Clinical features of limbic encephalitis with LGI1 antibody

Clinical features, cerebrospinal fluid changes, and prognosis in Chinese patients with autoimmune encephalitis

INTRODUCTION

Autoimmune encephalitis (AE) is a rare, treatable disease of the central nervous system (CNS) caused by an antibody-related immune response. This study is to investigate the correlation of clinical features, cerebrospinal fluid (CSF) characteristics, and prognosis in patients with AE.

METHODS

A total of 71 patients diagnosed with antibody-positive AE were retrospectively analyzed. The patients were divided into three groups: anti-NMDAR group, anti-LGI1 group, and other types. Clinical data were collected to analyze clinical features and CSF results, and prognosis was determined by modified Rankin Scale (mRS).

RESULTS

There was statistical difference in the incidences of decreased consciousness level (P < 0.001), memory loss (P = 0.017), speech disorders (P = 0.035), and dyskinesia (P = 0.001) in different antibodies groups. Younger age (P = 0.018), elevated CSF chloride content (P = 0.006), and white blood cells > 50/mm3 (P = 0.026) were highly correlated with ICU admission. Anti-LGI1 encephalitis had a relatively small risk for ICU admission (P = 0.034), and a lower risk of poor functional recovery (P = 0.048) and recurrence (P = 0.041). Patients with first-line treatment failure (P = 0.021) had an increased risk of poor functional recovery. Delayed treatment (P = 0.011) would increase the risk of recurrence.

CONCLUSION

There are differences in age, gender, clinical characteristics, and CSF results in different subtypes of AE. First-line therapy failure would have poor functional recovery, and delayed therapy would increase the risk of relapse. Chloride ion content and white blood cell count in cerebrospinal fluid are positively correlated with the patient's exacerbation and admission to ICU. These indicators have certain clinical value for the prognosis of AE patients.

Autoimmune encephalitis : Part 1 (Epidemiology, Pathophysiology and Clinical spectrum)

Since the identification of anti-N-methyl-D-aspartate (NMDA) receptor antibodies about 15 years ago, many patients with rapidly progressing psychiatric symptoms, abnormal movements, seizures or unexplained coma, have been diagnosed with autoimmune encephalitis (AE). The symptom onset is often unspecific and might mimic psychiatric disease, but the later course is frequently characterized by severe disease, often requiring intensive care. Clinical and immunological criteria are helpful in identifying the patients, but no biomarkers exist to guide the clinician in therapy or predict outcome. While persons of all ages can be affected by AE, some types of AE affect more children and young adults and are more prevalent in women. This review will focus on encephalitides associated with neuronal cell-surface or synaptic antibodies, which can result in characteristic syndromes, and are often recognizable on clinical grounds. AE subtypes associated with antibodies against extracellular epitopes can occur with or without tumours. Because the antibodies bind and alter the function of the antigen, the effects are often reversible if immunotherapy is initiated, and the prognosis is favourable in most instances. The first part of this series will introduce the topic, provide an overview of current neuronal surface antibodies and how they present, describe the most common subtype, anti-NMDA receptor encephalitis, and discuss the difficulties in recognizing patients with underlying AE amongst patients with new onset psychiatric disorders.

Anti-leucine-rich glioma inactivated protein 1 encephalitis with sleep disturbance as the first symptom: A case report and review of literature

BACKGROUND

Anti-leucine-rich glioma inactivated protein 1 (anti-LGI1) encephalitis is an infrequent type of autoimmune encephalitis (AE) characterized by acute or subacute cognitive and psychiatric disturbance, facio-brachial dystonic seizures (FBDSs), and hyponatremia. Anti-LGI1 AE has increasingly been considered a primary form of AE. Early identification and treatment of this disease are clearly very important.

CASE SUMMARY

Here, we report that a male patient developed severe anti-LGI1 encephalitis, which was initially misdiagnosed as a sleep disturbance. He was hospitalized for epileptic seizures and typical FBDSs half a month after he developed sleep disturbances. LGI1 antibodies were detected in his cerebrospinal fluid and serum (1:100 and 1:3.2, respectively), which led to the diagnosis of classic anti-LGI1 AE. No obvious abnormality was observed on brain computed tomography images. T2-weighted fluid-attenuated inversion recovery and T2-weighted scans of brain magnetic resonance imaging (MRI) showed slightly elevated signals within the left basal ganglia area. No tumor was detected within the brain of this patient using MRI. After hormone and antiepileptic drug treatment, the patient’s symptoms improved significantly.

CONCLUSION

Anti-LGI1 antibody-associated encephalitis has characteristic clinical manifestations, such as cognitive impairment, psychiatric symptoms, seizures, sleep disorders, hyponatremia, and FBDSs. LGI1 antibodies are present in the serum and/or cerebrospinal fluid, but their production is sensitive to immunosuppressants, and this disease has a relatively good prognosis. In particular, we should be aware of the possibility of anti-LGI1 antibody-associated encephalitis in adolescents with sleep disorders to avoid missed diagnoses and misdiagnoses.

