Treatment of immune-mediated temporal lobe epilepsy with GAD antibodies

Anti-GAD65 musicogenic epilepsy: Bilateral and independent mesial temporal seizures revealed by foramen ovale electrodes

Musicogenic epilepsy (ME) is characterized by seizures triggered by music. The epileptogenic focus in this rare reflex epilepsy is often in the temporal lobe, although the precise localization is still unclear. A correlation between ME and the presence of GAD65 antibodies indicates a potential immunological pathogenic mechanism. We evaluated a 32-year-old woman with drug-resistant temporal lobe epilepsy as a candidate for epilepsy surgery. In the absence of clear clinical lateralizing signs, video-EEG monitoring with intracranial electrodes inserted through the foramen ovale was performed to record from the amygdalo-hippocampal regions. The foramen ovale electrodes revealed bilateral, asynchronous, and independent seizure onsets in the mesial temporal regions triggered by music. Testing for GAD65 antibodies confirmed high-titer positivity. The efficacy of epilepsy surgery in antiGAD65-positive ME patients remains limited. We highlight the use of semi-invasive recording with foramen ovale electrodes in ME, as it can reveal bilateral seizures of mesial origin that contraindicate surgery and support the consideration of immunotherapy options. PLAIN LANGUAGE SUMMARY: Musicogenic epilepsy is a type of epilepsy in which music triggers seizures. Our understanding of its origin and cause is still limited. We assessed a patient with music-induced seizures to see if surgery was an option. Since noninvasive tests before surgery were not clear, we used a minimally invasive method with electrodes inserted through a small opening in the skull called the foramen ovale to record the seizures. Thus, we found that the seizures started independently from both temporal lobes, contraindicating epilepsy surgery. We also found high levels of GAD65 antibodies indicating an immunological pathogenic mechanism.

CSF and blood signatures support classification of limbic encephalitis subtypes

Autoimmune limbic encephalitis (ALE) represents a heterogeneous disease associated with antibodies targeting extracellular (ALEextra) epitopes, intracellular (ALEintra) epitopes, anti-glutamic acid decarboxylase65 ALE (ALEGAD65), and ALE without detectable antibodies (ALEabneg). Combining analysis of cellular parameters, investigated by flow cytometry, and soluble parameters in the blood and cerebrospinal fluid (CSF) from a large cohort of 148 ALE patients (33 ALEextra, 12 ALEintra, 28 ALE-GAD65, 37 ALEabneg) in comparison to paradigmatic examples for neuro-inflammatory (51 relapsing remitting MS patients (RRMS)), and neuro-degenerative (34 Alzheimer's disease patients (AD)) diseases revealed discrete immune signatures in ALE subgroups. Identification of ALE-subtype specific markers facilitated classification of rare ALE-associated tumors, which may prompt further diagnostic efforts in clinical practice. While ALEintra exhibited features of neuro-inflammation, ALEextra displayed features of neuro-inflammation as well as neuro-degeneration. Moreover, ALEGAD65 and ALEabneg lacked hallmarks of inflammation. This may explain the low efficacy of anti-inflammatory treatment regimens in ALEGAD65 and presumably also ALEabneg.

Identifying Key Prognostic Indicators for Relapse and Chronic Epilepsy in Autoimmune Encephalitis: Insights from a Multicenter Retrospective Study

Objective

The aims of this study were to investigate clinical factors associated with encephalitis relapse and chronic epilepsy development, and to evaluate the effectiveness of immunotherapy on encephalitis relapse.

Methods

Patients with autoimmune encephalitis diagnosed as positive for neuronal surface antibodies in five general hospitals were included. A minimum 12-month follow-up period was conducted, and binary logistic regression analysis was used to identify predictors of encephalitis relapse and chronic epilepsy development. Additionally, decision curve analysis (DCA) was employed to assess the clinical net benefit of predicting encephalitis relapse and chronic epilepsy.

