Anti-NMDA receptor encephalitis presenting as an acute psychotic episode misdiagnosed as dissociative disorder: a case report

Hystero-epilepsy in the Tuesday Lessons and NMDA receptor function: A hypothesis for dissociative disorder

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis patients demonstrate characteristic multistage progression and movement disorders, which are analogous to hystero-epilepsy in Jean-Martin Charcot's Tuesday Lessons. First, based on a review of the Tuesday Lessons recorded by Charcot's pupils, we hypothesized that there were patients with anti-NMDAR encephalitis among those diagnosed with hystero-epilepsy in the nineteenth century. We found acute-onset multiple neuropsychiatric manifestations resembling anti-NMDAR encephalitis among patients with hystero-epilepsy. Patients with drug withdrawal syndrome, dissociative and conversion disorders and patients under hypnosis from the modern point of view were also identified. These results suggested that hystero-epilepsy in the Tuesday Lessons could encompass dissociative and conversion disorders, hypnosis, drug withdrawal syndrome, and anti-NMDAR encephalitis-like manifestations. Based on Charcot's observations and current progress in molecular biology, such as the identification of glutamate/NMDAR system dysfunction in drug withdrawal syndrome, we then hypothesized that patients with dissociative and conversion disorders and those under hypnosis could also have hypofunction of the glutamatergic system. The NMDAR hypofunction hypothesis is emerging as a pathogenesis of schizophrenia. NMDAR antagonists are known to evoke symptoms similar to schizophrenia, anti-NMDAR encephalitis and near-death experiences. In current clinical reports, spectrum disorders such as dissociative disorder and conversion disorder have been observed in patients with anti-NMDAR encephalitis. Our hypothesis will offer an expansion of the NMDAR hypofunction hypothesis from psychosis to functional neurological disorders and normal specific situations, such as hypnosis, thanatosis, and near-death experiences.

Rituximab Was Effective for Treatment of Anti-N-Methyl-d-Aspartate Receptor Encephalitis in Early Adolescence in Initially Suspected Dissociative Disorder

OBJECTIVES

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is an increasingly recognized etiology of psychiatric symptoms. Because patients with anti-NMDAR encephalitis frequently show aggression, mania, hallucination, depression, or delusion, they are initially diagnosed with schizophrenia or mood disorders. There is only 1 case report of an initially diagnosed dissociative disorder.

METHODS

We obtained consent for the presentation and have not identified individuals for ethical reasons.

RESULTS

We first report an adolescent female patient with anti-NMDAR encephalitis who was initially suspected of having dissociative disorder but was responsive to immunotherapies including rituximab. In this case, her symptoms and electroencephalogram findings were proportional to the antibody titer in the cerebrospinal fluid.

CONCLUSIONS

It is important to consider the possibility of autoimmune encephalitis and immunotherapy including rituximab in cases of not only acute psychosis but also dissociation.

Anti-NMDAR Encephalitis: Higher Suspicious Needed for Earlier Diagnosis (Case Report, Literature Review and Diagnostic Criteria)

Background

Auto-immune mediated anti-NMDA receptor encephalitis is a very common delayed diagnosed encephalitis which predominately affecting young population.

Objectives

This encephalitis is relatively unknown amongst emergency physicians and a majority of patients are admitted to psychiatric wards before their diagnosis is confirmed and appropriate treatments are commenced. We reported a case of a 22-year-old female presented to our emergency department with acute psychiatric symptoms. She was initially diagnosed with first presentation of acute psychosis and was hospitalised under mental health act. further assessment in the emergency department identified possible an organic cause for her acute psychosis and she was later admitted under medical team after her mental health assessment order was revoke. Several days later, her CSF result was positive with anti-NMDA receptor anti-bodies. Appropriate treatments were instituted leading to her full recovery.

Conclusion

This case was the first confirmed anti-NMDA receptor encephalitis in our emergency department. It highlights the importance of thorough assessment of psychiatric presentations to emergency departments and consideration of auto-immune medicated encephalitis as one of the differential diagnosis in young patients presenting with first acute psychotic episode.

Clinical Characterization of Definite Autoimmune Limbic Encephalitis: A 30-case Series

Objective Limbic encephalitis (LE) is an inflammatory condition of the limbic system that has an acute or subacute onset. Several types of antibodies are related to the onset of LE, including anti-N-methyl D-aspartate receptor (NMDAR) antibodies and voltage-gated potassium channel (VGKC)-complex antibodies. However, the characteristics and prevalence of LE remain unclear, especially in Asian cohorts, due to the rarity. We aimed to survey their characteristics. Materials and Methods Data of 30 cases clinically defined as "definite autoimmune LE" (based on the standard criteria) were retrospectively collected. These patients were categorized into four subtypes: NMDAR (+) (n=8), VGKC (+) (n=2), antibodies related to paraneoplastic syndrome (n=2), and an antibody-negative group (uncategorized) (n=18). Results LE is rare in Japan, and affected only 30 of 16,759 hospital patients (0.2%) over a ten-year period. The NMDAR (+) group showed distinctive symptoms, while the other three groups had similar indications. Brain MRI indicated significant medial temporal lobe atrophy at one year follow up after discharge. The prevalence of cognitive dysfunction as a complication was 64% (9/14). First-line immunotherapy resulted in a good outcome. A drastic improvement was seen from 4.0±1.1 to 1.1+ on the modified Rankin Scale. A good treatment outcome was observed in all groups (NMDAR, VGKC, and uncategorized), suggesting the importance of an early clinical diagnosis and the early initiation of treatment. Furthermore, we reviewed 26 cases that were clinically diagnosed as definitive autoimmune LE in previous case reports. Conclusion Our findings show that the establishment of a clinical diagnosis based on the clinical criteria of definitive autoimmune LE is important for the initiation of immunotherapy.

Autoimmunity in psychotic disorders. Where we stand, challenges and opportunities

Psychotic disorders are debilitating mental illnesses associated with abnormalities in various neurotransmitter systems. The development of disease-modifing therapies has been hampered by the mostly unknown etiologies and pathophysiologies. Autoantibodies against several neuronal antigens are responsible for autoimmune encephalitis. These autoantibodies disrupt neurotransmission within the brain, resulting in a wide range of psychiatric and neurologic manifestations, including psychosis. The overlap of symptoms of autoimmune encephalitis with psychotic disorders raised the question as to whether autoantibodies against a number of receptors, ion channel and associated proteins could ultimately be responsible for some forms of psychosis. Here we review our current knowledge, on antibody mediated autoimmunity in psychotic disorders, the different diagnostic methods and their limitations, as well as on varying therapeutic approaches targeting the immune system.