The clinical course was complicated with the patient developing neutropenic fever and cerebrospinal fluid cultures (CSF) growing methicillin-sensitive Staphylococcus aureus (MSSA). immunoglobulins (IVIG) was started followed by rituximab. The clinical course was Nodinitib-1 complicated with the patient developing neutropenic fever and cerebrospinal fluid cultures (CSF) growing methicillin-sensitive Staphylococcus aureus (MSSA). She underwent pelvic imaging which showed a right ovarian teratoma. Evidence suggests that removal Nodinitib-1 of ovarian tumor prospects to better clinical and mortality outcomes in patients with Anti-NMDAR encephalitis. It is important for the internist to consider paraneoplastic syndromes in patients with Anti-NMDAR encephalitis. Keywords: ovarian teratoma, nmda, nmdar encephalitis, anti-nmdar, anti-nmda receptor encephalitis Introduction Anti-N-methyl-D-aspartate-receptor encephalitis was initially explained by Dalmau and colleagues in 2007 when they discovered the anti-N-methyl-D-aspartate (NMDA) receptor antibody in a set of females who experienced an array of neurological symptoms (short-term memory loss, followed by psychiatric symptoms or confusion and a decreased level of consciousness) in association with c-Raf ovarian teratomas [1]. The patients can present with a viral-like prodromic syndrome [1], which can be in the beginning confused as viral encephalitis, much like our case. Realizing the syndrome is crucial as most of the cases can achieve better clinical and mortality outcomes by the removal of the teratoma and immunotherapy [2]. In our statement, we describe a similar presentation of a female patient with an ovarian teratoma that was successfully managed after being misdiagnosed as infectious encephalitis. Informed consent statement was obtained for this study. Case presentation A 26-year-old female presented with new onset seizures and bizarre behavior. Review of systems was normally unremarkable. Her social history was significant for alcohol intake and surgical history included an abortion with intra-uterine device (IUD) placement three months back. On examination, the patient was hemodynamically stable. She was oriented to time and place but not to a person. Shortly thereafter, she developed automatisms with back and forth body movements. Initial electroencephalogram (EEG) showed left frontal spikes (Physique ?(Figure11). Open in a separate window Physique 1 Electroencephalogram image showing spikes in the left frontal areaSpikes in the left frontal area is usually indicated by the grey arrows She continued to have seizures and disturbed behavior. A repeat EEG was performed which revealed?right temporal delta activity (Physique ?(Figure22). Open in a separate window Physique 2 Repeat image of the electroencephalogramPersistent polymorphic delta activity in the right temporal region indicated by the reddish arrow EEG was discontinued due to a seizure-free interval of 24 hours. Magnetic resonance imaging (MRI) of the brain was performed, which showed right temporal hyper-intensity. She was treated with acyclovir prophylaxis due to suspected herpes simplex virus (HSV) encephalitis. However, both HSV serology and HSV deoxyribonucleic acid (DNA) in the CSF by polymerase chain reaction (PCR) were unfavorable. Further workup revealed serum and cerebrospinal fluid to be?positive for Anti-NMDAR antibodies and increased leukocytes with neutrophilic predominance, because of which, prophylactic vancomycin and steroids were started. Due to the progressive decline in mental status Nodinitib-1 and unresponsiveness, steroids were discontinued. She was also started on valproic acid (VA), which had to be increased to 750 mg 12 hourly due to progressive psychosis. The dose of VA had to be increased again to 1000 mg 12 hourly [as latest VA levels were 53 g/mL (therapeutic 50-125 g/mL)] to better manage worsening agitation and psychosis. In addition, she was given a five-day course of intravenous immunoglobulins (IVIG) with a further plan to start rituximab. However, after the first dose of rituximab, she developed neutropenia, fever, and tachycardia. CSF NMDA titers were 1:840. Prophylactic vancomycin was discontinued after CSF cultures were positive for methicillin-sensitive Staphylococcus aureus (MSSA), for which methicillin was started. Over the course of 24 hours, she developed opisthotonic posturing, fever, agitation, and tachycardia. Glycopyrrolate was started for increased secretions. Due to the association of anti-NMDAR antibodies with ovarian teratomas, a transvaginal ultrasound was performed which was suggestive of a 2 x 3 cm right ovarian cyst. Nodinitib-1 Magnetic resonance imaging (MRI) of the pelvis further confirmed the presence of nonmalignant transformation. Eventually, due to the deteriorating condition of the patient, right oophorectomy was planned. Her condition remained the same.