Important Clues for the Diagnosis of Anti-LGI1-Antibody Autoimmune Encephalitis: A Case Report

Anti-leucine-rich-glioma-inactivated 1 (LGI1) antibody autoimmune encephalitis is a rare autoimmune encephalitis. We present a 68-year-old female patient who initially presented with episodic confusion, hallucinations, behavioral changes, and unexplained hyponatremia. History was also remarkable for intermittent abnormal movement affecting the left upper extremity and face. She was initially thought to be suffering from dementia and was discharged home. However, progressive symptoms led to her second admission, where evidence of autonomic dysfunction with episodic bradycardia and persistent symptomatic orthostatic hypotension were evident. Generalized cortical hyperexcitability and subclinical seizures were seen. Diagnosis of LGI1 encephalitis was confirmed with a positive Anti-LGI1 antibody in the cerebrospinal fluid, and treatment with intravenous immunoglobulin and steroids improved her cognitive function. This case helps to highlight important features that should raise early clinical suspicion of LGI1 encephalitis, including unexplained progressive hyponatremia, autonomic dysfunction, and frequent refractory seizures. This can lead to earlier recognition of this condition, where earlier implementation of immunosuppressive therapy is linked to better clinical outcomes and brain structural preservation.

Overlapping Autoimmune Neurological Syndrome: A Case Report of Triple-Positive Antibody

The presentation of several autoimmune neurological disorders in a single patient is rare and often debilitating. However, early diagnosis and efficacious treatment can lead to a significant recovery. Here, we present an interesting case of a triple antibody-positive autoimmune neurological syndrome patient who manifested the clinical features of neuromyelitis optica (NMO) spectrum disorder (NMOSD), N-methyl-D-aspartate (NMDA) receptor (NMDAR) encephalitis, and myasthenia gravis (MG). Hence, the patient manifested both central and peripheral nervous system immune-mediated neurological syndromes. A middle-aged female with a history of seropositive aquaporin-4 (AQP4) NMOSD on mycophenolate 1 g twice daily presented with severe fatigue and right eye ptosis (three months since NMOSD diagnosis) and tested positive for acetylcholine receptor (AchR) binding antibody, consistent with MG. Six months after the patient’s NMOSD diagnosis, she began to experience subacute progressive cognitive decline, behavioral changes, imbalance, anxiety/panic attacks, and paranoid delusions. NMDAR encephalitis was suspected, and she tested positive for cerebrospinal fluid NMDAR antibodies. After treatment with steroids failed, she was given two doses of rituximab 1 g, two weeks apart, and reported improvement in her symptoms shortly after the second dose.

Neuropsychological and Structural Neuroimaging Outcomes in LGI1-Limbic Encephalitis: A Case Study

OBJECTIVE

Anti-leucine-rich glioma-inactivated 1 limbic encephalitis (LGI1-LE) is a rare autoimmune condition that affects the structural integrity and functioning of the brain's limbic system. Little is known about its impact on long-term neuropsychological functioning and the structural integrity of the medial temporal lobe. Here we examined the long-term neuropsychological and neuroanatomical outcomes of a 68-year-old male who acquired LGI1-LE.

METHODS

Our case patient underwent standardized neuropsychological testing at two time points. Volumetric analyses of T1-weighted images were undertaken at four separate time points and qualitatively compared with a group of age-matched healthy controls.

RESULTS

At the time of initial assessment, our case study exhibited focal impairments in verbal and visual episodic memory and these impairments continued to persist after undergoing a course of immunotherapy. Furthermore, in reference to an age-matched healthy control group, over the course of 11 months, volumetric brain imaging analyses revealed that areas of the medial temporal lobe including specific hippocampal subfields (e.g., CA1 and dentate gyrus) underwent a subacute period of volumetric enlargement followed by a chronic period of volumetric reduction in the same regions.

CONCLUSIONS

In patients with persisting neurocognitive deficits, LGI1-LE may produce chronic volume loss in specific areas of the medial temporal lobe; however, this appears to follow a subacute period of volume enlargement possibly driven by neuro-inflammatory processes.

Confusion and Hallucination in a Geriatric Patient. Pitfalls of a Rare Differential: Case Report of an Anti-LGI1-Encephalitis

Background

Confusion and hallucinations in geriatric patients are frequent symptoms and typically associated with delirium, late-life psychosis or dementia syndromes. A far rarer but well-established differential in patients with rapid cognitive deterioration, acute psychosis, abnormal movements and seizures is autoimmune encephalitis. Exemplified by our case we highlight clinical and economic problems arising in management of geriatric patients with cognitive decline and psychotic symptoms.

Case Presentation

A 77-year-old female caucasian patient with an unremarkable medical history was hospitalized after a fall in association with diarrhea and hyponatremia. Upon adequate therapy, disorientation and troubled short-term memory persisted. Within a week the patient developed visual hallucinations. Basic blood and urine samples and imaging (cranial computed tomography and magnetic resonance imaging) were unremarkable. With progressive cognitive decline, amnestic impairment, word finding difficulty and general apathy, psychiatric and neurologic expertise was introduced. Advanced diagnostics did not resolve a final diagnosis; an electroencephalogram showed unspecific generalized slowing. Extended clinical observation revealed visual hallucinations and faciobrachial dystonic seizures. A treatment with anticonvulsants was initiated. Cerebrospinal fluid ultimately tested positive for voltage-gated potassium channel LGl1 (leucine-rich-inactivated-1) antibodies confirming diagnosis of autoimmune anti-LGI1 encephalitis. Immediate immunotherapy (high-dose glucocorticoids and administration of intravenous immunoglobulin G) led to a rapid improvement of the patient’s condition. After immunotherapy was tapered, the patient had one relapse and completely recovered with reintroduction of glucocorticoids and initiation of therapy with rituximab.

Conclusion

Rapidly progressive dementia in geriatric patients demands a structured and multidisciplinary diagnostic approach. Accurate management and financially supportable care is a major issue in rare diseases such as anti-LGI1-encephalitis. Education and awareness about autoimmune encephalitis of all physicians treating a geriatric population is important in order to involve expertise and establish treatment within reasonable time.

