anti-LGI1 encephalitis.

METHODS

Patients with anti-LGI1 encephalitis and non-inflammatory controls (NIC) underwent [18F]-DPA714 PET scans were enrolled. Standardized uptake value ratios normalized to the cerebellum (SUVRc) in LGI1-AE patients were calculated for semi-quantitative analysis. The microglial activation marker, soluble triggering receptor expressed on myeloid cells 2 (sTREM2) was measured in cerebrospinal fluid (CSF) to demonstrate its correlation with [18F]-DPA714 PET imaging. Logistic regression analysis was used to identify potential predictors of prognosis.

RESULTS

Forty-six patients with anti-LGI1 encephalitis were included in this study. Increased TSPO uptake was identified in the hippocampus, frontal cortex, and caudate nucleus. Montreal Cognitive Assessment (MoCA) score was significantly correlated with SUVRc in the hippocampus (R2 = 0.13, p = 0.034) and frontal cortex (R2 = 0.13, p = 0.017). Overexpressed sTREM2 in CSF was correlated with SUVRc in the hippocampus (R2 = 0.18, p = 0.04). SUVRc in the hippocampus significantly decreased after immunotherapy and was associated with improvement of MoCA score (R2 = 0.54, p = 0.023). Increased SUVRc in the frontal cortex and hippocampus was associated with unfavorable disability recovery (odds ratio [OR] = 7.1, 95% CI 1.67-29.9, p = 0.008) and persistent amnesia (OR = 5.4, 95% CI 1.3-22.2, p = 0.021) respectively.

CONCLUSION

Microglial activation visualized by [18F]-DPA714 PET is associated with clinical features and may be used as a potential biomarker for therapeutic and prognostic evaluation.

Investigating the frequency of neural autoantibodies in refractory focal epilepsy

OBJECTIVES

There have been conflicting reports about the frequency of neural autoantibodies in epilepsy cohorts, which is confounded by the lack of clear distinction of epilepsy from acute symptomatic seizures due to encephalitis. The aim of this study was to determine the frequency of neural autoantibodies in a well characterised population of refractory focal epilepsy of known and unknown cause.

METHODS

Cases were recruited from epilepsy outpatient clinics at the Princess Alexandra, Mater, Royal Brisbane and Women's and Cairns Base Hospitals from 2021 - 2023. Included cases were refractory to medical therapy, met the ILAE definition of focal epilepsy and were characterised using anatomo-electro-clinical correlation. Cases with prior encephalitis, inflammatory neurological disease or prior parenchymal brain insults were excluded.

RESULTS

A total of 100 patients were recruited. No cases with clinically significant neural autoantibodies were discovered. One was positive for serum anti-NMDAR antibodies, however autoantibodies were absent from CSF. Cases were also screened using a predictive score (McGinty et al.). From this, 2 cases were identified as seronegative autoimmune associated epilepsy and demonstrated significant reduction in seizure frequency with administration of immunotherapy. These cases had common features including temporo-perisylvian semiology especially ictal piloerection and high seizure frequency.

CONCLUSION

Clinically relevant neural autoantibodies are uncommon in well characterised chronic focal epilepsy populations. Despite this there are isolated cases that still demonstrate improved seizure control with the use of immunotherapy. Such cases highlight the need for further studies to understand the role of immunity in novel pathophysiological mechanisms in epilepsy.

Case report: Overlapping syndrome of MOG-IgG associated optic neuritis and autoimmune encephalitis with co-existence of anti-NMDAR and anti-GABABR antibodies

We report a case of optic neuritis (ON) secondary to autoimmune encephalitis (AE) in a patient with concomitant antibodies to N-methyl-D-aspartate receptor (NMDAR), gamma-aminobutyric acid-B receptor (GABABR), and myelin oligodendrocyte glycoprotein (MOG). The patient exhibited a constellation of symptoms, including vision loss, seizures, mental and behavioral disorders, cognitive impairment, and speech abnormalities. At the two-year follow-up, the patient's symptoms had abated entirely. Overlap syndrome of triple autoimmune antibodies is rare and the coexistence of antibodies to NMDAR, GABABR and MOG has not been reported till now. This case report provides novel experience of diagnosis and treatment in autoimmune overlap syndromes.

Seizures and status epilepticus in anti-NMDA receptor encephalitis

BACKGROUND

Seizures, including status epilepticus (SE), are common in anti-NMDA receptor encephalitis (NMDARE). We aimed to describe clinical and electrographic features of patients with seizures with NMDARE, determine factors associated with SE, and describe long-term seizure outcomes.

METHODS

We retrospectively identified patients with seizures in the setting of NMDARE treated at inpatient Mayo Clinic sites during the acute phase of encephalitis between October 2008 and March 2023. Seizure semiology, clinical symptoms, electrographic features, neuroimaging, treatment course, complications, and outcome were abstracted. We compared clinical features between patients with and without SE.

RESULTS

We identified 29 patients with seizures during acute NMDARE. Temporal onset was the most common EEG localization (n = 14, 48.3%). Subclinical seizures were recorded in 15 (51.7%). Twelve (41.4%) patients had SE, which was associated with temporal T2-signal hyperintensity, seizures with unilateral clonic and/or tonic movements, multiple seizure foci on EEG, temporal and midline/central onset seizures, higher acute CASE scores, intensive care unit (ICU) admission, longer length of hospitalization, and need for post-hospitalization rehabilitation. One patient (3.4%) died during the acute encephalitis. One patient (3.4%) developed chronic epilepsy. The remaining patients were seizure-free at the last follow-up (median 23 months, range 2-163 months). SE was not associated with differences in outcome at last follow-up.

DISCUSSION

Seizures in NMDARE are frequently temporal onset. SE is common and associated with higher likelihood of ICU level care, longer hospitalization, and higher need for post-hospital rehabilitation. Despite the significant short-term impact of SE, long-term outcome was not affected, and seizure prognosis was favorable.

Predicting the future of autoimmune encephalitides

The concept that many neurologic and psychiatric disorders of unknown cause are immune-mediated has evolved fast during the past 20 years. The main contribution to the expansion of this field has been the discovery of antibodies that attack neuronal or glial cell-surface proteins or receptors, directly modifying their structure and function. These antibodies facilitate the diagnosis and prompt treatment of patients who often improve with immunotherapy. The identification of this group of diseases, collectively named "autoimmune encephalitides", was preceded by many years of investigations on other autoimmune CNS disorders in which the antibodies are against intracellular proteins, occur more frequently with cancer, and associate with cytotoxic T-cell responses that are less responsive to immunotherapy. Here, we first trace the recent history of the autoimmune encephalitides and address how to assess the clinical value and implement in our practice the rapid pace of autoantibody discovery. In addition, we review recent developments in the post-acute stage of the two main autoimmune encephalitides (NMDAR and LGI1) focusing on symptoms that are frequently overlooked or missed, and therefore undertreated. Because a better understanding of the pathophysiology of these diseases relies on animal models, we examine currently available studies, recognizing the existing needs for better and all-inclusive neuro-immunobiological models. Finally, we assess the status of biomarkers of disease outcome, clinical scales, current treatment strategies, and emerging therapies including CAR T-cell technology. Altogether, this overview is intended to identify gaps of knowledge and provide suggestions for improvement and insights for future research.

Clinical characteristics and prognosis analysis of acute symptomatic seizures secondary to autoimmune encephalitis

Objective

This study aimed to analyze the clinical characteristics and prognosis of patients with autoimmune encephalitis (PWAE) who experienced seizures during the acute phase.

Methods

Clinical data were collected from 84 patients diagnosed with AE at the General Hospital of Ningxia Medical University between January 2015 and January 2023. Patients were divided into seizure and non-seizure groups. Clinical characteristics of both groups were compared, including differences between anti-NMDAR and anti-LGI1 encephalitis within the seizure group. Due to the limited sample size and to avoid overfitting, we focused on univariate logistic regression analysis to identify individual prognostic factors.

Results

A total of 84 patients were enrolled, with 76.19% (64/84) in the seizure group and 23.81% (20/84) in the non-seizure group. The seizure group had a longer hospital stay (p = 0.013), higher rates of impaired consciousness (p = 0.001), and more frequent intensive care unit (ICU) admission (p = 0.011). They also had higher peripheral blood neutrophil-to-lymphocyte ratio (NLR), leukocyte count, and uric acid levels (p = 0.038, p = 0.006, p = 0.020), and were more likely to show slow-wave rhythms on electroencephalography (EEG) (p = 0.031). At 2-year follow-up, there was no significant difference in prognosis between the seizure and non-seizure groups (p = 0.653), with 35.94% (23/64) of the seizure group having a poor prognosis. Status epilepticus (SE), complications, endotracheal intubation, mRS score at discharge, APE2, and RITE2 scores increased the risk of poor prognosis (OR > 1), while intensive care and albumin reduced the risk (OR < 1).

