The largest published retrospective study of 501 patients with ANMDARE showed that nearly all (97%) patients that were treated with first-line immunotherapy, methylprednisolone, IVIG, and/or PLEX had symptoms improve within the first four weeks . Our discussion focuses primarily on the sinus dysrhythmias associated with ANMDARE, and their management. 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. strong class=”kwd-title” Keywords: anti-N-methyl-d-aspartate receptor encephalitis (ANMDARE), Lock Step Phenomenon, autoimmune encephalitis, ovarian teratoma, autonomic dysregulation, sinus node dysfunction 1.?Introduction ANMDARE is a rare and severe form of autoimmune encephalitis affecting primarily young adults and children at an incidence rate of about 5 to 8 per 100,000 . Though only recently described, ANMDARE is the third most common form of encephalitis after viral encephalitis and acute disseminated encephalitis . ANMDARE may present with a wide array of manifestations ranging from symptoms such as decreased consciousness, insomnia and defects in memory recall to more severe manifestations like seizures and psychiatric changes. Consequences of Moxonidine HCl autonomic dysregulation are the primary cause of death . Autonomic dysregulation can manifest as bradycardia, tachycardia, cardiac pauses, hypo/hyperthermia, blood pressure dysregulation and hypoventilation . ANMDARE affects the brain primarily by attacking the extracellular NMDA receptors on neuronal surfaces which lead to internalization of the receptor and inflammation . Internalization of the antigen-antibodies complex result in intracellular inflammation and neuronal destruction. Antibodies generated against the NMDA receptor may represent an underlying paraneoplastic process, most commonly ovarian teratomas . The pathophysiology is a cross immune response secondary to molecular mimicry between the teratoma antigens and neuronal NMDA receptors . Our case highlights the cardiac complications associated with ANMDARE followed by an in-depth review of the topic. 2.?Case Presentation A 36-year-old woman who was 16-weeks pregnant with no known past medical history was brought to NAV3 the Moxonidine HCl hospital by her sister for 2 weeks of headaches and insomnia, followed by vivid hallucinations and bizarre delusions. Her vital signs at arrival were significant for a heart rate of 104 bpm, temperature of 97.60 F, blood pressure of 111/64 mmHg and a respiratory rate of 18 breaths per minute saturating of 100% on room air. She was agitated, disoriented and speaking incoherently. Her cardiac and respiratory exams were normal. Neurological evaluation was limited as the patient was agitated and non-cooperative. Her deep tendon reflexes were +2 in bilateral upper and lower extremities. She was moving all extremities and reacted to pain stimuli. EKG on admission was significant for sinus tachycardia at 110 bpm [Figure 1]. CT scan of the head which was negative for any intracranial bleeding or intracranial masses. Arterial blood gas analysis, thyroid function testing, blood cultures and urine analysis were noncontributory [Table 1]. Open in a separate window Figure 1. Sinus Tachycardia 110 bpm (Admission EKG) Table 1. Admission workup for altered mental status Comprehensive PanelNa141K+3.4Cl?104C0221BUN9Cr0.67Glucose101Mg2+2.24P043.5ALT14AST12ALP57MicrobiologyParasite – BloodNegativeSARS-CoV-2Negative x3Syphilis PCRNegativeBlood CultureNegativeUrine CultureNegativeSputum CultureNegativeHepatitis A/B/C/D/ENegativeThyroid Function TestTSH1.28Total T412Free T41.16Arterial Blood GasPh-Arterial7.378PC02-Arterial36.2PA02-Arterial169 on 2L Moxonidine HCl NCLactate0.8Cerebral Spinal FluidApearanceClearTotal Cell Count100Glucose71Monocytes2WBC64RBC44Lymphocyte98Protein39Bacterial CultureNegativeMengitis Panel PCRNegative Open in a separate window On day 2 of admission, the patient experienced refractory generalized tonic-clonic seizures necessitating endotracheal intubation for airway protection. Evaluation with an MRI of the brain, MRA and MRV of the cerebral circulation did not reveal any intracranial pathology. Cerebrospinal fluid analysis showed lymphocytic pleocytosis [Table 1]. Electroencephalography (EEG) demonstrated an extreme delta brush pattern consistent with ANMDARE. ANMDARE antibody and glial fibrillary acidic protein antibody positivity confirmed the diagnosis of ANMDARE. During her seizure episodes the patient demonstrated rhythmic oral grimacing and intermittent adduction of bilateral lower extremities. These findings correlated with the delta brush pattern seen on EEG. The patient required four anti-epileptic agents (phenobarbital, levetiracetam, clobazam, and lacosamide) to suppress the seizures. NMDARE was subsequently treated with 5 cycles of plasmapheresis, a course of stress dose methylprednisolone*, IVIG and rituximab. During the course of her stay, telemetry identified sinus node dysrhythmias. Episodes of sinus tachycardia alternating (HR ~ 110C125 bpm) [Figure 2A] Moxonidine HCl with sinus bradycardia (HR ~ 30C35 bpm) [Figure 2B] and sinus arrest (longest pause ~ 7 secs) [Figure 2B] related and unrelated to vagal stimuli (ultrasound fetal monitoring). A transvenous pacemaker.