Antibody-mediated Encephalitis Research Articles

Pediatric autoimmune encephalitis: a review

Autoimmune encephalitis has been an emerging disease in the pediatric age group for the last few years. It is of utmost importance to recognize the disease for the timely initiation of immunotherapy. The antibody-mediated encephalitis should be considered in the differentials apart from vasculitic, metabolic encephalopathy after ruling out bacterial, viral, tubercular, parasitic, and rickettsial causes. It can even coexist with herpes encephalitis in a quarter of the cases. The prodromal symptoms and progression to psychiatric, memory, speech disturbance, movement disorder, altered mental status, dysautonomia, and seizures within a span of a month characterize the disease. The approach to diagnosis involves various antibody testing in serum and cerebrospinal fluid along with brain imaging and electroencephalography. Early treatment with steroids, intravenous immunoglobulin, and plasmapheresis leads to better outcomes. A literature search was made using keywords in the Google Scholar and Pubmed databases before January 2024. The collected materials were reviewed for appropriate titles and content focusing on diagnosis and management. The article aims to provide a comprehensive review regarding the differential diagnosis and management of autoimmune encephalitis in children.

Unusual imaging findings associated with abdominal pediatric germ cell tumors.

Germ cell tumors of childhood are tumors arising from germline cells in gonadal or extragonadal locations. Extragonadal germ cell tumors are characteristically located in the midline, arising intracranially or in the mediastinum, retroperitoneum, or pelvis. These tumors are generally easily diagnosed due to typical sites of origin, characteristic imaging findings, and laboratory markers. However, germ cell tumors can be associated with unusual clinical syndromes or imaging features that can perplex the radiologist. This review will illustrate atypical imaging/clinical manifestations and complications of abdominal germ cell tumors in childhood. These features include unusual primary tumors such as multifocal primaries; local complications such as ovarian torsion or ruptured dermoid; atypical presentations of metastatic disease associated with burned-out primary tumor, growing teratoma syndrome, and gliomatosis peritonei; endocrine manifestations such as precocious puberty and hyperthyroidism; and antibody mediated paraneoplastic syndrome such as anti-N-methyl-D-aspartate-receptor antibody-mediated encephalitis. This review aims to illustrate unusual imaging features associated with the primary tumor, metastatic disease, or distant complications of abdominal germ cell tumors of childhood.

Leucine-Rich Glioma-Inactivated 1 (LGI1) Protein Stimulates Proliferation and IL-10 Production in Peripheral Blood Mononuclear Cells of Patients with LGI1 Antibody-Mediated Autoimmune Encephalitis In Vitro.

Limbic encephalitis (LE) due to anti-leucine-rich glioma-inactivated 1 (LGI1) antibodies is an autoimmune disease characterized by distinct clinical features unique to LGI1 LE, such as faciobrachial dystonic seizures. However, it is unclear whether an additional disease-related LGI1 antigen-specific T cell response is involved in the pathogenesis of this disease. To address this question, we studied the effect of recombinant LGI1 on the proliferation and effector-specific cytokine production (IFN-γ, IL-5, IL-10, and IL-17) of peripheral blood mononuclear cells (PBMCs) from patients with LGI1 LE and healthy controls. We observed that recombinant LGI1 stimulated the proliferation of PBMCs from patients with LGI1 LE, but not from healthy controls. Cytokine measurement of cell culture supernatants from PBMCs incubated with recombinant LGI1 revealed a highly significant increase in IL-10 release in PBMCs from patients with LGI1 LE in comparison with healthy controls. These results suggest that LGI1-mediated stimulation of PBMCs from patients with LGI1 LE leads to the establishment of an IL-10-dominated immunosuppressive cytokine milieu, which may inhibit Th1 differentiation and support B cell proliferation, IgG production, and IgG subclass switching.

