Refractory status epilepticus caused by anti-NMDA receptor encephalitis that markedly improved following combination therapy with rituximab and cyclophosphamide

Anti-N-methyl-D-aspartate receptor-associated encephalitis: A review of clinicopathologic hallmarks and multimodal imaging manifestations

Anti-N-methyl-D-aspartate receptor-associated encephalitis (NMDARE) is a rare immune-mediated neuroinflammatory condition characterized by the rapid onset of neuropsychiatric symptoms and autonomic dysfunction. The mechanism of pathogenesis remains incompletely understood, but is thought to be related to antibodies targeting the GluN1 subunit of the NMDA receptor with resultant downstream dysregulation of dopaminergic pathways. Young adults are most frequently affected; the median age at diagnosis is 21 years. There is a strong female predilection with a female sex predominance of 4:1. NMDARE often develops as a paraneoplastic process and is most commonly associated with ovarian teratoma. However, NMDARE has also been described in patients with small cell lung cancer, clear cell renal carcinoma, and other benign and malignant neoplasms. Diagnosis is based on correlation of the clinical presentation, electroencephalography, laboratory studies, and imaging. Computed tomography, positron emission tomography, and magnetic resonance imaging are essential to identify an underlying tumor, exclude clinicopathologic mimics, and predict the likelihood of long-term functional impairment. Nuclear imaging may be of value for prognostication and to assess the response to therapy. Treatment may involve high-dose corticosteroids, intravenous immunoglobulin, and plasma exchange. Herein, we review the hallmark clinicopathologic features and imaging findings of this rare but potentially devastating condition and summarize diagnostic criteria, treatment regimens, and proposed pathogenetic mechanisms.

Successful treatment with immunoadsorption therapy in four patients with severe and refractory anti-N-methyl-D-aspartate receptor encephalitis

There is still no optimal treatment for patients with severe anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis refractory to first-line therapy (including intravenous methylprednisolone [IVMP] and intravenous immunoglobulin [IVIG]). A small study has shown that immunoadsorption (IA) is effective in treating anti-NMDAR encephalitis. However, the effectiveness and safety of IA in the treatment of patients with refractory and severe anti-NMDAR encephalitis is not fully known. Four patients with severe anti-NMDAR encephalitis are reported, which were refractory to the first-line immunotherapy including IVMP and IVIG. Immunoadsorption is performed during the fulminant stage of disease, and the effectiveness and safety of IA are assessed. The modified Rankin Scale (mRS) is used to assess neurological conditions before and after IA. Four patients with the most severe form of anti-NMDAR encephalitis (two with teratoma and two with unknown origin) did not respond to one or more rounds of IVMP plus IVIG. They all required intensive care unit (ICU) support including long-term mechanical ventilation, and thus developed ICU-related complications. Gradual and steady improvement was observed after IA treatment. Except for mild hypotension in patient 1, no other adverse events were observed during IA. Two patients had good early overall recovery on discharge. The other two patients had a good outcome with mRS of 2 at the 12-month follow-up. This small case series suggests that IA may be an effective treatment option to accelerate the recovery of patients with severe and refractory anti-NMDAR encephalitis.

Super-Refractory Status Epilepticus: Prognosis and Recent Advances in Management

Super-refractory status epilepticus (SRSE) is a life-threatening neurological emergency with high morbidity and mortality. It is defined as “status epilepticus (SE) that continues or recurs 24 hours or more after the onset of anesthesia, including those cases in which SE recurs on the reduction or withdrawal of anesthesia.” This condition is resistant to normal protocols used in the treatment of status epilepticus and exposes patients to increased risks of neuronal death, neuronal injury, and disruption of neuronal networks if not treated in a timely manner. It is mainly seen in patients with severe acute onset brain injury or presentation of new-onset refractory status epilepticus (NORSE). The mortality, neurological deficits, and functional impairments are significant depending on the duration of status epilepticus and the resultant brain damage. Research is underway to find the cure for this devastating neurological condition. In this review, we will discuss the wide range of therapies used in the management of SRSE, provide suggestions regarding its treatment, and comment on future directions. The therapies evaluated include traditional and alternative anesthetic agents with antiepileptic agents. The other emerging therapies include hypothermia, steroids, immunosuppressive agents, electrical and magnetic stimulation therapies, emergent respective epilepsy surgery, the ketogenic diet, pyridoxine infusion, cerebrospinal fluid drainage, and magnesium infusion. To date, there is a lack of robust published data regarding the safety and effectiveness of various therapies, and there continues to be a need for large randomized multicenter trials comparing newer therapies to treat this refractory condition.