Results

The study encompassed 65 patients with autoimmune encephalitis. The one-year relapse rate for encephalitis was 13.9%. The CASE score (P=0.045) was associated with encephalitis relapse, with subsequent immunotherapy proving beneficial in enhancing outcomes. Chronic epilepsy prevalence at one year was 26.2%, particularly higher among patients with positive LGI1 antibodies. Although adjustments in antiseizure medications were partially effective, 41.2% of patients developed drug-resistant epilepsy (DRE). DCA confirmed that the predictive models provided significant net clinical benefit in assessing the risk of encephalitis relapse and chronic epilepsy. Notably, the presence of diffuse cortical atrophy, medial temporal lobe atrophy, or cerebellar hemisphere atrophy was linked to relapsing encephalitis and chronic epilepsy.

Conclusion

Most cases of autoimmune encephalitis are effectively managed, however, a minority of patients experience relapse or chronic epilepsy. The CASE score and LGI1 antibodies are independent risk factors for encephalitis relapse and chronic epilepsy development, respectively. Immunotherapy remains beneficial for relapsing patients, yet a portion may progress to DRE. Individuals with relapses and chronic epilepsy are predisposed to the development of cortical, temporal lobe, and cerebellar atrophy.

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.

Focused review: Clinico-neuropathological aspects of late onset epilepsies: Pathogenesis

The aim of the present study was to review the current knowledge on the neuropathological spectrum of late onset epilepsies. Several terms including 'neuropathology*' AND 'late onset epilepsy' (LOE) combined with distinct neuropathological diagnostic terms were used to search PubMed until November 15, 2023. We report on the relevance of definitional aspects of LOE with implications for the diagnostic spectrum of epilepsies. The neuropathological spectrum in patients with LOE is described and includes vascular lesions, low-grade neuroepithelial neoplasms and focal cortical dysplasias (FCD). Among the latter, the frequency of the FCD subtypes appears to differ between LOE patients and those with seizure onset at a younger age. Neurodegenerative neuropathological changes in the seizure foci of LOE patients require careful interdisciplinary interpretation with respect to the differential diagnosis of primary neurodegenerative changes or epilepsy-related changes. Innate and adaptive neuroinflammation represents an important cause of LOE with intriguing therapeutic options.

Immunotherapy in a case of low titre GAD65 antibody-associated spectrum neurological disorders

We present a rare case of low titre GAD65 antibody-associated autoimmune encephalitis and status epilepticus in a young woman. She initially presented with left arm dystonic movements, contractures and status epilepticus. Due to the concern of autoimmune encephalitis and seizures, the patient received intravenous immunoglobulin empirically. After the detection of low serum GAD65 antibodies, the patient underwent immunomodulation therapy with significant improvement. This case demonstrated that in autoimmune encephalitis, it is important to monitor serum GAD65 antibodies levels and consider immunotherapy, despite mildly elevated serum levels. The patient's history of left arm dystonic movements without impaired awareness may have been due to limb dystonia, a presenting symptom of stiff person syndrome (SPS), despite SPS more commonly affecting axial muscles. This case further demonstrates that GAD65 antibody-related syndromes can manifest with different neurological phenotypes including co-occurrence of epilepsy with possible focal SPS despite low GAD65 antibodies titres.

Anticonvulsive treatment in autoimmune encephalitis: a systematic literature review

BACKGROUND

Epileptic seizures are a common manifestation of autoimmune encephalitis (AIE). Immunosuppression (IT) is an efficient therapeutic approach, particularly in AIE associated with antibodies against extracellular structures. The role of antiseizure medication (ASM) is less clear. However, it may be beneficial in disease refractory to IT or in chronic post-AIE epilepsy.

METHODS

We conducted a systematic review assessing the PubMed and Cochrane databases to identify all reports on patients with epileptic seizures due to AIE in whom ASM was used and report it according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. We included case series (minimum 3 eligible patients), retrospective and prospective observational studies, and randomized controlled trials. The main outcome assessed was therapeutic efficacy of ASM. Secondary outcomes comprise number, type, and adverse effects of ASM. Descriptive statistics were used. The level of evidence was assessed according to the Centre for Evidence-Based Medicine.

