A former 27‐week‐gestation Hispanic male aged 2 years and 9 months with a history of grade 2 intraven‐tricular hemorrhage in the neonatal period presented with sub‐acute onset of ataxia, difficulty with hand coordination, speech deterioration, and sleep disturbance. His symptoms had begun 3 weeks prior to admission and initially manifested as right toe walking and limping. His presenting physical exam was significant for truncal ataxia and an ataxic gait. His initial diagnostic laboratory testing was unremarkable, including cerebrospinal fluid (CSF) cell counts, protein, and infection studies. Oligoclo‐nal bands were detected in the CSF. Brain MRI/MRA was normal. A video electroencephalogram showed no seizure activity. Over the next 9 days, he developed progressive chor‐eoathetoid movements of his hands and left leg, tardive dyski‐nesia, complete mutism, insomnia with night terrors, and aspiration. Given the presence of oligoclonal bands in the CSF and a possible autoimmune/inflammatory etiology, he was given 3 days of intravenous immunoglobulin with no improvement. This was followed by 5 days of high‐dose intravenous corticosteroid therapy with mildly improved symptoms. A SPECT study was normal. A PET metabolic scan of the brain was also unremarkable. Over the next few days, CSF analysis for anti–NMDA receptor antibodies returned positive. He was started on a course of rituximab and discharged home. Over the following 2 weeks, his symptoms improved. Two months after rituximab therapy, he was back to his premorbid baseline with no neurologic sequelae.
Anti–NMDA receptor encephalitis is becoming an increasingly recognizable disorder with defined clinical criteria. The mechanism is thought to involve formation of antibodies to the NR1/NR2 heteromers of the NMDA receptors, ultimately causing inhibition of these receptors in the presynaptic GABAergic interneurons. The pathogenesis of anti–NMDA receptor antibodies is still poorly understood. The clinical picture usually involves neuropsychia‐tric manifestations such as mood, behavior, and personality changes as well as oromotor and limb dyskinesias, progressive speech and cognitive regression, and autonomic instability. Diagnosis is established through immunocytochemical analysis and ELISA assays for the detection of antibodies in the serum and CSF. However, this testing is only available at certain academic centers. Individuals are managed with immunotherapy (corticosteroids, immunoglobulin, plasmapheresis, and possibly rituximab). This disorder is highly treatment responsive with good outcomes.
Anti–NMDA receptor encephalitis is an immune‐mediated neurologic disorder with distinct treatment and prognostic implications. Early recognition and effective treatment are crucial for the care of these patients. Pe‐diatric hospitalists are critical in suspecting, identifying, and managing this potentially devastating disorder.
R. Jacobs ‐ none