Acute retrobulbar optic neuritis with anti-myelin oligodendrocyte glycoprotein antibody-associated disease complicated with microscopic polyangiitis: A case report.

Rationale: Anti-myelin oligodendrocyte protein antibody-associated disease (MOGAD) is a new disease entity with various clinical phenotypes. MOGAD often present with recurrent optic neuritis (ON), and it can also develop as a compartment of neuromyelitis optica spectrum disorder (NMOSD). Moreover, multiple autoantibodies such as an anti-myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) had been reported in the serum of patients with NMOSD.

Patient Concerns: We report an 86-year-old woman with a 2-year history of microscopic polyangiitis (MPA). The patient had a rapid loss of vision in her left eye. No abnormal findings were observed on her left fundus, and she tested negative for MPO-ANCA upon admission. However, anti-MOG antibodies were observed in the patient's serum and cerebrospinal fluid.

Diagnosis: A diagnosis of MOGAD complicated with MPA was made.

Interventions: The patient received twice steroid pulse therapy and oral azathioprine as maintenance therapy.

Outcomes: Her vision rapidly recovered, and no subsequent relapse was observed during the 8-month observation period.

Conclusion: To the best of our knowledge, this is the first case of MOGAD complicated with MPA, and steroid pulse therapy and azathioprine therapy were effective for ON caused by MOGAD.