# Lewy body dementia | Symptoms, Causes, Tests and Treatment | OSANG > Lewy body dementia is a degenerative dementia caused by the accumulation of Lewy bodies made of aggregated alpha-synuclein in the cerebrum. It accounts for approximately… - Official page: https://osns.co.kr/en/encyclopedia/lewy-body-dementia - Organization: OSANG Neurosurgery ## Page content Dementia/Cognition ## Lewy body dementia Dementia with Lewy Bodies · G31.83 Dementia with Lewy bodies is a degenerative dementia characterized by cognitive fluctuations, repetitive visual hallucinations, Parkinsonism, and REM sleep behavior disorder caused by the accumulation of Lewy bodies in the cerebral cortex. ## At a glance Lewy body dementia is a degenerative dementia caused by the accumulation of Lewy bodies made of aggregated alpha-synuclein in the cerebrum. It accounts for approximately 4-5% of clinically diagnosed degenerative dementia, and is reported to be higher than this based on autopsy standards. Fluctuating cognitive function, specific and repetitive visual hallucinations, parkinsonism, and REM sleep behavior disorder are the core symptoms. Hypersensitivity to antipsychotic drugs occurs in about half of patients, so caution is required when using them, and cholinesterase inhibitors are helpful in controlling cognition and hallucinations. - 01Definition and Overview - 02Causes and Pathophysiology - 03core symptoms - 04diagnosis - 05Treatment and Precautions ## Definition and Overview Dementia with Lewy bodies is a degenerative dementia caused by the widespread accumulation of Lewy bodies, which are abnormal aggregates of alpha-synuclein protein, in the cerebral cortex and limbic system. It accounts for approximately 4-5% of clinically diagnosed degenerative dementia, and even higher rates are reported in autopsy-based neuropathological studies. It is one of the most common neurodegenerative diseases following Alzheimer's disease and Parkinson's disease. Lewy body dementia shares the same alpha-synuclein pathology as Parkinson's disease dementia. If cognitive decline occurs before or within a year of Parkinson's motor symptoms, it is classified as Lewy body dementia, and if dementia appears several years before motor symptoms, it is classified as Parkinson's disease dementia. In ICD-10, it is classified as G31.83. ## Causes and Pathophysiology The core pathology is Lewy bodies and Lewy neurites, which are abnormal aggregates of alpha-synuclein protein. As these aggregates are deposited throughout the brainstem, limbic system, and cerebral cortex, nerve cells lose their function and are lost. Several neurotransmitter systems, including dopamine and acetylcholine, are damaged together, and cholinergic nerve deficiency is particularly prominent, acting as a mechanism for cognitive fluctuations and hallucinations. In a significant number of patients, amyloid beta and tau pathology of Alzheimer's disease coexists, and this co-occurrence pathology influences the rate of progression and clinical presentation. ## core symptoms ### cognitive fluctuations Attention, level of alertness, and clarity of consciousness fluctuate markedly depending on the time of day or day. The dazed state appears repeatedly, and the same patient sometimes appears relatively clear and at other times appears confused. ### repetitive hallucinations Specific and clearly defined visual hallucinations appear repeatedly. It is common for people or animals to be seen, and the fact that it appears from an early stage is an important clue to diagnosis. ### Parkinsonism It is accompanied by Parkinsonian motor symptoms such as bradykinesia, rigidity, and postural instability. Resting tremor tends to be less pronounced than in idiopathic Parkinson's disease. ### REM sleep behavior disorder This is a symptom of turning dreams into action, screaming or flailing one's arms and legs while sleeping, and may appear years before cognitive decline. This period is considered prodromal Lewy body dementia. In addition, autonomic dysfunction, such as orthostatic hypotension, constipation, and urinary disorders, and hypersensitivity to antipsychotic drugs are accompanied. ## diagnosis Diagnosis follows the 4th consensus criteria (McKeith criteria) of the DLB Consortium in 2017. Cognitive fluctuations, repetitive visual hallucinations, Parkinsonism, and REM sleep behavior disorder are considered key clinical features, and the certainty of diagnosis is determined using their combination and biomarkers. - History taking: Checking