Rapidly progressive dementia in a nonagenarian with acute disseminated encephalomyelitis.

We describe a case of rapidly progressive dementia (RPD) in a nonagenarian. Dementia was caused by an acute disseminated encephalomyelitis (ADEM). Although not frequently diagnosed in the very elderly acute disseminated encephalomyelitis should not be overlooked for it is a treatable condition. A recent infection followed by rapid cognitive deterioration and multifocal neurologic signs should raise the attention to curable autoimmune diseases. Although the cause of ADEM is still unclear, immune suppression is the mainstay of treatment. Most patients improve on high-dose glucocorticoids and eventually immune globulin treatment or plasma exchange if steroid-unresponsive.