A systematic review and quantitative synthesis of the long-term psychiatric sequelae of pediatric autoimmune encephalitis

BACKGROUND

Long-term neuropsychiatric sequelae of autoimmune encephalitis (AE) remain understudied, particularly in pediatric-onset AE. We aimed to synthesize the published data on ongoing psychiatric symptoms in pediatric-onset AE.

METHODS

The Pubmed, PyscINFO, Web of Science databases were searched from their inception years to August 23, 2021, and 29 studies were identified and analyzed. We also performed a quantitative synthesis of available patient data from the 29 studies combined with a cohort of anti-NMDA receptor (NMDAR) AE from our institution to examine the associations between acute treatment course and long-term psychiatric outcome.

RESULTS

At long-term follow up, 52.4% of the cases with pediatric-onset AE had any persistent symptom and 36.0% had at least one psychiatric symptom. Pooled data found that 36.3% of pediatric-onset anti-NMDAR AE had ongoing psychiatric symptoms. Using a univariate logistic regression analysis, we found that abnormal initial EEG, use of certain immunotherapies, and persistent cognitive impairments were associated with ongoing psychiatric symptoms.

LIMITATIONS

Limitations of the existing literature included a significant paucity of outcomes measured using consistent, objective methods. Limitations of the systematic review included the wide variability among the studies reviewed, which rendered a meta-analysis impossible and beyond the scope of the paper.

CONCLUSION

Chronic psychiatric and behavioral problems remain present in one-third of children months to years after onset of AE. Larger scaled prospective observational studies with a consistent standardized battery of testing are needed to examine impact of specific clinical features and immunotherapies on long-term mental health outcomes.

Faciobrachial Dystonic Seizures as a Sign of Relapse in a Child with LGI-1 Encephalitis

We report an interesting case of a young girl with LGI1-antibody encephalitis who presented at 7 years old with very frequent seizures and severe neurocognitive decline. She responded very well to high dose corticosteroids and intravenous immunoglobulin (IVIG) initially but relapsed after 7 months. The relapse included frequent faciobrachial dystonic seizures (FBDS) that were successfully treated with rituximab. This case report highlights a few important points about LGI1-antibody encephalitis in children to help clinicians recognize this condition early and start prompt treatment with immunosuppressants. Data is lacking about LGI1-antibody encephalitis in children as it is mostly reported in adults. Our patient presented with frequent drug-resistant seizures including FBDS, along with amnesia, confusion, medial temporal lobe involvement, and hyponatremia similar to the presentation in adults. In contrast, none of the patients in the recent systematic review had FBDS or hyponatremia, making our case unique and suggesting variability in clinical presentation in children similar to adults. To our knowledge, FBDS have never been reported in children and our patient was initially misdiagnosed as having Childhood Epilepsy with Centrotemporal spikes. Since receiving rituximab, our patient is seizure-free for 1 year and 9 months and was successfully weaned of topiramate. She is going to school and has normal attention, concentration, memory, and mood. We propose early consideration of rituximab to accelerate recovery and prevent relapse.

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.

Immunopsychiatry: An Update on Autoimmune Encephalitis for Neuropsychiatrists

INTRODUCTION

Autoimmune encephalitis (AIE) is a group of immune-mediated inflammatory processes of the brain with marked psychiatric features. Although relatively rare, they might offer difficult differential diagnosis with psychiatric conditions, especially catatonia and psychotic syndromes. Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is the most common AIE, presenting with psychiatric syndromes in 90% of cases. The associated psychopathology is complex, pleomorphic and best characterized when there is involvement of a psychiatrist in the assessment.

AREAS COVERED

This text will review the main aspects of AIE to psychiatrists and/or neuropsychiatrists.

EXPERT OPINION

Immune system dysfunction has been implicated in the pathophysiology of psychiatric symptoms and disorders. The use of diagnostic criteria of possible AIE, especially when specific antibodies of AIE are not available, allows early diagnosis and prompt treatment which are associated with better clinical outcomes. The study of the psychiatric aspects of AIE can broaden our knowledge of the underlying mechanisms of various psychiatric manifestations.

Altered Mental Status in the Emergency Department - When to Consider Anti-LGI-1 Encephalitis: Case Report

Introduction

Anti-leucine-rich glioma inactivated-1 (LGI-1) is one of few antibodies implicated in limbic encephalitis, a syndrome that can result in permanent neurological symptoms if left untreated.

Case Report

We present a patient with dystonic seizures, progressive cognitive decline, psychiatric symptoms and short-term memory loss, and mild hyponatremia diagnosed with anti-LGI-1 antibody limbic encephalitis.

Conclusion

There are few reports in the emergency medicine community describing anti-LGI-1 antibody limbic encephalitis. Delay in diagnosis can risk irreversible limbic damage. Therefore, it is important for the emergency physician to be aware of anti-LGI-1 antibody limbic encephalitis when presented with adult-onset seizures and altered mental status of unknown etiology.

Sleep Disturbances in Autoimmune Neurologic Diseases: Manifestation and Pathophysiology

Autoimmune neurologic diseases are a new category of immune-mediated disease demonstrating a widely varied spectrum of clinical manifestations. Recently, sleep disturbances in patients with autoimmune neurologic diseases have been reported to have an immense negative impact on the quality of life. Excessive daytime sleep, rapid eye movement sleep behavior disorder (RBD), and narcolepsy are the most frequent sleep disorders associated with autoimmune neurologic diseases. Sleep disturbances might be the initial symptoms of disease or persist throughout the course of the disease. In this review, we have discussed sleep disturbances in different autoimmune neurologic diseases and their potential pathophysiological mechanisms.

