Anti-N-Methyl-d-Aspartate Receptor Encephalitis in Adult Patients Requiring Intensive Care

Abstract

Rationale: Encephalitis caused by anti-N-methyl-d-aspartate receptor (NMDAR) antibodies is the leading cause of immune-mediated encephalitis. There are limited data on intensive care unit (ICU) management of these patients.

Objectives: To identify prognostic factors of good neurologic outcome in patients admitted to an ICU with anti-NMDAR encephalitis.

Methods: This was an observational multicenter study of all consecutive adult patients diagnosed with anti-NMDAR encephalitis at the French National Reference Centre, admitted to an ICU between 2008 and 2014. The primary outcome was a good neurologic outcome at 6 months after ICU admission, defined by a modified Rankin Scale score of 0-2.

Measurements and main results: Seventy-seven patients were included from 52 ICUs. First-line immunotherapy consisted of steroids (n = 61/74; 82%), intravenous immunoglobulins (n = 71/74; 96%), and plasmapheresis (n = 17/74; 23%). Forty-five (61%) patients received second-line immunotherapy (cyclophosphamide, rituximab, or both). At 6 months, 57% of patients had a good neurologic outcome. Independent factors of good neurologic outcome were early (≤8 d after ICU admission) immunotherapy (odds ratio, 16.16; 95% confidence interval, 3.32-78.64; for combined first-line immunotherapy with steroids and intravenous immunoglobulins vs. late immunotherapy), and a low white blood cell count on the first cerebrospinal examination (odds ratio, 9.83 for <5 vs. >50 cells/mm³; 95% confidence interval, 1.07-90.65). Presence of nonneurologic organ failures at ICU admission and occurrence of status epilepticus during ICU stay were not associated with neurologic outcome.

Conclusions: The prognosis of adult patients with anti-NMDAR encephalitis requiring intensive care is good, especially when immunotherapy is initiated early, advocating for prompt diagnosis and early aggressive treatment.

Keywords: anti–N-methyl-d-aspartate receptor; critical care; encephalitis; immunotherapy; incidence.