Dementia with Lewy bodies
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|Dementia with Lewy bodies|
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Dementia with Lewy bodies
For patient information, click here
|Dementia with Lewy bodies|
WikiDoc Resources for Dementia with Lewy bodies
Evidence Based Medicine
Guidelines / Policies / Govt
Patient Resources / Community
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. ; Associate Editor(s)-in-Chief: Yazan Daaboul, M.D.; Kiran Singh, M.D. 
Synonyms and Keywords: Lewy Body dementia (LBD), Diffuse Lewy Body disease (DLBD), Cortical Lewy Body disease (CLBD), and Senile dementia of Lewy type
Dementia with Lewy bodies (DLB) is the second most common cause of dementia following Alzheimer's disease. It usually affects patients aged > 50 years. The hallmark of DLB is the presence of Lewy bodies, which are intracytoplasmic inclusion bodies that contain synuclein proteins located in the cortical and subcortical neurons. However, these findings are not specific to DLB and may similarly be present in other neurodegenerative diseases. Although the majority of DLB cases are due to sporadic development, DLB may be familial, suggesting a genetic predisposition. Clinically, DLB is characterized by the development of a triad of features, namely cognitive, neurological, and psychiatric symptoms. The diagnosis of DLB is difficult, given the absence of distinguishing features on imaging and neuropathology. Instead, physicians should rely exclusively on the presence of core and suggestive clinical features that may distinguish DLB from other neurodenegerative disorders that cause dementia and symptoms of parkinsonism, such as Alzheimer's disease (AD) and Parkinson's disease with dementia (PDD). Distinguishing features of DLB include the presence of dementia followed by early parkinsonism symptoms within less than 1 year of symptoms-onset, vivid and detailed visual hallucinations, depressive symptoms, REM sleep disorders, neuroleptic sensitivity, early-onset postural instability and falls, and prominent visuospatial and verbal learning impairment. There is currently no cure for DLB, but management is generally aimed at improving quality of life via pharmacologic and non-pharmacologic interventions. Cholinesterase inhibitors, such as rivastigmine and memantine, have demonstrated efficacy in the treatment of behavioral symptoms among patients with DLB, and they are the first-line pharmacologic agents for the management of DLB. The prognosis of DLB is poor with a median survival time comparable to that of AD (3-8 years), but more aggressive forms have also been described.
- Lewy body dementia (LBD) was named after Frederich Heinrich Lewy, a German-American neurologist who discovered the characteristic intracytoplasmic inclusions in 1912.
- In 1961, Okazaki suggested that the presence of cortical Lewy bodies in brain tissue was associated with the development of dementia.
- In 1984, Kosaka and colleagues hypothesized that the presence of Lewy bodies may correspond to a new disease entity, which was eventually named "diffuse Lewy body disease". The disease name was then changed in 1996 at the First International Workshop of the Consortium on Dementia with Lewy Bodies to become "dementia with Lewy bodies" (DLB).
- DLB was not considered a diagnosis of dementia in the first 4 versions of the Diagnostic and Statistical Manual (DSM) for Mental Disorders. In 2013, DSM-5 incorporated DLB as a differential diagnosis for dementia.
Familial predisposition to DLB has been frequently described in observational studies, suggesting the role of genetics in the development of DLB. To date, genetic mutations that are exclusively implicated in DLB have not been described; genetic determinants of DLB have also been frequently reported in Parkinson's disease.
Predisposition to DLB may be caused by autosomal dominant genetic mutations of the Synuclein gene family. Synuclein proteins are members of a pre-synpatic protein family located in the central and peripheral nervous systems. Although the majority of reports describe defects of the α-synuclein protein overexpression in DLB, the β- and γ-synuclein protein variants have also been associated with development of DLB. Mutations of α-synuclein (SNCA) gene have been classically associated with Parkinson's disease with dementia (PDD), but triplication defects and mutations of the E46K and A53T loci within the SNCA gene have been described in patients with DLB.
Mutations of the following genes are also associated with the development of DLB are:
- Glucocerebrosidase (GBA) gene mutation among patients with Gaucher's disease and their relatives
- 2q35-q36 locus on chromosome 2 (adjacent to PARK11 locus whose mutation is associated with PD)
The hallmark of dementia with Lewy bodies (DLB) is the presence of Lewy bodies (LB) that are accompanied by dystropic Lewy neurite (LN) in cortical, brainstem, and limbic system neurons. Lewy bodies are eosinophilic, filamentous, intracytoplasmic inclusion bodies com