Anti-NMDA receptor encephalitis presenting as a progression of disease in a patient with underlying congenital leukodystrophy: Case report.

Anti-NMDA Receptor (NMDAR) Encephalitis (NMDARE) is an autoimmune disorder that is often debilitating and difficult to diagnose. Patients, especially those with underlying neuropsychiatric disorders, may experience delayed or misdiagnosis of NMDARE. Here, we report on a patient with known congenital leukodystrophy (CLD) and epilepsy with a challenging diagnosis of NMDARE. The patient first presented with progressive behavior changes and seizure-like episodes. Initial workup, including video EEG and brain MRI, were mostly unremarkable, and the patient's symptoms were resistant to treatment with multiple anti-epileptic drugs. Given the patient's complicated clinical history, his presentation was initially thought of as progression or exacerbation of his chronic disease. With continued lack of improvement, autoimmune encephalitis was considered. The patient was started on immunotherapy and autoimmune encephalitis panels were sent, which came back positive. He continued to improve over the next weeks and months. Despite a growing body of literature, our knowledge on confirmed risk factors for NMDAR remains limited outside of young age, ovarian teratomas, and herpes encephalitis. We know that maintenance of the blood brain barrier is key to preventing autoimmune disorders of the central nervous system (CNS), and multiple congenital leukodystrophies exhibit pathology in the neurovascular unit. This is the first described case of anti-NMDA receptor encephalitis in a patient with an underlying congenital leukodystrophy, which may reflect an underreported NMDAR encephalitis risk factor. With limited known risk factors and time to diagnosis and treatment so important, this case may reflect an important and underreported risk factor for NMDAR.