Conclusion

Seizures are common in the early stages of AE, with faciobrachial dystonic seizures (FBDS) characteristic of anti-LGI1 encephalitis and SE and super-refractory status epilepticus (Sup-RSE) frequently observed in anti-NMDAR encephalitis. Seizure semiology across AE subtypes lacks specificity, and no symptoms clearly distinguish immune-mediated from non-immune causes. While seizures are linked to AE severity, particularly in anti-NMDAR encephalitis, they do not appear to impact overall prognosis. SE, complications, endotracheal intubation, modified Rankin Scale (mRS) score at discharge, Antibody-Prevalence in Epilepsy and Encephalopathy (APE2) score, Response to Immunotherapy in Epilepsy and Encephalopathy (RITE2) score, intensive care, and albumin were identified as significant prognostic factors.

Olanzapine vs. magnesium valproate vs. lamotrigine in anti-N-methyl-D-aspartic acid receptor encephalitis: a retrospective study

BACKGROUND

This study aimed to compare the impact of olanzapine, magnesium valproate, and lamotrigine as adjunctive treatments for anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. And it is expected to add supporting points related to the rebalance of neurotransmitters in the brain through adjuvant therapy in the clinical management of anti-NMDAR encephalitis.

METHODS

This retrospective study included patients diagnosed with anti-NMDAR encephalitis who received standardized immunotherapy at Hunan Brain Hospital between January 2018 and December 2020.

RESULTS

Compared to the olanzapine group, both the magnesium valproate and lamotrigine groups showed lower scores on the positive and negative symptom scale (PANSS) total score after 3 weeks of treatment (all P < 0.05). The Montreal Cognitive Assessment Scale (MoCA) scores in the magnesium valproate and lamotrigine groups were significantly higher than in the olanzapine group after 3 weeks and 3 months of treatment (all P < 0.05). After 3 months of treatment, the proportions of patients with a modified Rankin scale score (mRS) of 0-1 in the magnesium valproate and lamotrigine groups were significantly higher than in the olanzapine group (all P < 0.05). The electroencephalogram (EEG) abnormality ranks at 3 months were significantly lower in the magnesium valproate and lamotrigine groups compared with the olanzapine group (all P < 0.05). Furthermore, the Glx/Cr ratio significantly decreased after 3 months of treatment (all P < 0.05) in the magnesium valproate and lamotrigine groups, while the Glx/Cr ratio in the olanzapine group showed no significant change (P > 0.05).

CONCLUSION

Compared with olanzapine, the addition of magnesium valproate or lamotrigine to immunotherapy might be associated with a lower PANSS score, higher MoCA score, and lower mRS score. The improvement of neurological functions and cognitive function may be related to the decreased Glx/Cr ratio.

LGI1 Autoantibodies Enhance Synaptic Transmission by Presynaptic Kv1 Loss and Increased Action Potential Broadening

BACKGROUND AND OBJECTIVES

Autoantibodies against the protein leucine-rich glioma inactivated 1 (LGI1) cause the most common subtype of autoimmune encephalitis with predominant involvement of the limbic system, associated with seizures and memory deficits. LGI1 and its receptor ADAM22 are part of a transsynaptic protein complex that includes several proteins involved in presynaptic neurotransmitter release and postsynaptic glutamate sensing. Autoantibodies against LGI1 increase excitatory synaptic strength, but studies that genetically disrupt the LGI1-ADAM22 complex report a reduction in postsynaptic glutamate receptor-mediated responses. Thus, the mechanisms underlying the increased synaptic strength induced by LGI1 autoantibodies remain elusive, and the contributions of presynaptic molecules to the LGI1-transsynaptic complex remain unclear. We therefore investigated the presynaptic mechanisms that mediate autoantibody-induced synaptic strengthening.

METHODS

We studied the effects of patient-derived purified polyclonal LGI1 autoantibodies on synaptic structure and function by combining direct patch-clamp recordings from presynaptic boutons and somata of hippocampal neurons with super-resolution light and electron microscopy of hippocampal cultures and brain slices. We also identified the protein domain mediating the presynaptic effect using domain-specific patient-derived monoclonal antibodies.

RESULTS

LGI1 autoantibodies dose-dependently increased short-term depression during high-frequency transmission, consistent with increased release probability. The increased neurotransmission was not related to presynaptic calcium channels because presynaptic Cav2.1 channel density, calcium current amplitude, and calcium channel gating were unaffected by LGI1 autoantibodies. By contrast, application of LGI1 autoantibodies homogeneously reduced Kv1.1 and Kv1.2 channel density on the surface of presynaptic boutons. Direct presynaptic patch-clamp recordings revealed that LGI1 autoantibodies cause a pronounced broadening of the presynaptic action potential. Domain-specific effects of LGI1 autoantibodies were analyzed at the neuronal soma. Somatic action potential broadening was induced by polyclonal LGI1 autoantibodies and patient-derived monoclonal autoantibodies targeting the epitempin domain, but not the leucin-rich repeat domain.

DISCUSSION

Our results indicate that LGI1 autoantibodies reduce the density of both Kv1.1 and Kv1.2 on presynaptic boutons, without actions on calcium channel density or function, thereby broadening the presynaptic action potential and increasing neurotransmitter release. This study provides a molecular explanation for the neuronal hyperactivity observed in patients with LGI1 autoantibodies.

A Case Report of Autoimmune Encephalitis after Anti-SARS-CoV-2 Vaccination: The Role of Cognitive Impairments in the Diagnostic Process

OBJECTIVE

Autoimmune encephalitis includes a heterogeneous group of rare and complex diseases, usually presenting with severe and disabling symptoms, such as behavioral changes, cognitive deficits, and seizures.

METHOD

This report presents the case of a 26-year-old man who was diagnosed with autoimmune encephalitis following SARS-CoV-2 vaccination (<40 days). Symptoms first appeared in February 2022 with a temporal seizure, associated with confusion and memory loss. Psychiatric manifestations such as disorientation and altered thought contents emerged soon after.

RESULTS

Neuroimaging testing showed signs of hypometabolism in occipital, prefrontal, and temporal regions, whereas an extensive neuropsychological assessment revealed the presence of multiple alterations in memory, executive, and visuoconstructive processes.

CONCLUSIONS

In this case, a combination of neuroimaging testing, psychiatric evaluation, and neuropsychological assessment provided evidence for a diagnosis of autoimmune encephalitis post-vaccination. Early recognition is essential in order to prevent clinical progression; avoid intractable epilepsy, brain atrophy, and cognitive impairment; and improve prognosis.

Two Cases of Pediatric Leucine-Rich Glioma-Inactivated Protein-1 Encephalitis: Clinical Course, Challenges, and Implications

BACKGROUND

Leucine-rich glioma-inactivated protein 1 (LGI-1) encephalitis is a rare form of autoimmune limbic encephalitis. Although relatively well documented in adults, pediatric cases are rare and remain poorly understood.

METHODS

We reviewed two pediatric cases of LGI-1 encephalitis from a single tertiary care facility retrospectively. The detailed analysis included assessment of the initial presentation, clinical progression, diagnostic challenges, treatments, and outcome. To contextualize the differences between pediatric and adult manifestations of disease, we compared these findings with existing literature.

RESULTS

Both cases illustrate the diagnostic challenges faced at initial presentation due to the rarity of this diagnosis in children and the absence of characteristic faciobrachial dystonic seizures, which is common in adults. The constellation of neuropsychiatric symptoms and refractory focal seizures led to a high clinical suspicion for autoimmune encephalitis, therefore, both cases were treated empirically with intravenous methylprednisolone. The diagnosis in both cases was confirmed with positive serum antibody testing, reinforcing that LGI-1 antibodies are more sensitive in the serum rather than the cerebrospinal fluid (CSF). Seizure control and improvement in cognitive symptoms was achieved through a combination of immunotherapy and antiseizure medications.

CONCLUSIONS

This case series underscores the significance of considering LGI-1 encephalitis in the differential diagnosis of pediatric patients exhibiting unexplained neuropsychiatric symptoms and focal seizures and emphasizes the importance of performing both serum and CSF antibody testing. It is necessary to conduct further research to identify the full range of pediatric presentations and to determine the optimal treatment protocol.

Therapeutic Approach to Autoimmune Neurologic Disorders

OBJECTIVE

Autoimmune neurologic disorders encompass a broad category of diseases characterized by immune system attack of the central, peripheral, or autonomic nervous systems. This article provides information on both acute and maintenance immunotherapy used to treat autoimmune neurologic disorders as well as a review of symptomatic management and special considerations when caring for patients with these diseases.