Clinical features of nine cases of leucine-rich glioma inactivated 1 protein antibody-associated encephalitis

To investigate clinical features of leucine-rich glioma inactivated 1 protein (LGI1) antibody-associated autoimmune encephalitis (AE). The clinical data were collected and analyzed in nine patients with LGI1 AE. All nine patients (100%) presented acute/subacute onset, had seizures, cognitive impairment, mental/behavioral abnormalities, six had sleep disorders and seven showed hyponatremia. Seizures manifested in three types: faciobranchial dystonia seizure (FBDS) (44%), mesial temporal lobe epilepsy (MTLE)-like seizure (66%), and focal to bilateral tonic-clonic seizure (FBTCS) (77%). Six of nine cases (66%) showed abnormalities in brain MRI, among them four showed high T2/flair signal on unilateral/bilateral hippocampus, two showed high T1/T2 signal on unilateral basal ganglia. All nine patients (100%) showed abnormalities in EEG, among them 1 (11%) showed diffuse slow waves, 8 (88%) showed focal slow waves; 6 (66%) revealed interictal epileptic discharges; ictal EEG was recorded in five patients, two were FBDS, three were MTLE-like seizure.LGI1 antibodies in serum and cerebrospinal fluid were both positive. No signs of tumor were found in all patients. Eight of nine patients received immunotherapy and antiepileptic drug (AED) treatment, one only treated with AED without immunotherapy. Eight patients improved significantly with seizure-free after immunotherapy, only one still had FBDS after immunotherapy and AED treatment. In LGI1 AE hippocampus and basal ganglia were two main targets, the corresponding seizure type was MTLE-like seizure and FBDS respectively. Diagnosis depended on detection of LGI1 antibodies in CSF. The incidence of tumor was low. The effect of immunotherapy was good and AEDs should be considered as add-on symptomatic treatment.

Case Report/Case Series: Rare case of anti-LGI1 limbic encephalitis with rapidly progressive dementia, psychiatric symptoms, and frequently seizures: A case report

RATIONALE

Anti leucine-rich glioma inactivated 1 (LGI1) limbic encephalitis (LE) is rare autoimmune encephalitis, characterized by acute or subacute cognitive impairment, faciobrachial dystonic seizures, mental disorders, and refractory hyponatremia. As a type of treatable rapidly progressive dementia with a good prognosis, early, and accurate diagnosis is essential. We present a case of anti-LGI1 LE who was initially misdiagnosed with Alzheimer disease because his clinical manifestations were similar to Alzheimer disease.

PATIENT CONCERNS

A male patient presenting with rapidly progressive dementia, faciobrachial dystonic seizures, psychiatric disturbance, and refractory hyponatremia was admitted. The scores of Mini-Mental State Examination, Montreal Cognitive Assessment, and Neuropsychiatric Inventory were 19/30, 16/30, and 91/144, respectively. Brain magnetic resonance images indicated moderate atrophy of the hippocampus and abnormally hyperintensities in the left medial temporal and hippocampus.

DIAGNOSIS

The patient was diagnosed with anti-LGI1 LE based on the presence of LGI-1 antibodies in the cerebrospinal fluid and serum and clinical manifestations.

INTERVENTIONS

Patient was treated with glucocorticoid against LGI1, antiepileptic drug, cholinesterase inhibitors, and other adjuvant therapy.

OUTCOMES

The patient showed marked improvement on immunotherapy. Clinical symptoms were disappeared and the LGI-1 antibodies in cerebrospinal fluid and serum were both negative at the time of discharge.

CONCLUSIONS

Recognition of the specific symptoms and LGI-1 antibody test will be helpful for the early diagnosis, prompt immunotherapy, and good prognosis. This case raises the awareness that rapidly progressive dementia with frequent seizures could be caused by immunoreactions.

Clinical Characteristics and Long-Term Prognosis of Anti-LGI1 Encephalitis: A Single-Center Cohort Study in Beijing, China

Background: This study aimed to analyze the clinical characteristics of anti-leucine-rich glioma-inactivated protein 1 (LGI1) encephalitis patients and investigate prognostic factors by using a large-sample and long-term follow-up cohort.

Methods: The clinical data of 45 patients (29 males; mean age, 57.0 years) from May 2014 to August 2019 were collected. All patients were followed up by face-to-face interviews in the third month after discharge and then by telephone and/or face-to-face interviews every 6 months until November 2020. We evaluated each patient's response to the initial treatments at the first interview and divided them into “responders” and “nonresponders.” Relapses were recorded. At the end of follow-up, each patient was evaluated and reclassified into “complete recovery” or “unhealed” groups. Intergroup differences were assessed.

Results: All patients presented with seizures at the initial consultation. Other common manifestations included cognitive dysfunction (82.2%), psychiatric disturbance (66.7%), sleep disorder (54.5%), and hyponatremia (66.7%). During the follow-up period (32.8 ± 13.5 months), six patients experienced relapse within 6–37 months. We observed that the patients who did not respond to the initial treatments and those who relapsed all had a poor long-term prognosis. The patients in the “unhealed” group were older (p = 0.009), had a lower incidence of generalized tonic–clonic seizures (p = 0.041), and had a higher probability of cerebrospinal fluid (CSF) abnormalities (p = 0.024) than those in the “complete recovery” group.

Conclusion: Anti-LGI1 encephalitis was characterized by seizures, cognitive impairment, psychiatric disturbance, and sleep disorders and was often accompanied by hyponatremia. Patients who responded poorly to the initial treatments and those patients who relapsed had dismal long-term prognoses. Advanced age and CSF abnormalities may be risk factors for poor prognosis, but these still need to be verified.