New-onset seizures misdiagnosed as psychogenic non-epileptic seizures: a case of paraneoplastic limbic encephalitis with primary testicular cancer

BackgroundBehavioral psychiatric symptoms can be the only warning signs of more serious conditions such as paraneoplastic limbic encephalitis. Differentiating between primary psychiatric disorders and paraneoplastic neurological syndromes is crucial as they require distinct treatment approaches. In this case report, we provide an overview of paraneoplastic encephalitis and introduce a unique case that showcases a misdiagnosis of psychogenic non-epileptic seizures (PNES) in a male as the primary symptom of paraneoplastic encephalitis due to pure seminoma. This case highlights the underlying pathophysiology of antibody-mediated paraneoplastic encephalitis and its significance.Case presentationA 31-year-old male with no known past medical history presented due to recurrent seizures. There was no prior history of epilepsy or exposure to seizure-triggering agents. Imaging and electroencephalogram findings during his initial hospitalizations pointed to a potential diagnosis of PNES. The patient continued to experience seizures following discharge, leading to repeat hospitalizations. During the fourth hospitalization, the patient received mood-stabilizing anti-seizure medications and benzodiazepines, but he deteriorated and required intubation. It was during this time that the patient was transferred to our facility. Magnetic resonance imaging of the brain revealed multifocal areas of hyperintensity and restricted diffusion with avid enhancement. Immunotherapy was initiated with improvement of non-epileptic spells and encephalopathy. Outpatient workup uncovered malignant pure seminoma with metastases to the retroperitoneum. The authors theorize that paraneoplastic neurological disorders stemming from testicular cancer led to the neurological symptoms seen in this case.ConclusionThis report highlights a rare occurrence of paraneoplastic limbic encephalitis associated with pure testicular seminoma, clinically manifested as PNES. The diagnostic challenge posed by variability of presenting symptoms in paraneoplastic encephalitis emphasizes the importance of accurate differentiation from conditions such as autoimmune encephalitis. Current diagnostic approaches for paraneoplastic and autoimmune etiologies involve detection of known antibodies, as well as brain imaging. Notable antibodies associated with psychogenic non-epileptic seizures symptoms include anti-GAD-65, anti-Ma2, KLH11-antibodies, anti-Hu, and NMDA receptor antibodies. Recognizing paraneoplastic limbic encephalitis symptoms is challenging and often leads to misdiagnosis or overlooking of malignancies highlighting the need for awareness, comprehensive evaluation and timely treatment. Through this comprehensive case analysis, we enhance the understanding of underlying mechanisms, associated symptoms, and treatment options.

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

ObjectiveTo validate the different predictive scoring scales in the Chinese population with new-onset epileptic seizures or epilepsy of unknown etiology related to neuronal surface antibody (Ab)-mediated autoimmune encephalitis (AE). MethodsWe retrospectively reviewed the charts of 174 consecutive patients from October 2018 to December 2022, whose serum and cerebrospinal fluid samples were tested for neuronal surface Abs. The antibody prevalence in epilepsy and encephalopathy (APE2), antibodies contributing to focal epilepsy signs and symptoms (ACES), “obvious” indications for neural antibody testing in epilepsy or seizures (ONES) checklist, and the combinations were used to validate the predictive models of neuronal surface Ab-mediated AE. ResultsA total of 139 patients with new-onset epileptic seizures or epilepsy of unknown etiology were enrolled. Abs were detected in 37 patients (26.6%). The APE2/ONES reflex score had the highest sensitivity (89.2%) and lowest specificity (41.7%). The ACES score had the lowest sensitivity (67.5%) and highest specificity (64.7%). Variations in the performance were observed in the different types of AE.100% of patients with anti-γ-aminobutyric acid B-B receptor encephalitis were predicted by ONES, APE2/ONES reflex, and ACES/ONES reflex scores. Only 75% of patients with anti-N-methyl-D-aspartate receptor encephalitis were predicted by the APE2/ONES and ACES/ONES reflex scores. ConclusionOur study was the first to validate various predictive scoring scales in the Chinese cohort of patients with new-onset epileptic seizures or epilepsy of unknown etiology related to neuronal surface Ab-mediated AE. Based upon clinical suspicion, more than one scoring scale should be performed to predict the chance of AE in those patients.

Antibody-Mediated Striatal Encephalitis and Aseptic Meningitis in A Child with Neuropsychiatric Lupus: A Case Report

Antibody-Mediated Striatal Encephalitis and Aseptic Meningitis in A Child with Neuropsychiatric Lupus: A Case Report

Clinical scales in autoimmune encephalitis-A retrospective monocentric cohort study.