Evaluation and Management of Seizures and Status Epilepticus

Seizures are frequently triggered by an inciting event and result from uninhibited excitation and/or decreased inhibition of a pool of neurons. If physiologic seizure abortive mechanisms fail, the ensuing unrestrained synchronization of neurons-status epilepticus-can be life-threatening and is associated with the potential for marked morbidity in survivors and high medical care costs. Prognosis is intimately related to etiology and its response to therapeutic measures. Timely implementation of pharmacologic therapy while concurrently performing a stepwise workup for etiology are paramount. Neurodiagnostic testing should guide titration of pharmacologic therapies, and help determine if there is a role for immune modulation.

[Anti-NMDAR encephalitis associated with relapsing optic neuritis]

Autoimmune encephalitis with antibodies to NMDA receptors (anti-NMDAR encephalitis), is the most common form of autoimmune encephalitis. The disease is curable, however, the lack of timely therapy can lead to the disability of patients or to the death. Difficulties in the diagnosis of anti-NMDAR encephalitis are caused by the heterogeneity of its manifestations, a possible overlapping with other autoimmune diseases and insufficient awareness about this form of encephalitis. This article describes the case of anti-NMDAR encephalitis associated with recurrent optic neuritis which might be an atypical manifestation for this disease. Optic neuritis could not be explained by overlapping with multiple sclerosis or neuromyelitis optica spectrum disorders.

Catatonia in N-methyl-d-aspartate receptor antibody encephalitis: Phenomenological characteristics from a systematic review of case reports

OBJECTIVE

To ascertain the phenomenological characterisation of catatonia in N-methyl-d-aspartate receptor antibody encephalitis (NMDAr-AbE).

METHODS

A systematic review of case reports was undertaken in accordance with PRISMA guidelines. Case reports of NMDAr-AbE containing sufficient information on the cases' clinical presentation and meeting the study's inclusion criteria were selected. Cases were searched for clinical data in keeping with core catatonic signs by applying the screening instrument of the Bush-Francis Catatonia Rating Scale. When two or more core signs were ascertained catatonia was considered to be present.

RESULTS

2645 records were identified through the database search. Following screening and application of eligibility/inclusion criteria 139 articles were selected reporting on 189 individual subjects. Catatonia was present in 60% of these cases. The most prevalent signs were immobility/stupor (70%), mutism (67%), excitement (50%), posturing/catalepsy (34%), stereotypies (31%), and rigidity (30%). Immobility/stupor and excitement co-occurred in the same patient in 33% of cases.

CONCLUSION

The phenomenological profile of catatonia in this sample of cases of NMDAr-AbE was characterised by a preponderance of signs in the hypokinetic spectrum. However, excitement often co-occurred in these patients suggesting that fluctuations in catatonic semiology may be frequent.

[Anti-NMDAR encephalitis associated with relapsing optic neuritis: a case report and differential diagnosis]

Autoimmune encephalitis with antibodies to NMDA receptors, or anti-NMDAR encephalitis, is the most common form of autoimmune encephalitis. The disease is curable, however, the lack of timely therapy can lead to the disability of patients or to the death. Difficulties in the diagnosis of anti-NMDAR encephalitis are caused by the heterogeneity of its manifestations, a possible overlapping with other autoimmune diseases and insufficient awareness about this form of encephalitis. This article presents the literature review and describes the case of anti-NMDAR encephalitis associated with recurrent optic neuritis, which might be an atypical manifestation for this disease. Optic neuritis could not be explained by overlapping with multiple sclerosis or neuromyelitis optica spectrum disorders.

