Electroencephalographic findings in anti-N-methyl-d-aspartate receptor encephalitis in children: A series of 12 patients

Functional connectivity changes of the hippocampal subregions in anti-N-methyl-D-aspartate receptor encephalitis

The hippocampus plays an important role in the pathophysiological mechanism of Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. Nevertheless, the connection between the resting-state activity of the hippocampal subregions and neuropsychiatric disorders in patients remains unclear. This study aimed to explore the changes in functional connectivity (FC) in the hippocampal subregions of patients with anti-NMDAR encephalitis and its association with clinical symptoms and cognitive performance. Twenty-three patients with anti-NMDAR encephalitis and 23 healthy controls (HC) were recruited. All participants underwent resting-state functional magnetic resonance imaging (rs-fMRI) scans and completed clinical cognitive scales. Based on the Brainnetome Atlas, the rostral (anterior) and caudal (posterior) hippocampi of both the left and right hemispheres were selected as regions of interest (ROIs) for FC analysis. First, a one-sample t-test was used to observe the whole-brain connectivity distribution of hippocampal subregions within the patient and HC groups at a threshold of p < 0.05. The two-sample t-test was used to compare the differences in hippocampal ROIs connectivity between groups, followed by a partial correlation analysis between the FC values of brain regions with statistical differences and clinical variables. This study observed that the distribution of whole-brain functional connectivity in the rostral and caudal hippocampi aligned with the connectivity differences between the anterior and posterior hippocampi. Compared to the HC group, the patients showed significantly decreased FC between the bilateral rostral hippocampus and the left inferior orbitofrontal gyrus and between the right rostral hippocampus and the right cerebellum. However, a significant increase in FC was observed between the right rostral hippocampus and left superior temporal gyrus, the left caudal hippocampus and right superior frontal gyrus, and the right caudal hippocampus and left gyrus rectus. Partial correlation analysis showed that FC between the left inferior orbitofrontal gyrus and the right rostral hippocampus was significantly negatively correlated with the California Verbal Learning Test (CVLT) and Brief Visuospatial Memory Test (BVMT) scores. The FC between the right rostral hippocampus and the left superior temporal gyrus was negatively correlated with BVMT scores. FC abnormalities in the hippocampal subregions of patients with anti-NMDAR encephalitis were associated with cognitive impairment, emotional changes, and seizures. These results may help explain the pathophysiological mechanisms and clinical manifestations of anti-NMDAR encephalitis and NMDAR dysfunction-related diseases such as schizophrenia.

Long-Term Outcome of Pediatric Patients with Anti-NMDA Receptor Encephalitis in a Single Center

BACKGROUND

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is the most common autoimmune encephalitis in children. There is a high probability of recovery if treated promptly. We aimed to analyze the clinical features and long-term outcomes of pediatric patients with anti-NMDA receptor encephalitis.

METHOD

We conducted a retrospective study with definite diagnoses of anti-NMDA receptor encephalitis in 11 children treated in a tertiary referral center between March 2012 and March 2022. Clinical features, ancillary tests, treatment, and outcomes were reviewed.

RESULTS

The median age at disease onset was 7.9 years. There were eight females (72.7%) and three males (27.3%). Three (27.3%) patients initially presented with focal and/or generalized seizures and eight (72.7%) with behavioral change. Seven patients (63.6%) revealed normal brain MRI scans. Seven (63.6%) had abnormal EEG results. Ten patients (90.1%) received intravenous immunoglobulin, corticosteroid, and/or plasmapheresis. After a median follow-up duration of 3.5 years, one patient was lost to follow-up at the acute stage, nine (90%) had an mRS ≤ 2, and only one had an mRS of 3.

CONCLUSIONS

With the early recognition of anti-NMDA receptor encephalitis based on its clinical features and ancillary tests, we were able to treat patients promptly with first-line treatment and achieve favorable neurological outcomes.

Case of anti-NMDA receptor encephalitis in a female adolescent with favourable response to second-line treatment with cyclophosphamide

We report the case of a female adolescent who presented with behavioural changes. She was admitted to our institution due to worsening psychiatric and neurological symptoms, subsequently diagnosed with anti-N-methyl-D-aspartate receptor encephalitis. Additional workup was facilitated to rule out a possible underlying teratoma, but all tests turned out unremarkable. First-line treatment with methylprednisolone pulse therapy and intravenous immunoglobulin was started, to which she showed marked improvement from baseline. One month after discharge, a decision for readmission was made because of persistent episodes of hallucinations, agitation and dyskinesias. In this case report, we highlight the use of cyclophosphamide over rituximab as second-line treatment in a resource-limited setting, owing to its greater availability and lesser cost. Cyclophosphamide treatment was given resulting in a more sustained clinical improvement with return to baseline function.

