Anti-NMDA receptor encephalitis is characterized by dyskinesias, psychosis, and seizures 1 secondary to antibodies to the NR1-NR2B heteromer of the NMDA receptor.2 This syndrome, more common in women, is often related to an ovarian tumor 1 ; the prognosis is better if the tumor is identified within 3 months of onset. Our case had nonconvulsive status epilepticus lasting 6 months, with marked improvement following removal of the ovarian tumor.Case report. A 35-year-old woman, previously healthy and without history of psychosis, had a 3-week history of progressive headaches, short-term memory loss, and irritability. On admission, she was psychotic, requiring physical and chemical restraints. She was unable to follow commands, had echolalia, and had occasional dystonic posturing of her limbs. One week later, she became unresponsive to external stimuli. An EEG demonstrated persistent nonconvulsive status epilepticus (NCSE). Initial CSF studies were remarkable for a lymphocytic pleocytosis with 386 leukocytes. Brain MRI showed diffusionweighted imaging hyperintensity in the right medial temporal lobe transitioning to fluid-attenuated inversion recovery hyperintensity on repeat imaging (figure 1A). Tests for multiple viral and bacterial pathogens, including herpes simplex virus, were negative. A paraneoplastic panel was negative for clinically available antibodies with the exception of a neuron-specific antibody, not otherwise identified. The CSF, sent to the University of Pennsylvania, had an antibody for the NR1/NR2B heteromer of the NMDA receptor (figure 1B).She was intubated and monitored with continuous EEG, which showed a cyclical pattern of moderate to high voltage, generalized, anteriorly biased 2-Hz alternating with 5-6 Hz sharp wave activity that lacked a triphasic morphology ( figure 1C). The NCSE was refractory to phenytoin, levetiracetam, and valproic acid, and incompletely suppressed by benzodiazepines. Propofol produced abrupt cessation of this rhythmic pattern, thus supporting an epileptic etiology (figure e-1 on the Neurology ® Web site at www.neurology.org). Pentobarbital was used to maintain EEG burst-suppression; she remained in this state for 5 months, with each attempt to minimize the depth of pentobarbital coma resulting in resumption of electrical status epilepticus. Three months into the course further reduction of pentobarbital produced a distinct EEG pattern with moderate voltage diffuse spindle-like rhythms and diffuse slowing consistent with sedation and independent, discrete, left and right hemispheric seizures at a rate of 3-4 per hour, lasting 30 seconds to 3 minutes. Rhythmic sharp wave activity evolved stereotypically in each hemisphere and was accompanied by subtle myoclonus and tonus.To suppress the NMDA receptor antibody, she received IV immunoglobulin, rituximab, and cyclophosphamide sequentially, without improvement. Multiple CT scans and ultrasounds of her ovaries revealed only a hemorrhagic cyst. After 5 months in pentobarbital-induced burst suppression, she had an oopherectomy...
