To describe a series of pediatric patients developing life-threatening arrhythmias related to dysautonomia in anti-NMDA receptor encephalitis (NMDARE)

Case 1: A previously healthy, neurotypical 17-year-old male presented with cognitive decline, psychiatric symptoms, and dystonia. Serum and CSF NMDA receptor IgG were positive. In the ICU, he had multiple episodes of brief sinus pauses and PVCs on telemetry. He subsequently experienced a 30-second bradycardic cardiac arrest and underwent pacemaker placement. He has since experienced significant neurological recovery with mild residual cognitive deficits. He continued to require about 20% pacing at electrophysiology follow-up.

Case 2: A previously healthy, neurotypical 15-year-old female presented with weeks of somnolence, stuttering speech, and visual hallucinations. She developed chorea and autonomic lability, requiring ICU care. Serum and CSF NMDA receptor IgG were positive. She initially had sinus pauses lasting seconds on ICU admission and subsequently had two separate 30-second asystole episodes requiring CPR and underwent pacemaker placement. She went on to experience significant neurologic recovery following ovarian teratoma resection and immunotherapy. At 3-week follow-up, she was noted to have intermittent episodes of backup pacing.

Dysautonomia is a life-threatening complication of NMDARE in the acute/subacute illness phase. This case series highlights the need to remain vigilant for dysrhythmia in pediatric patients with NMDARE utilizing cardiac monitoring. Pacemaker placement should be considered in patients with refractory, life-threatening arrhythmias detected on monitoring or cardiac arrest. Notably, this cohort continued to require pacing beyond the acute/subacute phase of their disease, which may indicate long-term risk for dysrhythmia in NMDARE.