Diagnosis and Clinical Features in Autoimmune-Mediated Movement Disorders.

Background and ObjectivesTo 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).MethodsMulticenter nationwide prospective cohort study of the German Network for Research in Autoimmune Encephalitis.ResultsThree 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 déjà-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.DiscussionSeizures 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.

Faciobrachial motor seizures: A more apt description?

A 30-year-old man developed right faciobrachial dystonic seizures (FBDS).1 Ictal and interictal EEGs were normal. CSF analysis was unremarkable. Brain MRI revealed a gadolinium-enhancing lesion involving the left caudate and globus pallidus (figure 1). Leucine-rich glioma inactivated protein 1 (LGI1) antibodies were detected in the serum. Total-body CT scan revealed no malignancies. The patient underwent 5 cycles of plasmapheresis followed by long-term steroid therapy with complete benefit. A brain MRI performed after 5 months showed reduction of contrast enhancement (figure 2). LGI1, a secreted protein complexed with voltage-gated potassium channels, is highly expressed in the neocortex and hippocampus.2 LGI1 mutations have been described in patients with autosomal dominant partial epilepsy with auditory features (ADPEAF). Our patient had no clinical features of ADPEAF. Whether FBDS can be classified as epilepsy or dystonia is a matter of debate.3 The involvement of basal ganglia described in our patient can be relevant to the ongoing debate.

BackgroundAutoimmune encephalitis related to the leucine-rich glioma-inactivated protein 1(LGI1) antibody is the most prevalent in older adults, manifesting as seizures, faciobrachial dystonic seizures (FBDS), cognitive impairment, memory disturbance, hyponatremia and neuropsychiatric disorders. However the data pertaining to children affected by the disease is still limited.Case presentation and literature reviewsThis study presents a detailed report of a 6-year-old Chinese girl who experienced nose aches and faciobrachial dystonic seizures (FBDS). Electrolyte testing revealed that she had hyponatremia and brain MRI showed an abnormality in the left temporal pole. Additionally, anti-LGI1 antibodies were detected in both her serum (1:100) and CSF (1:30). The patient was treated with immunotherapy and symptom management, which proved effective. Furthermore, we provide a summary of 25 pediatric cases of anti-LGI1 encephalitis. Pediatric patients rarely exhibited FBDS and hyponatremia, and some cases presented with isolated syndromes. But the therapeutic outcomes of pediatric patients were generally good.ConclusionsIn this report, we describe a patient who developed a rare symptom of nose aches possibly as one of symptoms of anti-LGI1 encephalitis, which highlights the possibility of atypical symptoms in children that may be misdiagnosed. Reviewing the literature, the clinical features differed between pediatric and adult cases. Therefore, it is crucial to collect and analyze data from more cases to promote accurate diagnosis and timely treatment.

Antibodies against leucine-rich glioma inactivated protein 1 (LGI1) constitute a common form of autoimmune encephalitis. On MR imaging, it may show T2 FLAIR hyperintensities of the medial temporal lobe (T2 FLAIR-MTL), involve the basal ganglia, or be unremarkable. We performed a systematic review and meta-analysis to obtain prevalence estimates of abnormal findings on MR imaging in anti-LGI1 encephalitis. A human brain map of the LGI1 microarray gene expression was derived from the Allen Human Brain Atlas. PubMed and Web of Science were searched with the terms "LGI1" and "encephalitis" from inception to April 7, 2022. Thirty-one research publications, encompassing case series and retrospective cohort and case-control studies, with >10 patients with anti-LGI1 encephalitis and MR imaging data were included. Pooled prevalence estimates were calculated using Freeman-Tukey double-arcsine transformation. Meta-analysis used DerSimonian and Laird random effects models. Of 1318 patients in 30 studies, T2 FLAIR-MTL hyperintensities were present in 54% (95% CI, 0.48-0.60; I2 = 76%). Of 394 patients in 13 studies, 27% showed bilateral (95% CI, 0.19-0.36; I2 = 71%) and 24% unilateral T2 FLAIR-MTL abnormalities (95% CI, 0.17-0.32; I2 = 61%). Of 612 patients in 15 studies, basal ganglia abnormalities were present in 10% (95% CI, 0.06-0.15; I2 = 67%). LGI1 expression was highest in the amygdala, hippocampus, and caudate nucleus. Only part of the spectrum of MR imaging abnormalities in anti-LGI1 encephalitis could be included in a meta-analysis. MR imaging findings were not the main outcomes in most studies, limiting available information. I2 values ranged from 62% to 76%, representing moderate-to-large heterogeneity. T2 FLAIR-MTL hyperintensities were present in around one-half of patients with anti-LGI1. The prevalence of unilateral and bilateral presentations was similar, suggesting unilaterality should raise the suspicion of this disease in the appropriate clinical context. Around 10% of patients showed basal ganglia abnormalities, indicating that special attention should be given to this region. LGI1 regional expression coincided with the most frequently reported abnormal findings on MR imaging. Regional specificity might be partially determined by expression levels of the target protein.