RESULTS

We screened a total of 3371 studies and included 30 (7 prospective, 23 retrospective). The reports cover a total of 708 patients, the majority (72.5%) suffering from AIE with antibodies against extracellular structures. Type of AIE, seizure frequency, and number and type of ASM used were heterogenous. While most patients profited from IT and/or ASM, the effect of ASM could rarely be isolated. Nine studies report on patients who received ASM monotherapy or were on ASM for a relevant length of time before IT initiation or after IT failure. One study reports a significant association between seizure freedom and use of sodium channel inhibitors. However, levels of evidence were generally low.

CONCLUSION

Few robust data exist on the particular efficacy of ASM in autoimmune epileptic seizures. While these patients generally seem to respond less well to ASM or surgical interventions, sodium channel blockers may have an additional benefit compared to other substances. However, levels of evidence are low and early IT remains the mainstay of AIE therapy. Future trials should address optimal ASM selection and dosing in AIE.

Paraneoplastic encephalitis

The first reports of encephalitis associated with cancer date to the 1960s and were characterized by clinical and pathologic involvement of limbic areas. This specific association was called limbic encephalitis (LE). The subsequent discovery of several "onconeural" antibodies (Abs), i.e., Abs targeting an antigen shared by neurons and tumor cells, supported the hypothesis of an autoimmune paraneoplastic etiology of LE and other forms of rapidly progressive encephalopathy. Over the past 20 years, similar clinical pictures with different clinical courses have been described in association with novel Abs-binding neuronal membrane proteins and proved to be pathogenic. The most well-known encephalitis in this group was described in 2007 as an association of a complex neuro-psychiatric syndrome, N-methyl-d-aspartate (NMDA) receptor-Abs, and ovarian teratoma in young women. Later on, nonparaneoplastic cases of NMDA receptor encephalitis were also described. Since then, the historical concept of LE and Ab associated encephalitis has changed. Some of these occur in fact more commonly in the absence of a malignancy (e.g., anti-LG1 Abs). Lastly, seronegative cases were also described. The term paraneoplastic encephalitis nowadays encompasses different syndromes that may be triggered by occult tumors.

An update on malignant tumor-related stiff person syndrome spectrum disorders: clinical mechanism, treatment, and outcomes

Stiff person syndrome (SPS) is a rare central nervous system disorder associated with malignancies. In this review, we retrieved information from PubMed, up until August 2023, using various search terms and their combinations, including SPS, stiff person syndrome spectrum disorders (SPSSDs), paraneoplastic, cancer, and malignant tumor. Data from peer-reviewed journals printed in English were organized to explain the possible relationships between different carcinomas and SPSSD subtypes, as well as related autoantigens. From literature searching, it was revealed that breast cancer was the most prevalent carcinoma linked to SPSSDs, followed by lung cancer and lymphoma. Furthermore, classic SPS was the most common SPSSD subtype, followed by stiff limb syndrome and progressive encephalomyelitis with rigidity and myoclonus. GAD65 was the most common autoantigen in patients with cancer and SPSSDs, followed by amphiphysin and GlyR. Patients with cancer subtypes might have multiple SPSSD subtypes, and conversely, patients with SPSSD subtypes might have multiple carcinoma subtypes. The first aim of this review was to highlight the complex nature of the relationships among cancers, autoantigens, and SPSSDs as new information in this field continues to be generated globally. The adoption of an open-minded approach to updating information on new cancer subtypes, autoantigens, and SPSSDs is recommended to renew our database. The second aim of this review was to discuss SPS animal models, which will help us to understand the mechanisms underlying the pathogenesis of SPS. In future, elucidating the relationship among cancers, autoantigens, and SPSSDs is critical for the early prediction of cancer and discovery of new therapeutic modalities.

