A Complex Case of Triumphantly Treated Anti-N-Methyl-D-Aspartate (NMDA) Receptor Encephalitis

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is a rare autoimmune disorder characterized by neuropsychiatric symptoms and the presence of immunoglobulin G (IgG) antibodies against the N-methyl-D-aspartate receptor 1 (NR1) subunit of NMDA receptors. It is often triggered by ovarian teratomas, especially in young women, and presents with a combination of psychiatric and neurological symptoms. Here, we present a case of a 25-year-old woman with a history of schizoaffective disorder and post-partum depression who presented with two months of bizarre behavior, agitation, and decreased sleep. Initially admitted for suspected psychosis, her condition worsened with episodes of loss of consciousness and failure to respond to psychiatric medications. After extensive investigations, including computed tomography (CT), magnetic resonance imaging (MRI), and electroencephalogram (EEG), NMDA receptor encephalitis was suspected and confirmed by positive autoantibodies. Imaging revealed bilateral ovarian teratomas, and she underwent a cystectomy. The patient was treated with intravenous immunoglobulin (IVIG), which led to complications, including desaturation and the need for intubation. Initially, five IVIG sessions were given. Based on their experience, and due to sub-optimal recovery, a shared decision was made between the neurology team and the intensive care unit (ICU) team to administer two additional IVIG sessions. The single dose of each IVIG session was 35 g (0.4 g/kg). After seven sessions of IVIG, she showed gradual improvement. This case underscores the importance of considering NMDA receptor encephalitis in patients with unexplained neuropsychiatric symptoms and highlights the critical roles of autoantibody testing, tumor resection, and immunotherapy in the management of this condition.