Anti-NMDAR encephalitis triggered by EBV and HSV-1: A case report and literature review

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is a central nervous system disorder driven by autoantibodies, characterized by a wide range of complex clinical manifestations. Although tumors, such as teratomas, and viral infections have been identified as potential triggering factors, the precise etiology of this condition remains to be elucidated. While herpes simplex virus type 1 (HSV-1) has been linked to the onset of anti-NMDAR encephalitis, cases involving coinfection with Epstein-Barr virus (EBV) and HSV-1 as causative factors are exceedingly rare.

A 46-year-old female patient who exhibited mental abnormalities, epileptic seizures, and altered consciousness. Analysis of cerebrospinal fluid samples revealed the presence of EBV and HSV-1 infections. The initial autoimmune encephalitis antibody test returned negative results. However, a subsequent test indicated the presence of anti-NMDAR antibodies in the cerebrospinal fluid, whereas serum analysis remained negative.

The patient was diagnosed with anti-NMDAR encephalitis resulting from infection with the EBV and HSV-1.

Antiviral treatments were administered to the patient in conjunction with intravenous methylprednisolone and human immunoglobulin pulse therapy. This initial treatment did not yield satisfactory results, and the patient's condition remained critical, necessitating the introduction of rituximab for immunosuppressive therapy. Subsequently, the treatment regimen was adjusted to include intravenous tocilizumab, along with an intrathecal injection of 10 mg methotrexate and 10 mg dexamethasone. Ultimately, the patient's clinical symptoms improved relative to their previous condition, and repeated examinations demonstrated a gradual decrease in the white blood cell count in the cerebrospinal fluid, indicating that the treatment was effective.

This case is the first diagnosed at our hospital and represents a rare instance in the literature of anti-NMDAR encephalitis directly triggered by co-infection with EBV and HSV-1. The diagnostic process emphasizes the need to maintain a high level of suspicion and repeat antibody tests in patients suspected of autoimmune encephalitis, even when initial antibody tests are negative.