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.

GAD65 Antibody-Associated Epilepsy

Autoimmune processes are an increasingly recognized cause of seizures. Antibodies against neuronal surface antigens are implicated in the development of acute symptomatic seizures secondary to autoimmune encephalitis, whereas antibodies against intracellular antigens (anti-glutamic acid decarboxylase (GAD) and onconeural antibodies) are found in cases of autoimmune-associated epilepsy (AAE). AAE is described as isolated drug-resistant epilepsy without any specific magnetic resonance imaging (MRI) or cerebrospinal fluid changes and with a very limited response to immunotherapy. We present a clinical case and a literature review on autoimmune-associated epilepsy to increase awareness of this disease and illustrate its complexity. This is a clinical case of a female with a history of refractory focal epilepsy. The patient had been given several trials of multiple antiepileptic drugs and their combinations without any clear effect. Multiple evaluations including brain MRI, PET, and interictal and ictal electroencephalograms were performed. An APE2 score was calculated with a result of 4 and, in the presence of anti-GAD65 antibodies in the serum, the diagnosis of AAE was confirmed. There was no effect after five sessions of plasma exchange; however, after a course of intravenous immunoglobulin, a positive but temporary clinical effect was noticed: anti-GAD65 levels initially decreased but rebounded to previous levels 6 months later.

Glutamic acid decarboxylase antibody-associated neurological syndromes: Clinical and antibody characteristics and therapy response

BACKGROUND

Antibodies against glutamic acid decarboxylase (GAD-abs) at high serum levels are associated with diverse autoimmune neurological syndromes (AINS), including cerebellar ataxia, epilepsy, limbic encephalitis and stiff-person syndrome. The impact of low serum GAD-ab levels in patients with suspected AINS remains controversial. Specific intrathecal GAD-ab synthesis may serve as a marker for GAD-ab-associated nervous system autoimmunity. We present characteristics of a multicentric patient cohort with suspected AINS associated with GAD antibodies (SAINS-GAD+) and explore the relevance of serum GAD-ab levels and intrathecal GAD-ab synthesis.

METHODS

All patients with SAINS-GAD+ included in the registry of the German Network for Research on Autoimmune Encephalitis (GENERATE) from 2011 to 2019 were analyzed. High serum GAD-ab levels were defined as RIA>2000 U/mL, ELISA>1000 U/mL, or as a positive staining pattern on cell-based assays.

RESULTS

One-hundred-one patients were analyzed. In descending order they presented with epilepsy/limbic encephalitis (39%), cerebellar ataxia (28%), stiff person syndrome (22%), and overlap syndrome (12%). Immunotherapy was administered in 89% of cases with improvements in 46%. 35% of SAINS-GAD+ patients had low GAD-ab serum levels. Notably, unmatched oligoclonal bands in CSF but not in serum were more frequent in patients with low GAD-ab serum levels. GAD-ab-levels (high/low) and intrathecal GAD-ab synthesis (present or not) did not impact clinical characteristics and outcome.

CONCLUSIONS

Overall, immunotherapy in SAINS-GAD+ was moderately effective. Serum GAD-ab levels and the absence or presence of intrathecal GAD-ab synthesis did not predict clinical characteristics or outcomes in SAINS-GAD+. The detection of unmatched oligoclonal bands might outweigh low GAD-ab serum levels.

