Brazilian autoimmune encephalitis network (BrAIN): antibody profile and clinical characteristics from a multicenter study

Exploring seizure characteristics in individuals with autoimmune encephalitis: A comprehensive retrospective study in a low-middle-income country setting

INTRODUCTION

Seizures and epilepsy are well-documented in association with autoimmune encephalitis. Despite this, a notable gap exists in understanding the persistence of seizures beyond the acute phase, particularly within the context of low- and low-middle-income settings.

OBJECTIVE

To evaluate the frequency, clinical characteristics, diagnosis, and potential factors associated with the occurrence and persistence of seizures in autoimmune encephalitis patients.

METHODS

This was a retrospective, cross-sectional study. Patients diagnosed with possible, probable or confirmed autoimmune encephalitis according to the Graus criteria at the "Instituto Nacional de Ciencias Neurológicas" in Lima, Peru, were included between January 2018 and April 2023. Demographic, clinical, diagnosis, and management information was recorded. A bivariate analysis was performed considering the persistence of seizures at one-year follow-up and a second analysis was performed to compare the groups according to the anti N-methyl-D-aspartate receptor (NMDAR) antibody results.

RESULTS

Sixty patients predominantly male (40; 66.7 %) were included. Only 36 (60 %) patients were tested for antibodies, 16 (44.4 %) were NMDAR positive. 46 (76.7 %) patients had at least one seizure and 13 (37.1 %) had seizures after 1 year of follow-up. Patients with seizure relapse were younger, 20 (IQR: 18-28) versus 29.5 years (IQR: 21-48), p=0.049. Four (44.4 %) patients with persistent seizures had positive NMDAR results. Similar sex distributions, no differences in seizure characteristics, and higher CSF cell count in the NMDAR-positive group were observed. Neuroimaging, EEG findings, and follow-up times were comparable between the groups.

CONCLUSIONS

We found a 37.1 % seizures rate after one year of follow-up, predominantly in younger patients.

Anti-GABAB Receptor Autoimmune Encephalitis: A Report of a Rare Case in Central America

Autoimmune encephalitis (AE) is a rare disease. There have been very few reports of anti-GABAB receptor encephalitis, and no case of this subtype has ever been reported in Central America. We present a case of a 21-year-old male patient with an unremarkable previous medical history who was hospitalized because of a new onset of seizures and status epilepticus. Central nervous system infections, neoplastic disorders, cerebrovascular disease, septic and metabolic encephalopathy, and drug toxicity were ruled out. Cerebrospinal fluid (CSF) revealed lymphocytic pleocytosis and oligoclonal bands. Initial head computed tomography (CT) scans with and without contrast were normal, and brain magnetic resonance imaging (MRI) showed no abnormalities. An electroencephalogram showed slow waves and spike waves in the frontal and temporal areas. During hospitalization, encephalopathy progressed, along with seizures and altered mental status requiring mechanical ventilation and admission to the intensive care unit. Intravenous valproic acid and phenytoin for seizure control were given. The unexplained seizures, persisting altered mental status despite the reduction of sedatives, CSF pleocytosis, and oligoclonal bands, along with reasonable exclusion of alternative disorders, suggested AE. The diagnosis was confirmed with positive anti-GABAB1-B2 receptor antibody titers in serum and CSF. A whole-body CT scan showed increased pancreatic head size, but endoscopic ultrasonography ruled out malignancy, and a normal IgG4 range excluded IgG4 disease. The patient received treatment with methylprednisolone, plasmapheresis, and immunoglobulin therapy, with excellent response. The patient has been followed up for seven months, taking immunomodulation with mycophenolate. He is seizure-free with valproic acid and levetiracetam treatment and is receiving cognitive rehabilitation after mild cognitive decline was noted in the psychometric analysis.

Encephalitis associated with anti-mGluR5 antibodies

A 30-year-old woman had 5 days of visual hallucinations, nystagmus, memory impairment and mutism. On examination, she was disorientated with reduced attention span, gaze-evoked nystagmus, paratonia and abnormal frontal reflexes. Cerebrospinal fluid (CSF) showed 80 cells, protein 0.41 g/L and glucose 3.2 mmol/L (plasma glucose 5.0 mmol/L). MR scan of the brain showed involvement of limbic and extra-limbic regions and brainstem. Commercial cell-based assays were negative, but tissue-based assays showed neuropil staining, and cell-based assays for anti-metabotropic glutamate receptor 5 (mGluR5) antibodies were positive in serum and CSF. Six months later, she was diagnosed with Hodgkin's lymphoma. This case emphasises the broader clinical spectrum of anti-mGluR5 encephalitis, challenging its initial characterisation as Ophelia syndrome. It underscores the significance of interpreting commercial cell-based assays and advocates for tissue-based assay testing followed by cell-based assay testing in serum and CSF for diagnosing rare autoimmune encephalitis.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Clinical features in antiglycine receptor antibody-related disease: a case report and update literature review

Background and objectives

Antiglycine receptor (anti-GlyR) antibody mediates multiple immune-related diseases. This study aimed to summarize the clinical features to enhance our understanding of anti-GlyR antibody-related disease.

Methods

By collecting clinical information from admitted patients positive for glycine receptor (GlyR) antibody, the clinical characteristics of a new patient positive for GlyR antibody were reported in this study. To obtain additional information regarding anti-GlyR antibody-linked illness, clinical data and findings on both newly reported instances in this study and previously published cases were merged and analyzed.

Results

A new case of anti-GlyR antibody-related progressive encephalomyelitis with rigidity and myoclonus (PERM) was identified in this study. A 20-year-old man with only positive cerebrospinal fluid anti-GlyR antibody had a good prognosis with first-line immunotherapy. The literature review indicated that the common clinical manifestations of anti-GlyR antibody-related disease included PERM or stiff-person syndrome (SPS) (n = 179, 50.1%), epileptic seizure (n = 94, 26.3%), and other neurological disorders (n = 84, 24.5%). Other neurological issues included demyelination, inflammation, cerebellar ataxia and movement disorders, encephalitis, acute psychosis, cognitive impairment or dementia, celiac disease, Parkinson's disease, neuropathic pain and allodynia, steroid-responsive deafness, hemiballism/tics, laryngeal dystonia, and generalized weakness included respiratory muscles. The group of PERM/SPS exhibited a better response to immunotherapy than others.

Conclusions

The findings suggest the presence of multiple clinical phenotypes in anti-GlyR antibody-related disease. Common clinical phenotypes include PERM, SPS, epileptic seizure, and paraneoplastic disease. Patients with RERM/SPS respond well to immunotherapy.