Assessing severity of antibody-mediated encephalitis (AE) or paraneoplastic encephalitis (PE) requires valid and reliable scores to guide treatment decisions and predict outcome both in clinical routine and studies. We aimed to validate the prognostic value of the clinical assessment scale in autoimmune encephalitis (CASE) and the anti-NMDAR-encephalitis one-year functional status (NEOS) score in patients suffering from AE and PE in a large monocentric cohort. We retrospectively applied the CASE and NEOS score to patients with definite AE and PE treated at a tertiary hospital. Correlations were established between the CASE and NEOS score and the modified Rankin scale (mRs). Multivariable analyses were calculated to identify predictors of outcome. Thirty-four patients (27 AE, 7 PE) were included. Correlations between mRS and CASE score were strongest in patients with AE compared to PE at all intervals, but in the subgroups (LGI1, NMDAR, GAD, miscellaneous surface antibodies, PE) the correlation was strongest in the interval after baseline. Patients with AE seemed to display better outcomes compared to PE, which was underlined by multivariable analysis. Improvement was mostly observed within 6-12 months after disease onset, after which little or no further improvement was noted with some exception for two patients with anti-NMDARE who recovered substantially even after 12 months of treatment. The NEOS score significantly predicted the outcome at last follow-up in patients with AE with a sensitivity of 79% at a cut-off value of 2 points (AUC 0.79, 95% CI 0.58-0.99, p = 0.04). The CASE and NEOS score are suitable supplementary tools in addition to the mRS for capturing diverse symptoms, for grading and monitoring symptom severity.

Clinical characteristics of Leucine-rich glioma-inactivated protein 1 antibody-mediated autoimmune encephalitis in a 6-year-old girl: case report and literature reviews

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.

The three pillars in treating antibody-mediated encephalitis.

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

A Rare Case of Anti-N-Methyl-D-Aspartate Receptor Encephalitis in an Infant Presenting with Regression and Movement Disorder.

A Rare Case of Anti-N-Methyl-D-Aspartate Receptor Encephalitis in an Infant Presenting with Regression and Movement Disorder.

Spectrum of Brain MRI Features in CASPR2 Associated Autoimmune Encephalitis: A Case Report With Parietal Lobe Involvement

Objective Contactin-associated-protein-like 2 (CASPR2)-antibody-mediated autoimmune encephalitis (AE) is characterized by diverse clinical manifestations with involvement of both central and peripheral nerve systems. Background Furthermore, approximately 50-55% of the patients with this condition present with an abnormal brain MRI including bilateral/unilateral T2-hyperintensity in the mesial temporal lobes, thalami, basal ganglia, brainstem, or cerebellum and hippocampal atrophy/sclerosis. To our knowledge this is the first case of CASPR-Ab-related AE reporting concurrent parieto-occipital lobes enhancing and non-enhancing brain lesions. Design/Methods A 71-year-old male presented with 3-months of cognitive decline, generalized tonic-clonic seizures, and parasomnias. Initial neurological examination showed diminished attention with neuropsychology evaluation revealed episodic memory deficits and executive dysfunction, otherwise no focal abnormality. Results Brain MRI with and without contrast from showed subtle cortical enhancement in the anterior left parietal lobe, additionally T2 FLAIR hyperintensities in the bilateral hippocampi, left centrum semiovale and left dorsal pons. CSF analysis revealed 5 nucleated cells, protein and glucose were normal. Serum and CSF paraneoplastic panel was positive for CASPR-2 auto antibodies. His memory and executive function improved after plasma exchange and long-term steroids. One year later the patient developed ataxia and gait instability. Repeated examination revealed diminished vibration in bilateral lower extremities, prominent left upper extremity ataxia compared to the right and a wide based gait. Updated brain MRI demonstrated progression of T2 FLAIR hyperintensities in the cortical and subcortical areas of the left parieto-occipital fissure. IVIG was started with stabilization of the progression. Conclusions CASPR2-autoantibody is associated to a wide range of neurological manifestations and diagnosing this condition could be challenging. This case demonstrates the possible involvement of the parietal and occipital cortex as a target of the antibodies directed against this membrane protein. Recognition of this spectrum of symptoms and imaging findings are important for early diagnosis of this disorder and appropriate treatment.