Use of anti-seizure medications in different types of autoimmune encephalitis: A narrative review

Seizures are the main manifestation of the acute phase of autoimmune encephalitis (AE). Anti-seizure medications (ASMs) play an important role in controlling seizures in AE patients, but there is currently a lack of consensus regarding the selection, application, and discontinuation of ASMs. This narrative review focuses on the use of ASMs in patients with AE driven by different antibodies. The PubMed, Embase, and MEDLINE databases were searched up until 30 October 2022 using prespecified search terms. We identified 2,580 studies; 23 retrospective studies, 2 prospective studies and 9 case reports were evaluated based on our inclusion criteria. Anti-N-methyl-D-aspartic-acid-receptor (anti-NMDAR) encephalitis is the type of AE that responds best to ASMs, and long-term or combined use of ASMs may be not required in most patients with seizures; these results apply to both adults and children. Sodium channel blockers may be the best option for seizures in anti-leucine-rich-glioma-inactivated-1 (anti-LGI1) encephalitis, but patients with anti-LGI1 encephalitis are prone to side effects when using ASMs. Cell surface antibody-mediated AE patients are more likely to use ASMs for a long period than patients with intracellular antibody-mediated AE. Clinicians can score AE patients' clinical characteristics on a scale to identify those who may require long-or short-term use of ASMs in the early stage. This review provides some recommendations for the rational use of ASMs in encephalitis mediated by different antibodies with the aim of controlling seizures and avoiding overtreatment.

Seizures, Epilepsy, and NORSE Secondary to Autoimmune Encephalitis: A Practical Guide for Clinicians

The most recent International League Against Epilepsy (ILAE) classification has included "immune etiology" along with other well-known causes of epilepsy. This was possible thanks to the progress in detection of pathogenic neural antibodies (Abs) in a subset of patients, and resulted in an increased interest in identifying potentially treatable causes of otherwise refractory seizures. Most autoimmune encephalitides (AE) present with seizures, but only a minority of cases evolve to long-term epilepsy. The risk of epilepsy is higher for patients harboring Abs targeting intracellular antigens (T cell-mediated and mostly paraneoplastic, such as Hu, CV2/CRMP5, Ma2, GAD65 Abs), compared with patients with neuronal surface Abs (antibody-mediated and less frequently paraneoplastic, such as NMDAR, GABAbR, LGI1, CASPR2 Abs). To consider these aspects, conceptual definitions for two entities were provided: acute symptomatic seizures secondary to AE, and autoimmune-associated epilepsy, which reflect the different pathophysiology and prognoses. Through this manuscript, we provide an up-to-date review on the current state of knowledge concerning diagnosis and management of patients with Ab-mediated encephalitis and associated epilepsy. Special emphasis is placed on clinical aspects, such as brain magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) specificities, electroencephalographic (EEG) findings, cancer screening and suggestions for a rational therapeutic approach.

Diagnosis and Clinical Features in Autoimmune-Mediated Movement Disorders

Movement disorders are common manifestations in autoimmune-mediated encephalitis. This group of diseases is suspected to be triggered by infection or neoplasm. Certain phenotypes correlate with specific autoantibody-related neurological disorders, such as orofacial-lingual dyskinesia with N-methyl-D-aspartate receptor encephalitis and faciobrachial dystonic seizures with leucine-rich glioma-inactivated protein 1 encephalitis. Early diagnosis and treatment, especially for autoantibodies targeting neuronal surface antigens, can improve prognosis. In contrast, the presence of autoantibodies against intracellular neuronal agents warrants screening for underlying malignancy. However, early clinical diagnosis is challenging because these diseases can be misdiagnosed. In this article, we review the distinctive clinical phenotypes, magnetic resonance imaging findings, and current treatment options for autoimmune-mediated encephalitis.

Histopathologic Characterization and Neurodegenerative Markers in Patients With Limbic Encephalitis Undergoing Epilepsy Surgery

Purpose

Limbic encephalitis is an increasingly recognized cause of medial temporal lobe epilepsy (mTLE) and associated cognitive deficits, potentially resulting in hippocampal sclerosis (HS). For several reasons, these patients usually do not undergo epilepsy surgery. Thus, histopathologic examinations in surgical specimens of clearly diagnosed limbic encephalitis are scarce. The purpose of this study was a detailed histopathologic analysis of surgical tissue alterations, including neurodegenerative markers, in patients with limbic encephalitis undergoing epilepsy surgery.

