QuestionSBA
QuestionChoice
Charles-Bonnet syndrome is a condition causing visual hallucinations (usually of people or animals) associated with severe visual impairment. There is nothing in this question to suggest this patient has any visual impairment; therefore, this is not the most likely diagnosis
33705
c
Charles-Bonnet syndrome
QuestionChoice
This is a progressive neurological condition characterised by Lewy Body (alpha-synuclein) deposition in the brain. Key features demonstrated in this question include fluctuating symptoms (worse on some days) and visual hallucinations (he has a dog his wife can't see). The patient may also present with Parkinsonism, but cognitive symptoms must occur either before, or within 12 months of the onset of motor symptoms
33703
a
Dementia with Lewy Bodies
QuestionChoice
Parkinson's dementia presents with dementia in the presence of Parkinson's disease. Parkinsonism (e.g. resting tremor, bradykinesia, resting tremor) must occur at least 12 months before the onset of cognitive symptoms. As this patient has developed cognitive symptoms before symptoms of Parkinsonism, dementia with Lewy Bodies is the more likely diagnosis
33704
b
Parkinson's dementia
QuestionChoice
Alzheimer's disease typically presents with short term memory loss, word-finding difficulties and difficulty recognising objects and people. Alzheimer's does not typically present with visual hallucinations, making dementia with Lewy Bodies the more likely diagnosis
33706
d
Alzheimer's disease
QuestionChoice
Vascular dementia is characterised by a stepwise cognitive decline due to either macrovascular (e.g. stroke) or microvascular events. Symptoms are largely dependent on the area affected; however, it would not present as a fluctuant dementia with visual hallucinations. Therefore, dementia with Lewy Bodies is the more likely diagnosis
33707
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Vascular dementia
QuestionComment
How do we know this is a visual hallucination?
6049
QuestionComment
yeah should definitely be made clearer

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Dermis Cystic
QuestionComment
Yes this seemed to me like he still thought he had a dog - it's not clearly a hallucination since its not currently in room
8276
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Jaundice RNA
User
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Hypertension Sclerosis
QuestionComment
Isn't the dog thing more a memory problem than a hallucination?
22137
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Camiodarone
QuestionComment
Needs to be made clearer that the dog is a hallucination, it sounds more like a memory problem
24186
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Not2Crows
QuestionComment
plot twist
25928
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Travis Scott
QuestionComment
I don't think this sounds like a visual hallucination - mistakenly believing he has a dog doesn't mean he thinks he can see it
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Sir Pep Guardiola
QuestionComment
As a dog I can confirm that I am not a hallucination
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Abdul Kareem
Concept
Chapter
# Summary

Dementia with Lewy bodies (DLB) is a progressive, complex condition, accounting for approximately 10-15% of dementia cases. DLB is characterised by the presence of Lewy bodies, abnormal protein deposits, within brain cells, particularly in the substantia nigra, paralimbic, and neocortical areas. The clinical picture is often characterised by fluctuating cognition, Parkinsonism, and visual hallucinations. A diagnosis is primarily clinical, although dopamine uptake scanning can provide supplementary data. Patients with DLB are highly sensitive to neuroleptics, potentially exacerbating Parkinsonism.  

# Definition

Dementia with Lewy bodies (DLB) is a type of progressive dementia caused by deposits of an abnormal protein, alpha-synuclein, forming cytoplasmic inclusions known as Lewy bodies within brain cells. These aggregates disrupt normal cell functioning and eventually lead to neuronal death.

# Epidemiology

DLB is the third most common type of dementia, following Alzheimer's disease and vascular dementia. It represents around 10-15% of all dementia cases.

# Aetiology

The primary pathological feature of DLB is the presence of Lewy bodies in the brain's substantia nigra, paralimbic, and neocortical areas. However, the exact cause of this accumulation remains unknown. An association with Parkinson's disease has been noted, with many patients exhibiting overlapping symptoms. 

New research suggests that LBD and Parkinson’s disease have much more overlap than originally thought. Parkinson’s disease starts in the basal ganglia/brainstem and then progresses upwards towards cerebral cortex (hence dementia is late), whereas in LBD the process progresses downwards from the cerebral cortex.

# Clinical Features

The clinical features of DLB include:

- Fluctuating cognition: Changes in attention and alertness may occur
- Parkinsonism: Rigidity, bradykinesia, and postural instability are common
- Visual hallucinations: Patients often experience complex and recurrent visual hallucinations
	- Classically, patients complain of seeing small mammals around them 
- High sensitivity to neuroleptics: These drugs can induce or worsen parkinsonism

A general rule of thumb that can help with distinguishing LBD form Parkinson's disease (PD) is if cognitive impairment and parkinsonism develop <1 year of each other, it is likely LBD. If diagnosed with PD and dementia develops >1 year later this is Parkinson’s disease.

# Differential Diagnosis

Differential diagnoses for DLB include:

- Alzheimer's disease: Characterised by gradual memory loss, difficulties with problem-solving, and changes in mood or behaviour. However, Alzheimer's patients do not typically exhibit the severe sensitivity to neuroleptics seen in DLB.
- Parkinson's disease dementia: While it shares many symptoms with DLB, Parkinson's disease dementia typically starts with motor symptoms before cognitive decline. 
- Vascular dementia: This condition features stepwise cognitive decline and evidence of cerebrovascular disease. Parkinsonism and hallucinations are less common.

# Investigations

Diagnosis is primarily clinical, involving a careful medical history and physical examination. However, some additional investigations may be useful, such as:

- Dopamine transporter (DaT) scan: This can help distinguish DLB from other types of dementia.
- Neuropsychological testing: To assess cognitive functioning and fluctuations.
- Electroencephalography (EEG): Although not diagnostic, a slowing background rhythm may be seen in DLB.


# Management

Management of DLB includes should follow the biopsychosocial model - please see our Dementia section for holistic management principles.

- Non-pharmacological interventions: These include cognitive stimulation, physical therapy, and occupational therapy.
- Supportive care: As DLB is a progressive disorder, palliative and end-of-life care considerations are essential.
- Medications: Cholinesterase inhibitors can help manage cognitive symptoms. However, caution is required with antipsychotic medications due to neuroleptic sensitivity.


# NICE Guidelines

[Click here to see information on NICE CKS on dementia](https://cks.nice.org.uk/topics/dementia/)
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Dementia with Lewy bodies
Topic
34
Neurology
6741
A 76-year-old man presents to the GP with his wife, who has noticed that his memory has worsened over the last 18 months. She thinks that his memory is worse on some days compared to others. The patient does not think he has a problem with his memory and is eager to leave as he left his dog tied up outside the GP surgery. His wife is confused as they do not own a dog. Neurological examination shows no abnormalities.

What is the most likely diagnosis?
a