Morvan syndrome associated with LGI1 antibody: a case report

Background

Morvan syndrome (MoS) is a rare autoimmune syndrome associated with antibodies against two kinds of potassium channel proteins, contactin associated protein-like 2 (CASPR2) and leucine-rich glioma inactivated protein 1 (LGI1). MoS patients with only LGI1-antibody seropositivity have rarely been reported. Here, we describe a 64-year-old male MoS patient with only LGI1-antibody seropositivity.

Case presentation

A 64-year-old male patient was referred to our hospital due to limb pain, widespread myokymia, insomnia, constipation, and hyperhidrosis for 1 month. The patient was diagnosed with MoS based on the clinical symptoms and positive LGI1-antibody in serum. He was treated with intravenous immunoglobulin (IVIG), intravenous methylprednisolone followed by oral prednisone, and other drugs for symptomatic relief. Several days later, myokymia and insomnia symptoms improved. After 60 days of follow-up, all the drugs had been stopped for 2 weeks, and the patient achieved complete remission without any medical side effects.

Conclusion

We report the clinical characteristics of a Chinese MoS patient with only LGI1-antibody seropositivity, and further support the view that non-neoplasm MoS patients respond well to immunotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02205-9.

Clinical features of anti-leucine-rich glioma-inactivated 1 encephalitis in northeast China

AIM

To examine the clinical characteristics, laboratory tests, imaging and electroencephalography presentation, treatment, and prognosis of anti-leucine-rich glioma-inactivated 1 (anti-LGI1) encephalitis and improve the awareness of this disease.

METHOD

We performed a retrospective analysis of the clinical data of 41 patients who were diagnosed with anti-LGI1 encephalitis. Their clinical characteristics, laboratory tests, and imaging and electroencephalography data were collected, and the treatment results and prognosis were evaluated. The modified Rankin Scale (mRS) was used to evaluate neurological function.

RESULTS

A total of 41 patients were included in the study, the average follow-up time is 33.0 months.The initial symptoms included cognitive impairment (n = 16, 39.0%),faciobrachial dystonic seizures (FBDS) (n = 12, 29.3%), grand mal seizures (n = 5, 12.2%) hallucinations (n = 4, 9.8%), loss of consciousness (n = 2, 4.9%), nausea and vomiting (n = 1, 2.4%),and head discharge-like sensation and radiate one limb (n = 1, 2.4%). There were 20 and 21 patients in the good (mRS ≤ 2) and poor (mRS > 2) prognosis groups, respectively. In the good prognosis group, the initial symptoms included faciobrachial dystonic seizures (FBDS) (n = 6, 30.0%), cognitive impairment (n = 6, 30.0%), hallucinations (n = 4, 20.0%), grand mal seizures (n = 3, 15.0%), loss of consciousness (n = 2, 10.0%), and nausea and vomiting (n = 1, 5.0%). There were 10 patients with hyponatremia. Magnetic resonance imaging (MRI) showed limbic system involvement in 12 patients (60.0%).17 patients (85.0%) recovered, 2 (10.0%) showed significant improvement, and 1 (5.0%) died after a mean follow-up period of 36.9 months. In the poor prognosis group, the initial symptoms included FBDS (n = 6, 28.5%), cognitive impairment (n = 10, 47.6%), grand mal seizures (n = 2, 9.5%), and electric shock-like sensation in the left limbs (n = 1, 4.7%). There were 20 patients with hyponatremia. MRI showed limbic system involvement in 11 patients (52.4%). 11 patients (52.4%) recovered, 8 (38.1%) showed significant improvement, and 2 (9.5%) died after a mean follow-up period of 29.0 months.

CONCLUSIONS

The clinical characteristics of anti-LGI1 encephalitis include hyponatremia, FBDS, epileptic seizures, hallucinations, cognitive impairment, and loss of consciousness, while the rarely seen characteristics are nausea, vomiting, and other autonomic dysfunctions and electric shock-like sensation. The appearance of hallucinations often indicates a good prognosis.Hyponatremia and elevated cerebrospinal fluid protein levels can be used as indicators that affect the prognosis of patients.Limbic system involvement has nothing to do with prognosis.Attention should be paid to early diagnosis and timely first-line immunotherapy.

Case Report: Anti-LGI1 Limbic Encephalitis Associated With Anti-thyroid Autoantibodies

Anti-LGI1 encephalitis is an autoimmune encephalitis with antibodies against leucine-rich glioma-inactivated 1 (LGI1), first described in 2010. It is a non-frequent and poorly understood entity that represents the second most frequent cause of autoimmune encephalitis. This entity is characterized by the presence of limbic encephalitis, hyponatremia, and faciobrachial dystonic seizures. Herein, we present the case of a male patient with an onset of epileptic seizures (generalized tonic-clonic seizure), and involuntary dystonic movements that affect the right side of his face and right upper limb associated with mental disorder, and affectation of higher functions. The electroencephalogram showed continuous generalized slowing of the background activity. The brain magnetic resonance imaging showed signal hyperintensity at the level of both mesial temporal lobes and hippocampi and in the head of the right caudate nucleus. Anti-thyroglobulin antibodies were positive, and he was initially diagnosed as Hashimoto's encephalopathy (HE). However, the response to corticosteroids was not completed as it is usually observed in HE. For that, antibodies for autoimmune encephalitis were tested, and the anti-LGI1 antibodies were positive in serum and cerebrospinal fluid. HE is an important differential diagnosis to consider. Furthermore, the presence of Anti-thyroglobulin antibodies should not be taken as the definitive diagnostic criteria, since these antibodies could be associated with other autoimmune encephalopathies, which include in addition to anti-LGI1, anti-NMDA and anti-Caspr2.