Methods

We investigated the surgical specimens of six patients operated on with mTLE related to limbic encephalitis (among them four patients were with GAD65 and one with Ma1/2 antibodies), and compared the findings to a control group with six patients matched according to age at the time of surgery without limbic encephalitis and without early inciting events.

Results

Histopathologic analysis in the group with limbic encephalitis revealed HS in four patients, while three of them also displayed signs of an active inflammatory reaction with lymphocytes. In one of the patients with GAD65-encephalitis who was suffering from a late-onset mTLE and a long disease course, neurodegenerative protein markers (β-amyloid and hyperphosphorylated tau) were found coexisting with inflammatory reactions and HS. Investigations in the control group did not reveal any inflammatory reaction or neurodegenerative marker.

Conclusion

Our findings suggest a possible link between long-lasting immune reactions in the medial temporal lobe, HS, and further toward the development of neurodegenerative diseases. Presently, however, a causal relationship between these entities cannot yet be established. Furthermore, our results suggest that an immunological etiology should always be considered in late onset (> 18 years) mTLE, also in cases of long disease duration and the presence of HS.

Case Report: Multisystem Autoimmune and Overlapping GAD65-Antibody-Associated Neurological Disorders With Beneficial Effect of Epilepsy Surgery and Rituximab Treatment

Glutamic acid decarboxylase (GAD) antibodies are associated with disabling conditions such as stiff person syndrome, temporal lobe epilepsy (TLE), limbic encephalitis, cerebellar ataxia (CA), and ocular movement disorders, which are usually chronic and difficult to treat. GAD-related TLE has poor response to anti-seizure medications and immune therapies, and epilepsy surgery is rarely successful. We report on a 47-year-old female with history of migraine, autoimmune thyroid disease, ankylosing spondylitis, and drug-resistant TLE. A video electroencephalography recorded frequent seizures with temporo-insular semiology, correlating to left temporal epileptiform activity and left mesiotemporal hyperintensity on magnetic resonance imaging. GAD autoimmunity was confirmed by very high GAD antibody titers in serum and cerebrospinal fluid. Steroids, immunoglobulins, and cyclophosphamide had no effect, and selective left amygdalectomy was performed based on very restricted hypermetabolism on positron-emission tomography. After transient seizure freedom, significant epilepsy improvement was observed in spite of memory decline. Transient worsening was noted 1 year later during diabetes mellitus manifestation and 5 years later during presentation of progressive CA, which stabilized on rituximab treatment. We believe this case illustrates the diversity and the frequent overlap of GAD-associated disorders, the need of early and aggressive immunotherapy in severe patients, as well as the possible benefit from epilepsy surgery in some GAD-TLE.

Hyperosmolar hyperglycaemic state causing atypical status epilepticus with hippocampal involvement

Diabetes mellitus may arise abruptly and decompensate suddenly, leading to a hyperglycaemic hyperosmolar state. Coma often ensues, although this usually reverses after the metabolic abnormalities have resolved. Acute symptomatic seizures can also occur in patients who are conscious, although these usually resolve after osmolarity and glycaemia have normalised. We describe an elderly woman who failed to regain vigilance despite prompt treatment; the cause was an unusual non-convulsive status epilepticus arising from the mesial temporal lobe and promoting a progressive and selective hippocampal involvement. During follow-up, her seizures recurred after stopping antiseizure medication and she developed hippocampal sclerosis, although she subsequently became seizure-free with antiseizure medications. Patients who are unresponsive in a hyperglycaemic hyperosmolar state may be having subclinical epileptiform discharges and risk developing permanent brain damage and long-term epilepsy.

Rituximab Treatment and Long-term Outcome of Patients With Autoimmune Encephalitis: Real-world Evidence From the GENERATE Registry

BACKGROUND AND OBJECTIVES

To determine the real-world use of rituximab in autoimmune encephalitis (AE) and to correlate rituximab treatment with the long-term outcome.

