Epileptic seizure presenting as dementia with Lewy bodies.

Psychotic symptoms and cognitive fluctuation are common manifestations of dementia with Lewy bodies (DLB). However, the differentiation of these symptoms is difficult because many psychiatric, neurologic, and medical conditions in addition to drug effects can mimic DLB in elderly people. We report on an 83-year-old woman who complained of vivid, recurrent visual hallucinations associated with fluctuating cognition. The patient was diagnosed as probable DLB. However, laboratory findings were consistent with an epileptic phenomenon and the patient improved completely with use of anti-epileptic drugs. This case illustrates the fact that epileptic seizure may cause symptoms that mimic DLB, and clinicians should consider an epileptic condition as a differential diagnosis for elderly patients with psychiatric symptoms and fluctuating cognition.