Clinical Features and Long-Term Outcomes of Anti-Leucine-Rich Glioma-Inactivated 1 Encephalitis: A Multi-Center Study

PURPOSE

To describe the clinical manifestation, immunotherapy, and long-term outcomes of anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis.

PATIENTS AND METHODS

This study was a retrospective analysis of 117 patients with a diagnosis of anti-LGI1 encephalitis identified from the databases of multiple clinical centers between September 2014 and December 2019. The clinical features, ancillary test results, and details of long-term outcomes were evaluated.

RESULTS

Among the 117 patients with anti-LGI1 encephalitis, 69.2% (81/117) were male and 30.8% (36/117) were female. The median age of all patients at the onset of the disease was 57 years (interquartile range [IQR], 52-67). The median time from symptom onset to diagnosis was 8.7 weeks (IQR, 4.2-25). The main clinical features identified were seizures, cognitive impairment, and mental and behavioral abnormalities. Of the 117 patients, 109 were treated with immunotherapy. Symptoms including memory, mental ability, and behavior improved in all 109 patients after 3-5 days of treatment. The median time of follow-up for the treated patients was 33 months (IQR, 17-42). Of the treated patients, 16.2% (19/117) experienced a relapse, with a median delay of 5 months (IQR, 2.1-17) between onset and the first relapse. There were no mortalities over the follow-up period.

CONCLUSION

The long-term outcome of patients with anti-LGI1 encephalitis was mostly favorable, although some patients continued to experience cognitive dysfunction. Early recognition is important for prompt initiation of immunotherapy that can improve clinical symptoms of anti-LGI1 encephalitis.

[Ictal electroencephalography (EEG) activity and cerebral blood flow dynamics as potential pathological indicators: a case of anti-leucine-rich glioma-inactivated 1 protein (LGI1) encephalitis]

A 29 year-old, right-handed woman was admitted to our hospital due to her headache with fever elevation lasting for two months followed by a prolonged loss of awareness with an involuntary movement in her left hand and mouth. This movement appeared very frequently, and the duration was very short, so called "faciobrachial dystonic seizures (FBDS)". Some of FBDS were followed by prolonged loss of awareness. Brain MRI fluid attenuated inversion recovery (FLAIR) image revealed high intensity lesion in the left mesial temporal lobe. Arterial spin labeling (ASL) image indicated hyper perfusion in this lesion and also the lateral temporal region. No ictal electroencephalography (EEG) change was observed before the onset of FBDS. FBDS was often followed by focal impaired awareness seizure (FIAS) in which ictal EEG showed rhythmic alpha activity arising from left mid-temporal region. This EEG seizure pattern was clearly visible in the time-frequency analysis. Given these clinical findings, along with an evidence of serum anti-leucine-rich glioma-inactivated 1 (LGI1) antibody positive, she was diagnosed with anti-LGI1 encephalitis. Immunotherapy (methylpredonisolone and intravenous immunoglobulin) with a multiple anti-epileptic drugs therapy (lacosamide, perampanel, and lamotrigine) was highly responsible to her symptoms. Although the high intensity lesion in FLAIR image still remained after the treatment, findings of ASL and EEG showed clear correlation to her cognitive function and seizures, respectively. Temporal change in ASL imaging suggested that the hyper perfusion in ASL during the acute stage could be provided by inflammation of the encephalitis its self and also the seizures activities (FBDS and FIAS). The pathophysiological indication of anti-LGI1 encephalitis was limited in terms of the therapeutic strategy, however, our findings collectively suggested that the combination analysis of EEG activity and cerebral blood flow dynamics (ASL) could be the potential candidate.

The neuropsychological spectrum of anti-LGI1 antibody mediated autoimmune encephalitis

Anti-Leucine Glioma Inactivated 1 (LGI-1) autoimmune encephalitis (AE) is a rare neuroinflammatory brain condition. Individuals afflicted with this condition can present with cognitive and psychological manifestations that can impact the individual's quality of life, day to day functioning, independence, return to work and interpersonal relationships. Our knowledge of the cognitive profiles and disease associated psychopathology is severely lacking. This review provides a comprehensive summary of the currently available literature, conceptualising our current understanding of the neuropsychological manifestations of anti LGI-1 AE and summarises methodological limitations of the current research to inform and improve future investigations. Key Terms: Autoimmune Diseases; Neuroimmunology; Autoimmune Encephalitis, Limbic Encephalitis; Anti-LGI1 Encephalitis, LGI1; Neuropsychology, Cognitive Assessment.

Into a Shaking Limbo: Case Report of a Nonneoplastic Limbic Encephalitis with Faciobrachial Dystonic Seizures and Parkinsonism

This case report describes a rare but classic presentation of a non-paraneoplastic, antibody-mediated limbic encephalitis. The clinical course did put us in a limbo as it evolved from seizure to Parkinsonism and then from metastasis to stroke, before it finally announced itself by its pathognomonic finding. Knowledge of this rare condition is important as early identification and treatment can change the course.

