Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is a type of autoimmune encephalitis (AE) characterized by antibodies against NMDA receptor. As the most common AE, anti-NMDAR encephalitis affects 54% ~ 80% of patients with AE. It is associated with a high percentage of severe illness. It typically manifests as behavioral and psychiatric disturbance, epilepsy, cognitive decline, decreased level of consciousness, involuntary movements, autonomic dysfunction, central hypoventilation, etc. We report two refractory anti-NMDAR encephalitis. One of them describes a case of anti-NMDA encephalitis coexisting with MOG antibodies. The two patients were administered first-line therapy with glucocorticoids and intravenous immunoglobulin but did not improve clinically. Therefore, the patient was switched to the fully human anti-CD20 monoclonal antibody, ofatumumab. Their consciousness, behavioral and psychiatric disturbance, and capacity to conduct daily tasks improved markedly after sequential therapy with ofatumumab, as demonstrated by the modified Rankin scale (mRS) score. For the first time, we report a successful approach to the treatment of refractory anti-NMDAR encephalitis using the fully human anti-CD20 monoclonal antibody ofatumumab, which serves as an important reference for the treatment of AE.

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Numerous studies have demonstrated that low-dose subanesthetic intravenous ketamine infusion treatment leads to rapid improvement of treatment-resistant depression. The following case report describes the use of a very low-dose subcutaneous ketamine as a form of maintenance in a patient with severe treatment-resistant depression using a retrospective chart review.

BACKGROUND: Overlap syndromes of anti-NMDA receptor encephalitis and MOG-mediated demyelination have been reported. In this case we provide a long-term longitudinal follow-up of clinical and imaging characteristics as well as of antibody dynamics.
METHODS: We report a 32-year-old male patient who presented with psychosis, decreased consciousness and movement disorders and was tested positive for anti-NMDA receptor antibodies. Forty-four months after symptom onset and diagnosis of autoimmune encephalitis, he suffered from relapse. At this time, the patient developed anti-MOG and anti-Caspr2 antibodies. Treatment with plasmapheresis, steroids and rituximab eventually led to substantial clinical and radiological improvement. Anti-Caspr2 antibodies persisted, anti-NMDA receptor antibodies decreased, while anti-MOG antibodies turned negative again.
CONCLUSIONS: We provide long-term longitudinal follow-up of a patient with anti-NMDA receptor encephalitis who developed triple antibody positivity at the time of relapse. Antibody dynamics were associated with clinical disease course.

The majority of patients with anti-N-Methyl-D-Aspartate receptor (NMDAR) encephalitis present with psychiatric symptoms and subsequently develop neurological features. However, isolated psychiatric episodes occur in <5% of affected individuals, less frequent at disease onset (<1%) compared to relapse (4%). We report the case of a previously healthy 24-year-old female who presented with psychotic symptoms and behavioral alterations. Despite therapy, she showed no improvement and subsequently developed catatonic features. While the ancillary tests were normal, the clinical warning signs raised the suspicion of anti-NMDAR encephalitis which we later confirmed. Given its strong association with underlying tumors, we screened the patient and found an ovarian teratoma. Once removed, the patient displayed a substantial improvement in the mental status. Besides being extremely rare, this case illustrates the need to maintain clinical suspicion of anti-NMDAR encephalitis even in the absence of neurological features or paraclinical anomalies.

BACKGROUND: There is a paucity of literature around sedation and anesthesia in patients with severe anorexia nervosa. Chronically malnourished patients are known to have myopathy, neuropathy, and altered neurotransmitter signaling. Ketamine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist that is an established general anesthetic and short-acting dissociative analgesic agent. It generally has a reassuring adverse event profile and rarely has been reported to result in apnea. We aim to raise awareness of this untoward adverse event in patients with severe anorexia nervosa among sedation providers and those referring patients for hospitalization or sedation.
METHODS: We describe an episode of apnea, a rare adverse event of ketamine, which was given for procedural sedation to a severely malnourished 13-year-old female with anorexia nervosa, generalized anxiety disorder, and high-functioning autism spectrum disorder. She had no history of apnea nor of ketamine sedation. She was given a standard dose of ketamine and had no other central nervous system depressants within 24 h. Within 1 min after slow medication administration, she had a 9-min period of apnea without laryngospasm. She was supported with bag-valve-mask ventilation throughout this period and did not require intubation. She returned to baseline shortly after procedural sedation.
CONCLUSIONS: This case describes apnea after ketamine sedation in a patient with severe anorexia nervosa. It supports the importance of a thorough pre-procedure review of a patient\'s underlying medical problems and the consideration of how sedatives may interact with these conditions. We aim to alert those who care for this complex population of the possible altered neurotransmitters, myopathy, and adverse response to sedation, anesthetics, and analgesics.

