Transplacental transfer of NMDA receptor antibodies in an infant with cortical dysplasia

A confused and agitated 18-year-old woman presented to the emergency unit with orolingual movements, eye deviation, and a temperature of 38°C. The symptoms had begun 2 weeks prior to the admission when she developed a severe headache associated with pathologic laughing and intermittent episodes of upgaze deviation. A urine pregnancy test was positive and a transvaginal ultrasonography showed a 9-week-old fetus. An MRI of the brain was unremarkable and results of the CSF analysis were also unremarkable apart from a CSF pleocytosis (62 lymphocytes) and slightly elevated protein (55 mg/dL; normal range 0-45 mg/dL). Extensive microbiologic and serologic studies with CSF were all negative. She gradually lost consciousness, experienced respiratory failure, and was intubated. There were semirhythmic movements consisting of complex patterns of mouth opening, chewing, facial grimacing, synchronous flexion-extension, and supination-pronation limb movements, which persisted during the period of unresponsiveness. She also had generalized hyperreflexia, persistent hyperthermia, and a full bladder. Three EEGs showed diffuse slow waves with no epileptic discharges. A diagnosis of anti-NMDA receptor (NMDAR) encephalitis was made on clinical grounds and strongly positive serum NMDAR antibodies.