METHODS

Patients with NMDA receptor (NMDAR)-AE, leucine-rich glioma-inactivated-1 (LGI1)- AE, contactin-associated protein-like-2 (CASPR2)-AE, or glutamic acid decarboxylase 65 (GAD65) disease from the GErman Network for Research on AuToimmune Encephalitis who had received at least 1 rituximab dose and a control cohort of non-rituximab-treated patients were analyzed retrospectively.

RESULTS

Of the 358 patients, 163 (46%) received rituximab (NMDAR-AE: 57%, CASPR2-AE: 44%, LGI1-AE: 43%, and GAD65 disease: 37%). Rituximab treatment was initiated significantly earlier in NMDAR- and LGI1-AE (median: 54 and 155 days from disease onset) compared with CASPR2-AE or GAD65 disease (median: 632 and 1,209 days). Modified Rankin Scale (mRS) scores improved significantly in patients with NMDAR-AE, both with and without rituximab treatment. Although being more severely affected at baseline, rituximab-treated patients with NMDAR-AE more frequently reached independent living (mRS score ≤2) (94% vs 88%). In LGI1-AE, rituximab-treated and nontreated patients improved, whereas in CASPR2-AE, only rituximab-treated patients improved significantly. No improvement was observed in patients with GAD65 disease. A significant reduction of the relapse rate was observed in rituximab-treated patients (5% vs 13%). Detection of NMDAR antibodies was significantly associated with mRS score improvement. A favorable outcome was also observed with early treatment initiation.

DISCUSSION

We provide real-world data on immunosuppressive treatments with a focus on rituximab treatment for patients with AE in Germany. We suggest that early and short-term rituximab therapy might be an effective and safe treatment option in most patients with NMDAR-, LGI1-, and CASPR2-AE.

CLASS OF EVIDENCE

This study provides Class IV evidence that rituximab is an effective treatment for some types of AE.

The Search for Autoimmune-Associated Epilepsy Continues-Are We Getting Closer to Our Target?

Clinical Features Which Predict Neuronal Surface Autoantibodies in New-Onset Focal Epilepsy: Implications for Immunotherapies

McGinty RN, Handel A, Moloney T, et al. J Neurol Neurosurg Psychiatry. 2020;92(3):291-294. doi:10.1136/jnnp-2020-325011

Objective:

To generate a score which clinically identifies surface-directed autoantibodies in adults with new-onset focal epilepsy and evaluate the value of immunotherapy in this clinical setting.

Methods:

Prospective clinical and autoantibody evaluations in a cohort of 219 consecutive patients with new-onset focal epilepsy.

Results:

A total of 10.5% (23/219) of people with new-onset focal epilepsy had detectable serum autoantibodies to known or novel cell surface antigenic targets. Nine of 23 with autoantibodies were diagnosed with encephalitis, by contrast to 0/196 without autoantibodies (P < .0001). Multivariate analysis identified 6 features which predicted autoantibody positivity (area under the curve = 0.83): age ≥54 years, ictal piloerection, lowered self-reported mood, reduced attention, magnetic resonance imaging limbic system changes, and the absence of conventional epilepsy risk factors. Eleven (79%) of 14 patients with detectable autoantibodies, but without encephalitis, showed excellent long-term outcomes (modified Rankin Score = 0) despite no immunotherapy. These outcomes were superior to those of immunotherapy-treated patients with confirmed autoantibody-mediated encephalitis (P < .05).

Conclusions:

Seizure semiology, cognitive and mood phenotypes, alongside inflammatory investigation findings, aid the identification of surface autoantibodies among unselected people with new-onset focal epilepsy. The excellent immunotherapy-independent outcomes of autoantibody-positive patients without encephalitis suggest immunotherapy administration should be guided by clinical features of encephalitis, rather than autoantibody positivity. Our findings suggest that, in this cohort, immunotherapy-responsive seizure syndromes with autoantibodies largely fall under the umbrella of autoimmune encephalitis.