LATEST DEVELOPMENTS

Over the past 20 years, more than 50 antibodies have been identified and associated with autoimmune neurologic disorders. Although advances in diagnostic testing have allowed for more rapid diagnosis, the therapeutic approach to these disorders has largely continued to rely on expert opinion, case series, and case reports. With US Food and Drug Administration (FDA) approval of biologic agents to treat neuromyelitis optica spectrum disorder (NMOSD) and myasthenia gravis as well as ongoing clinical trials for the treatment of autoimmune encephalitis, the landscape of immunotherapy options continues to expand. Consideration of the unique pathogenesis of individual autoimmune neurologic disorders as well as the mechanism of action of the diverse range of treatment options can help guide treatment decisions today while evidence from clinical trials informs new therapeutics in the future.

ESSENTIAL POINTS

Recognizing patients who have a clinical history and examination findings concerning for autoimmune neurologic disorders and conducting a thorough and directed imaging and laboratory evaluation aimed at ruling out mimics, identifying specific autoimmune syndromes, and screening for factors that may have an impact on immunotherapy choices early in the clinical course are essential to providing optimal care for these patients. Providers must consider immunotherapy, symptomatic treatment, and a multidisciplinary approach that addresses each patient's unique needs when treating patients with autoimmune neurologic disorders.

Autoimmune-associated seizure disorders

With the discovery of an expanding number of neural autoantibodies, autoimmune etiologies of seizures have been increasingly recognized. Clinical phenotypes have been identified in association with specific underlying antibodies, allowing an earlier diagnosis. These phenotypes include faciobrachial dystonic seizures with LGI1 encephalitis, neuropsychiatric presentations associated with movement disorders and seizures in NMDA-receptor encephalitis, and chronic temporal lobe epilepsy in GAD65 neurologic autoimmunity. Prompt recognition of these disorders is important, as some of them are highly responsive to immunotherapy. The response to immunotherapy is highest in patients with encephalitis secondary to antibodies targeting cell surface synaptic antigens. However, the response is less effective in conditions involving antibodies binding intracellular antigens or in Rasmussen syndrome, which are predominantly mediated by cytotoxic T-cell processes that are associated with irreversible cellular destruction. Autoimmune encephalitides also may have a paraneoplastic etiology, further emphasizing the importance of recognizing these disorders. Finally, autoimmune processes and responses to novel immunotherapies have been reported in new-onset refractory status epilepticus (NORSE) and febrile infection-related epilepsy syndrome (FIRES), warranting their inclusion in any current review of autoimmune-associated seizure disorders.

Risk of Seizure Recurrence Due to Autoimmune Encephalitis With NMDAR, LGI1, CASPR2, and GABABR Antibodies: Implications for Return to Driving

BACKGROUND AND OBJECTIVES

Patients with ongoing seizures are usually not allowed to drive. The prognosis for seizure freedom is favorable in patients with autoimmune encephalitis (AIE) with antibodies against NMDA receptor (NMDAR), leucine-rich glioma-inactivated 1 (LGI1), contactin-associated protein-like 2 (CASPR2), and the gamma-aminobutyric-acid B receptor (GABABR). We hypothesized that after a seizure-free period of 3 months, patients with AIE have a seizure recurrence risk of <20% during the subsequent 12 months. This would render them eligible for noncommercial driving according to driving regulations in several countries.

METHODS

This retrospective multicenter cohort study analyzed follow-up data from patients aged 15 years or older with seizures resulting from NMDAR-, LGI1-, CASPR2-, or GABABR-AIE, who had been seizure-free for ≥3 months. We used Kaplan-Meier (KM) estimates for the seizure recurrence risk at 12 months for each antibody group and tested for the effects of potential covariates with regression models.

RESULTS

We included 383 patients with NMDAR-, 440 with LGI1-, 114 with CASPR2-, and 44 with GABABR-AIE from 14 international centers. After being seizure-free for 3 months after an initial seizure period, we calculated the probability of remaining seizure-free for another 12 months (KM estimate) as 0.89 (95% confidence interval [CI] 0.85-0.92) for NMDAR, 0.84 (CI 0.80-0.88) for LGI1, 0.82 (CI 0.75-0.90) for CASPR2, and 0.76 (CI 0.62-0.93) for GABABR.

DISCUSSION

Taking a <20% recurrence risk within 12 months as sufficient, patients with NMDAR-AIE and LGI1-AIE could be considered eligible for noncommercial driving after having been seizure-free for 3 months.

Brazilian consensus recommendations on the diagnosis and treatment of autoimmune encephalitis in the adult and pediatric populations

BACKGROUND

 Autoimmune encephalitis (AIE) is a group of inflammatory diseases characterized by the presence of antibodies against neuronal and glial antigens, leading to subacute psychiatric symptoms, memory complaints, and movement disorders. The patients are predominantly young, and delays in treatment are associated with worse prognosis.

OBJECTIVE

 With the support of the Brazilian Academy of Neurology (Academia Brasileira de Neurologia, ABN) and the Brazilian Society of Child Neurology (Sociedade Brasileira de Neurologia Infantil, SBNI), a consensus on the diagnosis and treatment of AIE in Brazil was developed using the Delphi method.

METHODS

 A total of 25 panelists, including adult and child neurologists, participated in the study.

RESULTS

 The panelists agreed that patients fulfilling criteria for possible AIE should be screened for antineuronal antibodies in the serum and cerebrospinal fluid (CSF) using the tissue-based assay (TBA) and cell-based assay (CBA) techniques. Children should also be screened for anti-myelin oligodendrocyte glucoprotein antibodies (anti-MOG). Treatment should be started within the first 4 weeks of symptoms. The first-line option is methylprednisolone plus intravenous immunoglobulin (IVIG) or plasmapheresis, the second-line includes rituximab and/or cyclophosphamide, while third-line treatment options are bortezomib and tocilizumab. Most seizures in AIE are symptomatic, and antiseizure medications may be weaned after the acute stage. In anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis, the panelists have agreed that oral immunosuppressant agents should not be used. Patients should be evaluated at the acute and postacute stages using functional and cognitive scales, such as the Mini-Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), the Modified Rankin Scale (mRS), and the Clinical Assessment Scale in Autoimmune Encephalitis (CASE).

CONCLUSION

 The present study provides tangible evidence for the effective management of AIE patients within the Brazilian healthcare system.

A Case of Anti-Leucine-Rich Glioma-Inactivated Protein 1 (Anti-LGI1) Limbic Encephalitis With Normal Imaging

Anti-leucine-rich glioma-inactivated 1 limbic encephalitis (anti-LGI1 LE) is a rare autoimmune limbic encephalitis with a potentially misleading presentation that can delay diagnosis and treatment. The incremental progression of widely variable symptoms with a prominent behavioral disturbance can conceal the disease and prompt an initial psychiatric diagnosis. Although specific MRI findings ought to be evident by the time the disease progresses to frank limbic encephalitis, it appears inconsistent and ill-defined and is thus unreliable. Nevertheless, brain imaging remains prominent in the discussion, even included in some guidelines for diagnosing anti-LGI1 LE. Here, we present a case of a patient who presented after a suicide attempt with a long history of psychiatric issues, aberrant "spasms," and subsequently encephalopathy, who was eventually diagnosed with anti-LGI1 LE only after delayed CSF antibodies studies. In this patient, symptoms emerged over two years, with multiple brain MRIs being negative, including the one completed during the hospital admission in focus. The purpose of this case report is to encourage maintaining a broad differential when patients present with bizarre symptoms. This report underlies the importance of thorough clinical evaluation, utilization of multiple diagnostic resources, and the need for heightened awareness among healthcare providers about the subtleties of autoimmune encephalitis presentations. With anti-LGI1 LE already being severely underdiagnosed, it is important to continue reviewing various cases of patients who are diagnosed with anti-LGI1 LE and further review to understand its pathophysiology and common clinical presentation. This case also underscores the ongoing evolution in understanding anti-LGI1 LE and highlights that patients may present with unfamiliar symptoms or diagnostic challenges. The overall objective is to help providers recognize anti-LGI1 LE earlier, so treatment can be initiated sooner, leading to a better prognosis for patients.

Predictors and Clinical Characteristics of Relapses in LGI1-Antibody Encephalitis

BACKGROUND AND OBJECTIVES

Relapses occur in 15%-25% of patients with leucine-rich glioma-inactivated 1 antibody (LGI1-Ab) autoimmune encephalitis and may cause additional disability. In this study, we clinically characterized the relapses and identified factors predicting their occurrence.

METHODS

This is a retrospective chart review of patients with LGI1-Ab encephalitis diagnosed at our center between 2005 and 2022. Relapse was defined as worsening of previous or appearance of new symptoms after at least 3 months of clinical stabilization.