Seizure semiology in leucine-rich glioma-inactivated protein 1 antibody-associated limbic encephalitis

Autoimmune encephalitis (AE) associated with autoantibodies against leucine-rich glioma-inactivated protein-1 (LGI1) can present with faciobrachial dystonic seizures (FBDS) and/or limbic encephalitis (LE). The reasons for this heterogeneity in phenotypes are unclear. We performed autoantibody (abs) characterization per patient, two patients suffering from LE and two from FBDS, using isolated antibodies specified with single amino acid epitope mapping. Electrophysiological slice recordings were conducted alongside spine density measurements, postsynaptic Alpha-amino-3-hydoxy-5-methyl-4-isoaxole-proprionate-receptors (AMPA-R) and N-methyl-D-aspartate-receptors receptor (NMDA-R) cluster counting. These results were correlated with the symptoms of each patient. While LGI1 abs from LE patients mainly interacted with the Leucine-rich repeat section of LGI1, abs from both FBDS patients also recognized the Epitempin section as well. Six-hour incubation of mouse hippocampal slices with LE patients autoantibodies but not from the FBDS patients resulted in a significant decline in long-term potentiation (p = 0.0015) or short-term plasticity at CA3-CA1 neurons and in decreased hippocampal synaptic density. Cluster differentiation showed no decrease in postsynaptic AMPA-R and NMDA-R. LGI1 autoantibodies selected by phenotype show an almost distinct epitope pattern, elicit disparate functional effects on hippocampal neurons, and cause divergent effects on spine density. This data illuminates potential pathomechanisms for disease heterogeneity in LGI1 AE.

Autoimmune encephalitis (AE) results from immune-mediated damage to the central nervous system (CNS) with varying clinical manifestations depending on autoimmune antibodies present and the antigens they target. Leucine-rich glioma-inactivated protein 1 (LGI1) has been recognized as one of the leading causes of limbic encephalitis (LE), presenting with seizures, memory loss, and faciobrachial dystonic seizures. A better understanding of the unique presentations of these AE allows for quick and effective diagnosis and treatment. We are presenting a very unusual case of LGI1 autoimmune LE with two additional autoantibodies, anti-acetylcholine receptor (AChR) and anti-striational, in a patient with an underlying thymoma. We will discuss the pathophysiology and common clinical presentation of anti-LGI1 autoimmune LE.

Autoantibodies to leucine-rich glioma-inactivated protein 1 (LGI-1) are associated with inflammation of the limbic system. Faciobrachial dystonic seizures are pathognomonic for LGI1-antibiodies and their treatment with immunotherapy is effective in seizure control with a potential to prevent cognitive decline. We report a 57-year-old man who presented to the emergency department with recurrent seizures, visual hallucinations and severe memory impairment over a seven-week period; he reported a background of alcohol excess. Initial investigations revealed hyponatremia, indicating syndrome of inappropriate anti-diuretic hormone secretion. Magnetic resonance imaging of the brain revealed bilateral asymmetrical high-T2 and low-T1 signal in the medial temporal lobes. Serum immunofluorescence assay tested positive for LGI-1 antibody. Patient responded to treatment with levetiracetam, intravenous methylprednisolone and five plasma exchange sessions. Patient remains on a maintenance dose of prednisolone and azathioprine. It is imperative that clinicians recognize signs of autoimmune encephalitis in order to curb long-term sequelae and improve clinical outcomes.

