Abstract
Acute disseminated encephalomyelitis（ADEM） is a demyelinating disorder of the central nervous system that occurs in association with viral or bacterial infections and vaccinations. An autoimmune reaction against myelin components is the proposed pathogenesis; however，the mechanism details are not yet fully clarified. Although various neurologic symptoms may appear because of multiple scattered foci of demyelination in the central nervous system，they are often reversible. We herein report an unusual case of ADEM in a 2-year-old boy who underwent surgical closure of a ventricular septal defect. The patient developed a high fever followed by conjugated deviation of the eyes，hypertonia，and dystonia on the 5th postoperative day. Cerebrovascular disorders were initially suspected; however，diffusion-weighted images of brain magnetic resonance imaging （MRI） demonstrated diffuse high signals throughout the white matter suggesting demyelination. As encephalitis or demyelinating disease were suspected，therapy against brain swelling and empiric antibacterial and antiviral treatment were immediately initiated; in addition，high-dose intravenous steroid was administered after ruling out infectious disease. The patientʼs neurologic symptoms were gradually resolved，coupled with rapid resolution of MRI abnormalities. Although the etiology could not be identified based on laboratory studies，the clinical presentation and rapid resolution of radiological findings led to the diagnosis of ADEM. The patient showed good recovery with steroid therapy and was discharged without neurological deficits.