RESULTS

Among 210 patients, 30 (14%) experienced a total of 33 relapses. The median time to first relapse was 23.9 months (range: 4.9-110.1, interquartile range [IQR]: 17.8). The CSF was inflammatory in 11/25 (44%) relapses, while LGI1-Abs were found in the serum in 16/24 (67%) and in the CSF in 12/26 (46%); brain MRI was abnormal in 16/26 (62%) relapses. Compared with the initial episode, relapses manifested less frequently with 3 or more symptoms (4/30 patients, 13% vs 28/30, 93%; p < 0.001) and had lower maximal modified Rankin scale (mRS) score (median 3, range: 2-5, IQR: 1 vs 3, range: 2-5, IQR: 0; p = 0.001). The median mRS at last follow-up after relapse (2, range: 0-4, IQR: 2) was significantly higher than after the initial episode (1, range: 0-4, IQR: 1; p = 0.005). Relapsing patients did not differ in their initial clinical and diagnostic features from 85 patients without relapse. Nevertheless, residual cognitive dysfunction after the initial episode (hazard ratio:13.8, 95% confidence interval [1.5; 129.5]; p = 0.022) and no administration of corticosteroids at the initial episode (hazard ratio: 4.8, 95% confidence interval [1.1; 21.1]; p = 0.036) were significantly associated with an increased risk of relapse.

DISCUSSION

Relapses may occur years after the initial encephalitis episode and are usually milder but cause additional disability. Corticosteroid treatment reduces the risk of future relapses, while patients with residual cognitive dysfunction after the initial episode have an increased relapse risk.

Utilization of APE2 and RITE2 scores in autoimmune encephalitis patients with seizures

PURPOSE

Immune-mediated seizures are rare but are increasingly recognized as an etiology of seizures resistant to anti-seizure medications (ASMs). Antibody Prevalence in Epilepsy 2 (APE2) and Response to Immunotherapy in Epilepsy 2 (RITE2) scores were developed recently to identify patients who may be seropositive for serum central nervous system (CNS) specific antibodies (Ab) and may benefit from immunotherapy (Dubey et al. 2018). The goal of this study was to apply APE2 and RITE2 scores to an independent cohort of patients with seizures secondary to autoimmune encephalitis (AE) and to further verify the sensitivity and specificity of the scores.

PRINCIPAL RESULTS

We conducted a retrospective study at Stanford University Hospital between 2008 and 2021 and included patients who had acute seizures and AE using diagnostic criteria from Graus (n = 34 definite AE, 10 probable AE, and 12 possible AE) (Graus et al. 2016). Patients were excluded if they did not have a serum Ab panel investigated or had alternate diagnoses (n = 55). APE2 and RITE2 scores were calculated based on clinical and diagnostic data (n = 56). Serum Ab were positive in 73 % of patients, in which 63 % cases carried CNS specific Ab. An APE2 score ≥ 4 had a sensitivity of 97 % and specificity of 14 % to predict a positive serum CNS specific Ab. A RITE2 score ≥ 7 had a sensitivity of 93 % and specificity of 60 % to predict seizure responsiveness to immunotherapy.

CONCLUSION

APE2 and RITE2 scores had high sensitivities but low specificities to predict seropositivity and seizure responsiveness to immunotherapy in patients with autoimmune encephalitis with seizures.

Acute Symptomatic Seizures and Risk of Seizure Recurrence in Patients with Anti-NMDAR, Anti-LGI1, and Anti-GABABR Encephalitis

AIMS

To analyze the clinical characteristics of acute symptomatic seizures and predict the risk factors for seizure recurrence in patients with anti-N-methyl-D-aspartate receptor (NMDAR), anti-leucine-rich glioma-inactivated 1 (LGI1), and anti-gamma-aminobutyric acid B receptor (GABABR) encephalitis.

METHODS

In this retrospective study, we included hospitalized patients who had been diagnosed with anti-NMDAR, anti-LGI1, and anti-GABABR encephalitis between November 2014 and April 2021. Binary logistic regression analysis was performed to identify the potential risk factors for seizure recurrence.

RESULTS

In total, 262 patients with anti-NMDAR, anti-LGI1, and anti-GABABR encephalitis were included, 197 (75.2%) of whom presented with acute symptomatic seizures. During follow-up, 42 patients exhibited seizure recurrence. In anti-NMDAR encephalitis, frontal lobe abnormality on brain magnetic resonance imaging, delayed immunotherapy, early seizures, and focal motor onset were associated with seizure recurrence.

CONCLUSIONS

Acute symptomatic seizure is a common clinical feature observed in patients with anti-NMDAR, anti-LGI1, and anti-GABABR encephalitis, with 50% of patients presenting with seizures as an initial symptom. The prognosis of patients with acute symptomatic seizures can be improved after receiving immunotherapy. Nevertheless, a minority of patients will experience seizure recurrence; therefore, restarting immunotherapy is recommended.

Predictive value of persistent antibodies at 6 months for relapse in neuronal surface antibody-associated autoimmune encephalitis

BACKGROUND

For patients with neuronal surface antibody-associated autoimmune encephalitis (NSAE) whose clinical symptoms gradually improve, the recommended course of immunotherapy in China is about 6 months. We aim to explore the relationship between persistent antibody positivity when immunotherapy is discontinued at 6 months and subsequent relapse.

METHODS

Prospective inclusion of NSAE patients with clinical remission after 6-month immunotherapy. Their antibody titers and other clinical data were collected at onset and 6 months later. Based on the antibody test results at 6 months, patients were divided into an antibody-persistent group and an antibody-negative conversion group, and then the rate of relapse between the two groups were compared.

RESULTS

The study included 28 NSAE patients who were antibody-positive at diagnosis. After 6-month immunotherapy, there were 16 (57.1%) cases with persistent antibodies and 12 (42.9%) cases with antibody-negative conversion. In the acute phase of onset, seizures were more common in patients with persistent antibodies (87.5% vs. 50.0%, p = 0.044). During a mean follow-up period of 22 months, patients with persistent antibodies were more likely to experience relapse than those with antibody-negative conversion (37.5% vs. 0.0%, p = 0.024). There were no significant differences in antibody types, CSF findings, results of MRI and EEG, tumor combination, immunotherapy, and long-term outcome between the two groups (p > 0.05).

CONCLUSIONS

For patients with persistent antibodies when immunotherapy is discontinued at 6 months, persistent antibody positivity was associated with a higher relapse rate.

Prevalence and risk factors of early postoperative seizures in patients with glioma: a systematic review and meta-analysis

Objective

This study aimed to explore the prevalence and risk factors of early postoperative seizures in patients with glioma through meta-analysis.

Methods

Case-control studies and cohort studies on the prevalence and risk factors of early postoperative seizures in glioma patients were retrieved from various databases including CNKI, Wanfang, VIP, PubMed, Embase, Cochrane Library, and Web of Science, and the retrieval deadline for the data was 1 April 2023. Stata15.0 was used to analyze the data.

Results

This review included 11 studies consisting of 488 patients with early postoperative seizures and 2,051 patients without early postoperative seizures. The research findings suggest that the prevalence of glioma is complicated by seizures (ES = 19%, 95% confidence interval [CI] [14%-25%]). The results also indicated a history of seizures (RR = 1.94, 95% CI [1.76, 2.14], P = 0.001), preoperative dyskinesia (RR = 3.13, 95% CI [1.20, 8.15], P = 0.02), frontal lobe tumor (RR = 1.45, 95% CI [1.16, 1.83], P = 0.001), pathological grade ≤2 (RR = 1.74, 95% CI [1.13, 2.67], P = 0.012), tumor≥ 3 cm (RR = 1.70, 95% CI [1.18, 2.45], P = 0.005), tumor resection (RR = 1.60, 95% CI [1.36, 1.88], P = 0.001), tumor edema ≥ 2 cm (RR = 1.77, 95% CI [1.40, 2.25], P = 0.001), and glioma cavity hemorrhage (RR=3.15, 95% CI [1.85, 5.37], P = 0.001). The multivariate analysis results showed that a history of seizures, dyskinesia, tumor ≥3 cm, peritumoral edema ≥2 cm, and glioma cavity hemorrhage were indicated as risk factors for glioma complicated with early postoperative seizures.

Significance

Based on the existing evidence, seizure history, dyskinesia, frontal lobe tumor, pathological grade ≤2, tumor ≥3 cm, partial tumor resection, edema around tumor ≥2 cm, and glioma cavity hemorrhage are indicated as risk factors for glioma complicated with early postoperative seizures.

Canadian Consensus Guidelines for the Diagnosis and Treatment of Autoimmune Encephalitis in Adults

Autoimmune encephalitis is increasingly recognized as a neurologic cause of acute mental status changes with similar prevalence to infectious encephalitis. Despite rising awareness, approaches to diagnosis remain inconsistent and evidence for optimal treatment is limited. The following Canadian guidelines represent a consensus and evidence (where available) based approach to both the diagnosis and treatment of adult patients with autoimmune encephalitis. The guidelines were developed using a modified RAND process and included input from specialists in autoimmune neurology, neuropsychiatry and infectious diseases. These guidelines are targeted at front line clinicians and were created to provide a pragmatic and practical approach to managing such patients in the acute setting.