Faciobrachial dystonic seizure is a distinctive phenomenology that is considered pathognomonic of leucine-rich glioma-inactivated protein 1 (LGI1) antibody-associated autoimmune limbic encephalitis. However, similar phenomenology has been described with other neurological disorders as well. Here, we report the case of a 26-year-old man with subacute sclerosing panencephalitis who presented with multiple episodes of involuntary movements resembling faciobrachial dystonic seizure. Serum and cerebrospinal fluid autoimmune encephalitis panel, including leucine-rich glioma-inactivated protein 1 antibody, were negative. Classical periodic stereotypical slow wave discharges on the electroencephalogram and raised measles antibody titre in cerebrospinal fluid confirmed the diagnosis of subacute sclerosing panencephalitis.

Autoimmune Encephalitis–Related Seizures and Epilepsy: Diagnostic and Therapeutic Approaches

Chapter 20 - Autoimmune-Mediated Encephalitis With Antibodies to NMDA-Type GluRs: Early Clinical Diagnosis

The clinical phenotype of leucine-rich glioma-inactivated protein 1 (LGI1) and contactin-associated proteinlike 2 (CASPR2) autoimmunity is well defined in adults. Data for children are limited (<10 cases). Among 13,319 pediatric patients serologically tested for autoimmune neurological disorders (2010-2017), 264 were seropositive for voltage-gated potassium channel-complex-IgG (radioimmunoprecipitation). Only 13 (4.9%) were positive by transfected cell-binding assay for LGI1-IgG (n = 7), CASPR2-IgG (n = 3), or both (n = 3). This is significantly less than in adults. Encephalopathy, seizures, and peripheral nerve hyperexcitability were common, as was coexisting autoimmunity. No faciobrachial dystonic seizures or cancers were identified. Functional neurologic disorders were frequently the initial diagnosis, and immunotherapy appeared beneficial. Ann Neurol 2018;84:473-480.

Objective To demonstrate a case of suspected post-vaccine autoimmune encephalitis associated with leucine-rich glioma-inactivated protein (LGI1) antibodies with significant clinical improvement after initiation of immunotherapy nearly a year after symptom onset. Background Although the autoimmune encephalitides have overlap in presentation, some have unique manifestations (such as orofacial dyskinesias seen with NMDA encephalitis). These unique associations can serve as a clinical marker of response to treatment and even allow for earlier initiation of immunotherapy while awaiting results from antibody testing. LGI1 encephalitis characteristically presents with faciobrachial dystonic seizures (FBDS) that are refractory to anti-seizure medications (ASMs) but responsive to immunotherapy. Design/Methods Case report Results A previously healthy and highly independent 89-year-old woman developed what she described as abnormal posturing and spasms of the right shoulder two to three weeks after receiving the J&amp;J COVID-19 vaccine. The abnormal movements progressed to involve the right side of her face and were refractory to multiple ASMs. EEG captured multiple events without epileptiform correlate. Several months later she developed paranoia, delusions, and hallucinations. Autoimmune encephalopathy panel returned positive for the LGI1-antibody around nine months after the onset of FBDS. Upon our initial exam, she had a fluctuating level of arousal, impaired recall of recent events, and was tangential in conversation. There were frequent, brief, repetitive, dystonic movements of the right side of the face consistent with FBDS. Admission was arranged for immunotherapy (intravenous methylprednisolone and intravenous immunoglobulin). Upon follow-up four weeks later, there was significant improvement in arousal and concentration with resolution of FBDS and delusions. Conclusions This case highlights a classic case of LGI1 encephalitis after vaccination presenting with FBDS and progressive cognitive changes. Despite immunotherapy being delayed, there was marked clinical improvement. It is important to recognize this entity and that it typically has a favorable outcome.

The leucine-rich glioma-inactivated protein 1 (LGI1) antibody-related autoimmune encephalitis can occur alone or in the setting of a malignancy and manifest with faciobrachial dystonic seizures (FBDS), cognitive decline, hyponatremia, and neuropsychiatric disorders. The importance of differentiating this entity from acute delirium cannot be overemphasized. This review provides a detailed account of a 71-year-old man with previous diagnosis of lung cancer who presented with subacute onset behavioural changes, urinary retention, and FBDS. Investigation revealed hyponatremia, bilateral mesial temporal lobe high signal abnormality worse on the right on MRI and CSF positive anti-LGI1 antibodies (1:30). The patient was treated with immunosuppressive therapy with consequent symptom improvement. This case emphasizes the need to have a high index of suspicion for this disease entity in patients presenting with new onset behavioural changes and the importance of identifying the typical FBDS, as early initiation of treatment confers a positive outcome for diseased patients.