Occipital intermittent rhythmic delta activity (OIRDA) in pediatric focal epilepsies: A case series

In this case series, we have identified an atypical pattern of OIRDA (Occipital intermittent rhythmic delta activity) on the electroencephalograms (EEGs) of three pediatric patients with self-limited focal epilepsies, including Childhood Epilepsy with Centrotemporal Spikes (CECTS), and Panayiotopoulos syndrome (PS). Previously, OIRDA was described as a symmetric sinusoidal occipital-maximal activity, often associated with childhood idiopathic generalized epilepsies, although it was also reported among other physiologic or pathological entities including focal epilepsy. We have observed in our case series that OIRDA, without prominent field effect, is lateralized or maximal on the hemispheric side ipsilateral to the more defining epileptiform discharges in these focal epilepsies. They also exhibit a notched morphology due to the intermixed sharp wave activities, although the sharp waves are not occurring repetitively. This report provides additional evidence that OIRDA can be associated with a spectrum of idiopathic focal epilepsies and may suggest a cortical origin of OIRDA in these patients as opposed to a hypothesized subcortical generator in patients with primary generalized absence epilepsy, even though further investigation is warranted for either hypothesis.

Antibody-Mediated Encephalitis in Children: Focus on Diagnostic Clues and Acute Symptom Management

Antibody-mediated encephalitis is a treatable cause of encephalitis that manifests over days to weeks as changes in behavior and cognition, seizures, movement disorders, and autonomic dysfunction. Patients with autoimmune encephalitis develop a variety of symptoms. As such, they require a multidisciplinary approach to care. In this review we summarize the clinical presentation and practical diagnostic approach to pediatric autoimmune encephalitis, review treatments of the autoimmune process, and discuss the management of the acute symptoms encountered in children.

[Research progress on electroencephalogram characteristics of anti-N-methyl-D-aspartate receptor encephalitis]

Anti-N-methyl-d-aspartate (NMDA) receptor encephalitis is a kind of autoimmune disease aiming at NR1 subunit of NMDA receptor. In the early stage, functional damage is the main cause. Electroencephalogram (EEG) can reflect the abnormal brain function by recording the changes of EEG signals. The common EEG patterns of anti NMDA receptor encephalitis are slow wave abnormality, epileptic discharge, a large number of β activity, extreme delta brush, etc. Here we review the waveform characteristics, origin, pathogenesis and clinical value of EEG in patients with NMDA receptor encephalitis.

Analysis of Risk Factors for a Poor Prognosis in Patients with Anti-N-Methyl-D-Aspartate Receptor Encephalitis and Construction of a Prognostic Composite Score

BACKGROUND AND PURPOSE

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is the most-common form of autoimmune encephalitis, but its early diagnosis is challenging. This study aimed to identify the risk factors for a poor prognosis in anti-NMDAR encephalitis and construct a prognostic composite score for obtaining earlier predictions of a poor prognosis.

METHODS

We retrospectively analyzed the clinical data, laboratory indexes, imaging findings, and electroencephalogram (EEG) data of 60 patients with anti-NMDAR encephalitis. The modified Rankin Scale (mRS) scores of patients were collected when they were discharged from the hospital. The mRS scores were used to divide the patients into two groups, with mRS scores of 3-6 defined as a poor prognosis. Logistic regression analysis was used to analyze independent risk factors related to a poor prognosis.

RESULTS

This study found that 23 (38.3%) and 37 (61.7%) patients had good and poor prognoses, respectively. Logistic regression analysis showed that age, disturbance of consciousness at admission, and ≥50% slow waves on the EEG were significantly associated with patient outcomes. An age, consciousness, and slow waves (ACS) composite score was constructed to predict the prognosis of patients with anti-NMDAR encephalitis at an early stage based on regression coefficients.

CONCLUSIONS

Age, disturbance of consciousness at admission, and ≥50% slow waves on the EEG were independent risk factors for a poor prognosis. The ACS prognostic composite score could play a role in facilitating early predictions of the prognosis of anti-NMDAR encephalitis.

Persistent extreme delta brush in anti-NMDA-receptor encephalitis: Does it portend a poor prognosis?

We describe an adolescent girl with non-paraneoplastic anti-NMDA-receptor encephalitis (ANMDARE), who despite persistence of the extreme delta brush (EDB) pattern for nearly 2 years in her serial EEGs, she exhibited a speedy and sustained response to immunotherapy. To the best of our knowledge, our patient had the longest persistence of the EDB pattern on EEG reported to date. Our patient illustrates that, although presence of EDB supports the diagnosis of ANMDARE, its presence and persistence may not be a reliable predictor of response to immunotherapy and overall clinical prognosis.

