Myelin-oligodendrocyte glycoprotein (MOG) antibody-associated acute disseminated encephalomyelitis (ADEM) in an adult with dengue.

Dengue is the most worldwide arbovirus and uncommonly causes encephalitis or acute disseminated encephalomyelitis (ADEM). Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) has recently been recognized as a spectrum of monophasic or relapsing course demyelininating syndromes. We present the first case of MOGAD ADEM in an adult with dengue from Brazil. The patient was a 21-year-old man with no relevant medical or epidemiological history and a confirmed diagnosis of dengue with no warning signs after three days of classical clinical manifestations. In the next days, the patient had lower limb weakness, acute urinary retention, diplopia, sonolence, and mental confusion. MRI showed multiple cerebral and spinal cord lesions compatible with ADEM. CSF analysis demonstrated pleocytosis (135 WBC/μL) and elevated protein (155 mg/L). Dengue-IgM antibodies were positive in the CSF. Serum MOG-IgG cell-based immunofluorescence assay was positive with a titer >1:160. The patient received methylprednisolone for five days, showing progressive and unequivocal improvement of neurological manifestations and he was discharged with oral prednisone This report suggests an emerging association between dengue induced immune dysregulation and the development of MOGAD-associated ADEM. The presence of MOG antibodies should be considered in adults with dengue-related ADEM and timely syndromic management may determine favorable outcomes.