Anti–N-Methyl-D-Aspartate Receptor Encephalitis: A Potential Mimic of Neuroleptic Malignant Syndrome

Abstract Background Anti–N-methyl-D-aspartate receptor encephalitis is an autoimmune disorder characterized by behavioral changes, dyskinesia, and autonomic instability. Patient Description We describe a 14-year-old girl who initially presented with acute behavioral changes and seizures and who over a 2-week period developed high fever, tachycardia, and elevated blood pressures. Results Because she received multiple medications including anticonvulsants and a neuroleptic, our patient was initially diagnosed with neuroleptic malignant syndrome, a disorder characterized by autonomic dysfunction, hyperthermia, muscle rigidity, and mental status changes usually caused by the use of a neuroleptic agent. Further investigation, however, revealed the presence of N-methyl-D-aspartate receptor antibodies and an ovarian teratoma. Symptoms resolved after teratoma resection and intravenous immunoglobulin therapy. Conclusion We propose that anti–N-methyl-D-aspartate receptor encephalitis can cause a paraneoplastic syndrome mimicking neuroleptic malignant syndrome.