Functional and Structural Brain Alterations in Encephalitis With LGI1 Antibodies

Objective: The purpose of this study was to examine the neural substrates and mechanisms that generate memory deficits, seizures and neuropsychiatric abnormalities in encephalitis with LGI1 antibodies using a data-driven, multimodal magnetic resonance imaging (MRI) approach. Methods: Functional MRI data were acquired from 14 anti-LGI1 encephalitis patients and 14 age and gender matched normal controls. Independent component analysis with hierarchical partner matching (HPM-ICA) was used to assess the whole-brain intrinsic functional connectivity. Granger causality (GC) was applied to investigate the effective connectivity among the brain regions that identified by HPM-ICA. Diffusion tensor imaging (DTI) was utilized to investigate white matter microstructural changes of the patients. Results: Participants with LGI1 antibodies encephalitis presented reduced functional connectivity in the brain areas associated with memory, cognition and motion circuits, while increased functional connectivity in putamen and caudate in comparison to the normal controls. Moreover, the effective connectivity in patients was decreased from the frontal cortex to supplementary motor area. Finally, patients had significant reductions in fractional anisotropy (FA) for the corpus callosum, internal capsule, corona radiata and superior longitudinal fasciculus, accompanied by increases in mean diffusivity (MD) for these regions as compared to controls. Conclusion: Our findings suggest that the neural disorder and behavioral deficits of anti-LGI1 encephalitis may be associated with extensive changes in brain connectivity and microstructure. These pathological alterations affect the basal ganglia and limbic system besides the temporal and frontal lobe.

Neuronal Surface Antibody Syndrome: A Review of the Characteristics of the Disease and Its Association with Autoantibodies

Several studies have certified that autoantibodies play an important role in the manifestation of neuromuscular diseases. Scientists have discovered specific neuronal tumor antibodies in patients with typical paraneoplastic neurological disorders. But in some clinical cases, it is not useful to cure this disease with common treatments unless the autoantibodies are addressed. In addition, recent studies have shown a close relationship between certain antibodies and neuronal surface proteins in some special cases. These antibodies, which act on the surface of neurons, mainly include voltage-gated calcium channel (VGKC) antibodies. VGKC antibodies are further divided into several types including anti-leucine-rich glioma inactivated 1 (LGI1), anti-contactin-associated protein-like 2 (Caspr2), anti-N-methyl-D-aspartate receptor (NMDAR), anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), anti-γ-aminobutyric acid receptor (GABAR), and glycine receptor. For the purpose of this review, cases of clinical studies of autoantibody-associated encephalitis were collected, the key points regarding the pathogenesis were summarized, the clinical manifestation was discussed, and all this information was organized as this review in order to introduce the relationship between autoantibodies and autoimmune encephalitis. Furthermore, it is hoped that it can effectively direct the development of diagnostic and therapeutic approach in the future.

Hyponatraemia: the importance of obtaining a detailed history and corroborating point-of-care analysis with laboratory testing

We describe a 67-year-old man admitted from a mental health unit with an incidental finding of hyponatraemia on routine blood tests. Laboratory investigations were in keeping with syndrome of inappropriate antidiuretic hormone secretion (SIADH). He had been recently commenced on mirtazapine. During his inpatient stay, he became increasingly confused. Review of a previous admission with hyponatraemia raised the possibility of voltage-gated potassium channel antibody-associated limbic encephalitis, although subsequent investigations deemed this unlikely as a cause of hyponatraemia. Although his sodium levels improved with fluid restriction, serial point-of-care testing proved misleading in monitoring the efficacy of treatment as inconsistencies were seen in comparison with laboratory testing. The cause of hyponatraemia may have been medication-induced SIADH and/or polydipsia. This case highlights the importance of collating detailed histories and laboratory blood testing to guide management in cases of hyponatraemia of unknown aetiology.

Relevance of Surface Neuronal Protein Autoantibodies as Biomarkers in Seizure-Associated Disorders

The detection of neuronal surface protein autoantibody-related disorders has contributed to several changes in our understanding of central nervous system autoimmunity. The clinical presentation of these disorders may be associated (or not) with tumors, and often patients develop an inexplicable onset of epilepsy, catatonic or autistic features, or memory and cognitive dysfunctions. The autoantigens in such cases have critical roles in synaptic transmission and plasticity, memory function, and process learning. For months, patients with such antibodies may be comatose or encephalopathic and yet completely recover with palliative care and immunotherapies. This paper reviews several targets of neuronal antibodies as biomarkers in seizure disorders, focusing mainly on autoantibodies, which target the extracellular domains of membrane proteins, namely leucine-rich glioma-inactivated-1 (LGI1), contactin-associated protein-like 2 (CASPR2), the N-methyl-D-aspartate receptor (NMDAR), γ-aminobutyric acid receptor-B (GABA_BR), the glycine receptor (GlyR), and a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs). In order to restore health status, limit hospitalization, and optimize results, testing these antibodies should be done locally, using internationally certified procedures for a precise and rapid diagnosis, with the possibility of initiating therapy as soon as possible.

Syncope and Twitching at the Emergency Department

Patient: Female, 49

Final Diagnosis: Anti-LGI1 limbic encephalitis

Symptoms: Seizure • sinus arrest

Medication: —

Clinical Procedure: Immunosupression

Specialty: Neurology

A novel LGI1 missense mutation causes dysfunction in cortical neuronal migration and seizures

BACKGROUND

To explore the causative genes and pathogenesis of autosomal dominant partial epilepsy with auditory features in a large Chinese family that includes 7 patients over four generations.

METHODS

We used targeted exome sequencing and Sanger sequencing to validate the mutation. Zebrafish were used to explore the epileptic behavior caused by the mutation. Primary cortical neuronal culturing and in utero electroporation were used to observe the influences of the mutation on neuronal polarity and migration.

RESULTS

We report the identification of a novel missense mutation, c.128C > G (p. Pro43Arg), in exon 1 of LGI1. The heterozygous missense mutation, which cosegregated with the syndrome, was absent in 300 unrelated and matched-ancestor controls. The mutation inhibited the secretion of LGI1 and could not rescue the hyperactivity caused by lgi1a knockdown in zebrafish. In vitro, mutant LGI1 interrupts normal cell polarity. In agreement with these findings, dysfunctional cortical neuron migration was observed using in utero electroporation technology, which is reminiscent of the subtle structural changes in the lateral temporal region observed in the proband of this family.

