Abstract | March 15, 2023
Acute Psychosis Secondary to Anti-NMDA Receptor Encephalitis: A Commonly Underdiagnosed Disorder in Healthy, Young Women
Learning Objectives
- The goal of the presentation is to discuss a rare, yet potentially fatal phenomenon of a typically benign condition in a healthy, female patient
- Upon completion of this lecture, learners should be better prepared to recognize the association of acute psychosis secondary to anti-NMDAR encephalitis as a serious complication of commonly benign mature cystic (dermoid) teratomas.
- Increase awareness of anti-NMDAR encephalitis secondary to dermoid cysts as a potential differential for acute psychosis in young, healthy female patients.
INTRODUCTION: Autoimmune anti-NMDA receptor (NMDAR) encephalitis is a rare paraneoplastic disease often associated with mature cystic (dermoid) teratomas. Though well-documented and treatable, anti-NMDAR encephalitis is underdiagnosed in young, healthy females. A vague prodromal state prior to acute psychotic symptoms can delay diagnosis and expose a previously healthy patient to serious and potentially fatal complications.
CASE PRESENTATION: We describe a healthy 28-year-old nulliparous patient who developed neurologic and psychiatric symptoms. She was eventually diagnosed with anti-NMDAR encephalitis after a neurologist recognized her characteristic new-onset erratic behavior and lapses in consciousness as possible autoimmune in etiology. The patient’s mentation continued to deteriorate after empiric anti-NMDAR encephalitis treatment with methylprednisolone and IVIG immunotherapy. Pelvic ultrasound visualized a left adnexal cyst and an urgent laparoscopic left salpingo-oophorectomy was performed to resect a teratoma, a known potential source of anti-NMDR antibodies. The patient’s clinical deterioration stabilized after her oophorectomy. An anti-NMDAR IgG antibody test confirmed the diagnosis. Though her post-operative recovery is complicated by respiratory failure secondary due to esophageal perforation and pneumomediastinum, deep venous thrombosis, seizures, and enterocutaneous fistula, over the next several months patient’s status improved and she experienced a complete recovery within one year, except for complete memory loss of her acute psychosis phase and her hospital stay.
FINAL DIAGNOSIS: The patient’s positive anti-NMDAR IgG antibody test is diagnostic for anti-NMDA receptor encephalitis.
MANAGEMENT/DISCUSSION: We present an interesting case of a previously healthy 28-year-old female who demonstrated a clinical deterioration in her behavior and mentation over the course of several weeks. She was seen in the emergency department several times before she was correctly diagnosed with anti-NMDAR encephalitis. This is a rare but well-documented disease most typically seen in women of reproductive age and frequently caused by anti-NMDAR antibodies produced by an ovarian teratoma. Failure to diagnose this disease promptly puts patients at risk for chronic or permanent neurological sequelae due to untreated encephalitis. Increased clinical suspicion and inclusion of anti-NMDAR encephalitis in the differential diagnosis of acute psychosis facilitates early treatment, which can markedly improve patient recovery and outcomes.
References
Samanta D, Lui F. Anti-NMDA Receptor Encephalitis. [Updated 2022 Jul 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551672/