Challenging Cases in Neuroimmunology.

Neuroimmunology is rapidly evolving field extending from well-known, but incompletely understood conditions like multiple sclerosis, to novel antibody-mediated disorders, of which dozens have been described in the past 10 years. The ongoing expansion in knowledge needed to effectively diagnose and treat these patients presents myriad challenges for clinicians. Here, we discuss six informative cases from our institution. By highlighting these challenging cases, we hope to instill fundamental points on the nuances of diagnosis and management for conditions including tumefactive multiple sclerosis, antibody-mediated encephalitis, antiphospholipid antibody syndrome, neuromyelitis optica, and myelin oligodendrocyte glycoprotein IgG-associated disease.

Autoimmune Encephalitis

Autoimmune encephalitides form a heterogeneous group of neurological and psychiatric diseases. In antibody-mediated encephalitis, autoantibodies are pathogenic and directly cause the encephalitis. In antibody-associated encephalitis, which is paraneoplastic most of the time, autoantibodies serve as diagnostic biomarkers and are able to predict the underlying tumour.

Antibody-mediated autoimmune encephalitis evaluated by 18F-DPA714 PET/MRI

SARS-CoV-2 vaccine has considered being the most effective method to prevent SARS-CoV-2 infection. The safety and effectiveness of the SARS-CoV-2 vaccine has been confirmed. However, in very rare cases, autoimmune neurological diseases may occur. In this article, we report three rare cases of autoimmune encephalitis with definite auto-antibody after SARS-CoV-2 vaccination. They all have good prognosis after treatment. In addition, we first use 18F-DPA-714 PET/MRI to evaluate microglia activation in our patients. We found that 18F-DPA-714 PET/MRI may be a powerful tool for quantitative analysis of neuroinflammation in patients of autoimmune encephalitis. Finally, although rare complications may happen after vaccination, we still consider the benefits of vaccination far outweigh the risks. People without contraindications should be vaccinated without delay to prevent infection in current outbreak situation.

Encephalitis with Extensive Cortical Brain Magnetic Resonance Imaging Changes Secondary to Myelin Oligodendrocyte Glycoprotein Antibody Disease

Patient: Male, 17-month-old Final Diagnosis: Fluid attenuated inversion recovery (FLAIR) imaging showing cortical hyperintense lesions in myelin-oligodendrocyte-glycoprotein (MOG) associated encephalitis with seizures (FLAMES Symptoms: Encephalopathy • fever • left sided weakness • seizures Medication: — Clinical Procedure: Plasmapharesis Specialty: Neurology Objective: Rare disease Background:The relatively new autoimmune disorder, anti-myelin oligodendrocyte glycoprotein (MOG) disease is particularly interesting because of its broad range of presentations. This entity’s appearance on magnetic resonance imaging (MRI) of the brain often makes identifying this disease a challenging process. Younger patients tend to present with an acute disseminated encephalomyelitis picture, with encephalopathy and multifocal neurological signs, while older patients are more likely to present with optic neuritis. We, however, report an atypical case of a patient who presented with encephalopathy, seizures, and significant cortical and subcortical gray matter involvement and was found to have anti-MOG positivity in serum.Case Report:A 17-month-old previously healthy boy presented to Emergency Department with fever, lethargy, vomiting, and left-sided weakness. Eventually, he required intubation due to a prolonged seizure. Continuous electroencephalogram captured several focal seizures, and MRI of the brain showed cortical and subcortical T2 hyperintensities. After extensive laboratory evaluation, he tested positive for anti-MOG antibody. He was empirically started on high-dose intravenous pulse methylprednisolone, followed by plasma exchange, given the poor response to the intravenous steroids. At the 5-month follow-up, the results of the neurological examination had dramatically improved, and MRI findings had largely resolved.Conclusions:This case highlights the importance of suspecting anti-MOG antibody-mediated encephalitis, even while ruling out infectious etiologies, in children presenting with encephalopathy, seizures and MRI abnormalities. Prompt recognition would allow for less delay in treatment and hopefully improve prognosis.

