2026 FSA Podium and Poster Abstracts

Background: Anti–N-methyl-D-aspartate (NMDA) receptor encephalitis is a rare autoimmune disorder characterized by rapidly progressive psychiatric symptoms, seizures, movement disorders, autonomic instability, and hypoventilation. It predominantly affects young women and is frequently associated with ovarian teratomas. Antibodies against the GluN1 subunit of the NMDA receptor lead to receptor downregulation, raising concern for exaggerated or unpredictable responses to NMDA-antagonist anesthetics such as ketamine and nitrous oxide. Optimal perioperative anesthetic strategies remain poorly defined. Early diagnosis, tumor resection, and immunotherapy are critical for improving neurologic outcomes and reducing morbidity. This case describes the perioperative anesthetic management for ovarian teratoma resection in a patient with confirmed anti-NMDA-Receptor encephalitis.

Methods: A 26-year-old female with acute psychosis, catatonic features, seizure-like activity, and elevated creatine kinase was transferred from a psychiatric facility and evaluated for autoimmune encephalitis. While brain MRI was unremarkable, pelvic ultrasound revealed a 4.2-cm complex right ovarian mass with calcifications consistent with a mature cystic teratoma. Cerebrospinal fluid later confirmed anti-NMDA-Receptor antibodies. Empiric immunotherapy with intravenous immunoglobulin and high-dose methylprednisolone was initiated prior to surgery. Due to severe agitation and autonomic lability, a continuous dexmedetomidine infusion was used preoperatively. The patient underwent robotic assisted right ovarian cystectomy under general anesthesia with avoidance of NMDA-antagonistic agents. Anesthesia was induced with propofol, fentanyl, and rocuronium, and maintained with sevoflurane and intermittent opioid dosing. Standard ASA monitors and continuous temperature monitoring were utilized.

Results: Intraoperatively, the patient remained hemodynamically stable without seizure activity, arrhythmias, or autonomic crises. Estimated blood loss was minimal, and no anesthetic complications occurred. She was extubated in the operating room and transferred to the intensive care unit for close monitoring. Postoperatively, the patient developed significant delirium requiring pharmacologic management with olanzapine, lorazepam, and continuation of dexmedetomidine. Immunotherapy was continued. Her hospital course was complicated by respiratory decline and development of right lower lobe pneumonia with associated atelectasis and small pleural effusions, necessitating prolonged ICU care.

Discussion: Anti-NMDA-Receptor encephalitis poses significant perioperative challenges due to altered anesthetic responses, seizure risk, and autonomic instability. Avoidance of ketamine and nitrous oxide is widely recommended given their NMDA-antagonistic effects. In this case, a combination of propofol, sevoflurane, opioids, benzodiazepines, and dexmedetomidine provided stable anesthesia without neurologic or hemodynamic complications, suggesting volatile agents may be used cautiously in select patients. Dexmedetomidine was particularly beneficial for perioperative sedation and autonomic control with minimal respiratory depression. Postoperative delirium and infection highlight the need for vigilant ICU-level monitoring and multidisciplinary care. Early tumor resection combined with immunotherapy remains essential for optimizing neurologic recovery in patients with anti-NMDA-Receptor encephalitis. Anesthesiologists should be prepared for prolonged recovery and evolving neurologic and respiratory challenges in this population.