Status Epilepticus Manifested as Continuous Epileptic Spasms

Objective: The etiology and outcome of status epilepticus with continuous epileptic spasms have not been fully understood; and only rare cases have been reported in the literature. Here, we described 11 children, who manifested continuous epileptic spasms with various etiologies and different outcomes. Methods: This is a case series study designed to systematically review the charts, video-electroencephalography (video-EEG), magnetic resonance images, and longitudinal follow-up of patients who presented continuous epileptic spasms lasting more than 30 min. Results: Median age at onset was 2 years old, ranging from 2 months to 5.6 years. The etiology of continuous epileptic spasms for these 11 cases consisted of not only some known electro-clinical epilepsy syndromes like West Syndrome and Ohtahara Syndrome, but also secondary symptomatic continuous epileptic spasms, caused by acute encephalitis or encephalopathy, which extends the etiological spectrum of continuous epileptic spasms. The most characteristic feature of these 11 cases was prolonged epileptic spasms, lasting for a median of 13.00 days (95% CI: 7.26-128.22 days). The interictal EEG findings typically manifested as hypsarrhythmia or its variants, including burst suppression. Hospital stays were much longer in acute symptomatic cases than in primary epileptic syndromic cases (59.67 ± 50.82 vs. 15.00 ± 1.41 days). However, the long-term outcomes were extremely poor in the patients with defined electro-clinical epilepsy syndromes, including severe motor and intellectual developmental deficits (follow-up of 4.94 ± 1.56 years), despite early diagnosis and treatment. Continuous epileptic spasms were refractory to corticosteroids, immuno-modulation or immunosuppressive therapies, and ketogenic diet. Conclusion: Continuous epileptic spasms were associated with severe brain impairments in patients with electro-clinical syndromes; and required long hospital stays in patients with acute symptomatic causes. We suggest to include continuous epileptic spasms in the international classification of status epilepticus, as a special form. Further investigations are required to better recognize this condition, better understand the etiology, as well as to explore more effective treatments to improve outcomes.

Pharmacotherapy for Pediatric Convulsive Status Epilepticus

Convulsive status epilepticus (CSE) is one of the most common pediatric neurological emergencies. Ongoing seizure activity is a dynamic process and may be associated with progressive impairment of gamma-aminobutyric acid (GABA)-mediated inhibition due to rapid internalization of GABA_A receptors. Further hyperexcitability may be caused by AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) and NMDA (N-methyl-D-aspartic acid) receptors moving from subsynaptic sites to the synaptic membrane. Receptor trafficking during prolonged seizures may contribute to difficulties treating seizures of longer duration and may provide some of the pathophysiological underpinnings of established and refractory SE (RSE). Simultaneously, a practice change toward more rapid initiation of first-line benzodiazepine (BZD) treatment and faster escalation to second-line non-BZD treatment for established SE is in progress. Early administration of the recommended BZD dose is suggested. For second-line treatment, non-BZD anti-seizure medications (ASMs) include valproate, fosphenytoin, or levetiracetam, among others, and at this point there is no clear evidence that any one of these options is better than the others. If seizures continue after second-line ASMs, RSE is manifested. RSE treatment consists of bolus doses and titration of continuous infusions under continuous electro-encephalography (EEG) guidance until electrographic seizure cessation or burst-suppression. Ultimately, etiological workup and related treatment of CSE, including broad spectrum immunotherapies as clinically indicated, is crucial. A potential therapeutic approach for future studies may entail consideration of interventions that may accelerate diagnosis and treatment of SE, as well as rational and early polytherapy based on synergism between ASMs by utilizing medications targeting different mechanisms of epileptogenesis and epileptogenicity.

