QuestionSBA
QuestionChoice
Alzheimer's dementia is characterised by a gradual onset (over several years) of memory impairment, which is followed by difficulties in language and executive function. The patient's history of recurrent visual hallucinations and sleep disturbances are not typical features of Alzheimer's dementia. It should be suspected in adults who demonstrate long-lasting problems with spatial navigation and visual awareness, and usually manifests as wandering or becoming lost.
62015
c
Alzheimer's dementia
QuestionChoice
Multiple sclerosis (MS) is a chronic autoimmune disorder that affects the brain, spinal cord, and optic nerves. MS is more common in females under the age of 50 years, often presents as muscle (sensory) weakness, spasticity, loss of balance, and visual disturbances. The patient's wife mentions that he tends to hallucinate and become restless quite often, which are not typical symptoms of MS.
62017
e
Multiple sclerosis
QuestionChoice
Vascular dementia usually presents in patients with history of multiple cerebrovascular events, either transient ischaemic attacks or strokes. Typically there is a step-wise deterioration of cerebral function with each event. It should be considered in those with a history of cerebrovascular disease with global impairment of cognition.
62014
b
Vascular dementia
QuestionChoice
Pseudo-dementia is a functional psychiatric illness (or rarely a deliberate simulation) that can mimic the apparent cognitive decline of true dementia. It is believed that pseudo-dementia is triggered by intense stress and head injuries, and linked to depression. It will characteristically ameliorate once the depression has been treated.
62016
d
Pseudo-dementia
QuestionChoice
The most likely diagnosis in this scenario is Lewy-body dementia (LBD). It is a progressive degenerative dementia that is characterised by a decline in cognitive function, and symptoms such as visual hallucinations, sleep disturbances, and behavioural changes. The patient has difficulty maintaining attention and is easily distracted and disinterested, however, he is able to recall vivid details about his early life. This is an example of **fluctuating cognitive function** which is a common feature of LBD. Additionally, his examination findings (features of parkinsonism) further supports the diagnosis. Lewy-body dementia is characterised by the presence of Lewy bodies in the brainstem and cortex with a myriad of features of dementia and Parkinsonism.
62013
a
Lewy-body dementia
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/)
889
2447
Dementia with Lewy bodies
Topic
57
Geriatrics
12464
A 70-year-old man is brought to the emergency department after falling and breaking his hip. When questioned further, it becomes apparent that he is confused, has trouble maintaining attention and easily distracted and disinterested. However, when asked about his childhood memories, he is able to recall vivid details about his early life. His wife mentions that he tends to hallucinate and become restless quite often. On Mini-Mental State Examination, he scores 21 and exhibits bradykinesia, a shuffling gait, and a tremor in his left hand.

What is the most likely diagnosis?
a