PMC9923169_01
Disease duration in this case. Anti-NMDAR encephalitis, anti-N-methyl-D-aspartate receptor encephalitis; anti-NMDAR ab, anti-N-methyl-D-aspartate receptor antibody; MRI, magnetic resonance imaging; IVMP, intravenous methylprednisolone; MS, multiple sclerosis; NA, not available; OB, oligoclonal immunoglobulin bands.
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A graphical presentation of this patient is provided in  Figure 1 .
Brain MRI and antibodies in this case. (A) and (B) The MRI performed in October 2021 demonstrated normal results on T2 weight imaging and FLAIR imaging. (C-E) The MRI result showed significant hyperintensity in the right semioval center and the left posterior horn of the lateral ventricle on FLAIR imaging, T2 weight imaging, and DWI on June 1, 2022. (F) Enhanced magnetic resonance imaging performed on June 1, 2022, not showing a significant lesion. (G) and (H) The results of the MRI performed on June 1, 2022 demonstrated that the hyperintensity lesions were alleviated than before on T2 weight imaging and FLAIR imaging. (I) and (J) The results of the MRI performed on October 1, 2022 showed a new lesion with hyperintensity in the left posterior horn of the lateral ventricle on T2 weight imaging and FLAIR imaging. (K, L) Anti-NMDAR antibodies were found to be positive in serum (1:100) and in CSF (1:30) on June 1, 2022. (M) Anti-NMDAR antibodies were found to be positive in CSF (1:10). (N) OB was positive in CSF (counts, >=2). CSF, cerebrospinal fluid; DWI, diffusion-weighted imaging; FLAIR, fluid-attenuated inversion recovery; MRI, magnetic resonance imaging; OB, oligoclonal immunoglobulin bands; anti-NMDAR, anti-N-methyl-D-aspartate receptor; QC, quality control; SER, serum.
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The magnetic resonance imaging (MRI) result of the brain turned out normal ( Figures 2A, B ). Upon searching for antibodies (anti-NMDAR, anti-LGI1, anti-CASPR2, anti-AMPA1, anti-AMPA2, and anti-GABABR), the blood (1:100) and CSF (1:30) were found positive with anti-NMDAR antibodies by cell-based assay (CBA) (Kingmed Diagnostics Co., Ltd., which is the largest College of American Pathologists-certified laboratory in China) (PMID: 33106361) ( Figures 2K, L ). The CSF was positive (1:10) with anti-NMDAR antibodies ( Figure 2M ), but the antibody titer was lower than before. T2 weight imaging and fluid-attenuated inversion recovery (FLAIR) imaging ( Figures 2C-E ). The lesions were not found with significant enhancement using contrast-enhanced magnetic resonance imaging ( Figure 2F ). Figure 2N ). Furthermore, anti-NMDAR antibodies were detected using the CBA method. On June 26, 2022, the brain MRI result showed that the abnormally high signal lesions were alleviated compared with the prior T2 weight imaging and FLAIR imaging results ( Figures 2G, H ). T2 weight imaging and FLAIR imaging ( Figures 2I, J ). The results of all neurological examinations were observed to be in the normal range.
Basal EEG (recorded on day 7 from symptom onset). "Extreme delta brush" pattern with diffuse delta slowing and overriding high-frequency activity. EEG, electroencephalogram.
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An electroencephalogram image of the patient showed an "extreme delta brush" pattern ( Figure 3 ).