Dementia with Lewy bodies (DLB) is increasingly recognized clinically as the second most common type of degenerative dementia after Alzheimer disease (AD). In addition to dementia, distinctive clinical features include: visual hallucinations, parkinsonism, cognitive fluctuations, dysautonomia, sleep disorders, and neuroleptic sensitivity.
First described in the 1960s, DLB has a varied clinical presentation that shares features with other degenerative dementias. It was often overlooked pathologically because of the difficulty in identifying cortical Lewy bodies with routine cellular stains. With the advent of immunohistochemical stains for constituents of Lewy bodies, the prevalence of this disorder began to be recognized. However, challenges remain in defining this as an entity distinct from other degenerative dementias.
DLB may represent several diseases with the shared common finding of cortical Lewy bodies, or it may be a single disease with a spectrum of additional pathological features. This is reflected by the varied names by which it has been called, including diffuse Lewy body disease, Lewy body dementia, Lewy body variant of Alzheimer disease, cortical Lewy body disease, and senile dementia of the Lewy body type.
This topic will describe the epidemiology, neuropathologic findings, and potential pathogenic mechanisms of dementia with Lewy bodies. The clinical features, diagnosis, prognosis, and treatment are discussed separately. (See "Clinical features and diagnosis of dementia with Lewy bodies" and "Prognosis and treatment of dementia with Lewy bodies".)
In clinical and pathological series, dementia with Lewy bodies (DLB) accounts for approximately 10 to 22 percent of dementia cases [1-4]. The estimated prevalence is 3.5 per 100,000 person-years . Like Alzheimer disease (AD), DLB becomes more prevalent with age, generally affecting individuals in their sixth decade or older; the mean age at presentation is 75 years [6-10].