Authors: Dr. Tue Bui Chau , Dr. An Nguyen Thanh , Dr. Loc Le Quang , Dr. Thang Huynh Xuan , Dr. Lap Dinh Van

Abstract

Background: Anti–N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is a severe autoimmune encephalitis characterized by progressive neuropsychiatric symptoms and the presence of IgG antibodies targeting the GluN1 subunit of NMDA receptors. Although typically associated with viral infections or ovarian teratomas, a variety of immune triggers have been reported. Early recognition is essential because prompt immunotherapy significantly improves outcomes.

Case Presentation: We describe a previously healthy 20-year-old woman who developed acute memory impairment, seizures, and progressive decline in consciousness shortly after undergoing first-trimester pregnancy termination. Initial cerebrospinal fluid (CSF) analysis demonstrated marked neutrophilic pleocytosis, closely mimicking bacterial meningitis and leading to a delay in diagnostic consideration of autoimmune encephalitis. Subsequent testing revealed anti-NMDAR IgG antibodies in the CSF, establishing the diagnosis.

The patient required intensive care unit management, including mechanical ventilation and treatment for refractory status epilepticus. First-line immunotherapy with high-dose corticosteroids and intravenous immunoglobulin produced partial neurological improvement. Significant clinical recovery occurred after the initiation of rituximab.

Conclusion: This case underscores the diagnostic difficulty posed by atypical CSF findings in anti-NMDAR encephalitis, particularly when neutrophilic pleocytosis suggests a bacterial process. It also raises the possibility that pregnancy termination may serve as an immunological trigger in susceptible individuals. Clinicians should maintain a high index of suspicion for autoimmune encephalitis in patients presenting with acute neuropsychiatric symptoms following abortion to avoid delays in definitive treatment.

Keywords: Anti-NMDAR encephalitis, autoimmune encephalitis, post-abortum complications, immunotherapy