Anti-NMDA Encephalitis Co-positive with Aquaporin 4 Antibodies in a 4-year-old Female
Chloe LaRochelle1, Kirsten Consing2, Carla Zingariello3
1College of Medicine, 2Child Neurology, University of Florida, 3University of Florida
Objective:
To report the co-existence of anti-NMDAR antibodies and aquaporin-4 antibodies in a toddler with refractory multifocal seizures and spinal cord myelopathy.
Background:
Anti-NMDAR encephalitis with other autoimmune antibodies is not well studied in young children. We report an unusual case of a toddler with co-positive Anti-NMDAR and aquaporin-4 antibodies (AQP4).
Results:
A healthy, normally developing 3-year-old African-American female presented with new-onset generalized seizures. Over the course of 2.5 months, she developed refractory seizures, language regression, and sleep dysfunction resulting in admission for status epilepticus, during which she developed choreiform movements, orofacial dyskinesias, and dysautonomia. EEG showed generalized delta activity. Work-up revealed positive CSF and serum anti-NMDAR antibodies (CSF titer 1:40, serum titer 1:620) with 7 oligoclonal bands, and elevated AQP4 antibodies (20.8 U/mL). Neuroimaging revealed bilateral supratentorial atrophy and hyperintense lesions of the thoracic spine suggestive of anti-NMDAR associated myelopathy. Pelvic ultrasound was negative for tumor. She was treated with high-dose steroids, plasmapheresis, IVIG, mycophenolate, and rituximab with improvement of symptoms.
Conclusions:
We report a 3 year old with anti-NMDAR encephalitis presenting with status epilepticus and found to have co-positive AQP4 antibodies with myelopathy. In case reports documenting co-positive anti-NMDAR and AQP4 antibodies, patients initially present with features of neuromyelitis optica spectrum disorder (NMOSD), making our patient’s presentation unusual. Overlapping demyelinating disease is uncommon in anti-NMDAR encephalitis. The origin of anti-NMDAR antibodies is debated. Our patient’s primary presentation with anti-NMDAR encephalitis argues suggests a general pro-inflammatory state in the brain increases the risk of developing autoimmune antibodies.