Objective:

To describe a case of anti-NMDAr encephalitis presenting 6 months following HSV encephalitis in a pregnant patient.

Background:

Anti-NMDAr encephalitis, the most common autoimmune encephalitis, is associated with epilepsy and neuropsychiatric symptoms, and can be seen after HSVE. Per literature review, a certain subset of HSVE patients later develop anti-NMDAr encephalitis, often within 2 months of onset of HSV infection.

Design/Methods:

NA

Results:

30 yo F presented at 39 weeks gestation with headache, fever, disorientation, and speech disturbances in October 2021. She was diagnosed with HSV-1 encephalitis based on positive HSV1 PCR in CSF and brain MRI findings. vEEG demonstrated focal non-convulsive status epilepticus originating from the left temporal lobe. Patient underwent labor induction, received 21 days of IV acyclovir, and discharged upon improvement on levetiracetam and phenytoin. She re-presented in March 2022 with new-onset severe paranoia, mood lability, and insomnia. CSF was positive for NMDAr antibodies. Patient was admitted to the hospital in April for treatment of NMDA encephalitis. She became disoriented and combative. Patient underwent 5 sessions of PLEX and 5 days of intravenous methylprednisolone. Patient discharged on prednisone taper and lacosamide for seizure control. Patient achieved only moderate improvement of memory and speech issues, receiving monthly IVIG, forgoing rituximab given risks of HSVE recurrence.

Conclusions:

This case highlights the importance of suspecting anti-NMDAr encephalitis in patients with previous HSVE and the value of close follow-up of a patient in neuroimmunology. Although post-infectious anti-NMDAr encephalitis typically presents within a few weeks following HSVE, delayed presentation is still a possibility and must be considered. Furthermore, HSV infection may trigger in these patients a persistent autoimmune activation, as opposed to classic anti-NMDAr encephalitis which is more often monophasic. Treatment of these patients is challenged by the need to weigh the therapeutic benefits of rituximab with potential risks of HSV reactivation secondary to immunosuppression.