First-line immunotherapy of neuronal surface antibody-mediated autoimmune encephalitis: Assessment of therapeutic effectiveness and cost-efficiency

ObjectiveTo evaluate the therapeutic effectiveness and cost-efficiency of first-line immunotherapies on neuronal surface antibody-mediated autoimmune encephalitis (AE) based on a real-world observational study in China. MethodsOur study retrospectively collected the clinical and paraclinical data of patients with definite neuronal surface antibody-mediated AE between July 2014 and July 2020. Regular follow-up was performed after administering standard regimens of first-line immunotherapies, including intravenous methylprednisolone (IVMP) and / or intravenous immunoglobulin (IVIG). Therapeutic effectiveness was reflected by modified Rankin Scale scores. The health resource utilization and direct medical costs were extracted to analyze the cost-efficiency. ResultsAmong the 78 eligible patients, 48 (61.5%) were males with a median age of 40 years. More than half (56, 71.8%) were treated with combination therapy, with the rest receiving IVMP and IVIG monotherapy (both of 11, 14.1%). Related objective variables, i.e., sex, onset age, disease course, onset symptoms, antibody types, abnormal paraclinical results, disease severity, and the health insurance, showed insignificant differences on the selection of therapy. Each therapy showed similar short-term (4-week) and long-term (1-year) therapeutic effects. Yet the single or combination of IVIG had a slightly better effectiveness but higher cost than the monotherapy of IVMP. ConclusionThe combination of IVMP and IVIG was used more frequently than either alone, which may be associated with neurologist's personal experience and patient's wishes. Though with similar therapeutic effectiveness, the use of IVMP alone might be a better choice with a better cost-efficiency.

Clinical Characteristics and Short-Term Prognosis of Children With Antibody-Mediated Autoimmune Encephalitis: A Single-Center Cohort Study.

BackgroundThe incidence and prevalence of autoimmune encephalitis (AE) is gradually increasing in pediatric patients (between the ages of 3 months and 16 years). The aim of this retrospective observational study was to investigate the clinical characteristics and short-term prognosis of children with antibody-mediated AE at Hunan Children's Hospital.MethodsAntibody analysis of blood and/or cerebrospinal fluid was performed in suspected AE patients admitted to the Department of Neurology, Hunan Children's Hospital from June 2014 to June 2021. Ultimately, 103 patients were diagnosed with antibody-mediated AE and were enrolled in this study. Clinical data and corresponding demographic, clinical characteristics, laboratory and imaging data, treatment, and prognosis data were collected and analyzed.ResultsIn our study, 103 AE patients with antibody-positive were identified. The main subtype of AE in our cohort was anti-NMDAR encephalitis. Few patients have anti-CASPR2 encephalitis, anti-GABABR encephalitis, or anti-LGI1 encephalitis. In our AE patients, the most common clinical manifestations were behavioral symptoms, seizures, and involuntary movements, with seizures being the most common initial symptom. All patients underwent brain magnetic resonance imaging (MRI) and electroencephalography (EEG). Forty-five (43.7%) patients had abnormal MRI findings. And 96 (93.2%) patients had abnormal EEG results. All 103 patients were given first-line immunotherapy, 21 of which were also treated with the combination of the second-line immunotherapy. All surviving patients were followed up for at least 6 months. Seventy-seven patients recovered completely, 23 had sequelae of different degrees, and 3 died. Eight patients had one or more relapses during the follow-up period.ConclusionsAE is a treatable disease that can occur in children of all ages. The mortality rate is low, as most patients have a good response to immune therapy. Compared with the older children, infants and young children (≤ 3 years old) with anti-NMDAR encephalitis have a higher incidence of fever and status epilepticus, more severe condition, higher PICU admission rate and worse prognosis. AE patients with high maximum mRS scores and PICU admissions may require second-line immunotherapy.

Clinical Features, Treatment, and Prognostic Factors in Neuronal Surface Antibody-Mediated Severe Autoimmune Encephalitis.