Autoimmune and paraneoplastic seizures

Seizures are a common feature of autoimmune encephalitis and are especially prevalent in patients with the commonest autoantibodies, against LGI1, CASPR2 and the NMDA, GABAB, and GABAA receptors. In this chapter, we discuss the classification, clinical, investigation, and treatment aspects of patients with these, and other autoantibody-mediated and -associated, illnesses. We highlight distinctive and common seizure semiologies which, often alongside other features we outline, can help the clinical diagnosis of an autoantibody-associated syndrome. Next, we classify these syndromes by either focusing on whether they represent underlying causative autoantibodies or T-cell-mediated syndromes and on the distinction between acute symptomatic seizures and a more enduring tendency to autoimmune-associated epilepsy, a practical and valuable distinction for both patients and clinicians which relates to the pathogenesis. We emphasize the more effective immunotherapy response in patients with causative autoantibodies, and discuss the emerging evidence for various first-, second-, and third-line immunotherapies. Finally, we highlight available clinical rating scales which can guide autoantibody testing and immunotherapy in patients with seizures of unknown etiology. Throughout, we relate the clinical and therapeutic observations to the immunobiology and neuroscience which drive these seizures.

The three pillars in treating antibody-mediated encephalitis

The rapid initiation of immunotherapy has a decisive impact on the course of the disease in patients with antibody-mediated encephalitis (AE). The importance of treating AE with antiseizure medication and antipsychotics is discussed controversially; however, standardized procedures should be ensured, especially for the initiation of treatment in severe disease. Recommendations and guidelines for further interventions in refractory courses are needed. In this review, we contrast the three mainstays of treatment options in patients with AE and attempt to highlight the importance of 1) antiseizure therapy, 2) antipsychotic therapy, and 3) immunotherapy/tumor resection from today's perspective.

Antibodies to neural cell surface and synaptic proteins in paraneoplastic neurologic syndromes

Among patients with paraneoplastic neurologic syndromes (PNS), emphasis has historically been placed on neural antibodies against intracellular proteins that have a strong association with malignancy. Because of the intracellular location of their antigenic targets, these antibodies are typically considered to be non-pathogenic surrogate markers of immune cell-mediated neural injury. Unfortunately, patients with these antibodies often have suboptimal response to immunotherapy and poor prognosis. Over the last two decades, however, dramatic advancements have been made in the discovery and clinical characterization of neural antibodies against extracellular targets. These antibodies are generally considered to be pathogenic, given their potential to directly alter antigen structure or function, and patients with these antibodies often respond favorably to prompt immunotherapy. These antibodies also associate with tumors and may thus occur as PNS, albeit more variably than neural antibodies against intracellular targets. The updated 2021 PNS diagnostic criteria, which classifies antibodies as high-risk, intermediate-risk, or lower-risk for an associated cancer, better clarifies how neural antibodies against extracellular targets relate to PNS. Using this recently created framework, the clinical presentations, ancillary test findings, oncologic associations, and treatment responses of syndromes associated with these antibodies are discussed.

Overview of treatment strategies in paraneoplastic neurological syndromes

Treatment strategies in paraneoplastic neurological syndromes rely on the three pillars of tumor treatment, immunotherapy, and symptomatic treatment, the first one being by far the most important in the majority of patients and syndromes. Classically, antibodies against extracellular antigens are directly pathogenic, and patients with these syndromes are more responsive to immunomodulatory or immunosuppressive treatments than the ones with antibodies against intracellular targets. This chapter first discusses some general principles of tumor treatment and immunotherapy, followed by a closer look at specific treatment options for different clinical syndromes, focusing on symptomatic treatments.

[Report of two cases of anti-LGI1 autoimmune encephalitis in Mexico]

Background: Anti-LGI1 encephalitis is characterized by a pattern of inflammation that predominantly affects the limbic system It is part of the autoimmune encephalitis that attack neuronal surface antigens. It is characterized by the triad of subacute dementia, faciobrachial dystonic crises, and hyponatremia, presenting an excellent response to immunotherapy. The aim of this article is to describe the clinical evolution and functional outcome at 6 months of two patients with anti-LGI1 encephalitis using clinical cases.

Clinical cases

Case 1: 62-year-old man with 8-week symptoms manifested by changes in mood, disorientation, and focal motor seizures. Case 2 A 72-year-old woman with a 5-month evolution of rapidly progressive dementia, hyponatremia and bitemporal hyperintensities on MRI. In both, due to clinical suspicion, acute dual immunotherapy with steroid and immunoglobulin was given with substantial improvement. Subsequently, the existence of anti-LGI1 antibodies in cerebrospinal fluid was confirmed. Although both patients received a dose of rituximab during their hospitalization, only the patient in the first case continued biannual doses of rituximab. The second patient was not initially considered to continue long-term immunomodulatory treatment and experienced a relapse.

Conclusions

These clinical vignettes present the reader with the classic characteristics of this disease. This can facilitate its recognition and timely initiation of treatment, improving the functional prognosis of patients.

Mechanisms and Emerging Therapies for Treatment of Seizures in Pediatric Autoimmune Encephalitis and Autoinflammatory/Autoimmune-Associated Epilepsy

There has been increasing understanding of the role of inflammation in seizures and epilepsy, as well as targeted immunomodulatory treatments. In children, immune-mediated seizures often present acutely in the setting of autoimmune encephalitis and are very responsive to immunotherapy with low rates of subsequent epilepsy. Conversely, seizures in autoimmune-associated epilepsies, such as Rasmussen syndrome, can remain refractory to multimodal therapy, including immunomodulation. In this review, the authors discuss the presentations of immune-mediated seizures in children, underlying mechanisms, and emerging therapies.

Clinical Reasoning: A Young Adult With New Seizures and Chapeau de Gendarme

The evaluation of new seizures is a common clinical query for neurologists. It can be challenging to delineate between the numerous etiologies of new focal or generalized seizures and, if focal, to localize their onset. In this case report, we present a 26-year-old patient with a new onset of stereotyped events concerning for seizures featuring facial grimacing, dystonic left-hand posturing, and convulsions with immediate return to baseline. Throughout the case, we highlight a stepwise diagnostic approach to the evaluation of new-onset seizures, discuss clues that seizure semiology can provide for localization of ictal onset, and review a novel and atypical presentation of a disease entity frequently encountered by neurologists.

Validation of different predictive scoring scales in patients with new-onset epileptic seizures or epilepsy related to neuronal surface antibody-mediated autoimmune encephalitis

OBJECTIVE

To validate the different predictive scoring scales in the Chinese population with new-onset epileptic seizures or epilepsy of unknown etiology related to neuronal surface antibody (Ab)-mediated autoimmune encephalitis (AE).

METHODS

We retrospectively reviewed the charts of 174 consecutive patients from October 2018 to December 2022, whose serum and cerebrospinal fluid samples were tested for neuronal surface Abs. The antibody prevalence in epilepsy and encephalopathy (APE2), antibodies contributing to focal epilepsy signs and symptoms (ACES), "obvious" indications for neural antibody testing in epilepsy or seizures (ONES) checklist, and the combinations were used to validate the predictive models of neuronal surface Ab-mediated AE.

RESULTS

A total of 139 patients with new-onset epileptic seizures or epilepsy of unknown etiology were enrolled. Abs were detected in 37 patients (26.6%). The APE2/ONES reflex score had the highest sensitivity (89.2%) and lowest specificity (41.7%). The ACES score had the lowest sensitivity (67.5%) and highest specificity (64.7%). Variations in the performance were observed in the different types of AE. 100% of patients with anti-γ-aminobutyric acid B-B receptor encephalitis were predicted by ONES, APE2/ONES reflex, and ACES/ONES reflex scores. Only 75% of patients with anti-N-methyl-D-aspartate receptor encephalitis were predicted by the APE2/ONES and ACES/ONES reflex scores.

CONCLUSION

Our study was the first to validate various predictive scoring scales in the Chinese cohort of patients with new-onset epileptic seizures or epilepsy of unknown etiology related to neuronal surface Ab-mediated AE. Based upon clinical suspicion, more than one scoring scale should be performed to predict the chance of AE in those patients.

