Neurology Neuroimmunology & Neuroinflammation

Paraneoplastic anti-NMDA receptor encephalitis in 1830?

Our aim was to identify patients with probable anti-NMDA receptor encephalitis among historical medical cases. A case report published in leading Hungarian-, German- and Italian-language medical journals in the early 1840s was revisited. In 1830, an 18-year-old, healthy woman suffered epileptic seizures, followed by a 6-day-long state characterized by catalepsy, unresponsiveness, motionless, and light breathing. Her symptoms regularly returned in the following 1.5 years. Meanwhile, a progressively growing huge abdominal tumor appeared. One day, she suddenly started vomiting a large amount of foul-smelling pus mixed with blood, accompanied by bone fragments. Pus mixed blood with some membranous substance was also evacuated through the anus and vagina. After this event, she completely recovered; 1.5 years later, she married and later gave birth to 3 healthy children. The patient remained healthy during the 11-year follow-up. We suggest that in the description of a paraneoplastic case, an anti-NMDA receptor encephalitis can be dated back as far as to the 19th century, with an especially rare type of resolution: the disappearance of the symptoms after the spontaneous elimination of an ovarian teratoma.

Paraneoplastic AQP4-IgG–Seropositive Neuromyelitis Optica Spectrum Disorder Associated With Teratoma

To assess a case of paraneoplastic aquaporin-4 (AQP4)-immunoglobulin G (IgG)-seropositive neuromyelitis optica spectrum disorder (NMOSD) associated with teratoma and determine whether it is a paraneoplastic neurologic disorder. A single case study and literature review of 5 cases. A 27-year-old woman presented with diplopia, facial nerve palsy, paraplegia, sensory dysfunction of lower limbs, dysuria, nausea, and vomiting. Spinal cord MRI detected an extensive longitudinal lesion in the spinal cord, and brain MRI detected abnormal lesions in the right cerebral peduncle and tegmentum of the pons. CSF analysis revealed positive oligoclonal IgG bands (OCBs). The patient tested positive for AQP4-IgG, confirming a diagnosis of NMOSD. An abdominal CT scan detected an ovarian tumor. After steroid therapy and tumor removal, the patient progressively improved, with only mild sensory dysfunction. Histopathologic analysis of the tumor revealed a teratoma and the presence of glial fibrillary acidic protein (GFAP) This study suggests that ovarian teratoma may trigger the development of AQP4-IgG-seropositive NMOSD. Further studies are needed to elucidate the pathogenesis of teratoma-associated NMOSD.

Racial and Ethnic Disparities in the Incidence of Anti-NMDA Receptor Encephalitis

To estimate the incidence of anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis. We conducted a retrospective cohort study of >10 million person-years of observation from members of Kaiser Permanente Southern California, 2011-2022. The electronic health record of individuals with text-string mention of We identified 70 patients who met diagnostic criteria for anti-NMDAR encephalitis. The median age at onset was 23.7 years (IQR = 14.2-31.0 years), and 45 (64%) were female patients. The age-standardized and sex-standardized incidence of anti-NMDAR encephalitis per 1 million person-years was significantly higher in Black (2.94, 95% CI 1.27-4.61), Hispanic (2.17, 95% CI 1.51-2.83), and Asian/Pacific Island persons (2.02, 95% CI 0.77-3.28) compared with White persons (0.40, 95% CI 0.08-0.72). Ovarian teratomas were found in 58.3% of Black female individuals and 10%-28.6% in other groups. Anti-NMDA receptor encephalitis disproportionately affected Black, Hispanic, or Asian/Pacific Island persons. Ovarian teratomas were a particularly common trigger in Black female individuals. Future research should seek to identify environmental and biological risk factors that disproportionately affect minoritized individuals residing in the United States.