Abstract
Acute disseminated encephalomyelitis (ADEM) is an idiopathic inflammatory demyelinating disease of the CNS that is particularly difficult to differentiate from the first episode of multiple sclerosis. ADEM typically occurs as a post-infectious phenomenon, and usually presents a monophasic episode, but also includes recurrent and multiphasic forms. We report a case of ADEM associated with hepatitis B virus (HBV) reinfection. After steroid and IV immunoglobulin treatment, neurologic symptoms were improved. We suppose that the HBV reinfection was the cause of ADEM, but possible pathogenetic mechanism is still obscure.