Autoimmune Encephalitis Against NMDA Antibodies with Neuropsychiatric Manifestations in the Adult: Case Report and Literature Review

Background: Anti-NMDA encephalitis is an autoimmune disease characterized by autoantibodies against NMDA receptors, confused with a primary psychiatric condition. There is a broad spectrum of neuropsychiatric symptoms, including refractory psychosis, impaired consciousness, and catatonia. Signs of autonomic instability, abnormal movements, seizures, and coma have also been associated. Patients may improve with immunotherapy and, if necessary, tumor removal. Objective: To present the case of a 24-year-old woman with a diagnosis of anti-NMDA encephalitis without evidence of a tumor and with predominant psychiatric symptoms. Methods: Case report and literature review. Results: A brief review of the disorder is made with some data on its epidemiology, pathophysiology, therapeutic implications, and complex clinical expressions from the neuropsychiatric perspective, such as catatonic syndrome. Conclusion: This case report exemplifies a clinical situation increasingly recognized in primary psychiatric practice and the general hospital; atypical psychiatric progression and catatonic symptoms indicated the possible presence of anti-NMDA encephalitis. Maintaining clinical suspicion of anti-NMDA encephalitis is considered essential, even when there is no evidence of tumor. Psychiatrists must be familiar with this entity to promote timely diagnosis and treatment.