What is autoimmune encephalitis-associated epilepsy? Proposal of a practical definition

Seizures resulting from cerebral autoimmunity are either acutely symptomatic in the context of autoimmune encephalitis (AIE) with neural surface antibodies, or they are indicative of an enduring predisposition to seizures, that is, epilepsy. Here, we propose a practical definition for autoimmune encephalitis-associated epilepsy (AEAE): Seizures associated with antibodies against glutamic acid decarboxylase, paraneoplastic syndromes, or Rasmussen encephalitis are classified as AEAE. AEAE secondary to AIE with antibodies against the N-methyl-D-aspartate receptor, leucine-rich glioma inactivated protein 1, contactin-associated protein-2, or γ-aminobutyric acid-B receptor can be diagnosed if the following criteria are met: seizures persist for at least 2 years after immunotherapy initiation; no signs of encephalitis on magnetic resonance imaging and no fluorodeoxyglucose positron emission tomography hypermetabolism; normal cerebrospinal fluid cell count; and a substantial decrease in antibody titers. This classification corresponds to different disease mechanisms. While AIE results from the pathogenic effects of neural antibodies, AEAE is probably the consequence of encephalitis-related tissue damage and thereby mainly structurally mediated. The distinction between AIE and AEAE also has practical consequences: In AIE, immunotherapy is usually highly beneficial, whereas anti-seizure medication has little effect. In AEAE, immunotherapy is less promising and the usual anti-seizure interventions are preferable. In addition, the diagnosis of AEAE has social consequences in terms of driving and professional limitations.

Efficacy of immunotherapy and prognosis in anti-LGI1 encephalitis patients: A meta-analysis

OBJECTIVE

To assess the efficacy and safety of immunotherapy for LGI1 antibody encephalitis, and consider the predictors of poor outcomes following immunotherapy.

METHODS

We searched PubMed and Embase for articles reporting the immunotherapy data of anti-LGI1 encephalitis patients. The proportions of patients with poor outcomes (modified Rankin Scale [mRS] score > 2) at 3 months, 12 months, and the last follow-up, as well as the odds ratio [OR] of predictors were pooled.

RESULTS

The review included 162 articles with 1066 patients. The proportion of patients with poor functional outcomes was 21% at 3 months, 14% at 12 months, and 14% at the last follow-up after receiving immunotherapy. The proportion of patients with reported relapse was 16.6%. The mean duration from onset to the first relapse was 15.6 months. Predictors significantly associated with poor outcomes were age (increase of 1 year), the presence of cognitive impairment, and CSF LGI1 antibody positive. We did not find a statistically significant association between the worst mRS score in the acute phase, the presence of faciobrachial dystonic seizures (FBDS), days from symptom onset to immunotherapy, second-line treatment, maintenance immunotherapy, or follow-up time and outcomes.

INTERPRETATION

Although most patients respond to immunotherapy, a minority of patients still have poor outcomes. Advanced age, cognitive impairment, and CSF LGI1 antibody positive are associated with an increased risk of poor outcomes. However, due to the insufficiency of the data, these conclusions need to be interpreted with caution.

Is There a Continuum Between Acute Symptomatic Seizures Secondary to Autoimmune Encephalitis and Autoimmune-Associated Epilepsy?

Seizure Underreporting in LGI1 and CASPR2 Antibody Encephalitis Baumgartner T, Pitsch J, Olaciregui-Dague K, Hoppe C, Racz A, Rüber T, Becker A, von Wrede R, Surges R. Epilepsia . 2022;63(9): e100-e105. doi:10.1111/epi.17338 . PMID: 35735209 Patients with anti-leucine-rich glioma-inactivated1 protein (LGI1) or anti-contactin-associated protein 2 (CASPR2) antibody encephalitis typically present with frequent epileptic seizures. The seizures generally respond well to immunosuppressive therapy, and the long-term seizure outcome seems to be favorable. Consequentially, diagnosing acute symptomatic seizures secondary to autoimmune encephalitis instead of autoimmune epilepsy was proposed. However, published data on long-term seizure outcomes in CASPR2 and LGI1 antibody encephalitis are mostly based on patient reports, and seizure underreporting is a recognized issue. Clinical records from our tertiary epilepsy center were screened retrospectively for patients with LGI1 and CASPR2 antibody encephalitis who reported seizure freedom for at least 3 months and received video-electroencephalography (EEG) for >24 h at follow-up visits. Twenty (LGI1, n = 15; CASPR2, n = 5) of 32 patients with LGI1 (n = 24) and CASPR2 (n = 8) antibody encephalitis fulfilled these criteria. We recorded focal aware and impaired awareness seizures in four of these patients (20%) with reported seizure-free intervals ranging from 3 to 27 months. Our results question the favorable seizure outcome in patients with CASPR2 and LGI1 antibody encephalitis and suggest that the proportion of patients who have persistent seizures may be greater. Our findings underline the importance of prolonged video-EEG telemetry in this population.

Seizure characteristics and outcomes in patients with neurological conditions related to high-risk paraneoplastic antibodies

OBJECTIVE

Seizures are a common manifestation of paraneoplastic neurologic syndromes. The objective of this study was to describe the seizure characteristics and outcomes in patients with high-risk paraneoplastic autoantibodies (>70% cancer association) and to determine factors associated with ongoing seizures.

METHODS

Patients from 2000 to 2020 with seizures and high-risk paraneoplastic autoantibodies were retrospectively identified. Factors associated with ongoing seizures at last follow-up were evaluated.

RESULTS

Sixty patients were identified (34 males, median age at presentation = 52 years). ANNA1-IgG (Hu; n = 24, 39%), Ma2-IgG (n = 14, 23%), and CRMP5-IgG (CV2; n = 11, 18%) were the most common underlying antibodies. Seizures were the initial presenting symptom in 26 (43%), and malignancy was present in 38 (63%). Seizures persisted for >1 month in 83%, and 60% had ongoing seizures, with almost all patients (55/60, 92%) still being on antiseizure medications at last follow-up a median of 25 months after seizure onset. Ongoing seizures at last follow-up were associated with Ma2-IgG or ANNA1-IgG compared to other antibodies (p = .04), highest seizure frequency being at least daily (p = .0002), seizures on electroencephalogram (EEG; p = .03), and imaging evidence of limbic encephalitis (LE; p = .03). Death occurred in 48% throughout the course of follow-up, with a higher mortality in patients with LE than in those without LE (p = .04). Of 31 surviving patients at last follow-up, 55% continued to have intermittent seizures.

SIGNIFICANCE

Seizures in the setting of high-risk paraneoplastic antibodies are frequently resistant to treatment. Ongoing seizures are associated with ANNA1-IgG and Ma2-IgG, high seizure frequency, and EEG and imaging abnormalities. Although a subset of patients may respond to immunotherapy and achieve seizure freedom, poor outcomes are frequently encountered. Death was more common among patients with LE.

Autoimmune Encephalitis with Antibodies: Anti-NMDAR, Anti-AMPAR, Anti-GQ1b, Anti-DPPX, Anti-CASPR2, Anti-LGI1, Anti-RI, Anti-Yo, Anti-Hu, Anti-CV2 and Anti-GABAAR, in the Course of Psychoses, Neoplastic Diseases, and Paraneoplastic Syndromes

Encephalitis is a condition with a variety of etiologies, clinical presentations, and degrees of severity. The causes of these disorders include both neuroinfections and autoimmune diseases in which host antibodies are pathologically directed against self-antigens. In autoimmune encephalitis, autoantibodies are expressed in the central nervous system. The incidence of this disease is approximately 4% of all reported cases of encephalitis. Autoimmune encephalitis can be induced by antibodies against neuronal surface antigens such as N-methyl-D-aspartate-activated glutamate receptors (NMDAR), α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors (AMPAR) or gangliosides GQ1b, DPPX, CASPR2, LGI1, as well as by antibodies against neuronal intracellular antigens. The paper presents a number of both mental and neurological symptoms of autoimmune encephalitis. Moreover, the coexistence of psychoses, neoplastic diseases, and the methods of diagnosing autoimmune encephalitis are discussed. Attention was also drawn to the fact that early diagnosis, as well as early initiation of targeted treatment, increases the chance of a successful course of the therapeutic process. Strategy and Methodology: The articles on which the following paper was based were searched using search engines such as PubMed and Medline. Considering that anti-NMDAR antibodies were first described in 2007, the articles were from 2007 to 2023. The selection of papers was made by entering the phrases "autoimmune encephalitis and psychosis/paraneplastic syndromes or cancer". The total number of articles that could be searched was 747, of which 100 items were selected, the most recent reports illustrating the presented topic. Thirty-four of them were rejected in connection with case reports or papers that could not be accessed.

Predictors of seizure outcomes of autoimmune encephalitis: A clinical and morphometric quantitative analysis study

OBJECTIVE

Autoimmune encephalitis can be followed by treatment-resistant epilepsy. Understanding its predictors and mechanisms are crucial to future studies to improve autoimmune encephalitis outcomes. Our objective was to determine the clinical and imaging predictors of postencephalitic treatment-resistant epilepsy.

METHODS

We performed a retrospective cohort study (2012-2017) of adults with autoimmune encephalitis, both antibody positive and seronegative but clinically definite or probable. We examined clinical and imaging (as defined by morphometric analysis) predictors of seizure freedom at long term follow-up.