cognitive changes, visual hallucinations, behavior during sleep, and motor symptoms through guardians - Neuropsychological test: Assessment of decline in attention and visuospatial function - Dopamine transporter imaging test (DAT scan): Confirmation of loss of dopamine neurons in the basal ganglia - Myocardial MIBG scintigraphy: confirms cardiac sympathetic dysfunction. - Polysomnography: Confirmation of loss of muscle tension during REM sleep In 2020, diagnostic criteria for prodromal Lewy body dementia were proposed to evaluate the stage before cognitive decline begins. ## Treatment and Precautions There is no cure, and the goal is to control symptoms and maintain quality of life. ### Cognition and visual hallucinations Cholinesterase inhibitors (donepezil, rivastigmine) help control cognitive function and visual hallucinations. Due to the nature of the disease, in which cholinergic deficiency is prominent, there are cases where the response can be similar to or better than that seen in Alzheimer's disease. ### Antipsychotic hypersensitivity Approximately half of patients develop severe hypersensitivity to antipsychotic drugs, which can lead to decreased consciousness, rapid worsening of parkinsonism, and increased risk of death. Therefore, non-pharmacological approaches are given priority for hallucinations or agitation, and if drugs are unavoidable, select them carefully and use them in the lowest dose. ### Parkinsonism and accompanying symptoms Dopamine drugs are used for Parkinson's motor symptoms, but dosage adjustment is necessary as they can worsen hallucinations. It concurrently manages autonomic symptoms such as orthostatic hypotension and constipation and sleep disorders. ## Frequently asked questions ### Q01How is Lewy body dementia different from Alzheimer's disease? While Alzheimer's disease begins slowly with a decline in recent memory, Lewy body dementia differs from the beginning in that attention and arousal levels fluctuate significantly over time, specific visual hallucinations appear repeatedly, and Parkinsonism is accompanied. Memory decline often becomes noticeable relatively late. ### Q02I have hallucinations. Can I take psychiatric medication? Approximately half of patients with Lewy body dementia develop severe hypersensitivity to antipsychotic drugs, which can lead to decreased consciousness, worsening of Parkinsonism, and increased risk of death. Therefore, even if you have hallucinations, you must carefully decide on antipsychotic medication, confirm the diagnosis first, and consult with a specialist. ### Q03Is it normal for cognitive function to fluctuate from good to bad throughout the day? Cognitive fluctuations, in which attention and alertness levels fluctuate significantly depending on the hour or day, are one of the core symptoms of Lewy body dementia. If you are in a dazed state for a long time or if you suddenly lose track of the flow of conversation, you need to evaluate it rather than just chalk it up to aging. ### Q04Is it related to screaming and flailing arms and legs in your sleep? REM sleep behavior disorder is a symptom that translates dream content into action, and may appear years before cognitive decline in Lewy body dementia. If present, it is an important clue to diagnosis, so it must be reported at the time of treatment. ### Q05How is Lewy body dementia diagnosed? Cognitive fluctuations, visual hallucinations, parkinsonism, and REM sleep behavior disorder are confirmed through medical history and neurological examination, and the 2017 McKeith consensus criteria are applied. Confirmation of loss of basal ganglia dopamine neurons in a dopamine transporter imaging test (DAT scan) is helpful for diagnosis. ### Q06How is it treated? There is no cure and the goal is symptom control. Cholinesterase inhibitors are helpful in controlling cognition and hallucinations, and dopaminergic drugs are used cautiously in Parkinsonism. Due to antipsychotic hypersensitivity, non-pharmacological approaches are preferred for behavioral symptoms. ## Related articles - Dementia Overview - Alzheimer's disease - vascular dementia - frontotemporal dementia This article provides general medical information and does not replace an individual diagnosis or treatment plan. Please seek a medical assessment if symptoms persist. ## Important notice This Markdown alternative helps search and AI tools understand the public page accurately. It provides general health information and does not replace an individual diagnosis or treatment.