Tocilizumab for critically ill patients with refractory anti-NMDAR encephalitis: a case report.

BACKGROUND: Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis often requires intensive care and rapid escalation of immunotherapy. We report a critically ill woman with refractory anti-NMDAR encephalitis treated with tocilizumab (TCZ) as early second-line therapy and discuss the rationale for IL-6 receptor blockade over other treatment strategies. CASE REPORT: A previously healthy 30-year-old woman developed psychosis, catatonia, dyskinesias, and refractory status epilepticus; anti-NMDAR antibodies were detected in the CSF using a commercial fixed cell-based assay. She required mechanical ventilation and received methylprednisolone and IVIG 35 days after symptom onset, without improvement. The course was complicated by sepsis, dialysis-dependent acute kidney injury, anemia, and thrombocytopenia. Given active infection, cytopenias, and prior hepatitis B exposure, TCZ was initiated with tenofovir prophylaxis. Over the subsequent 30 days, she improved, was extubated, and became seizure-free. Rituximab (RTX) was started 9 months after onset. At 25-month follow-up, outcomes were mRS 2, CASE 1, and MoCA 26/30. CONCLUSION: This case describes rapid clinical improvement temporally associated with TCZ administration in a critically ill patient with refractory anti-NMDAR encephalitis. Although causality cannot be established, TCZ may offer a rapid and time-limited immunomodulatory option for carefully selected ICU patients when conventional second-line therapies are unsuitable. Prospective controlled studies are required to determine its efficacy and optimal timing.