RESULTS

Of 37 subjects with adequate follow-up data (mean 4.3 yrs, SD 2.5), 21 (57 %) achieved seizure freedom after a mean time of 1 year (SD 2.3), and one third (13/37, 35 %) discontinued ASMs. Presence of mesial temporal hyperintensities on the initial MRI was the only independent predictor of ongoing seizures at last follow-up (OR 27.3, 95 %CI 2.48-299.5). Morphometric analysis of follow-up MRI scans (n = 20) did not reveal any statistically significant differences in hippocampal, opercular, and total brain volumes between patients with postencephalitic treatment-resistant epilepsy and those without.

SIGNIFICANCE

Postencephalitic treatment-resistant epilepsy is a common complication of autoimmune encephalitis and is more likely to occur in those with mesial temporal hyperintensities on acute MRI. Volume loss in the hippocampal, opercular, and overall brain on follow-up MRI does not predict postencephalitic treatment-resistant epilepsy, so additional factors beyond structural changes may account for its development.

Development from recurrent anti-N-methyl-D-aspartate receptor encephalitis with seizures as the first symptom to autoimmune-associated epilepsy: a case report

BACKGROUND

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a novel autoimmune encephalitis (AE) first identified in 2007. It provides a new direction for clinicians when encountering unexplained symptoms such as seizures, psychotic behavioral abnormalities, speech disorders, and involuntary movements. Most patients have a good prognosis after immunotherapy, but some may experience relapses.

CASE PRESENTATION

We report a Chinese female patient diagnosed with anti-NMDAR encephalitis. Over the past 30 years, the patient had experienced eight episodes with seizures as the first symptom, which eventually progressed to autoimmune-associated epilepsy. In the last two episodes, both serum and cerebrospinal fluid of the patient were negative for AE-related antibodies, and brain magnetic resonance imaging (MRI) revealed abnormal hyperintensity in the bilateral hippocampi. The patient's symptoms were poorly controlled by immunotherapy but well controlled by anti-seizure medicines.

CONCLUSIONS

Patients with a long history of AE and multiple relapses that start with seizures may display alterations of brain structure. Physicians should pay attention to autoimmune-associated epilepsy.

Assessment of disease severity and patient prognosis in anti-GABABR encephalitis with and without comorbid tumors

Purpose

This study aimed to analyze the severity of the condition and prognosis of patients with anti-gamma-aminobutyric-acid type B receptor (anti-GABA_BR) encephalitis with tumors.

Methods

Patients with anti-GABA_BR encephalitis admitted to one of two hospitals from 2020 to 2022 were enrolled and divided into tumor and non-tumor groups. The clinical characteristics, condition severity, treatment options, and prognosis of the two groups of patients were compared and analyzed.

Results

Eighteen patients with anti-GABA_BR encephalitis were included, ten of whom had tumors. The comparison of clinical characteristics showed that rates of status epilepticus and coma were significantly higher in the group with tumors (P = 0.013 and P = 0.025, respectively); the incidences of pulmonary infection, respiratory failure, hyponatremia, and hypoproteinemia were also substantially more frequent in the tumor group (P = 0.054, P = 0.036, P = 0.015, and P = 0.025, respectively). The laboratory test result comparison showed that serum neuron-specific enolase (NSE) and carcinoembryonic antigen (CEA) were present only in the group with tumors (P = 0.036 and P = 0.092, respectively), but there was no significant difference in the occurrence of elevated CEA between the two groups. Conversely, the percentage of serum systemic autoimmune antibodies was higher in the group without tumors than in the group with tumors (P = 0.043). Patients with tumors tended to have poor outcomes (P = 0.152, OR: 7.000).

Conclusion

Severe brain damage and complications occur in patients with anti-GABA_BR encephalitis and comorbid tumors. Early screening for serum NSE and CEA helps in the early diagnosis and treatment of tumors. The prognosis is much worse for anti-GABA_BR encephalitis with tumors.

The micro and macro interactions in acute autoimmune encephalitis: a study of resting-state EEG

Objective

Early recognition of autoimmune encephalitis (AIE) is often difficult and time-consuming. Understanding how the micro-level (antibodies) and macro-level (EEG) couple with each other may help rapidly diagnose and appropriately treat AIE. However, limited studies focused on brain oscillations involving micro- and macro-interactions in AIE from a neuro-electrophysiological perspective. Here, we investigated brain network oscillations in AIE using Graph theoretical analysis of resting state EEG.

Methods

AIE Patients (n = 67) were enrolled from June 2018 to June 2022. Each participant underwent a ca.2-hour 19-channel EEG examination. Five 10-second resting state EEG epochs with eyes closed were extracted for each participant. The functional networks based on the channels and Graph theory analysis were carried out.

Results

Compared with the HC group, significantly decreased FC across whole brain regions at alpha and beta bands were found in AIE patients. In addition, the local efficiency and clustering coefficient of the delta band was higher in AIE patients than in the HC group (P < 0.05). AIE patients had a smaller world index (P < 0.05) and higher shortest path length (P < 0.001) in the alpha band than those of the control group. Also, the AIE patients' global efficiency, local efficiency, and clustering coefficients decreased in the alpha band (P < 0.001). Different types of antibodies (antibodies against ion channels, antibodies against synaptic excitatory receptors, antibodies against synaptic inhibitory receptors, and multiple antibodies positive) showed distinct graph parameters. Moreover, the graph parameters differed in the subgroups by intracranial pressure. Correlation analysis revealed that magnetic resonance imaging abnormalities were related to global efficiency, local efficiency, and clustering coefficients in the theta, alpha, and beta bands, but negatively related to the shortest path length.

Conclusion

These findings add to our understanding of how brain FC and graph parameters change and how the micro- (antibodies) scales interact with the macro- (scalp EEG) scale in acute AIE. The clinical traits and subtypes of AIE may be suggested by graph properties. Further longitudinal cohort studies are needed to explore the associations between these graph parameters and recovery status, and their possible applications in AIE rehabilitation.

Spatial and Ecological Factors Modulate the Incidence of Anti-NMDAR Encephalitis-A Systematic Review

Anti-NMDAR encephalitis has been associated with multiple antigenic triggers (i.e., ovarian teratomas, prodromal viral infections) but whether geographic, climatic, and environmental factors might influence disease risk has not been explored yet. We performed a systematic review and a meta-analysis of all published papers reporting the incidence of anti-NMDAR encephalitis in a definite country or region. We performed several multivariate spatial autocorrelation analyses to analyze the spatial variations in the incidence of anti-NMDA encephalitis depending on its geographical localization and temperature. Finally, we performed seasonal analyses in two original datasets from France and Greece and assessed the impact of temperature using an exposure-lag-response model in the French dataset. The reported incidence of anti-NMDAR encephalitis varied considerably among studies and countries, being higher in Oceania and South America (0.2 and 0.16 per 100,000 persons-year, respectively) compared to Europe and North America (0.06 per 100,000 persons-year) (p < 0.01). Different regression models confirmed a strong negative correlation with latitude (Pearson's R = -0.88, p < 0.00001), with higher incidence in southern hemisphere countries far from the equator. Seasonal analyses showed a peak of cases during warm months. Exposure-lag-response models confirmed a positive correlation between extreme hot temperatures and the incidence of anti-NMDAR encephalitis in France (p = 0.03). Temperature analyses showed a significant association with higher mean temperatures and positive correlation with higher ultraviolet exposure worldwide. This study provides the first evidence that geographic and climatic factors including latitude, mean annual temperature, and ultraviolet exposure, might modify disease risk.

Paraneoplastic Neurological Syndromes of the Central Nervous System: Pathophysiology, Diagnosis, and Treatment

Paraneoplastic neurological syndromes (PNS) include any symptomatic and non-metastatic neurological manifestations associated with a neoplasm. PNS associated with antibodies against intracellular antigens, known as "high-risk" antibodies, show frequent association with underlying cancer. PNS associated with antibodies against neural surface antigens, known as "intermediate- or low-risk" antibodies, are less frequently associated with cancer. In this narrative review, we will focus on PNS of the central nervous system (CNS). Clinicians should have a high index of suspicion with acute/subacute encephalopathies to achieve a prompt diagnosis and treatment. PNS of the CNS exhibit a range of overlapping "high-risk" clinical syndromes, including but not limited to latent and overt rapidly progressive cerebellar syndrome, opsoclonus-myoclonus-ataxia syndrome, paraneoplastic (and limbic) encephalitis/encephalomyelitis, and stiff-person spectrum disorders. Some of these phenotypes may also arise from recent anti-cancer treatments, namely immune-checkpoint inhibitors and CAR T-cell therapies, as a consequence of boosting of the immune system against cancer cells. Here, we highlight the clinical features of PNS of the CNS, their associated tumors and antibodies, and the diagnostic and therapeutic strategies. The potential and the advance of this review consists on a broad description on how the field of PNS of the CNS is constantly expanding with newly discovered antibodies and syndromes. Standardized diagnostic criteria and disease biomarkers are fundamental to quickly recognize PNS to allow prompt treatment initiation, thus improving the long-term outcome of these conditions.

