Anti-NMDA receptor encephalitis is a disease occurring when antibodies produced by the body’s own immune system attack NMDA receptors in the brain. Their functions are critical for judgement, perception of reality, human interaction, the formation and retrieval of memory, and the control of autonomic functions. The objective of treatment is to reduce the levels of antibodies in the blood and spinal fluid. Treatments include corticosteroids, intravenous immunoglobulin and plasmapheresis in addition to other immunomodulators, such as cyclophosphamide or rituximab.

To present a case of a 64 year-old patient who came to the emergency service of our hospital with long-standing anxiety, irritability, recurrent amnestic failures, visual hallucinations and recent-onset episodes of aggressiveness with his family. He required admission to the psychiatry department and was finally diagnosed with autoimmune anti-NMDA encephalitis by detecting antibodies in blood and CSF.

Clinical case presentation and literature review of cases, focusing on psychotic symptoms.

A 65-year-old patient who was being studied by neurology and psychiatry departments for cognitive impairment and psychotic symptoms was admitted to Neurology after a positive lumbar puncture result for NMDA antibodies.During admission, the patient continued with a significant behavioral alteration that gradually remitted with the use of Quetiapine, corticosteroids and rituximab.

NMDA-encephalitis has a highly variable clinical presentation, which can lead to confusion with infectious etiology or psychiatric disorders, making the diagnosis difficult, which is only possible by detecting anti-NMDA antibodies in CSF. Recognition of the disease and coordination between services is essential for early diagnosis and treatment.

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Anti-NMDA receptor (NMDAr) encephalitis is the most common autoimmune encephalitis in adults. It mimics psychiatric disorders so often that most patients are initially referred to a psychiatrist, and many are misdiagnosed. Without prompt and effective treatment, patients are likely to suffer a protracted course with significant residual disability, or death. This study focuses on the frequency and chronology of salient clinical features in adults with anti-NMDAr encephalitis who are likely to be first evaluated by a psychiatrist because their presentation suggests a primary psychiatric disorder.

A systematic search of PubMed and EMBASE databases identified published reports of anti-NMDAr encephalitis associated with prominent behavioral or psychiatric symptoms. After eliminating redundancies, the frequencies and relative timing of clinical features were tabulated. Signs and symptoms were assigned temporal ranks based on the timing of their first appearance relative to the first appearance of other signs and symptoms in each patient; median ranks were used to compare temporal sequencing of both individual features and major symptom domains.

Two hundred thirty unique cases (185 female) met study inclusion criteria. The most common features were seizures (60.4%), disorientation/confusion (42.6%), orofacial dyskinesias (39.1%), and mutism/staring (37.4%). Seizures, fever, and cognitive dysfunction were often the earliest features to emerge, but psychiatric features predominated and sequencing varied greatly between individuals.

Clinicians should consider anti-NMDAr encephalitis when new psychiatric symptoms are accompanied by a recent viral prodrome, seizures or unexplained fever, or when the quality of the psychiatric symptoms is unusual (e.g. non-verbal auditory hallucinations).