Anti-N-methyl-D-aspartate Receptor Encephalitis Associated with Acute West Nile Infection: A Case Report
Joyce Jimenez Zambrano1, Sean Montgomery1, Scott Belliston2
1Department of Neurology, University of North Dakota School of Medicine and Health Sciences & Sanford Health, 2Department of Neurology, Sanford Health
Objective:
To describe an unusual case of coexisting West Nile virus infection and anti-N-methyl-D-aspartate receptor encephalitis.
Background:
Anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis is often characterized by a multistage condition progressing from psychosis, cognitive deficits, and seizures to the development of autonomic and respiratory instability. While post-viral infectious autoimmune encephalitis has been documented in cases of herpes simplex virus and varicella zoster virus infections, there is currently no identified evidence linking anti-NMDA receptor encephalitis with West Nile virus infection. We report a case that broadens the spectrum of infection-related autoimmune encephalitis.
Results:
A 71-year-old woman presented with fluctuating confusion, fever and right lower extremity weakness. On examination, she was disoriented and had a lower right extremity weakness associated with hyporeflexia. Cerebrospinal fluid (CSF) analysis showed lymphocytic pleocytosis (24 leukocytes/µL), elevated protein of 467, normal glucose. West Nile virus IgM and IgG antibodies were positive in CSF and serum. Electroencephalogram showed mild diffuse background slowing and frontal predominant intermittent rhythmic delta activity. Contrast-enhanced brain and spine magnetic resonance imaging (MRI) were normal. Supportive care was given over the course of 2 weeks. Unfortunately, she continued to have fluctuations in her mental status along with paranoid delusions, visual and auditory hallucinations. N-methyl-D-aspartate receptor antibodies were detected in CSF and in serum confirming anti-NMDA receptor encephalitis. Malignancy screening was negative. Methyl-prednisone 1 g daily for 5 days was given along with 7 sessions of plasmapheresis over a 14-day period. This was followed by rituximab infusions.
Conclusions:
Anti-NMDA receptor encephalitis should be contemplated as a potential diagnosis in patients previously determined to have West Nile virus encephalitis who manifest persistent psychotic symptoms despite conventional supportive interventions. Maintaining a high clinical suspicion and achieving an early diagnosis of autoimmune etiologies are of particular importance given the imperative for the timely initiation of immunosuppressive therapies to improve clinical outcomes.