Shooting Your Own Foot: A Case Report on Autoimmune Encephalitis Following a Viral Trigger

Abstract

Aims: The aim of this case report is to highlight the frequently overlooked association between Anti-NMDA Receptor Encephalitis and a preceding Herpes Simplex Viral Encephalitis trigger, the clinical settings under which to suspect this autoimmune disease, the need for appropriate workup to clinch the diagnosis and the necessity of speedy initiation of immunotherapy, in a disease where timely treatment is paramount. Presentation of Case: A middle aged woman presented with a history of fever and syncope, followed by slurring of speech, quadriparesis, seizures and altered sensorium. She was diagnosed with HSV-1 Encephalitis on basis of CSF studies and MRI brain. Despite a timely 28-day course of intravenous acyclovir therapy, she showed incomplete clinical recovery. A serum and CSF autoantibody panel was performed, which clinched a diagnosis of Anti-NMDA Receptor Encephalitis. A course of steroids and IVIg was given and the patient was discharged after showing clinical improvement. Discussion: Anti-NMDA Receptor Encephalitis is an autoimmune encephalitis characterized by complex neuropsychiatric features and presence of IgG antibodies against NR1 subunit of NMDA receptor detectable in CSF and serum. It is associated with various malignancies, chiefly ovarian teratomas, and with HSV-1 viral encephalitis. Diagnosis involves autoantibody detection in CSF or serum and first line treatment is with steroids, IVIg or plasma exchange, and tumour resection. Conclusion: Prompt diagnosis of Anti-NMDA receptor encephalitis is crucial as it enables treatment with timely immunosuppression and tumour resection. This disease must be suspected in adults or children presenting with subacute onset of neuropsychiatric symptoms, with CSF lymphocytic pleocytosis and presence of autoantibodies to NMDA receptor in CSF or serum. Early treatment is associated with good outcomes.