Few reports describe the clinical course and acute-care management of patients with recurrent multi-antibody paraneoplastic encephalitis. We describe a rare case of a patient having thymoma with multiple paraneoplastic syndromes who was found to have antibodies to α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) followed by N-methyl-d-aspartate (NMDA) receptor in the setting of residual thymic tissue. He initially presented to the hospital with severe, rapidly progressive encephalitis with simultaneous antibodies to AMPA and voltage-gated potassium channel complex receptor. Brain magnetic resonance imaging revealed scattered white matter hyperintensities and an enhancing lesion adjacent to the left caudate. Computerized tomography showed an anterior mediastinal mass that was resected and revealed to be a thymoma. He was refractory to treatment with intravenous immunoglobulin, high-dose steroids, and plasmapheresis. He was then started on monthly cyclophosphamide. After 3 cyclophosphamide infusions, he began to show improvement in his alertness, ability to speak, and capacity to follow commands. One month later, he was readmitted to the hospital for new and unusual behavioral outbursts and agitation. He was found to have new anti-NMDA receptor antibodies in his cerebrospinal fluid in the setting of residual hyperplastic thymic tissue that required another resection. He was treated with rituximab and then cyclophosphamide (due to an infusion reaction with rituximab) with positive outcomes. The presence of multiple antibodies may be associated with poor prognosis, requiring prompt recognition and aggressive immunosuppressive treatment. New neurological symptoms should prompt a search for residual pathologic tissue or tumor recurrence causing new autoantibodies and additional paraneoplastic syndromes.

Anti-N-methyl D-aspartate (NMDA) receptor (anti-NMDAR) encephalitis is among one of the most common autoimmune encephalitides. However, variations in clinical presentation and nonsequential multiphasic course often lead to delays in diagnosis. The mild encephalitis (ME) hypothesis suggests a pathogenetic mechanism of low-level neuroinflammation sharing symptom overlap between anti-NMDAR encephalitis and other psychiatric disorders including schizophrenia. Clinical symptoms of anti-NMDAR encephalitis may mimic schizophrenia and psychotic spectrum disorders or substance-induced psychosis. Although initially described in association with ovarian teratomas in women, anti-NMDAR encephalitis has been reported in individuals without paraneoplastic association, as well as in males. It can affect all age groups but is usually lower in prevalence in individuals greater than 50 years old, and it affects females more than males. Clinical evaluation is supported by laboratory workup, which includes cerebrospinal fluid (CSF) assays. The latter often reveals lymphocytic pleocytosis or oligoclonal bands with normal to elevated CSF protein. CSF testing for anti-NMDAR antibodies facilitates diagnostic confirmation. Serum anti-NMDAR antibody assays are not as sensitive as CSF assays. Management includes symptomatic treatment and immunotherapy.

There has been much recent excitement about the possibility that some cases of psychosis may be wholly due to brain-reactive antibodies, with antibodies to N-methyl-D-aspartate receptor (NMDAR) and the voltage-gated potassium channel (VGKC)-complex reported in a few patients with first-episode psychosis (FEP).
Participants were recruited from psychiatric services in South London, UK, from 2009 to 2011 as part of the Genetics and Psychosis study. We conducted a case-control study to examine NMDAR and VGKC-complex antibody levels and rates of antibody positivity in 96 patients presenting with FEP and 98 controls matched for age and sex. Leucine-rich glioma inactiviated-1 (LGI1) and contactin-associated protein (CASPR) antibodies were also measured. Notably, patients with suspicion of organic disease were excluded.
VGKC-complex antibodies were found in both cases (n = 3) and controls (n = 2). NMDAR antibody positivity was seen in one case and one control. Either LGI1-Abs or CASPR2-Abs were found in three cases and three controls. Neuronal antibody staining, consistent with the above results or indicating potential novel antigens, was overall positive in four patients but also in six controls. Overall, antibody positivity was at low levels only and not higher in cases than in controls.
This case-control study of the prevalence of antibodies in FEP does not provide evidence to support the hypothesis that FEP is associated with an immune-mediated process in a subgroup of patients. Nevertheless, as other bio-clinical factors may influence the effect of such antibodies in a given individual, and patients with organic neurological disease may be misdiagnosed as FEP, the field requires more research to put these findings in context.

Anti-N-methyl-d-aspartate (anti-NMDA) receptor encephalitis is a treatable cause of autoimmune encephalitis. It remains unclear if the natural history of this disease is altered by choice of acute therapy or the employment of chronic immunotherapy. Chart review was undertaken for pediatric patients diagnosed with anti-NMDA receptor encephalitis. Data obtained included patient demographics, disease manifestations, treatment course, and clinical outcomes. Ten patients with anti-NMDA receptor encephalitis were identified. All patients were treated with immunotherapy in the acute period, and all patients experienced good recovery. Neurologic relapse did not occur in any patient. All patients received varied forms of chronic immunosuppression to prevent relapses. Complications of chronic immunotherapy occurred in 50% of patients. The benefits of chronic immunotherapy and the duration of use should be carefully weighed against the risks. Complications from immunotherapy are not uncommon and can be serious. Clinical trials assessing the benefit of long-term immunotherapy in this population are needed.