CONCLUSION

Our findings enrich the spectrum of LGI1 mutations and support the pathogenicity of the mutation. Furthermore, additional information regarding the role of LGI1 in the development of temporal lobe epilepsy was elucidated, and a potential relationship was established between cortical neuronal migration dysfunction and autosomal dominant partial epilepsy with auditory features.

Clinical characteristics and factors associated with short-term prognosis in adult patients with autoimmune encephalitis of non-neoplastic etiology

BACKGROUND

Reports that autoimmune encephalitis (AE) is associated with antibodies have increased; however, little is known about the distribution of clinical symptoms, imaging changes, and prognostic factors in patients with AE of non-neoplastic etiology. Accordingly, we evaluated the clinical characteristics and factors associated with short-term prognosis.

METHODS

From January 2016 to June 2018, 31 adult patients were diagnosed with AE of non-neoplastic etiology at Shengjing Hospital of China Medical University and their demographic and clinical characteristics were abstracted. Factors affecting disease severity and predictors of prognosis were analyzed.

RESULTS

Among 31 patients, 19 had anti-NMDAR, 5 had anti-GABABR, and 7 had anti-LGI1 antibody encephalitis. Status epilepticus, ataxia, and cognitive dysfunction were the most common neurological symptoms. Deep white matter (DWM) abnormalities were the most common changes observed on MRI. Logistic regression analysis indicated that conscious disturbance (odds ratio = 11.67, 95%, confidence interval 2.13-64.04; p = 0.005) is an independent factor associated with poor prognosis in AE.

CONCLUSION

The clinical manifestations of AE are diverse; status epilepticus, ataxia, and cognitive dysfunction are most common. The DWM of the brain, rather than the limbic lobe system, was most prone to MR signal abnormalities. Conscious disturbance may be an important predictor of poor short-term prognosis in patients with AE of non-neoplastic etiology.

Three cases of antibody-LGI1 limbic encephalitis and review of literature

PURPOSE

Antibody-LGI1 limbic encephalitis (LGI1-Ab LE) is an anti-neuronal surface antigen-related autoimmune encephalitis. we report three cases of LGI1-Ab LE, describe the characteristics of clinical manifestation, course of evolution, imaging manifestation and treatment outcomes.

METHODS

Data from patients diagnosed with LGI1-Ab LE in the Second Hospital, Hebei Medical University, from June 2016 to July 2017, were retrospectively collected and analyzed. We followed up the patients for 90 days.

RESULTS

Two of the three patients were females, the average age of onset is 53 years old. Epilepsy is the most common clinical manifestations, and one of patients developed faciobrachial dystonic seizures (FBDS), which was recently described as a characteristic feature of LGI1-Ab LE. All patients had cognitive impairment in different degrees and abnormal signal of hippocampus in cranial MRI. All serum LGI1 antibodies were positive, whereas one LGI1 antibodies of CSF were negative. All patients accepted first-line immune therapy and had a good outcome.

CONCLUSION

LGI1-Ab LE, which is an autoimmune disease, is rare clinically and mostly nonparaneoplastic. We suggest that LGI1-Ab LE be considered in any patient with acute or subacute onset, cognitive dysfunction , various types of seizures, accompanied by mental disorders and hyponatremia, MR showed the involvement of the limbic system. It is necessary to have LE-related antibodies tested. Early immunotherapy can significantly improve the patient's overall prognosis. At the same time, we should also pay attention to the possibility of potential tumors.

Clinical characteristics and short-term prognosis of LGI1 antibody encephalitis: a retrospective case study

Background

Recently, most reports of Leucine-rich glioma-inactivated 1 (LGI1) antibody encephalitis are from Europe and the US, while the short term outcome and clinical characteristics of Chinese patients are rarely reported,we study the clinical manifestations, laboratory results and brain magnetic resonance images (MRI) of eight patients who were recently diagnosed with LGI1 antibody encephalitis in our hospital to improve the awareness and knowledge of this disease.

Methods

Eight patients (five males and three females; mean age, 63.4) with LGI1 antibody encephalitis who were diagnosed and treated in the Department of Neurology of Shengjing Hospital of China Medical University from September 2016 to June 2017 were recruited for the current study. Their general information, clinical manifestations, treatment regimens, and short-term prognoses were retrospectively analyzed, as were the results from MRI and laboratory findings.

Results

Overall, patient symptoms included cognitive impairment, which manifested primarily as memory deficits (8/8), seizures (including faciobrachial dystonic seizure, (FBDS)) (8/8), psychiatric and behavioral disorders (7/8), sleep disorders (4/8), and autonomic abnormalities (3/8). Five patients also had abnormal findings on brain MRI, mainly involving the hippocampus, basal ganglia and insula. Hyponatremia occurred in six cases. All patients tested positive for LGI1 antibodies in their serum/cerebrospinal fluid (CSF)and patients were negative for tumors. Symptoms rapidly improved after treatment with immunoglobulin and/or steroid therapy. The patients were followed up for 4–13 months after discharge, and two patients relapsed.

Conclusion

Primary symptoms of LGI1 antibody encephalitis include memory impairments, seizures, FBDS, and mental and behavioral abnormalities. Increased titers of LGI1 antibodies are also present in the serum/CSF of patients. Patients often have hyponatremia, and MRIs show abnormalities in various brain regions. Finally, immunotherapy shows good efficacy and positive benefits, although patients may relapse in the short-term.