Anti-N-methyl-D-aspartate receptor antibodies: a potentially treatable cause of encephalitis in the intensive care unit.

Abstract

To report the occurrence of an unusual neurologic disorder requiring admission to the intensive care unit. Analysis of an observational cohort study of 31 patients with encephalitis admitted over a 4-yr period. Neurologic intensive care unit in a tertiary referral center. We identified N-methyl-D-aspartate receptor antibodies in six patients (two male and four female). All seropositive patients presented with a psychiatric prodrome, before developing seizures and obtundation requiring intensive care unit admission. They exhibited limb and truncal stereotypies and orofacial dyskinesias upon weaning sedation. Two patients had ovarian tumors. Patients were treated with sedation, antiepileptic drugs, and immunotherapy. One patient received a magnesium infusion and ketamine. N-methyl-D-aspartate receptor antibodies were identified in serum samples by an immunofluorescent cell-based assay. Three patients made a good but slow recovery; two were left with severe neurologic deficits; and one died after return to the referring hospital. These patients accounted for approximately 20% of all patients admitted with encephalitis to this referral center. N-methyl-D-aspartate receptor antibodies should be tested in patients with hyperkinetic encephalitis and neuropsychiatric prodrome admitted to the intensive care unit. The disorder is probably not rare and is potentially treatable.