RESUMO
INTRODUCTION: Anti-N-methyl-D-aspartate-receptor (anti-NMDAR) encephalitis is the most common antibody-defined autoimmune neuronal disorder. It may present with psychiatric symptoms, decreased consciousness, and hypoventilation. DATA SOURCES: A 33-year old female presented with agitation and psychotic symptoms following a flu-like illness. She was treated for a presumed psychiatric disorder before she developed seizures and respiratory failure. An extensive workup including routine blood work, brain imagining, electroencephalography, and cerebrospinal fluid analysis was unremarkable. After a prolonged hospital stay requiring multiple antiepileptic drugs and sedatives, a computerized tomography of the abdomen revealed an ovarian tumor. Immunosuppressive therapy was initiated and the tumor was resected, when anti-NMDAR encephalitis was suspected. The diagnosis was confirmed following a positive anti-NMDAR antibody. CONCLUSION: Anti-NMDAR encephalitis should be considered in the differential diagnosis of a diverse array of conditions. This case report emphasizes the importance of investigating such patients since proper treatment could potentially prevent neurologic complications or death.