Anti-N-methyl-D-aspartate receptor encephalitis: A review of pathogenic mechanisms, treatment, prognosis

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a treatable autoimmune disorder characterized by prominent neuropsychiatric symptoms that predominantly affects children and young adults. In this review, we discuss the pathogenic mechanisms and immunologic triggers of anti-NMDAR encephalitis, and provide an overview of treatment and prognosis of this disorder, with specific focus on the management of common symptoms, complications, and patients during pregnancy. Most patients respond well to first-line treatment and surgical resection of tumors. When first-line immunotherapy fails, second-line immunotherapy can often improve outcomes. In addition, treatment with immunomodulators and tumor resection are effective treatment strategies for pregnant patients. Benzodiazepines are the preferred treatment for patients with catatonia, and electroconvulsive therapy (ECT) may be considered when pharmacological treatment is ineffective. Age, antibody titer, cerebellar atrophy, levels of biomarkers such as C-X-C motif chemokine 13 (CXCL13), cell-free mitochondrial (mt)DNA in cerebral serum fluid (CSF), and timing from symptom onset to treatment are the main prognostic factors. Patients without tumors or those who receive insufficient immunotherapy during the first episode are more likely to relapse.

Treatment Options for Anti-N-methyl-D-aspartate Receptor Encephalitis

Anti-NMDAR encephalitis is an autoimmune limbic disorder with an unknown cause, which affects mostly young women. Behavioral changes, seizures, orofacial muscle contractions, and memory impairment are usually observed. The variability of the symptoms depends on which part of the brain is inflamed. Treatment options aim to reduce serious neurological damage. Early diagnosis combined with the proper treatment favorably impacts the outcome. In our facility, weekly induction therapy is started pending an investigation into an associated ovarian or other tumor. Two case studies are discussed with favorable outcomes. The first is an outstanding case study with refractory status epilepticus caused by anti-NMDA receptors with benign teratoma which improved following combination therapy with rituximab and cyclophosphamide. There was no response to benzodiazepines and to an abundant number of antiepileptic drugs. Brain magnetic resonance imaging clearly indicated severe brain atrophy in the first case. Serial EEG monitoring showed a multitude of abnormalities. Delta brush activity was interictal and distinctive of anti-NMDAR encephalitis.

Anti-NMDA receptor encephalitis presenting as isolated aphasia in an adult

Anti-NMDA receptor (NMDA-r) encephalitis is a relatively rare cause of autoimmune encephalitis with divergent clinical presentations. We report a case of an adult patient with anti-NMDA-r encephalitis presenting with isolated, abrupt-onset aphasia. Her condition remained unaltered over a period of 6 months. The patients' electroencephalogram findings were typical for NMDA-r encephalitis; however, her magnetic resonance imaging and cerebrospinal fluid analysis were normal. She responded well to immunotherapy, and aphasia eventually resolved. The natural course of the present case contradicts the rapidly progressive nature of typical NMDA-r encephalitis. Furthermore, it broadens the clinical spectrum of anti-NMDA-r encephalitis, to incorporate isolated, nonprogressive aphasia.

Auto-immune anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis: three case reports

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a recently identified auto-immune disorder characterised by severe memory deficit, a decreased level of consciousness, seizures, autonomic dysfunction and movement disorders. Three girls with the disorder are reported; they were aged 4 years, 5 years and 10 months. The 10-month-old infant who is one of the youngest patients reported with anti-NMDAR encephalitis worldwide, had MRI features suggestive of herpes simplex encephalitis (known to trigger anti-NMDAR encephalitis), but CSF PCR for herpes simplex was negative. All the patients presented with seizures, behavioural change, regression of speech, dystonia and choreo-athetosis. Anti-NMDAR antibodies were detected in all patients' sera and cerebrospinal fluid (CSF). Intravenous immunoglobulin, corticosteroids and rituximab were administered at different intervals. Cases 1 and 2 made a full recovery, but case 3 has mild motor and speech delay. Patients who present with encephalopathy, seizures and movement disorders should be tested for anti-NMDAR antibodies in serum and CSF in addition to being screened for herpes simplex encephalitis.

Anti-N-Methyl-D-aspartate Receptor Encephalitis: A Severe, Potentially Reversible Autoimmune Encephalitis

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is potentially lethal, but it is also a treatable autoimmune disorder characterized by prominent psychiatric and neurologic symptoms. It is often accompanied with teratoma or other neoplasm, especially in female patients. Anti-NMDAR antibodies in cerebrospinal fluid (CSF) and serum are characteristic features of the disease, thereby suggesting a pathogenic role in the disease. Here, we summarize recent studies that have clearly documented that both clinical manifestations and the antibodies may contribute to early diagnosis and multidisciplinary care. The clinical course of the disorder is reversible and the relapse could occur in some patients. Anti-NMDAR encephalitis coexisting with demyelinating disorders makes the diagnosis more complex; thus, clinicians should be aware of the overlapping diseases.

