Myelin oligodendrocyte glycoprotein antibody-associated disease presenting as unilateral cerebral cortical encephalitis: a case report

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an autoimmune disorder with diverse clinical manifestations including myelitis, meningitis, encephalitis, and optic neuritis. MOGAD rarely presents with unilateral cerebral cortical encephalitis (CCE), rendering the diagnosis difficult in these cases. Furthermore, MOGAD is frequently accompanied by other autoimmune diseases such as thyroid disease or inflammatory bowel disease. Herein, we report a case of unilateral CCE with positive anti-myelin oligodendrocyte glycoprotein (MOG) antibodies. In addition, our patient presented with systemic symptoms as well as neurologic symptoms and was finally diagnosed with ulcerative colitis (UC). A 60-year-old female was admitted to the hospital with an acute onset of headache and fever. Neurological examination revealed left-sided homonymous hemianopsia with intermittent visual hallucinations as flickering red-circular spots in the left visual field. Brain magnetic resonance imaging showed focal hyperintensities and enhancement in the right temporo-parieto-occipital cortex. Electroencephalography indicated a focal seizure in the right occipital cortex. After the administration of an antiepileptic drug, the patient showed clinical and radiological improvements. She tested positive for serum anti-MOG antibodies and was diagnosed with anti-MOG-associated unilateral CCE. However, the gastrointestinal symptoms persisted, thus, a sigmoidoscopy was performed. The patient was diagnosed with comorbid UC. Steroids were administered to treat the UC and the gastrointestinal symptoms improved. To the best of our knowledge, this is the first case of MOGAD presenting as a unilateral CCE in Korea. This case highlights the clinical phenotypes of MOGAD and the need to assess comorbid autoimmune diseases in patients with MOGAD.