Clinical analysis of adult MOG antibody-associated cortical encephalitis

To describe the clinical and neuroimaging features, treatment response and outcomes of adult myelin oligodendrocyte glycoprotein (MOG) antibody-associated cortical encephalitis.

In this retrospective study, adult patients fulling the criteria of encephalitis but not fulfilling those of ADEM and tested positive for serum MOG antibody were recruited from Xiangya Hospital, Central South University (2019-2021). Clinical symptoms, laboratory data, imaging, and outcomes were analyzed.

Eleven MOG antibody-associated cortical encephalitis patients consisting of 4 female (36.4%) and 7 male (63.6%) were included with a median onset age of 27 years (ranging: 16-32 years). Fever (8/11), headache (9/11) and seizures (7/11) were the most common symptoms of adult MOG cortical encephalitis, and generalized seizure was the dominant seizure type (4/7). Increased intracranial pressure (5/10, median 280 mm H2O, ranging 240-380 mm H2O), CSF pleocytosis (5/10, median 48 cells/μL, ranging: 18-1800 cells/μL), and protein elevation (4/10, median 0.67 g/L, ranging: 0.46-1.92 g/L) were common. Serum MOG antibody was detected in all patients and the coexistence of CSF NMDAR antibody was found in one case. Imaging showed abnormal brain MRI in 10 patients (90.9%) and 10/10 had the cortical involvement. 8/10 had unilateral lesions while 2/10 had bilateral lesions. 2/10 had the juxta cortical white matter lesions and 2/10 had the corpus callosum lesions. No involvement of deep gray matter or other white matter structure was noted. 5/11 had leptomeningeal and/or lesional enhancements. 10/11 patients had favorable outcomes and 2/11 had clinical relapses with persisting MOG antibody positive during the median follow-up interval of 10 months (ranging: 3-23months).

Atypical clinical features for demyelinating diseases including seizures, remarkably increased intracranial pressure, pleocytosis, and protein elevation are common in MOG cortical encephalitis. Involvement of the corpus callosum and cortex around the midline could be unique imaging features of MOG antibody-associated bilateral cortical encephalitis.