Our objective was to characterize the patients with anti-NMDAR encephalitis and identify the most common presenting symptoms and etiologies.

Anti N-methyl-d-aspartate receptor (NMDAR) encephalitis is a specific autoimmune CNS disorder that decouples electrochemical synapses from their neuronal network, causing seizures, neuropsychiatric symptoms, movement problems, and autonomic dysfunction. Although well studied in the adult population, the clinical characteristics and potential triggers in pediatric cases of anti-NMDAR encephalitis are not well understood.

We retrospectively analyzed patients with anti-NMDAR at Texas Children’s Hospital (TCH) between 2010 and 2021, characterizing the demographics, presenting symptoms, and underlying etiologies.

Of the 65 pediatric cases at TCH, our cohort is 65% female and 62% Hispanic, which is 1.6 times higher than the demographics of our TCH patient population and that of the Houston Metropolitan area at large (Harris County, 39% Hispanic). The average age of onset in our pediatric cohort was 7.2 years (range 3 months to 17.9 years). Post-herpetic NMDAR encephalitis and ovarian teratoma associated encephalitis made up 12.8% and 4.2% respectively. Among the idiopathic NMDAR encephalitis group, the most common presenting symptom was focal weakness associated with altered gait and speech regression (39.6%), while 12% presented with isolated psychiatric symptoms. Within our cohort, 100% had behavioral/cognitive symptoms, 79% had seizures, 73% had speech problems, 67% had movement disorder, and 61% had memory deficits.

Our study describes the clinical characteristics which help define the presenting symptoms and potential etiologies in a heterogenous population from the largest single center pediatric cohort of anti-NMDAR encephalitis to date.