Anti-N-Methyl-D-Aspartate receptor encephalitis by prior epstein barr infection

Case presentation: Female, 8 years old, previously healthy, referred to our service due to 10 days of agitation and excessive crying associated with a fever peak. Evolved with seizures, self-harm behavioral changes, dysarthria, visual hallucinations, and movement disorders. On admission, presence of drowsiness, mental confusion, and dyskinetic appendicular orofacial movements. General laboratory tests, cultures, and brain magnetic resonance imaging (MRI) without changes. Initial cerebrospinal fluid (CSF) analysis with lympho-monocytic pleocytosis without serology results. Treatment with an antiviral (acyclovir) was started due to the initial hypothesis of infectious encephalitis. Child with worsening symptoms, new seizures, lowered level of consciousness, and intubation need. Electroencephalogram (EEG) with moderate disorganization of background rhythm without epileptiform paroxysms. Given the patient's clinical deterioration over the days, a hypothesis of autoimmune encephalitis (AE) was made. Presence of IgM reagent for Epstein-Barr Virus (EBV) in the serum with remaining serologies negative. Herpes simplex virus-1 search on negative LQR. The patient received pulse therapy with methylprednisolone and intravenous immunoglobulin (IVIG). Encephalitis was confirmed by the positive presence of anti-NMDA receptor (anti-NMDAR) on LQR (1:16) and in the blood (1:800). Associated tumors were ruled out. 15 days past IVIG, there was a significant clinical improvement. Currently asymptomatic.

Discussion: Anti-NMDAR encephalitis is the second most frequent cause of encephalitis. The first stage with a prodromal phase both respiratory and gastrointestinal symptoms are around 70%, although systemic infections are not associated. Behavioral changes and epileptic seizures are the most frequent initial symptoms in children. In this case, we had the occurrence of AE after primary EBV infection. It is believed in viral DNA reactivation during an autoimmune condition, and it cannot be ruled out that neurotropic viruses are responsible for triggering the various cellular immune mechanisms that cause AE. Our patient evolved with complete recovery after ~1 month and normal MRI, thus suggesting that the AE resulted from a post-infectious autoimmune response.

Final comments: Anti-NMDAR encephalitis is still a challenging diagnosis, and may evolve after viral infections and with a wide range of symptoms and easily confused with other encephalitis or psychiatric conditions.

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Artikel online veröffentlicht:
18. September 2023