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.