Lower dosages of rituximab used successfully in the treatment of anti-NMDA receptor encephalitis without tumour

OBJECTIVE

The aim of this study was to evaluate the use and efficacy of lower dosages of rituximab for treating anti N-methyl-d-aspartate receptor (NMDAR) encephalitis without tumour.

METHODS

We performed a prospective study of 10 patients with anti-NMDAR encephalitis who did not respond to 10 to 14days first-line immunotherapy and received rituximab administered intravenously (IV) at a dosage of 100mg once per week for 4 consecutive weeks. Reinfusion of rituximab was given when CD19⁺ B-cell counts of total lymphocytes in peripheral blood >1%. The annualized relapse rate (ARR), modified Rankin scale (mRS) and CD19⁺ B-cell counts were measured every 4 to 10weeks after initial rituximab treatment in order to assess the clinical outcome and efficacy of rituximab.

RESULTS

Lower dosages of rituximab led to a significant reduction of mRS and CD19⁺ B-cells when compared with before the rituximab infusion (P<0.05) and allowed 9 (90%) patients to maintain a stabilised neurological status. One patient experienced a relapse at 19weeks after initial rituximab infusion. Although ARR reduction of all 10 patients did not achieve statistical significance (P>0.05), in the 4 patients who had relapses before rituximab treatment there was an apparent reduction in ARR over 56weeks. At the last follow up, 9 patients (90%) had a good outcome (mRS≤2) including 3 patients (30%) who recovered completely (mRS=0). Transient infusion adverse events occurred in 2 patients. We observed no serious delayed adverse events during the 56weeks follow-up.

CONCLUSIONS

In patients with anti-NMDAR encephalitis who did not respond to first-line immunotherapy, early application of lower dosages of rituximab could efficiently reduce CD19⁺ B-cell counts of peripheral blood and improve the prognosis of anti-NMDAR encephalitis.

Clinical characteristics and outcomes between children and adults with anti-N-Methyl-D-Aspartate receptor encephalitis

Anti-N-Methyl-D-Aspartate receptor (NMDAR) encephalitis is an acute neurological disorder affecting children and adults. We aimed to compare the clinical characteristics, treatments, and outcomes between children and adults with anti-NMDAR encephalitis and to assess the probable risk factors. In this observational study, patients who tested positive for anti-NMDAR antibody in the cerebrospinal fluid were enrolled. The patients were divided into children and adults group on the basis of age (whether <16 or not). Clinical outcomes were assessed at onset, 1, 3, 6, 9, and 12 months after the patients received treatment and were scored based on whether they required hospitalization and intensive care. A total of 15 children and 14 adults were examined. The adults more likely manifested status epilepticus, central hypoventilation, and pneumonia but less likely exhibited movement disorder than the children did. All of the patients were subjected to corticosteroid treatment, 11 children and 9 adults were treated with intravenous immunoglobulin, and only the adults received plasma exchange or cyclophosphamide. The children recovered faster than the adults, especially in the first 6 months. Risk factors included age, status epilepticus, changes in consciousness, central hypoventilation, and pneumonia. Adults exhibit worse outcomes than children mostly because of status epilepticus.

Anti-N-Methyl-D-Aspartate Receptor-Mediated Encephalitis: Recent Advances in Diagnosis and Treatment in Children

Anti-N-methyl-d-aspartate receptor-mediated encephalitis (anti-NMDAR encephalitis) is increasingly recognized in children and adolescents. There is a recognizable pattern of clinical symptoms, similar between children and adults. There are some differences in children including the frequency of presenting symptoms, the presence of hypoventilation, and the identification of an associated tumor. Early tumor removal and treatment with immunotherapy is important for rapid recovery. The prognosis can be surprisingly good but some children have lasting neurocognitive deficits.