Ovarian teratoma related anti-N-methyl-D-aspartate receptor encephalitis:A case series and review of the literature

BACKGROUND Anti-N-methyl-D-aspartate receptor(NMDAR)encephalitis is a rare but important complication of ovarian teratoma.Between July 2012 and December 2019,six patients with ovarian teratoma-associated anti-NMDAR encephalitis were enrolled in our hospital and their clinical characteristics,treatment,and follow-up were reviewed.We also conducted a systematic literature review of ovarian teratoma related anti-NMDAR encephalitis reports between January 2014 and December 2019.AIM To better understand anti-NMDAR encephalitis through literature review and patients enrolled in our hospital.METHODS The six patients enrolled in the study were those diagnosed with anti-NMDAR encephalitis.Their history,clinical manifestations,and medications were recorded and optimum treatment provided in addition to maintaining a record of the follow-ups.In addition,we also extensively surveyed the literature and provide summarized data from 155 published cases of anti-NMDAR encephalitis from 130 case reports.PubMed and Scopus were the sources of these publications and the time period covered was 6 years ranging from January 2014 through December 2019.RESULTS The six patients enrolled for this study presented with typical symptoms resulting in a diagnosis of ovarian teratoma induced anti-NMDAR encephalitis.Appropriate interventions led to a positive outcome in all the patients,with five of six patients reporting full recovery and the sixth patient recovering with a few deficits.No death was recorded.The literature survey comprising of 155 patients cases across 130 case reports of anti-NMDAR encephalitis clearly indicated an upward trend in the reports/diagnosis in China,particularly in the surveyed time from 2014 through 2019.The majority of patients(150/155)underwent surgical intervention resulting in positive outcome.No treatment intervention was mentioned for one case while the four patients who were not surgically operated succumbed to the disease.CONCLUSION Suspected anti-NMDAR encephalitis should be quickly evaluated for anti-NMDAR antibodies since early diagnosis is important.In case of a tumor,its earliest and complete removal is recommended.Finally,early use of corticosteroids and IgG-depleting strategies(intravenous immunoglobulin or plasma exchange)may improve outcome.