ObjectiveThis study aimed to determine the clinical characteristics and evaluate the efficacy of immunotherapy and the long-term prognosis of severe autoimmune encephalitis (AE) in China.MethodsClinical features, laboratory or radiological findings, and treatment outcomes of 60 severe patients with AE from January 1, 2014, to December 31, 2020, were collected. Continuous variables were compared using the t-test and the nonparametric Mann–Whitney U test, as appropriate. Univariate and multivariable logistic regression analyses were performed to assess the correlations between factors, treatment responses, and prognosis of severe AE.ResultsThe median age of symptom onset was 35 years. Tumors were identified in 23.3% of patients, and 36/60 (60%) patients responded to first-line immunotherapy. Second-line immunotherapy was implemented in 26/60 (43.3%) patients. A significant clinical benefit was observed in 19/26 (73.1%) patients treated with lower dosage rituximab; seven patients were still refractory and received bortezomib as an add-on therapy. During the last follow-up, 48/60 (80%) patients achieved good outcomes (mRS, 0–2), and 10 died. Seventeen patients experienced relapses. A high CD19+ B-cell count (OR, 1.197; 95% CI [1.043–1.496]; p = 0.041) and a lower neutrophil-to-lymphocyte ratio (NLR; OR, 0.686; 95% CI [0.472–0.884]; p = 0.015) predict the response to first-line treatment and good prognosis, respectively.ConclusionsPatients with severe AE were in critical condition at baseline but could be salvaged after effective rescue immunotherapy. A lower dosage of rituximab could be an optimal option for severe AE. CD19+ B-cell count and NLR may provide prognostic information for predicting treatment response and outcome of severe AE.

Life after autoantibody-mediated encephalitis: optimizing follow-up and management in recovering patients.

Timely diagnosis and treatment is essential to optimize outcomes in patients with antibody-mediated encephalitis (AME); yet even with early diagnosis and treatment, long-term outcomes may still fall short of expectations. Identifying patients at greater risk of adverse outcomes is key to personalizing care, supporting accurate counseling of patients and family members, and informing therapeutic decisions in patients with AME. This review considers long-term outcomes in recovering patients, including approaches to measure and manage common sequelae that influence life after AME. Cognitive impairment, fatigue, and sleep disturbances affect most recovering AME patients. This realization highlights the need for outcome measures that encompass more than motor function. Standardized questionnaires, surveys, and clinical assessment tools may be adapted to support comprehensive and reproducible clinical assessments and to identify patients who may benefit from additional therapies. Good outcomes continue to be reported in recovering patients, emphasizing the high potential for recovery following AME. However, cognitive, behavioral, and physical sequelae may limit the potential for great outcomes following AME. Multidisciplinary follow-up is needed to recognize and treat sequelae that compromise long-term recovery and limit quality of life in recovering patients.

Fulminant anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor GluR1 antibodies encephalitis in a Chinese boy: a case report

BackgroundAnti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) encephalitis is a rare autoimmune synaptic encephalitis associated with autoantibodies that cause a selective decrease in surface expression and changes in receptor localization. Anti-AMPAR encephalitis is poorly recognized, especially in children, and its clinical phenotype is incompletely described.Case presentationWe report a case of anti-AMPAR GluR1 antibody-mediated autoimmune encephalitis in a 12-year-old male. The patient manifested as a fulminant course, with ataxia, cerebellar degeneration at the onset, and rapidly evolved into hyperthermia, coma and rhabdomyolysis. Antibodies against AMPAR GluR1 receptors were detected in the cerebrospinal fluid by cell-based assay. Diffuse slow waves were found by electroencephalograph, and the left cerebellar vermis and hemisphere were affected on brain magnetic resonance imaging (MRI). The patient was treated with intravenous immunoglobulin (IVIG), methylprednisolone combined with plasma exchange. Symptoms were alleviated after immunotherapy and the patient sustained clinical improvement. This is the first time that acute rhabdomyolysis symptom has been identified in a pediatric patient with anti-AMPAR encephalitis.ConclusionsThis case expands the clinical spectrum of anti-AMPAR encephalitis and highlights that despite poor clinical manifestation at the outset, recovery remains possible.