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Extreme delta brush (EBD) supports diagnosis of anti-NMDA-R encephalitis (ANMDARE).

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EDB may persist for a long time despite complete resolution of symptoms of ANMDARE.

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EDB may not be reliable biomarker of response to immunotherapy and outcome.

Recognizing psychiatric presentations of anti-NMDA receptor encephalitis in children and adolescents: A synthesis of published reports

AIM

The aim of this study was to improve early recognition of anti-N-methyl-d-aspartate receptor encephalitis (anti-NMDArE) in children and adolescents by identifying characteristic temporal patterns of clinical features in patients likely to be referred for psychiatric evaluation. In this form of autoimmune encephalitis, NMDAr hypofunction is caused by autoantibodies to receptor surface components. Clinical outcomes following prompt immunotherapy are usually good, but delayed treatment often results in a protracted course with significant residual disability or death. Anti-NMDArE frequently mimics psychiatric disorders, so most patients are referred initially to a psychiatrist and treated for days or weeks before being correctly diagnosed.

METHODS

A systematic search of PubMed and EMBASE electronic databases identified all published reports of antibody-confirmed anti-NMDArE associated with psychiatric symptoms in patients <19 years old. Redundant reports were eliminated manually. For each patient, the order in which each feature was first observed was ranked relative to others. Median temporal ranks were used to compare the sequencing of individual features and major symptom domains.

RESULTS

One hundred and sixty seven cases (121 females) met the inclusion criteria. The most common features were dyskinesias (77.8%), seizures (72.5%), mutism or staring (40.7%), insomnia (39.5%), language dysfunction (36.5%), fever (31.1%), disorientation/confusion (28.7%), reduced arousal (28.1%), and memory disturbance (26.9%). The configuration and temporal sequencing of features were highly variable between individuals.

CONCLUSION

Clinicians need to suspect this disorder: if new behavioral symptoms arise in the context of a recent viral prodrome; if they are accompanied by dyskinesias, seizures or insomnia; or if psychiatric symptoms are unusual (e.g., non-verbal auditory hallucinations).

Predictive value of electroencephalography in anti-NMDA receptor encephalitis

OBJECTIVES

Anti-N-methyl-D-aspartate receptor encephalitis (anti-NMDARE) is a severe, but treatable disease. This study aims to give a detailed description of electroencephalogram (EEG) results in paediatric and adult patients to improve disease recognition, and analyses the predictive value of the first EEG for the final clinical outcome.

METHODS

This nationwide cohort study includes patients with N-methyl-D-aspartate receptor antibodies confirmed with cell-based assay and immunohistochemistry in serum and cerebrospinal fluid. EEG recordings were re-evaluated by two experienced neurophysiologists, mixed with control EEGs for blinding. Initial EEG as well as follow-up registrations were analysed.

RESULTS

35 adults and 18 children were included. Only two patients (4%) had a normal EEG. During the first recording, the majority of the patients had normal posterior rhythm (71%), which was associated with better modified Rankin Scale at final outcome (OR 4.74; 95% CI 1.56 to 14.47; p=0.006). In addition, EEGs showed focal (73%) or diffuse (67%) slowing. The first EEG was severely abnormal in 26%. However, 8 of 14 patients with a severely abnormal first EEG still had a favourable outcome. During the course of the disease, extreme delta brushes (EDBs) were present in 6 of 53(11%)patients.

CONCLUSIONS

The first EEG commonly shows normal posterior rhythm with focal or diffuse slowing. Although the sensitivity of an abnormal EEG is high (96%), normal EEG does not exclude anti-NMDARE. EDBs are only present in severely affected patients. The first EEG recording is predictive of the final clinical outcome.

Viral Encephalitis

Viruses are a frequent cause of encephalitis. Common or important viruses causing encephalitis include herpesviruses, arboviruses, enteroviruses, parechoviruses, mumps, measles, rabies, Ebola, lymphocytic choriomeningitis virus, and henipaviruses. Other viruses may cause an encephalopathy. Host factors and clinical features of infection are important to consider in identifying the cause for encephalitis. Cerebrospinal fluid evaluation, serologic/polymerase chain reaction studies, and neuroimaging are cornerstones of diagnostic evaluation in encephalitis. Treatable forms of encephalitis are important to consider in all cases. Central nervous system inflammation may also occur because of postinfectious autoimmunity, such as acute disseminated encephalomyelitis or antibody-mediated encephalitis after herpes simplex virus encephalitis.