Registry-Based Phenotyping to Improve the Diagnosis of Autoimmune Encephalitis

Seizure Semiology in Antibody-Associated Autoimmune Encephalitis

Kaaden T, Madlener M, Angstwurm K, Bien CG, Bogarin Y, Doppler K, Finke A, Gerner ST, Reimann G, Häusler M, Handreka R, Hellwig K, Kaufmann M, Kellinghaus C, Koertvelyessy P, Kraft A, Lewerenz J, Menge T, Paliantonis A, von Podewils F, Prüss H, Rauer S, Ringelstein M, Rostásy K, Schirotzek I, Schwabe J, Sokolowski P, Suesse M, Sühs K-W, Surges R, Tauber SC, Thaler F, Bergh FT, Urbanek C, Wandinger K-P, Wildemann B, Mues S, Zettl U, Leypoldt F, Melzer N, Geis C, Malter M, Kunze A; The Generate Study Group. Neurol Neuroimmunol Neuroinflamm. 2022;9(6):e200034. doi:10.1212/NXI.0000000000200034

Background and Objectives:

To assess seizure characteristics in antibody (ab)-associated autoimmune encephalitis (ab +AE) with the 3 most prevalent abs against N-methyl-D-aspartate receptor (NMDAR), leucine rich glioma-inactivated protein 1 (LGI1), and glutamic acid decarboxylase (GAD).

Methods:

Multicenter nationwide prospective cohort study of the German Network for Research in Autoimmune Encephalitis.

Results:

Three hundred twenty patients with ab + AE were eligible for analysis: 190 NMDAR+, 89 LGI1+, and 41 GAD+. Seizures were present in 113 (60%) NMDAR+, 69 (78%) LGI1+, and 26 (65%) GAD+ patients and as leading symptoms for diagnosis in 53 (28%) NMDAR+, 47 (53%) LGI+, and 20 (49%) GAD+ patients. Bilateral tonic-clonic seizures occurred with almost equal frequency in NMDAR+ (38/51, 75%) and GAD+ (14/20, 70%) patients, while being less common in LGI1+ patients (27/59, 46%). Focal seizures occurred less frequently in NMDAR+(67/113; 59%) than in LGI1+ (54/69, 78%) or in GAD+ patients (23/26; 88%). An aura with deja-vu phenomenon was nearly specific in GAD+ patients (16/20, 80%). Faciobrachial dystonic seizures (FBDS) were uniquely observed in LGI1+ patients (17/59, 29%). Status epilepticus was reported in one-third of NMDAR+ patients, but only rarely in the 2 other groups. The occurrence of seizures was associated with higher disease severity only in NMDAR+ patients.

Discussion:

Seizures are a frequent and diagnostically relevant symptom of ab + AE. Whereas NMDAR+ patients had few localizing semiological features, semiology in LGI1+ and GAD+ patients pointed toward a predominant temporal seizure onset. FBDS are pathognomonic for LGI1 + AE. Status epilepticus seems to be more frequent in NMDAR + AE.

Epileptic Phenotypes in Autoimmune Encephalitis: From Acute Symptomatic Seizures to Autoimmune-Associated Epilepsy

Matricardi S, Casciato S, Bozzetti S, Mariotto S, Stabile A, Freri E, Deleo F, Sartori S, Nosadini M, Pappalardo I, Meletti S, Giovannini G, Zucchi E, Di Bonaventura C, Di Gennaro G, Ferrari S, Zuliani L, Zoccarato M, Vogrig A, Lattanzi S, Michelucci R, Gambardella A, Ferlazzo E, Fusco L, Granata T, Villani F; On behalf of the Immune Epilepsies Study Group of the Italian League Against Epilepsy. J Neurol Neurosurg Psychiatry. 2022;93(11). doi:10.1136/jnnp-2022-329195

Objective:

To describe the clinical and paraclinical findings, treatment options and long-term outcomes in autoimmune encephalitis (AE), with a close look to epilepsy.

Methods:

In this retrospective observational cohort study, we enrolled patients with new-onset seizures in the context of AE. We compared clinical and paraclinical findings in patients with and without evidence of antibodies.

Results:

Overall, 263 patients (138 females; median age 55 years, range 4–86) were followed up for a median time of 30 months (range 12–120). Antineuronal antibodies were detected in 63.50%. Antibody-positive patients had multiple seizure types (p = 0.01) and prevalent involvement of temporal regions (p = 0.02). A higher prevalence of episodes of SE was found in the antibody-negative group (p < 0.001). Immunotherapy was prescribed in 88.60%, and effective in 61.80%. Independent predictors of favourable outcome of the AE were early immunotherapy (p < 0.001) and the detection of antineuronal surface antibodies (p = 0.01). Autoimmune-associated epilepsy was the long-term sequela in 43.73%, associated with cognitive and psychiatric disturbances in 81.73%. Independent predictors of developing epilepsy were difficult to treat seizures at onset (p = 0.04), a high number of antiseizure medications (p < 0.001), persisting interictal epileptiform discharges at follow-up (p < 0.001) and poor response to immunotherapy during the acute phase (p < 0.001).

Conclusions:

The recognition of seizures secondary to AE represents a rare chance for aetiology-driven seizures management. Early recognition and treatment at the pathogenic level may reduce the risk of long-term irreversible sequelae. However, the severity of seizures at onset is the major risk factor for the development of chronic epilepsy. This study provides class IV evidence for management recommendations.

Current and emerging pharmacotherapy for the treatment of Lennox-Gastaut syndrome

INTRODUCTION

Lennox-Gastaut syndrome (LGS) is a severe childhood-onset epileptic encephalopathy, characterized by multiple seizure types, generalized slow spike-and-wave complexes in the EEG, and cognitive impairment. Seizures in LGS are typically resistant to treatment with antiseizure medications (ASMs). Tonic/atonic ('drop') seizures are of particular concern, due to their liability to cause physical injury.

AREAS COVERED

We summarize evidence for current and emerging ASMs for the treatment of seizures in LGS. The review focuses on findings from randomized, double-blind, placebo-controlled trials (RDBCTs). For ASMs for which no double-blind trials were identified, lower quality evidence was considered. Novel pharmacological agents currently undergoing investigation for the treatment of LGS are also briefly discussed.

EXPERT OPINION

Evidence from RDBCTs supports the use of cannabidiol, clobazam, felbamate, fenfluramine, lamotrigine, rufinamide, and topiramate as adjunct treatments for drop seizures. Percentage decreases in drop seizure frequency ranged from 68.3% with high-dose clobazam to 14.8% with topiramate. Valproate continues to be considered the first-line treatment, despite the absence of RDBCTs specifically in LGS. Most individuals with LGS will require treatment with multiple ASMs. Treatment decisions should be individualized and take into account adverse effects, comorbidities, general quality of life, and drug interactions, as well as individual efficacy.

Anti-LGI1 encephalitis with initiating symptom of seizures in children

Background

Anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis is infrequently reported but more and more recognizable in children. Here we give detailed description of the clinical features and long-term outcome of three cases of childhood onset anti-LGI1 encephalitis.

Methods

Three anti-LGI1 encephalitis patients were hospitalized in the Department of Pediatrics at Qilu Hospital of Shandong University. Data about the clinical manifestations, treatments and long-term follow-up outcomes were described in detail.

Results

Case 1 showed an adolescent girl with initiating symptom of acute-onset frequent focal seizures. Her serum LGI1-antibody test was positive, and she had a good response to antiseizure medication (ASM) and IVIG. Case 2 showed a preschool-age boy with long-period refractory focal seizures and recent behavioral change. Both serum and cerebrospinal fluid (CSF) tests of LGI1-antibody were positive, and the MRI showed progressive atrophy in the left hemisphere. The symptoms got improved after receiving second-line immunotherapy initially but there are still the sequelae of drug-resistant epilepsy and mild to moderate intellectual disability. Case 3 showed an adolescent boy with initiating symptom of acute-onset frequent focal seizures. Both serum and CSF tests of LGI1-antibody were positive, and he had a good response to immunotherapy. By analyzing all literature-reported 19 pediatric cases, we found pediatric anti-LGI1 encephalitis is more common in female and adolescent. Seizures and behavioral changes were the most common symptoms. CSF pleocytosis and LGI1-antibodies results were mostly negative. Most patients showed good response to immunotherapy.

Conclusion

Childhood onset anti-LGI1 encephalitis is a heterogeneous clinical syndrome, ranging from typical limbic encephalitis to isolating focal seizures. It is important to test autoimmune antibodies when encountering similar cases and repeat antibody testing if necessary. Timely recognition leads to earlier diagnosis and more rapid initiation of effective immunotherapy and potentially better outcomes.