Anti-NMDAR Encephalitis in a 2-Year-Old Male Presenting with Acute Neuropsychiatric Changes
Elizabeth Chiu1, Raman Shrestha2, Ajay Menon2, Mekka Garcia3, Muhammed Sheikh3
1University of South Florida Morsani College of Medicine, 2Neurology, 3Child Neurology, Jefferson Health Lehigh Valley Health Network
Background:
Anti-N-methyl-D-aspartate receptor encephalitis presents with a wide array of autonomic, neurologic, and psychiatric symptoms, often leading to delays in diagnosis. The median age of onset is 21 years, with fewer than 20 documented cases in children under 2 years of age. Compared to adults, pediatric patients more commonly present with behavioral changes, speech difficulties, and dyskinesias.
Results:
A 2-year-old male presented to the emergency room following seizure-like episodes of right-sided facial twitching and facial droop. On initial examination, he had subtle truncal titubation and gait ataxia. MRI of the brain and spinal cord were largely unremarkable. EEG captured an electroclinical seizure arising from the left frontocentral region, so he was started on levetiracetam. The EEG also demonstrated delta slowing with superimposed beta activity resembling a delta brush pattern. On day 2, he began having worsening ataxia, encephalopathy, inconsolable agitation, and various dyskinesias including orofacial dyskinesias, myoclonus, choreoathetosis, and dystonia. On day 3, he became non-verbal and unable to ambulate. Cerebrospinal fluid analysis revealed lymphocytic pleocytosis (WBC 22/cm2, 83% lymphocytes). Infectious work up and body imaging were unremarkable. His Antibody Prevalence in Epilepsy and Encephalopathy (APE2) score was 7, so he was empirically treated for suspected autoimmune encephalitis with a 5-day course of IV methylprednisolone (30 mg/kg daily) and 5-days of IVIG (400 mg/kg daily). Studies later showed positive anti-NMDA receptor antibodies in serum and cerebrospinal fluid. Clinically, he had some improvement but continued to be non-verbal with fluctuating dyskinesias. He was subsequently discharged to rehabilitation and plans to start rituximab (initial dose of 750 mg/m2) and monthly IVIG treatments.
Conclusions:
This case highlights the importance of recognizing autoimmune encephalitis as a rare but possible differential for a young child with rapidly progressing neuropsychiatric symptoms. Prompt diagnosis and treatment are essential in preventing further neurocognitive decline and negative impacts on development.
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