eng Science and Education Publishing American Journal of Medical Case Reports 2374-216X 2020-09-25 8 12 503 507 10.12691/ajmcr-8-12-20 AJMCR202081220 article Krunal H. Patel 1 Yuvraj Chowdhury 2 Mrinali Shetty 3 Vaibhavi Uppin 3 Paul Madaj 3 Moro O. Salifu 3 Mary Youssef 3 Victoria L. Henglein 3 Samy I. McFaralne smcfarlane@downstate.edu 3 Department of Internal Medicine, State University of New York, Downstate Medical Center, Brooklyn, NY, USA - 11203 Division of Cardiovascular Disease, State University of New York, Downstate Medical Center, Brooklyn, NY, USA - 11203 Division of Cardiovascular Disease, University of Chicago (NorthShore), Evanston, IL, USA - 60201 Described in 2007, anti-N-methyl-d-aspartate receptor encephalitis (ANMDARE) is a rare autoimmune limbic encephalitis affecting young adults (predominantly women of reproductive age) and is a paraneoplastic manifestation of ovarian teratoma in about half of the cases. ANMDARE is characterized by psychiatric changes, neurological changes, autonomic instability and cardiac dysrhythmias. In this report, we present a 36-year-old woman who was 16 weeks pregnant and brought to the hospital with confusion and subsequently had a seizure with Electroencephalography (EEG) demonstrated an extreme delta brush pattern consistent with ANMDARE. Patient developed sinus nodal dysfunction and was also found to have ovarian teratoma, a rather typical presentation for ANMDARE, that is considered a paraneoplastic syndrome for ovarian teratoma. In this report, we highlight the cardiac manifestation of ANMDARE, the pathophysiology associated with autonomic instability, and management strategies of this rare, and largely devastating illness. http://pubs.sciepub.com/ajmcr/8/12/20/ajmcr-8-12-20.pdf anti-N-methyl-d-aspartate receptor encephalitis (ANMDARE) Lock Step Phenomenon autoimmune encephalitis ovarian teratoma autonomic dysregulation sinus node dysfunction