Forecasting outcomes in anti-NMDAR encephalitis

“It's dangerous to make forecasts, especially about the future.” Mark Twain's words hold true in many situations in medicine, particularly in critical illnesses that carry both risk of death and the chance of full recovery, exemplified by autoimmune encephalitis. A decade ago, the description of a unique syndrome of severe encephalitis associated with immunoglobulin G autoantibodies against the NMDA receptor (NMDAR) subtype 1 in young women with ovarian teratoma caught the attention of those interested in paraneoplastic syndromes, but it was considered rare.¹ Only 5 years later, it had become clear that this type of encephalitis spanned the spectrum of age and occurred in both sexes; and anti-NMDAR encephalitis (ANE) was now recognized as one of the most frequently occurring encephalitides in patients younger than 40 years of age with unknown etiologies.² In general, the disease takes a stepwise course with a prodromal state of irritability or depressive mood, then evolves to a limbic encephalitis with memory decline, psychosis, impaired consciousness/coma, and seizures, including status epilepticus. In addition, adventitious movements, including orofacial dyskinesias, and autonomic dysfunction with hypoventilation and blood pressure instability may occur later in the course and pose a substantial risk of prolonged and severe sequelae.³ Patients may need intensive care unit support for ventilation and treatment of refractory status epilepticus, or specific treatment for psychotic behavior.